ZITHROMAX (AZITHROMYCIN) SNDA H.3 CLINICAL TRIALS RELEVANT TO THE CLAIM STRUCTURE TABLE OF CONTENTS H.3.A. GENERAL APPROACH TO EVALUATION...

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1 ZITHROMAX (AZITHROMYCIN) SNDA H.3 CLINICAL TRIALS RELEVANT TO THE CLAIM STRUCTURE TABLE OF CONTENTS H.3.A. GENERAL APPROACH TO EVALUATION...2 H.3.A.1 Efficacy (Pfizer IND Studies)...2 H.3.A.1.A Summary Methods... 3 H.3.A.1.B Pivotal Study (Protocol 189/189B)... 4 H.3.A.1.C Primary Supportive Study (Protocol 131) H.3.A.1.D Primary Supportive Study (Protocol 148) H.3.A.1.E Compassionate-Use MAC Study (Protocols 162/162X/148B) H.3.A.1.F Compassionate-Use MAC Study (Protocol 169) H.3.A.1.G Compassionate-Use MAC Study (Protocol 354/354A) H.3.A.2 Safety (Pfizer IND Studies)...23 H.3.A.3 Query Plan (Pfizer IND Studies)...25 H.3.B. INDIVIDUAL STUDY SUMMARIES (PFIZER IND STUDIES)...25 H.3.B.1 Pivotal Study...25 Protocol 189/189B (U.S.) H.3.B.2 Primary Supportive Studies...31 Protocol 131 (U.S.) Protocol 148 (U.S.) H.3.B.3 Supportive Compassionate Use Studies...38 Protocol 162/162X/148B (U.S.) Protocol 169 (U.S.) Protocol 345/354A (Non-U.S.) H.3.C. PULMONARY MAC STUDIES -- UNIVERSITY OF TEXAS HEALTH CENTER (NOT CONDUCTED UNDER PFIZER IND)...47 H.3.C.1 Daily Treatment for Pulmonary MAC...47 H.3.C.2 Intermittent Treatment (Three Times Weekly) for Pulmonary MAC

2 Page 2 H.3.A. GENERAL APPROACH TO EVALUATION This section provides summaries of the individual studies conducted to evaluate both the efficacy and safety of azithromycin in the treatment of disseminated Mycobacterium avium intracellulare complex (MAC), primarily in subjects with the Acquired Immune Deficiency Syndrome (AIDS). Full reports for these studies are provided in NDA Clinical Data Section 8. Included is one Phase III double-blind, randomized, multicenter, comparative pivotal study (189) conducted in the U.S, but also with 10 sites outside the U.S. In this study, azithromycin 250 mg and 600 mg once daily, and clarithromycin 500 mg twice daily, were administered as treatment for disseminated MAC for 24 weeks to subjects with AIDS. Subjects responding to double-blind treatment had the opportunity to continue on a regimen of azithromycin 250 mg once daily plus ethambutol through an open-label maintenance phase of the study (189B). Both azithromycin and clarithromycin were taken with ethambutol. Data are also presented for two Phase II open-label, noncomparative studies (131, 148) conducted in the U.S. as primary supportive studies. Both studies provided azithromycin for treatment of disseminated MAC in subjects with AIDS. Study 131 was a small pilot study of sequential design in which subjects received single daily doses of azithromycin 500 mg orally for increasing durations (10, 20, then 30 days) based on toleration. Extended/suppressive therapy with azithromycin 250 mg once daily was available to subjects meeting prespecified criteria for response. Lastly, study 148 was a dose-ranging, muticenter, parallel design study in which subjects received single daily doses of either 600 mg azithromycin or 1200 mg azithromycin for up to 6 weeks. Three additional uncontrolled studies (162/162X/148B, 169, 354/354A) provide limited supportive efficacy data; these were compassionate-use studies in that the subjects enrolled had failed or were intolerant of available therapies. Studies 162/162X/148B (reported together because of their similarity in design) of disseminated MAC and 169 of serious nontuberculous nondisseminated mycobacterial disease were conducted in the U.S. Subjects received azithromycin 600 mg orally (or as 10 mg/kg for subjects <16 years old), or the equivalent intravenously, and nonresponders were allowed to increase their dose. Study 354/354A was a named-patient study of serious or life-threatening infections conducted outside the U.S. in which subjects received azithromycin 600 mg twice on the first day and then once daily thereafter. Lastly, brief summaries of published results from two studies conducted independently by the University of Texas Health Center in HIV-negative subjects with MAC lung infection are presented as support for a second and separate claim for treatment of pulmonary disease due to MAC. These data are also supportive of treatment of disseminated MAC in AIDS patients. A summary of methods of analyses is presented in Section H.3.A.1 (Efficacy) and H.3.A.2 (Safety) for Pfizer-sponsored studies. The methodology used in the independently conducted University of Texas Health Center studies are provided in the individual study summaries in Section H.3.C. H.3.A.1 Efficacy (Pfizer IND Studies) The following table summarizes the MAC studies in this submission and the extension studies into which subjects could enroll

3 Type of Study (or Study Report) Protocol # Extension Studies* MAC STUDIES Pivotal Study (full study report) B Primary Supportive Efficacy Studies (full study reports) /162X/148B /162X/148B Compassionate Use Supportive Studies (full study reports except /354A which is an abbreviated report) /162X/148B** *** /354A Page 3 * Extension studies include patients from the corresponding row in the previous column. ** /162X/148B is considered the same study since the protocols are identical except IV patients were allowed to enroll into /162X. Additionally, /162X/148B is considered both an extension study and a normal enrolling study since patients who were not previously enrolled in a Pfizer study were allowed in the study. *** Non-tuberculosis mycobacterial species study Since the MAC studies are grouped into pivotal, supportive or compassionate-use studies, the methods contained here are organized in a similar fashion with an introductory section summarizing the methods across all studies. The complete description of methods used for each protocol can be found in the individual study reports. H.3.A.1.A Summary Methods The primary endpoint in each MAC study was sterilization, excluding protocols 169 and 354/354A in which a primary endpoint was not specified. The following table contains the definition of sterilization for each study: Definition of Sterilization Protocol # Two consecutive negative cultures /189B One negative culture /162X/148B /354A Mycobacterial Response to Therapy (eradication, persistence, not evaluable) Other endpoints were considered secondary. Selected secondary endpoints are included in the following table. Protocol-specific endpoints and detailed definitions of the following endpoints are contained in the individual study sections presented below or the individual methods sections of each study report (NDA Clinical Data Section 8). Secondary Endpoint Protocol # Time to Sterilization /162X/148B /189B Time to First Positive Culture after Sterilization (relapse; /162X/148B durability of blood sterilization) /189B Positive Microbiologic Response /189B Time to Positive Microbiologic Response /189B MAC Colony Count /162X/148B /189B Change in Log Colony Count /162X/148B /189B MIC Results /189B Sponsor Defined Clinical Response /189B -202-

4 Page 4 Secondary Endpoint Protocol # Investigator Defined Clinical Response /162X/148B /189B Death /189B Time to Death /189B For each MAC study, analyses were performed for an intent-to-treat (ITT) subset. For studies 131, 148 and 189/189B, the intent-to-treat subset included all randomized patients who had a positive blood culture for MAC at baseline. For studies 162/162X/148B, there were 3 intent-to-treat subsets depending on the endpoint used (see methods description for these studies below). For study 169, the intent-to-treat subset included all enrolled subjects who had a non-tuberculosis mycobacterial species (Mycobacterium avium, mycobacterium species, or Mycobacterium chelonei) identified at baseline or had evidence of infection based on prior information (last positive data or date of the primary diagnosis is nonmissing). For 354/354A, subjects with MAC infection (the presence of symptoms indicative of invasive mycobacteria infection as recorded on the case report form) were analyzed. Evaluable subsets were analyzed for the pivotal (189/189B) and one primary supportive efficacy study (148). Evaluability rules for each study are defined below but include rules on pathogen resistance, HIV status, use of certain concomitant antibiotics and minimum amount of therapy received. The statistical methodology employed was study dependent since the purpose of each study (e.g., compassionate noncomparative, dose comparison, duration of therapy comparison) and the number of subjects enrolled differed. See below for details on a study by study basis. H.3.A.1.B Pivotal Study (Protocol 189/189B) Methods for analyzing protocol 189 are summarized in this section with full details included in the individual study report. Methods for analyzing the extension phase 189B are included in the individual study report. Subject Subsets and Evaluability Rules Intent-to-Treat (ITT) Analysis The intent-to-treat subgroup included data from all randomized subjects regardless of whether they took treatment. Eligible subjects were determined by the following criteria: Subject Level Exclusion Criterion: No Baseline Pathogen - Subject s baseline blood culture must have been positive for MAC. The baseline blood culture was defined as the culture drawn at the baseline visit (beginning of therapy). If there was no baseline culture or the subject was positive for another pathogen other than Mycobacterium avium, then that subject was excluded. Time Specific Exclusion Criteria: NONE Endpoint Specific Exclusion Criteria: NONE -203-

5 Page 5 Evaluable Subgroup Analysis The evaluable subgroup included data from eligible subjects while on treatment. This subgroup was used in an on-drug analysis. Eligible subjects were determined by the following criteria: Subject Level Exclusion Criteria: No Baseline Pathogen - Subject s baseline blood culture must have been positive for MAC. The baseline blood culture was defined as the culture drawn at the baseline visit (beginning of therapy). If there was no baseline culture or the subject was positive for another pathogen other than Mycobacterium avium, then that subject was excluded. Baseline Pathogen Resistant to Study Drug - The baseline positive culture cannot be resistant to the macrolide. Resistance was defined as MIC >256 micrograms/ml for azithromycin or >16 micrograms/ml for clarithromycin. If there was no MIC value for the baseline culture, then the subject was assumed to be not resistant at baseline. HIV Negative - Subject must not have been HIV negative at baseline. If the results of all three HIV tests were missing, the subject was assumed to be HIV positive. Time Specific Exclusion Criteria: Concomitant Antibiotic for Intercurrent Illness - Subject cannot have taken a concomitant antibiotic potentially effective against MAC, given prior to visit of analysis and lasting longer than 2 weeks, unless for MAC treatment failure. All data after taking the concomitant antibiotic for 2 weeks was ignored. Insufficient Therapy - Subject must have been on therapy at least 50% of the days since beginning of therapy. If a subject was on therapy less than 50% of the days since beginning of therapy, all data after that point was ignored. However, this rule did not apply until day 30 after the beginning of therapy, i.e. starting on day 31. On therapy was defined as taking azithromycin or clarithromycin; ethambutol was not taken into consideration. This criterion deviated from the protocol which specified on therapy to be 80% of days. Endpoint Specific Exclusion Criteria: NONE (other than missing data) The intent-to-treat and evaluable subgroup analyses should lead to similar conclusions. However, for this study we focused on the intent-to-treat subgroup analysis since in most cases, the evaluable subgroup contains so few subjects that the confidence intervals used for statistical inference were wider than expected. Analysis Windows The analysis windows were defined as follows. The start of study (day 1) was defined as the day on which a subject took the first dose as recorded in the CRF

6 Page 6 scheduled week window (weeks) 0-30 days to 1 day to < to < to < to < to < to < to < 26 For the purpose of defining the baseline culture, the last culture at day 0 or before, but within the window of (-30, 1) days was used; if the culture was missing then the first culture after day 0 within the window of (1, 31) days was used. Endpoints Primary The primary endpoint was: Sterilization - Defined as two consecutive negative cultures from the central laboratory (see sensitivity analyses below for alternative definitions). The first negative culture was considered to be the date of sterilization and only one of the two negative cultures was required to be in the analysis window. If a positive culture was also in the window, then the nearest observation, negative or positive, to that week was used in determining sterilization. If the assessment in the window was missing, then for the evaluable observed cases analysis, the subject was not evaluable unless both the previous and subsequent assessments were negative, in which case the subject was sterile, or both the previous and subsequent assessments were positive, in which case the subject was not sterile. The intent-to-treat analysis used the last observation carried forward for the missing data. The detailed algorithm for defining sterilization is contained in the study report. In the protocol week 12 was specified as primary. All weeks are reported in the tables although emphasis was placed on Week 24 as described in the Statistical Analysis Plan submitted to the U.S. Food and Drug Administration (FDA) in A distinction was not made in the protocol that the evaluable analysis was an observed case analysis. Secondary The secondary endpoints were (some of these variables were in addition to variables outlined in the protocol): Microbiologic (MAC Blood Cultures) The microbiologic endpoints were computed based on only the culture data from the central lab and also were computed based on culture data from the central and local laboratories. Sterilization - Central and Local Laboratory Data - Local lab data was used when there was missing data from the central laboratory. Time to Sterilization was the number of days since the beginning of therapy to the first of the two consecutive negative cultures

7 Page 7 Time to First Positive Culture after Sterilization (Durability of Blood Sterilization) - Defined for subjects achieving sterilization only was the number of days from the date of the first of the two negative cultures to the next positive culture (see sensitivity analyses below for alternative definitions). Positive Microbiologic Response - Defined as sterilization and/or a ten-fold (1 log) reduction in colony count (cfu/ml) since the baseline visit (beginning of therapy). Time to Positive Microbiologic Response was the number of days from beginning of therapy until the date of the first of two consecutive negative cultures or the date of a ten-fold (1 log) reduction in colony count (cfu/ml) since the beginning of therapy. MAC Colony Count (cfu/ml, log base 10) Colony counts of 0 are recorded as log(0.099) = since log base 10 of zero is undefined. Change in Log Colony Count (cfu/ml, log base 10) Since the Baseline Visit (beginning of therapy) Resistance - Defined as MIC >256 micrograms/ml for azithromycin or >16 mcg/ml for clarithromycin. MIC Results - summarized for each treatment group and visit. Clinical Sponsor Defined Clinical Response - Four point scale as follows: (3) Complete Resolution of Signs & Symptoms - Defined as absence of fever (daily temperature >100.5 F ) and night sweats since last visit, and weight loss of less than 5% of total body weight since baseline. The last visit must have occurred at least 7 days prior to the current visit. If this did not happen then the first visit that was at least 7 days prior to the current visit, was used. (2) Partial Resolution of Signs & Symptoms (2 of 3 symptoms) - Absence of two of the three symptoms needed to define complete resolution without the worsening of the other condition (weight loss of 5% of TBW since baseline was an automatic failure). (1) Partial Resolution of Signs & Symptoms (1 of 3 symptoms) - Absence of one of the three symptoms needed to define complete resolution without worsening of the other conditions (weight loss of 5% of TBW since baseline was an automatic failure). (0) Failure - No improvement or worsening of fever, night sweats and weight loss. Sponsor Defined Clinical Response (Complete Resolution) - Binary scale as defined above where success = complete resolution and failure = otherwise. Investigator Clinical Response (Seven Point Scale) - Subject s condition was evaluated by investigator at week 12 and 24 as marked, moderate or slight deterioration, no change, or slight, moderate or marked improvement. Investigator Clinical Response (Improved Condition - Binary Scale) - Improvement vs. no change or deterioration as defined in the 7 point investigator clinical scale above

8 Page 8 Death - Defined as death regardless of causality including all post-study deaths captured in the AEM database or project database for this protocol or any other Pfizer protocol if a subject continued onto another protocol (189B, 162, 162X). Time to Death - as measured from the beginning of therapy. Statistical Methodology General Per protocol, the comparison between the azithromycin 600mg group and the clarithromycin group would be examined first. If the confidence interval for the true difference in response rates met the requirements of equivalence, then the confidence interval for the difference between azithromycin 250 mg (therapeutic) and clarithromycin would be examined. No adjustments for multiple comparisons were made since this procedure kept the rate of false inference of equivalence for either of the azithromycin doses with clarithromycin to no more than 5% per efficacy variable. As a result of the interim analysis the azithromycin 250 mg (therapeutic) was dropped. Therefore, the procedure described above was not used. Thus, the primary comparison was azithromycin 600 mg versus clarithromycin 500 mg. Comparisons of the azithromycin 250 mg (therapeutic) and clarithromycin were not emphasized. Comparisons of the dropped azithromycin 250 mg (therapeutic) were made with the azithromycin 600 mg arm. The level of significance for the final analysis is as a result of the adjustment for the interim analysis. Therefore, 95.1% confidence intervals were used for all inferences. The primary model tested for equivalence treatment effects unadjusted for center. This model was used for dichotomous, ordinal and continuous endpoints. Additional analyses are described in the sensitivity analysis section below. One subject received a concomitant antibiotic potentially effective against MAC for treatment failure and this subject was considered both a clinical and microbiologic failure from the time of receiving the concomitant antibiotic. Binary Endpoints Sterilization rates at week 24 were examined to determine if azithromycin 600mg is at least as effective as clarithromycin. Success rates were calculated for each of the binary (dichotomous) endpoints. Inferential statistics and 95.1% confidence intervals for the difference in success rates were based on the normal approximation. Ordinal Endpoints Frequencies and percentages were reported for ordinal endpoints. Inferential statistics were not provided; however, both sponsor and investigator clinical response, which are collected on an ordinal scale, were analyzed on a binary scale of success versus failure. Continuous Endpoints Inferential statistics, confidence intervals and p-values were based on comparing observed means

9 Page 9 Time to Event Endpoints Inferential methods were based on the product-limit method, including the log-rank test, and the Cox Proportional Hazards Model. Event free (survival) curves and difference curves with 95.1% confidence bands (difference in event free curves) were plotted with product-limit (Kaplan-Meier) estimates. For time-to-sterilization and time-to-positive microbiological response if a subject did not develop an event, then the time to censoring was defined as the last culture prior to end of study. For time-to-first positive culture after sterilization (durability of blood sterilization) if the subject did not develop the event, then the time to censoring was computed from the last date of a negative culture, whether it is from 189 or 189B, or from the date of the telephone follow-up if the subject indicated that there was no relapse of MAC infection. For time-to-death, the censoring date was determined from the latest available date from several CRF blocks including the telephone follow-ups. If a subject developed an event, but the event was excluded per a time specific exclusion criteria, then that subject was considered censored with the time to censoring defined as the day the criterion went into effect. Missing Data In general, the intent-to-treat analyses used last observation carried forward algorithm for missing data for sterilization, positive microbiologic response, colony count and sponsor defined clinical response. For the other clinical endpoints including signs and symptoms, weight, and investigator defined clinical response, only observed cases were used for the intent-to-treat analysis. For sterilization and positive microbiologic response, the last observation was carried forward except for specific instances as specified in the algorithm (see algorithm near the end of the data analysis methods section). For colony count, the last observation was carried forward including baseline, if necessary. For sponsor defined clinical response, if one of the three symptoms used in the definition were missing, then that symptom was carried forward. However, baseline symptoms were not carried forward since the possibility existed of carrying forward a good response for that symptom. Local Laboratory Data Local laboratory data was captured as a telephone follow-up where the subject was classified as a either a MAC infection relapse or not. For subjects who were considered to be relapses, there were associated local laboratory cultures from blood, lymph node, spleen, bone marrow or liver. However, the number of colonies was not recorded in the case report from (CRF), but any positive culture was assumed to have >1 cfu/ml. For all microbiological endpoints with the exception of time to first positive culture after sterilization, the local laboratory data was only used if there was no central lab data in the analysis window. Since the local laboratory data was planned to collect post study data, there were very few instances where the local laboratory data was used. When local laboratory results were used to determine sterilization and time to sterilization, if the last central laboratory culture had a zero colony count and the subject was not a relapse based on local laboratory results, then the subject was assumed to be sterile at the time of follow-up. However, if the last central laboratory culture had a zero colony count, -208-

10 Page 10 and the subject was a relapse based on local laboratory results, then the subject was assumed to be not sterile at the time of follow-up. If the last central laboratory culture was a non-zero colony count, and the subject was a relapse based on local laboratory results, then the subject was considered to be not sterile at the time of the follow-up. However, if the last central laboratory culture was a non-zero colony count, and the subject was not a relapse, then the local laboratory data was ignored since it was not clear how that data should be interpreted and assessments were left as missing. When local laboratory results were used to determine positive microbiological response and time to positive microbiological response, the sterilization based on the central and local laboratories was determined and the same algorithm for positive microbiologic response was used. For time to first positive culture after sterilization, both central laboratory data collected from 189B and local laboratory data collected via the telephone follow-up were used. Pooling of Centers There was no pooling of centers used in conjunction with inferential statistics due to the large number of centers with small numbers of subjects. If the definition of a non-small center is a center with greater than 5 subjects randomized per treatment arm, then there were only 4 centers which meet this requirement. This does not take into account that not all subjects randomized are baseline positive for the pathogen of interest. Twenty five of the centers had three or fewer subjects. Since pooling would require many centers to be combined into psuedo-centers, the resulting analysis would not be easily interpreted. Sensitivity Analyses Sensitivity analyses were performed for the following variables: binary sterilization at week 24, time to sterilization, time to death, and time to first positive culture after sterilization (durability of blood sterilization). These analyses fell into three categories: endpoint definition, missing data, and covariate analysis and applied only to the azithromycin 600mg versus clarithromycin comparison. Endpoint definition sensitivity analyses involved the definition of sterilization for binary sterilization at week 24 and time to first positive culture after sterilization (durability of blood sterilization). In the protocol, analysis plan, and tables, sterilization is defined as two consecutive negative cultures. For a sensitivity analysis, sterilization was defined as one negative culture and the analyses were performed. For another sensitivity analysis, sterilization was defined as two consecutive negative cultures with all MAC colony counts recorded as 1 assumed to be zero. When the local laboratory qualitative culture (colony count not recorded) was positive, the colony account was assumed to be greater than 1 cfu/ml. The definition of sterilization requiring two consecutive negative cultures at week 24 was stated to be the primary efficacy measure. Nevertheless, as seen by the results provided in the study report in NDA Clinical Data Section 8, this particular assessment produced results which were nominally most disparate between treatment groups among all the definitions of sterilization subsequently considered. Furthermore, this definition requiring two consecutive negative cultures is not reflective of the results for mortality and other measures of bacteriologic response such as positive bacteriologic response, which arguably were more similar between treatment groups. Accordingly, although a priori stated as primary, the sterilization rate employing this definition may not reflect the overall similarity between treatments across the various measures and definitions of effectiveness and, in retrospect, may not be the most appropriate primary inference

11 Page 11 In the protocol, analysis plan, and tables relapse was defined as any nonzero colony count. A sensitivity analysis was performed for time to first positive culture after sterilization (durability of blood sterilization) where relapse was defined to be two consecutive nonzero MAC colony counts. When local laboratory qualitative cultures (colony count not recorded) were used, two consecutive relapses from the telephone follow-ups were required. A second definition was also used for time to first positive culture after sterilization (durability of blood sterilization) where MAC colony counts recorded as 1 were assumed to be zero When the local laboratory qualitative culture (colony count not recorded) was positive, the colony account was assumed to be greater than 1 cfu/ml. Missing data sensitivity analyses for binary sterilization at week 24 were performed to determine the effect of the missing data and the last observation carried forward algorithm. A summary of observations that had been carried forward was provided. An additional analysis was done where if a subject had missing data at week 24 because of death, then that subject was considered to be a failure for sterilization at week 24. A second missing data sensitivity analysis was done using post study central laboratory cultures which were drawn between week 26 and week 32, inclusive. These cultures were used as the subsequent assessment as described in the sterilization algorithm for the week 24 assessment, therefore only the week 24 timepoint was affected by this analysis. For sterilization at week 24 for the intent-to-treat subset, a multiple imputation analysis was performed as an alternative to the last observation carried forward for missing observations. The colony counts which were collected over time were imputed using the SOLAS program (Statistical Solutions, Ltd., ) for multiple imputation as described by Lavori, Dawson, and Shera ( ). Then sterilization at week 24 was derived from the imputed data. The results from the five imputed data sets were combined to form a confidence interval for the difference in the proportion of subjects sterile. Further details of the methodology for this analysis is given in Appendix III, Attachment IV of the individual study report. The following list of covariates collected at baseline were examined for the impact on binary sterilization at week 24, time to sterilization, and time to death: colony count (log base 10), CD4 count (cells/mm 3 ), hemoglobin, alkaline phosphatase, composite score from patient questionnaire (PHI), age, number of previous opportunistic infectious diseases (divided as < 2 diseases to >= 2 diseases), time since CD4 count has been <100 (cells/mm 3 ), MAC prophylaxis use, gender, race (categorized as White and non-white, for these purposes), concomitant protease inhibitor usage (at baseline or at any time during study), location of center (US subjects versus ex-us subjects), and timing of enrollment of centers (centers enrolled after the interim analysis versus those enrolled before), daily vs. non daily fever, daily vs. non daily night sweats. Each covariate was examined for the following: unbalanced allocation of the covariates to the treatment groups, significant effects of the covariate which might reduce the width of the confidence interval for the difference response rates for the treatment groups, and interaction effects where there might be a different effect of the covariate in the treatment groups. If any of these three criteria were met, then inferences with the model were presented. Other covariates which did not meet these criteria but were of interest were presented without inferences. An additional covariate sensitivity analysis was performed for time to death and time to first positive culture after sterilization (using the definition based on central and local laboratory data) controlling for MAC treatment after study 189 since both of these endpoints measure outcomes beyond the end of the study. Subjects were classified into four groups representing the post 189 drug treatment: Azithromycin: Subjects whose post-therapy antibiotics effective against MAC include azithromycin, but not clarithromycin; Clarithromycin: Subjects whose post-therapy antibiotics effective against MAC include -210-

12 Page 12 clarithromycin, but not azithromycin; Other: Subjects whose post-therapy antibiotics include both azithromycin and clarithromycin, or other antibiotics effective against MAC; or None: Subjects who have no record of post-therapy antibiotics. Note that the None category necessarily includes subjects who died during 189 therapy. The post study MAC treatment was determined by the CRA s for the subjects in the intent-to-treat subset using the case report form concomitant medication and records of death, records in the Adverse Event Monitoring (AEM) database and information obtained directly from the site. A subset of these subjects were also examined where only the subjects randomized to azithromycin and who also took azithromycin as one of the post study MAC treatment drugs and the subjects randomized to clarithromycin and who also took clarithromycin as one of the post study MAC treatment drugs and comparisons of time to first positive culture after sterilization were made. Time to death for the subset of sterile subjects was compared as a subset analysis. Additionally, this subset was further divided into subjects who relapsed and subjects who became sterile but did not relapse. Relapse was computed from the time to first positive culture after sterilization based on central laboratory data only and also based on both central and local laboratory data. References: 1. Statistical Solutions, Ltd. SOLAS for missing data analysis 1.0. Saugus, MA: Statistical Solutions; Lavori PW, Dawson R, Shera D. A multiple imputation strategy for clinical trials with truncation of patient data. Statistics in Medicine 1995;14: H.3.A.1.C Primary Supportive Study (Protocol 131) Subject Subsets The only subset defined for this study was the intent-to-treat subset which includes all enrolled subjects who had positive (colony count > 0) baseline blood cultures for MAC. There are two subjects included in the intent-to-treat subset who had only baseline clinical and microbiological data. Analysis Windows Scheduled visits and visit windows used for data analysis and summary purposes for treatment duration groups A, B, and C are given in the following tables. In some cases, different visit windows were required for treatment duration groups A, B, and C because the scheduled visits during therapy are different for the three groups. Different visit windows also were required for some of the endpoints because not all endpoints were collected at all visits. If more than one observation falls within a visit window, the observation closest to the scheduled visit day was used. If two observations in a window were equidistant from the scheduled visit day with one occurring before and one after, then the worst observation was used. Baseline was considered to be day 1 which is defined as the first day of study drug. Note that during therapy only applies for subjects in Treatment Duration Groups A and B. That is, subjects in Groups A and B continued to be followed even after they completed therapy, but no data during this follow-up period was summarized (this is the default based on the windowing defined below). All data for subjects in Group C were summarized according to the following analysis windows regardless of whether they were actually receiving drug

13 Page 13 Analysis Windows for Clinical Endpoints During Therapy Treatment Duration Group A Treatment Duration Group B Treatment Duration Group C Visit window Visit window Visit window Scheduled Visit Day (days) based on midpoints only Scheduled Visit Day (days) based on midpoints only Scheduled visit Day (days) based on midpoints only 1 (Baseline) -30 to 1 1 (Baseline) -30 to 1 1 (Baseline) -30 to to to to to to to to to to to to to to (1 month) 100 to (2 months) 130 to (3 months) 160 to (4 months) 190 to (5 months) 220 to (6 months) 250 to 279 Analysis Windows for Microbiological Endpoints During Therapy Treatment Duration Group A Treatment Duration Group B Treatment Duration Group C Visit window (days) based on midpoints only Visit window (days) based on midpoints only Visit window (days) based on midpoints only Scheduled visit Day Scheduled visit Day Scheduled visit Day 1 (Baseline) -30 to 1 1 (Baseline) -30 to 1 1 (Baseline) -30 to to to to to to to to to (1 month) 100 to (2 months) 130 to (3 months) 160 to (4 months) 190 to (5 months) 220 to (6 months) 250 to 279 Endpoints Microbiological Efficacy Endpoints Sterilization (Primary endpoint) - defined as one negative blood culture (colony count =0). Positive Microbiologic Response - defined as sterilization and/or a ten-fold (1 log) reduction in colony count (cfu/ml) since the baseline visit (binary response) For colony counts of 1, the log colony count is zero (log(1)=0). For colony counts of zero, the log of was used because 0.1 is the lower limit of measurability (log(0.099)= ). Colony Count during therapy (cfu/ml, log base 10) - (blood cultures only) Change in Colony Count (cfu/ml, log base 10) since baseline -212-

14 Page 14 Clinical Efficacy Endpoints Sponsor defined clinical response (4-point scale) Complete resolution of signs & symptoms - Absence of fever (>100.5 F) since last visit, absence of night sweats since last visit, and absence of weight loss (> 5% TBW) since baseline. Resolution of 2 of 3 signs & symptoms - Absence of two of the three symptoms needed to define complete resolution without the worsening of the other condition. Resolution of 1 of 3 signs & symptoms - Absence of one of the three symptoms needed to define complete resolution without worsening of the other conditions. Failure - No improvement or worsening of fever, night sweats and weight loss. Investigator clinical response (Four-point scale) Cure = resolution of symptoms of infection Response = substantial improvement of symptoms compared with baseline No response = minimal improvement compared with baseline, no change of symptoms Failure = symptoms worse compared with baseline. Investigator clinical response during extended and suppressive therapy for Group C (Fourpoint scale) No evidence of disease Continued improvement Recurrence or worsening after improvement or cure No change in condition Statistical Methodology All endpoints were summarized across time. All summaries were for the observed cases only, and thus, subjects who were missing a particular endpoint in a particular analysis visit window were not included in any summaries for that particular visit. Although the protocol states that comparisons will be made among treatment duration groups A, B, and C, no inferential statistics were calculated because the number of subjects in each group is too low. Subject Enrollments It turned out that several subjects enrolled in the study more than once. For these subjects, all data were combined (i.e. one PID per subject). For efficacy summaries, only the first enrollment was considered, and summaries were presented for each of the treatment duration groups. For safety summaries, data from all enrollments were used to summarize the entire safety experience. All safety summaries were presented for 250 mg and 500 mg. The summaries for 500 mg include all data while subjects were receiving 500 mg, and the summaries for 250 mg include all data while the subject was receiving 250 mg (maintenance and suppressive therapy). The safety data was summarized in this way to show the safety data for 250 mg given for extended durations. For the 500 mg tables, a 35 day lag was used. This is a conservative method for summarizing the safety data. For example, a subject who had a side effect that begins while receiving 500 mg and continued while receiving 250 mg will appear in the 500 mg tables and the 250 mg tables

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16 Page 16 Time Specific Exclusion Criteria: none Endpoint Specific Exclusion Criteria: Endpoint Not Measured at Baseline. Endpoint/Time Specific Exclusion Criteria: Endpoint Not Measured in Analysis Window. Analysis Windows The analysis windows are as follows. The start of study (day 0) was defined as the day on which a subject takes the first dose as recorded in the case report form. Scheduled Week Evaluable Subgroup Window Intent-to-Treat Window days 1-14 days days days days days Endpoints Primary The primary endpoint was: Secondary Sterilization - Defined as one negative culture. The secondary endpoints were: Microbiologic (MAC Blood Cultures) Positive Microbiologic Response - Defined as sterilization and/or a ten-fold (1 log) reduction in colony count (cfu/ml) since the baseline visit (beginning of therapy). For colony counts of 1, the log colony count is zero (log(1)=0). For colony counts of zero, the log of will be used because 0.1 is the lower limit of measurability (log(0.099)= ). Colony Count (cfu/ml, log base 10) Change in Colony Count (cfu/ml, log base 10) Since the Baseline Visit (beginning of therapy) MIC Results - Summarized for each treatment group and visit. Clinical Most clinical endpoints were analyzed on three scales: original scale collected, complete response where success is complete resolution and failure is all other categories, and satisfactory response where success is complete resolution or improvement/partial resolution and failure is all other categories

17 Page 17 Sponsor Defined Clinical Response (Four-Point Scale) as follows: Complete Resolution of Signs & Symptoms - Defined as absence of fever (daily temperature > F ) and night sweats since last visit, and weight loss of less than 5% of total body weight since baseline. The last visit must have occurred at least 7 days prior to the current visit. If this did not happen then the first visit that is at least 7 days prior to the current visit, was used. Partial Resolution of Signs & Symptoms (2 of 3 symptoms) - Absence of two of the three symptoms needed to define complete resolution without the worsening of the other condition (weight loss of 5% of total body weight since baseline was an automatic failure). Partial Resolution of Signs & Symptoms (1 of 3 symptoms) - Absence of one of the three symptoms needed to define complete resolution without worsening of the other conditions (weight loss of 5% of total body weight since baseline was an automatic failure). Failure - No improvement or worsening of fever, night sweats and weight loss. Investigator Clinical Response (Four-Point Scale) - Subject s condition was evaluated by the investigator at weeks 1, 3 and 6 as (2) complete, (1) partial or (0) no response, or (-1) progression. Investigator Clinical Response (Seven-Point Scale) - Subject s condition was evaluated by the investigator at week 6 as (-3) marked, (-2) moderate or (-1) slight deterioration, (0) no change, (1) slight, (2) moderate or (3) marked improvement. Statistical Methodology General Comparisons were made between both treatment groups, 600 mg and 1200 mg doses, and when appropriate, within a treatment group. The within treatment group comparisons were made when a suitable null hypothesis could be constructed, such as a hypothesis of no response. All p-values are from two-tail tests. For both the ITT and evaluable analyses, an observed cases analysis was performed unless the subject discontinued for lack of efficacy or took a concomitant antibiotic effective against MAC. For these circumstances, the last value prior to discontinuation or start of the antibiotic, respectively, was used. All post-study data were ignored. Binary Endpoints For dichotomous endpoints (e.g. success/failure), such as sterilization of blood cultures, positive bacterial response, complete clinical response and complete response for specific signs and symptoms, 95% confidence intervals were constructed from the normal approximation with a continuity correction and comparisons were made with the Cochran- Mantel-Haenszel test adjusted for center. Additionally, within-treatment 95% confidence intervals were calculated. Ordinal Endpoints Ordinal endpoints were treated as continuous endpoints for purposes of calculating inferential statistics (see below)

18 Page 18 Continuous Endpoints For continuous endpoints, such as colony count, clinical response and specific signs and symptoms, a mixed-effects model was used adjusting for center, baseline, treatment, time and treatment by time interaction in the model. From this model, results were reported for each timepoint and 95% confidence intervals were constructed from least-square (LS) means and their standard errors. Inferential statistics were provided for both between and within-treatment comparisons. H.3.A.1.E Compassionate-Use MAC Study (Protocols 162/162X/148B) Subject Subsets The clinical intent-to-treat population includes all enrolled subjects. There were 3 different microbiological intent-to-treat populations; one for each type of endpoint. Three different populations were required because subjects who transferred from protocol 148 may not have had a colony count or blood culture performed at the baseline visit. 1. Sterilization and Time-to-Sterilization - the intent-to-treat population includes all subjects with a baseline colony count > 0 based on the central lab culture results or a positive baseline blood culture based on local lab culture results. 2. Colony Count and Change from Baseline Colony Count - the intent-to-treat population includes all subjects with a baseline colony count > 0 based on central lab culture results. The local lab only provides information as to whether the culture is positive or negative; that is, colony counts were not provided. 3. Time-to-First Positive Culture after Sterilization - the intent-to-treat population includes all subjects who are sterile at some point during the study with colony count = 0 at some point during the study based on central lab culture results or a negative blood culture at some point during the study based on local lab culture results. Analysis Windows Scheduled visits and visit windows used for summary purposes are given in the following table. If more than one observation falls within a visit window, the observation closest to the scheduled visit was used. If two observations in a window were equidistant from the scheduled visit with one occurring before and one after, then the worst observation was used. Baseline was considered to be day 1 which is defined as the first day of study drug. Types of Analysis Scheduled visit Visit window (days) Day 1 (Baseline) -30 to 1 1 Month (Day 28) 2 to 42 2 Months (Day 56) 43 to 70 3 Months (Day 84) 71 to Months (Day 168) 127 to Months (Day 252) 211 to months (Day 336) 295 to months (Day 504) 421 to 588 Two types of efficacy analyses were performed to address missing data. One was a last observation carried forward (LOCF) analysis and the other was an observed cases (OC) -217-

19 Page 19 analysis. For the LOCF analysis, subjects who were missing a particular endpoint in a particular window had their last available result for this endpoint carried forward. For the OC analysis, subjects who were missing a particular endpoint in a particular window were not included in any summaries or tabulations for that particular endpoint in that particular window. The LOCF analysis was used so that the success rates were not inflated at the end of the study when many subjects may have withdrawn. For example, subjects who withdrew due to insufficient response were carried forward as failures throughout all subsequent summaries for the LOCF analysis. For subjects with only baseline information, the LOCF algorithm was not applied. Endpoints Mycobacterial Efficacy Endpoints Sterilization (Primary endpoint) Defined as one negative blood culture (based on colony count data from the central lab and other local lab blood culture results) Time-to-Sterilization Defined as the time from baseline (Day 1) to sterilization. Subjects who never become sterile were censored at the date of the last available culture result. Colony Count (cfu/ml, log base 10) Based on colony count data from the central lab only. For colony counts of 1, the log colony count is zero (log(1)=0). For colony counts of zero, the log of was used because 0.1 is the lower limit of measurability (log(0.099)= ). Change in Colony Count (cfu/ml, log base 10) since baseline Based on colony count data from the central lab only Time-to-first positive culture after sterilization For subjects who have a negative blood culture for MAC at baseline: Time to first positive culture after sterilization was defined as time from baseline to the first positive blood culture for MAC. If a subject remained negative throughout the study, the subject was censored at the time of the last available negative culture. For subjects who had a positive blood culture for MAC at baseline: Time to first positive culture after sterilization was defined as time from the first post-baseline negative blood culture for MAC to the first subsequent positive blood culture for MAC. If a subject remained negative after the first post-baseline negative culture, the subject was censored at the time of the last available negative culture

20 Page 20 Clinical Efficacy Endpoints Investigator clinical response (7-point scale) Statistical Methodology Marked improvement Moderate improvement Slight improvement No change in status Slight deterioration Moderate deterioration Marked deterioration All endpoints were summarized across time. For time-to-event type endpoints, Kaplan- Meier plots and summary statistics were produced. Subjects were categorized into two dose administration route groups, Oral only and IV with or without Oral, based on drug shipment records. Efficacy and safety data were summarized for each of these two categories. Several analyses proposed in the protocol were not provided. The first analysis that is excluded is the analysis for the patient self assessment scores. Similar information was collected based on the investigator s assessment of the signs and symptoms of infection. For analysis purposes, the investigator s assessment of the signs and symptoms of infection was selected. The patient self assessment scores were collected, but were not analyzed. The second analysis that was excluded was the multiple regression analysis to correlate MAC colony counts with other efficacy parameters. Protocols 162, 162X, and 148B are open-label compassionate use protocols, and thus, this type of analysis was not warranted. H.3.A.1.F Compassionate-Use MAC Study (Protocol 169) Subject Subsets The only subset defined for this study was the intent-to-treat subset which includes all enrolled subjects who had a non-tuberculosis mycobacterial species (Mycobacterium avium, mycobacterium species, or Mycobacterium chelonei) identified at baseline or had evidence of infection based on prior information (last positive data or date of the primary diagnosis is non-missing). Analysis Windows Scheduled visits and visit windows used for summary purposes are given in the following table. If more than one observation fell within a visit window, the observation closest to the scheduled visit was used. If two observations in a window were equidistant from the scheduled visit with one occurring before and one after, then the worst observation was used. If on the day selected for analysis multiple observations were collected (e.g., from multiple culture sites), then the worst case was used for the analysis. If multiple observations were collected each resulting in the same outcome, then one was selected randomly

21 Page 21 Scheduled visit Visit window (days) Day 1 (Baseline) -30 to 1 * 2 weeks (Day 14) 2 to 21 1 Month (Day 28) 22 to 42 2 Months (Day 56) 43 to 70 3 Months (Day 84) 71 to Months (Day 168) 127 to Months (Day 252) 211 to months (Day 336) 295 to months (Day 504) 421 to 588 *For the mycobacterial response, consider the baseline culture to be any culture performed prior to dosing even if the culture was performed years prior to entry into this study Types of Analysis Two types of efficacy analyses were performed to address missing data. One was a last observation carried forward (LOCF) analysis and the other was an observed cases (OC) analysis. For the LOCF analysis, subjects who were missing a particular endpoint in a particular window had their last available result for this endpoint carried forward. For the OC analysis, subjects who were missing a particular endpoint in a particular window were not be included in any summaries or tabulations for that particular endpoint in that particular window. Endpoints Mycobacterial Efficacy Endpoints Mycobacterial Response to Therapy (3-point scale) Eradication Persistence Not Evaluable Mycobacterial culture and smear results (2-point scale) Positive Negative If the subject grew something besides the 3 pathogens listed in the intent-to-treat definition, the subject s culture response was considered to be negative. If there was a species found in the culture, but the response was missing, the culture was assumed to be positive, and if the culture was positive, but no species was listed, the culture was assumed to have grown a mycobacterium species. Clinical Efficacy Endpoints Investigator clinical response (5-point scale) Complete Response Partial Response No Change Progression Clinical Relapse -220-

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24 Page 24 personnel, as well as those events volunteered by the subject or elicited by the investigator. For all studies in this submission, adverse events occurring during the study were reported either as side effects, or as intercurrent illnesses. Side effects which occurred during therapy or within 35 days of the end of therapy were coded to the COSTART dictionary and tabulated by body system and preferred term, severity (mild, moderate, severe), and by the investigator s assessment of their relationship to study drug therapy. Side effects of unknown or unspecified cause were included with those judged to be treatment-related by the investigator. Laboratory test findings classified by the investigator as side effects were not included in the side effect tables but were included in the analyses of laboratory data. Side effects that were not confirmed as having cleared by the last visit were assigned an outcome of still present. Also, if a previouslyreported side effect was not reported at a subsequent study visit, that side effect was assigned a stop date equal to the visit date, but the outcome was reported as still present. A side effect was regarded as treatment emergent if it first occurred during the treatment period, or if it first occurred prior to the treatment period, but its severity increased during the treatment period. Also, there were some additional analyses of side effects related to hearing combined across studies. Intercurrent illnesses were to be recorded separately from side effects, with information on date of onset and date of clearance. All intercurrent illnesses recorded as occurring during therapy or within 35 days of the end of therapy were tabulated. Assessments of their severity were neither provided by the investigator nor made by the sponsor. Reporting and Evaluation of Serious Adverse Events Serious adverse events reported were recorded in a separate database. Events judged to be reportable were filed according to regulatory requirements. Serious adverse events were listed by subject with information on gender, age, race, and weight, dosing, duration of treatment, day of onset of the event, any action taken, the investigator s assessment of causality, and the outcome of the event. In addition to the overall serious adverse event listings, a list of the subset of subjects who died was extracted. Narratives are provided for all deaths occurring during therapy and up to 35 days after the end of therapy, as well as for any treatment-related death occurring at any time. Serious adverse event tables are derived from a separate database that is based upon rapidly-communicated reports (usually made by telephone) from the investigators to the sponsor. Consequently, there may be occasional discrepancies between data in these tables and those obtained in the routine safety database. Reporting and Evaluation of Clinical Laboratory Abnormalities Laboratory tests were performed at central and local laboratories. A single set of age and gender specific normal ranges were applied to values from all laboratories, i.e., normal ranges were not laboratory specific. Post-baseline laboratory test values for a core set of tests up to 35 days after the end of study therapy were classified as to whether they were clinically significant using the sponsor s Worldwide Safety Standards (WSS) criteria based on normal ranges or an absolute cutoff value. Due to the level of illness of these HIVinfected subjects, additional criteria based on changes from baseline were applied for -223-

25 Page 25 subjects who had abnormal baseline values. Criteria for assigning clinical significance are listed in the individual study reports as well as in Attachment I of NDA Section 8.F (Methods of Evaluation and Statistical Presentation). The incidence of clinically significant abnormalities in individual laboratory parameters was tabulated for each treatment group, and subjects with clinically significant laboratory test abnormalities were listed. For selected hematologic, hepatic, and renal functions, the median baseline values and changes in value from baseline to last observation during therapy were also tabulated. Number of Subjects Treated Subjects were included as treated if they were known to have received at last one dose of study drug. Details of patient accounting (including accounting for subjects with multiple enrollments) are provided in section H.2 (Overview of Studies) of the NDA Application Summary Volume. H.3.A.3 Query Plan (Pfizer IND Studies) For the MAC treatment submission, a query plan was created to deal with the historically low response rate from investigators for compassionate-use studies in general. The plan was not used for the pivotal study, 189, where the investigators responded to all queries. For studies 148, 162/162X/148B, and 169 included in this section, as well as the following other studies, 133/133M/133Z, 143, 144, 147, 167, 167S, 170, and 185, discussed in NDA Section 3.H.5 (Other Studies), an investigator was declared non-responsive by the following procedure. If through the regular query process (sending queries to the sites, following up several times via mail, phone or over an extended time period) the investigator was non-responsive, a registered letter was sent to the investigator asking for a response to the queries. If, after two weeks, there was no response, then a second registered letter was sent. If, after an additional two weeks, there was no response, then due diligence was noted and the site was documented as unresponsive. Additional queries were no longer generated for unresponsive sites; however, if a query was deemed critical by the project team, it was given to the Global Candidate Team Leader for consideration. In some cases, a serious adverse event (SAE) was reported through the regular SAE reporting system but no CRF could be obtained from the investigator. H.3.B. INDIVIDUAL STUDY SUMMARIES (PFIZER IND STUDIES) H.3.B.1 Pivotal Study Protocol 189/189B (U.S.) Study Objectives: The purpose of study 189/189B was to evaluate the efficacy and safety of azithromycin administered at two different dose levels (600 mg or 250 mg single daily dose) in combination with ethambutol for treatment of Mycobacterium avium complex (MAC) infection and to determine whether a regimen containing azithromycin was at least as safe and effective as clarithromycin plus ethambutol. The primary purpose of the maintenance phase (189B) of study 189/189B was to continue to provide treatment and assess long-term safety in subjects who initially responded to treatment. A secondary objective was to assess the efficacy of azithromycin in combination therapy (with ethambutol) to maintain the initial bacteriologic and clinical improvement

26 Page 26 Study Design: The treatment phase (189) of this study was a multicenter, double-blind, randomized study comparing azithromycin (250 mg and 600 mg) plus ethambutol and clarithromycin plus ethambutol administered orally for 24 weeks to subjects with AIDS for treatment of disseminated MAC. Subjects were to be reevaluated bacteriologically and clinically for signs/symptoms every 3 weeks for 12 weeks and monthly thereafter through week 24. Global assessments of clinical response were to be made at weeks 12 and 24. At the investigator s discretion, subjects with a complete response to treatment by week 24 could enter the open-label, noncomparative phase (189B), receiving oral azithromycin 250 mg plus ethambutol once daily. Follow-up assessments were to be made every 3 months. Evaluation Groups: Number of Subjects: Treatment Maintenance Az 600 mg Az 250 mg Clarithro Az 250 mg Randomized/Enrolled (189B) Entered Study (treated) Completed Study Discontinued Study Discontinued Treatment Evaluated for Efficacy: Intent-to-Treat Evaluable Wk. 24 Sterilization* NA Assessed for Safety: Side Effects Laboratory Tests Az=azithromycin, Clarithro=clarithromycin, NA=not applicable * Sterilization=two consecutive cultures negative for MAC Diagnoses and Criteria for Inclusion of Subjects: Male/female HIV-infected inpatients/outpatients 13 years old, with culture (and clinical in Europe) evidence of MAC infection. The actual mean age of subjects in both the azithromycin 600 mg and clarithromycin groups in the therapeutic phase was approximately 38 years. Drug Administration: Dosage Form Azithromycin 600 mg tablet, azithromycin 250 mg tablet, clarithromycin 500 mg tablet, ethambutol 400 mg tablet and both azithromycin and clarithromcyin placebo tablets were provided under various lot/fid numbers. Azithromycin lot numbers were as follows: 600 mg tablets: N4270, N4373, ED-B , ED-B , ED-B , ED-O : 250 mg tablets: N4272, ED-G , ED-G , ED-B- 387-Z92. Complete dosage form information by clinical site is provided in Appendix II.D. Dosing Duration Azithromycin 600 mg or 250 mg (plus dummy placebo in treatment phase) single daily dose Clarithromycin 500 mg bid (plus dummy placebo) Ethambutol 15 mg/kg once daily (800 mg or 1200 mg) (study medications were taken without regard to meals) 24 weeks (treatment phase); indefinite (maintenance phase) -225-

27 Page 27 Efficacy and Safety Evaluations: Intent-to-treat (last observation carried forward) and evaluable subgroup analyses were performed. Bacteriologic endpoints were sterilization [zero colony count in blood; primary], time to sterilization, time to first positive culture after sterilization (relapse), positive bacteriologic response [sterilization and/or reduction from baseline of ten-fold (1 log) reduction in MAC colony forming units/ml of blood, cfu/ml], time to a positive bacteriologic response, and change from baseline in MAC colony count (log base 10). Clinical endpoints were death, time to death, sponsor (based on fever, night sweats, weight loss) and investigator (based on any sign/symptom) assessments of overall clinical response, investigator assessment of individual signs/symptoms (including but not limited to fever, night sweats, weight loss), and Perceived Health Index (derived from the quality of life questionnaire). Safety was assessed by incidences of side effects, laboratory test abnormalities, intercurrent illnesses, median changes from baseline in selected laboratory tests, serious adverse events including deaths and specific ophthalmologic and audiometric exams. Statistical Methods: The level of significance was due to a adjustment from the interim analysis. Bacteriologic and clinical endpoints were compared between treatment groups by 95.1% confidence intervals (CI) on the differences (azithromycin 600 mg-clarithromycin) in observed rates (sterilization, positive bacteriologic response, clinical response, death) and in mean values (MAC cfu/ml, change from baseline in MAC cfu/ml and in weight), and a p-value determined based on normal approximation or normal distribution using a t-test (colony count endpoints, weight change only). Time to event analyses were performed for sterilization, first positive culture after sterilization (relapse), positive bacteriologic response, and death using Cox Regression with a 95.1% CI on the hazard ratio. Descriptive statistics are presented for the incidence of fever and night sweats since the previous visit controlling for daily fever and night sweats, respectively, at baseline. The primary timepoint was week 24. Efficacy Results: Bacteriologic and Clinical Endpoints Azithromycin 600 mg vs. Clarithromycin - Observed Rates - Intent-to-Treat Analysis - Week 24 Azithromycin 600 mg Clarithromycin Bacteriologic Endpoints**** N Obs Rate (%) N Obs Rate (%) 95.1% CI* P-value* Sterilization , Pos Bact Res , N Median N Median NA NA Colony Count (log base 10, cfu/ml) *** *** Change Count (log base 10, cfu/ml)** Clinical Endpoints N Obs Rate (%) N Obs Rate (%) 95.1% CI* P-value* Death Rate , Sponsor Assessment + Complete Resolution (Cure) , Investigator Assessment Improved , N Mean N Mean NA NA Perceived Health Index Score Obs Rate = Observed Rate (%) is based on the number of subjects with events (sterilization, positive bacteriologic response, death) or proportions of subjects (sponsor and investigator assessments); CI = confidence interval, Pos Bact Res=positive bacteriologic response; NA=Not Applicable. *Statistical tests: 95.1% confidence interval on the difference (azithromycin 600 mg-clarithromycin) in observed rates and p-value are based on normal approximation (sterilization, positive bacteriologic response, clinical response, death); ** Change from baseline in MAC colony count (log base 10); *** log (0 cfu/ml)=-1.00-no growth;**** Bacteriologic endpoints based on quantitative blood culture data from a central laboratory; + Based on resolution of fever, night sweats, weight loss; ++ Improved=Assessed with marked, moderate, or mild improvement; +++ Score (scale of in which higher scores indicate a more favorable response) at week

28 Page 28 Time to Event Endpoints Azithromycin 600 mg vs. Clarithromycin - Observed Rates - Intent-to-Treat Analysis Time to Event Analysis Cox Regression Time to Event Endpoint Treatment N Observed Rate (%)** First Quartile* Median* Hazard Ratio*** 95.1% CI on Hazard Ratio P-value Bacteriologic Endpoints***: Sterilization Az 600 mg (52.9%) , Cl (59.6%) Pos Bact Res Az 600 mg (80.9%) , Cl (73.7%) Relapse Az 600 mg 36 6 (16.7%) , Cl 34 3 (8.8%) Relapse***** Az 600 mg (38.9%) , Cl 34 9 (26.5%) Clinical Endpoints: Death+ Az 600 mg (69.1%) , Cl (63.2%) Relapse=First Positive Culture after sterilization, Pos Bact Res=Positive Bacteriologic Response, Az=Azithromycin, Cl=Clarithromycin; * Number of days until 25% (first quartile) or 50% (median) of the events occurred as estimated by the Kaplan-Meier curve; ** Observed rate is based on number of subjects with events; *** Hazard ratio refers to the risk of having the event for azithromycin 600 mg relative to clarithromycin; **** Bacteriologic endpoints based on quantitative blood culture data from a central laboratory unless otherwise specified; ***** Second analysis of relapse based on documented quantitative and qualitative culture data from sterile sites from central and local laboratories; + Based on deaths through last follow-up Safety Results: Azithromycin 600 mg Clarithromcyin 500 mg Number of subjects evaluable for side effects Percent of subjects with Treatment-emergent side effects 63.1% (9.5%) 65.9% (5.9%) (all causality) Treatment-emergent side effects 50.0% (8.3%) 48.2% (5.9%) (treatment-related) Number of subjects evaluable for laboratory data Clinically significant laboratory abnormalities 80% 68% Clinically significant laboratory abnormalities* 20% 12% ( ) = resulted in discontinuation from study, * = subjects with normal baselines Summary and Conclusions: In this study the majority of subjects were male with AIDS, reflective of the normal disease population for MAC at the time of the study. The discussion of efficacy results in the therapeutic phase is based on the intent-to-treat analysis, either at the primary timepoint of week 24 or a time to event analysis. Azithromycin 600 mg versus Clarithromycin Median baseline MAC colony counts (log 10) were 1.41 cfu/ml in the azithromycin 600 mg group and 1.77 cfu/ml in the clarithromycin group. The two treatment groups were similar in the objective measurement of change from baseline to week 24 in MAC colony count (log 10), with median changes of cfu/ml in the azithromycin 600 mg group compared to cfu/ml in the clarithromycin group. In both treatment groups the median colony counts (log 10) at week 24 were zero. The MIC 90 of azithromycin was 32 µg/ml, and the MIC 90 of clarithromycin was 2 µg/ml. Colony count at baseline was determined to be the best predictor of sterility among the covariates assessed, with a lower colony count associated with a greater probability of becoming sterile

29 Page 29 Overall, the observed rates of sterilization (two consecutive negative blood cultures with a colony count of zero) at week 24 were comparable between groups, although somewhat lower in the azithromycin 600 mg group (45.6%) compared to the clarithromycin group (56.1%) (95.1% CI -28.1, 7.0; p=0.240). When employing this protocol-specified definition of sterilization as the primary endpoint, the observed difference in sterilization rates between groups was -10.6% in favor of clarithromycin. Alternative definitions of sterilization reduced this difference. Additionally, the overall time to sterilization was comparable (hazard ratio 0.74; 95.1% CI 0.459, 1.181). Sterilization appeared to occur somewhat sooner with clarithromycin, with the median time to sterilization estimated at 64 days in the azithromycin 600 mg group and 48 days in the clarithromycin group. Similarly, in an analysis based on all documented quantitative and qualitative culture data from sterile sites (central and local laboratory data), the overall time to relapse (first positive culture after sterilization) was comparable between groups (hazard ratio 1.71; 95.1% CI 0.734, 3.987). In general, the durability of sterilization appeared to be longer with clarithromycin than azithromycin 600 mg. No subjects receiving azithromycin 600 mg compared to 2 subjects receiving clarithromycin with susceptible pathogens at baseline developed a resistant pathogen postbaseline. In the small subgroup of subjects ( 16/group) who continued on their double-blind therapy after the study, the hazard ratio (0.86; 95.1% CI 0.268, 2.761) on the time to relapse was brought closer to 1 compared to the main analysis, supporting the similarity of these compounds for long-term therapy of disseminated MAC. The observed rates of a positive bacteriologic response (sterilization and/or a 1 log reduction from baseline of MAC cfu/ml of blood) were equivalent between the azithromycin 600 mg group (76.5%) and the clarithromycin group (73.7%) (95.1% CI -12.5, 18.1). The hazard ratio for the time to a positive bacteriologic response was 1.03 and one group did not appear to experience a positive response sooner than the other. The observed rates of death were comparable between groups. When subjects were followed beyond the study period, the observed rates were 69.1% for azithromycin 600 mg and 63.2% for clarithromycin (95.1% CI -10.8, 22.7; p=0.482). The overall time to death was comparable between the two treatment groups (hazard ratio 1.08, 95.1% CI 0.698, 1.671; p=0.729). The estimated time to death for the first quartile was 201 days in the azithromycin 600 mg group and 163 days in the clarithromycin group. Extending beyond the 24-week active treatment phase, the median time to death was estimated at 370 days in the azithromycin 600 mg group and 336 days in the clarithromycin group. Protease inhibitor use at any time during the study was found to be the most important of the covariates assessed in influencing time to death, with those subjects using protease inhibitors tending to live longer. Overall, the data suggest that azithromycin 600 mg subjects may have been somewhat more compromised clinically at baseline than clarithromycin subjects relative to the frequency of signs/symptoms of MAC and other indicators of health status, and this may have influenced the clinical course of the subjects. In addition, comparison of symptom resolution on the azithromycin 600 mg vs. 250 mg arm supports the possibility that underlying disease beyond that caused by MAC may have contributed to the lower rates of clinical improvement in the 600 mg treatment arm. In the week 24 sponsor s assessment of clinical response (based on fever, night sweats, weight loss), the proportions of subjects cured (resolution of all 3 signs/symptoms) was 25.8% in the azithromycin group and 36.2% in the clarithromycin group (95.1% CI -28.0, 7.2). In the corresponding investigator s assessment of clinical response (based on all -228-

30 Page 30 signs/symptoms data), the proportions of subjects showing some degree of improvement was similar at approximately 70% in both groups. In the intent-to-treat analysis at week 24, more azithromycin 600 mg subjects than clarithromycin subjects had experienced fever (41.2% vs. 29.2%) or night sweats (47.1% vs. 33.3%) since the previous visit. However, an uneven distribution of signs/symptoms at baseline may be affecting these results. Mean weights at week 24 in both treatment groups increased (0.36 kg in the azithromycin 600 mg group vs kg in the clarithromycin group; 95.1% CI , 0.638; p=0.112). From the quality of life questionnaire, the mean Perceived Health Index scores (higher scores on a scale of 100 are positive) at week 24 were in the azithromycin group and in the clarithromycin group. The overall assessment of safety was very similar for the subjects receiving azithromycin 600 mg and those receiving clarithromycin 500 mg. However, the actual duration of therapy was 25% greater for azithromycin 600 mg with a median of 86 days versus the median of 69.0 days for clarithromycin 500 mg. Treatment-emergent, all causality side effects were reported by 63.1% of subjects receiving azithromycin 600 mg and 65.9% of the individuals assigned to clarithromycin. Severe side effects were noted in 20.2% of the azithromycin 600 mg recipients and 23.5% of the subjects receiving clarithromycin 500 mg. Discontinuations due to side effects occurred in 9.5% and 5.9% of subjects receiving azithromycin 600 mg and clarithromycin, respectively. Specific ophthalmologic and audiometric assessments revealed no apparent differences between the two treatment groups. Among subjects receiving azithromycin 600 mg, 92.9% reported at least one intercurrent illness compared to 80% of those receiving clarithromycin. Clinically significant laboratory abnormalities were reported in 80% of the subjects assigned to azithromycin 600 mg and 68% of clarithromycin recipients. Azithromycin 250 mg (Double-Blind Therapeutic Phase) The azithromycin 250 mg arm was terminated as the result of a blinded interim analysis showing a relative lack of efficacy compared to azithromycin 600 mg and clarithromycin. Azithromycin 250 mg as double-blind, active therapy showed both bacteriologic and clinical efficacy against MAC. However, in the comparison to the azithromycin 600 mg dose, in the week 24 intent-to-treat analysis, the differences between these two dose groups was statistically significantly different in favor of the 600 mg dose for sterilization, time to sterilization, MAC colony count, and change from baseline in MAC colony count (p 0.032). Although the rates of a positive bacteriologic response were nominally lower in the azithromycin 250 mg group (63.8%) compared to the 600 mg group (76.5%), overall they were comparable (95.1% CI -29.8, 4.5; p=0.141). The time to the first positive culture after sterilization (relapse) and to a positive bacteriologic response were comparable between groups. In the interim analysis, the comparison of the number of deaths occurring during the study or post-study were higher in the intent-to-treat azithromycin 250 mg group (62.5%) than the azithromycin 600 mg group (52.6%), but the difference was not statistically significant (95% CI -12.0, 31.7; 99.9% CI -26.8, 46.5). Additionally, a similar trend was seen in the final intent-to-treat analysis of death rates for the subset of subjects in the interim analysis, with death rates through last follow-up of 87.5% for azithromycin 250 mg compared to 78.9% for azithromycin 600 mg (95.1% CI -8.0, 25.1; p=0.311). In the final analysis, in which subjects originally assigned to azithromycin 250 mg were followed through the close of the trial, the overall incidence of death and time to death analysis showed a statistically significant difference between groups (p 0.011), with a hazard ratio of 1.84 in favor of the 600 mg dose. Additionally, deaths occurred earlier in the azithromycin 250 mg group compared to the azithromycin 600 mg group, with the first -229-

31 Page 31 quartile estimated at 127 days and 201 days, respectively. Week 24 clinical cure rates in the sponsor s assessment of clinical response were similar (approximately 26%) between the two dose groups. However, although noting that the denominator in the 250 mg group was small (N=11), the investigator s assessment of clinical response showed more subjects improved in the azithromycin 250 mg group (90.9%) than the 600 mg group (71.0%). The number of days with fever was similar between the azithromycin 250 mg and 600 mg groups (risk ratio 0.964). However, the number of days with night sweats was greater in the azithromycin 600 mg group than the 250 mg group, with a risk ratio of (p<0.001). At week 24, mean changes in Perceived Health Index scores (higher scores on a scale of 100 are positive) from baseline were in the azithromycin 250 mg group and in the azithromycin 600 mg group (p=0.0484). Treatment-emergent, all causality side effects were reported by 65.1% of the subjects assigned to the azithromycin 250 mg treatment phase. Severe side effects were noted in 22.2% of these individuals and discontinuations due to side effects occurred in 4.8%. At least one intercurrent illness was noted in 79.4% of the subjects and the overall incidence of clinically significant laboratory abnormalities was 73% for these individuals. There were no significant findings related to ophthalmologic and audiometric exams. Azithromycin 250 mg (Open-Label Maintenance Phase) In the intent-to-treat analysis of the open-label phase of the study at month 12, the observed rate of sterilization was 91.7% (11 of 12) of subjects and the observed rate of subjects cured in the sponsor s assessment of clinical response 50.0%. The observed rate of death at month 12 was 48.3% and through last follow-up was 58.6%. Treatment-emergent, all causality side effects occurred in 17/34 of the subjects enrolled in the azithromycin maintenance regimen. Severe side effects were noted in 8/34 of these subjects. At least one intercurrent illness occurred in 32/34 of subjects and clinically significant laboratory abnormalities were noted in 19/29 subjects. There were no significant findings apparent during ophthalmologic exam. Conclusions In this study, azithromycin 600 mg once daily plus ethambutol was comparable to clarithromycin 500 mg bid plus ethambutol in the treatment of MAC infection in subjects with AIDS. Additionally, although the azithromycin 250 mg dose showed efficacy against MAC, the azithromycin 600 mg dose was superior bacteriologically and ultimately in its impact on prevention of mortality. Azithromycin 250 mg showed evidence of efficacy as maintenance therapy. The overall assessment of safety was very similar for the subjects receiving azithromycin 600 mg and those receiving clarithromycin despite the actual duration of therapy being 25% longer in subjects receiving azithromycin 600 mg. In general, all treatment regimens, i.e., azithromycin 600 mg, clarithromcyin 500 mg, azithromycin 250 mg treatment and maintenance, were well tolerated in this seriously ill patient population. H.3.B.2 Primary Supportive Studies Protocol 131 (U.S.) Study Objectives: This study was to determine whether azithromycin had any measurable efficacy in the treatment of Mycobacterium avium (MAC) bacteremia in -230-

32 Page 32 subjects with AIDS and to explore the safety profile of azithromycin when administered beyond a total of 1.5 gm. Study Design: This was an open-label, noncomparative pilot study of azithromycin 500 mg/day administered for 10 (Group A), 20 (Group B), or 30 (Group C) days to subjects with AIDS for treatment of MAC bacteremia. Subjects were to be enrolled into a longer duration of therapy group once there was clinical evidence that subjects had satisfactorily tolerated a shorter course of treatment. Subjects in Group C responding satisfactorily clinically after 30 days of therapy (with 50% increase in MAC colony count/ml of blood by the end of therapy) might extend therapy at a reduced dose of 250 mg azithromycin through day 84. Subjects were to be reevaluated both clinically and microbiologically at baseline and visit days 7, 14, 28, 56 and 84; additional clinical evaluations were made on days 21 and 42, and, for Group A subjects only, on days 3 and 10. Those satisfactorily completing extended therapy through day 84 (clinical improvement in signs/symptoms, 25% increase from baseline in MAC colony count/ml of blood) might continue on 250 mg azithromycin as suppressive therapy. Clinical and microbiologic evaluations were to be repeated monthly and at the end of therapy. For subjects taking concomitant zidovudine, serum zidovudine concentrations were to be determined to assess a potential interaction with azithromycin. Evaluation Groups: Azithromycin 500 mg Azithromycin 250 mg Enrolled (unique subjects) 29* 14 Entered (unique subjects treated) 29* 14 Completed Study 17 1 Evaluated for Sterilization: Intent-to-Treat 22** 10 Assessed for Safety: Side Effects 28*** 14 Laboratory Tests 26*** 14 * Four subjects were associated with six re-enrollments for a total of 35 PIDs ** Included if one or more visits post-baseline; 2 subjects had only baseline data *** One subject who did not return after the baseline visit was not assessed for side effects; three subjects did not have laboratory test data available after baseline Diagnoses and Criteria for Inclusion of Subjects: Male/female inpatients/outpatients with AIDS, 21 years old, with culture evidence of MAC infection. Prior to a protocol amendment which eliminated the requirement, subjects were also to be receiving concomitant zidovudine. Drug Administration: Dosage Form Dosing Duration Azithromycin 250 mg capsules (FID #YY , Lot #ED-G and ED-G ; FID #YY , Lot #ED-G ) single daily dose of 500 mg (primary) and 250 mg (extended/ suppressive therapy) (taken one hour before or two hours after a meal) 10, 20, 30 days (primary); >30-84 days (extended therapy), >84 days (suppressive therapy) Efficacy and Safety Evaluations: An intent-to-treat analysis was performed (first enrollment only). Bacteriologic endpoints were sterilization [zero colony count in blood], positive bacteriologic response [sterilization and/or reduction from baseline of 1 log (base 10) of MAC colony forming units], MAC colony count, and change from baseline in MAC colony count. Clinical endpoints were sponsor (based on fever, night sweats, weight -231-

33 Page 33 loss) and investigator (based on any sign/symptom) assessments of overall clinical response, investigator assessments of individual signs/symptoms (including but not limited to fever, night sweats, fatigue, weight loss), and Karnofsky performance status. Safety was assessed by incidences of side effects, laboratory test abnormalities, intercurrent illness; median changes from baseline in selected laboratory tests; and serious adverse events (including deaths). Serum azithromycin and zidovudine concentrations were also determined. Statistical Methods: No inferential statistics were performed because of the small numbers of subjects in each group. All endpoints are assessed across time based on observed cases. Descriptive statistics are used to display mean, median, and range of values for assessments of colony counts, actual weight change since baseline, and Karnofsky performance status; and to display the proportions of subjects experiencing all other bacteriologic and clinical endpoints. Mean colony counts for all intent-to-treat subjects were determined and plotted against time. Serum was assayed for azithromycin by HPLC-EC and for zidovudine by HPLC-UV. Efficacy Results: Primary Therapy with Azithromycin 500 mg Bacteriologic Endpoints Based on MAC Colony Count - Proportions of Subjects* Treated with 500 mg Azithromycin - Intent-to-Treat Analysis Day 7 Day 14 Day 28*** Endpoint N n Obs Rate (%) N n Obs Rate (%) N n Obs Rate (%) Sterilization Pos Bact Res Endpoint N Median N Median N Median Colony Count Change Count** Obs Rate=Observed Rate (n=subjects with endpoint); Pos Bact Res=Positive Bacteriologic Response; Total of Treatment Duration Groups A, B, C; ** Change from baseline in MAC colony count (log base 10), with median baseline 2.0 cfu/ml; *** Assessments for Day 28 were made for Group C only Clinical Endpoints - Satisfactory Response* Proportions of Subjects** Treated with 500 mg Azithromycin - Intent-to-Treat Analysis Day 7 Day 14 Day 28*** Endpoint N n Obs Rate (%) N n Obs Rate (%) N n Obs Rate (%) Sponsor Assessment Investigator Assessment Obs Rate=Observed Rate (n=subjects with endpoint); *Sponsor=complete/partial ( 1 sign/symptom) resolution, Investigator= response (substantial improvement) since no subjects were cured ; ** Total of Duration Groups A, B, C; ***Assessments for Day 28 were made for Group C only Extended/Suppressive Therapy with Azithromycin 250 mg Bacteriologic Endpoints Based on MAC Colony Count During Maintenance Therapy* - Intent-to-Treat Analysis Day 56 Day 84 Day 114 Day 144 Endpoint N n Obs Rate N n Obs Rate N n Obs Rate N n Obs Rate Sterilization Pos Bact Res Endpoint N Median N Median N Median N Median Colony Count Change Count** Obs Rate=Observed Rate (%) (n=subjects with endpoint); Pos Bact Res=Positive Bacteriologic Response; * Included subjects in Group C only; ** Change from baseline of primary treatment phase in MAC colony count (log base 10) -232-

34 Page 34 Clinical Endpoints - Satisfactory Response* During Maintenance Therapy** - Intent-to-Treat Analysis Day 56 Day 84 Day 114 Day 144 Endpoint N n Obs Rate N n Obs Rate N n Obs Rate N n Obs Rate Sponsor Investigator Obs Rate=Observed Rate (%)(n=subjects with endpoint);* Sponsor=complete/partial ( 1 sign/symptom) resolution, Investigator= continued improvement since no subjects were assessed with no evidence of disease ; ** Group C subjects only Safety Results: Azithromycin Number of subjects with: 500 mg 250 mg Treatment-emergent side effects (a/c)* 20/28 (2) 10/14 (0) Treatment-emergent side effects (t/r)** 19/28 (2) 9/14 (0) Clinically significant laboratory abnormalities 20/26 (0) 10/14 (2) * a/c = all causality, **t/r = treatment-related; ( ) = Resulting in discontinuation of study Summary and Conclusions: This first study of MAC therapy with azithromycin demonstrated that when given over brief intervals as monotherapy, signficant reductions in the circulating burden of M. avium, as well as clinically meaningful reductions in symptoms associated with MAC, can be achieved. However, conclusions are limited by the small numbers of subjects involved. In the intent-to-treat analysis of all treatment duration groups combined, the proportions of subjects who were sterile and who had a positive bacteriologic response appeared to increase gradually with longer duration of therapy. For example, of those subjects who received suppressive therapy with 250 mg azithromycin, 42.9% of subjects were sterile and 71.4% of subjects had a positive bacteriological response by visit day 114. Similarly, median decreases from baseline in colony counts were sustained through the follow-up period. Approximately 88% of subjects had a sponsor s assessment of a satisfactory response at both days 7 and 14, with respective rates of complete resolution of 27.8% and 56.3%. At the day 28 assessment point, 63.6% of subjects had a satisfactory response (36.4% with complete resolution). Clinical improvement was substantiated by the investigator s assessment, but in that analysis no subjects were cured at any timepoint. Based on the investigator s assessment of signs/symptoms, there was evidence of a positive effect on fever, night sweats, weight loss, and fatigue during primary and extended/ suppressive therapy. However, the sponsor s assessment of mean weight loss from baseline using actual weights did not suggest a beneficial effect of azithromycin therapy, although more than 50% of subjects experienced improvement in the sign/symptom of weight loss at day 14. Overall, the strongest positive effect was seen with fever and night sweats. In the 500 mg group, 6.9% (2 of 29) of subjects discontinued for reasons considered by the investigator to be related to study treatment (both due to side effects), and 14.3% (2 of 14) of subjects in the 250 mg group discontinued for treatment-related reasons (both due to laboratory test abnormalities). In both dose groups, the investigator considered the majority of treatment-emergent side effects related to study treatment (67.9% at 500 mg, 64.3% at 250 mg), with those of the digestive system predominant (60.7% and 50.0%, respectively). Most side effects were mild or moderate in severity. Two subjects receiving 500 mg azithromycin discontinued for side effects (1 nausea, 1 abdominal pain), both considered treatment-related

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36 Page 36 Drug Administration: Dosage Form Azithromycin 300 mg lactose-free tablets (FID #YY , lot #ED-G , ED-G , ED-G ; and FID #G00021AA, lot #ED-G , ED-G , ED-G , ED-G ). Dosing 600 mg or 1200 mg single daily dose (taken at least one hour before or two hours after a meal) Duration 6 weeks Efficacy and Safety Evaluations: Evaluable and intent-to-treat analyses were performed. Bacteriologic endpoints were sterilization [zero colony count in one blood culture; primary], positive bacteriologic response [reduction from baseline of 1 in log (base 10) of MAC colony forming units], MAC colony count (log base 10), and change from baseline in MAC colony count (log base 10). Clinical endpoints were sponsor (based on fever, night sweats, weight loss) and investigator (based on any sign/symptom) assessments of overall clinical response, investigator and subject assessments of individual signs/symptoms (including but not limited to fever, night sweats, fatigue, weight loss), Karnofsky performance status, and laboratory tests (alkaline phosphatase, hemoglobin, CD4 count, total lymphocyte count). Safety was assessed by incidences of side effects, laboratory test abnormalities, intercurrent illness; median changes from baseline in selected laboratory tests; and serious adverse events (including deaths). Serum drug concentrations were also determined. Statistical/Analytical Methods: Bacteriologic and clinical endpoints were compared between azithromycin groups by 95% confidence intervals on the difference in observed rates (sterilization, positive bacteriologic response, satisfactory/complete clinical response) or least squares (LS) mean scores (assigned to responses for all other endpoints). P-values were generated to compare groups using the Cochran-Mantel-Haenszel (CMH) statistic (based on Ridit scores) or a t-test based on a mixed effect model. The primary timepoint was visit week 6. Serum was assayed for azithromycin concentrations by HPLC- EC, with µg/ml as the lower limit of quantification. Efficacy Results: Bacteriologic Endpoints Based on MAC Colony Count (Log Base 10) Week 6 Azithromycin 600 mg Azithromycin 1200 mg Evaluable Subgroup Analysis Endpoint N Obs Rate (%) +++ N Obs Rate (%) % CI on Difference* CMH** p-value Sterilization , Pos Bact Res , N LS Mean (cfu/ml) N LS Mean (cfu/ml) 95% CI on Difference* p-value*** Colony Count , Change Count , Intent-to-Treat Analysis Endpoint N Obs Rate (%)+++ N Obs Rate (%)+++ 95% CI on Difference* CMH** p-value Sterilization , Pos Bact Res , N LS Mean (cfu/ml) N LS Mean (cfu/ml) 95% CI on Difference* p-value*** Colony Count , Change Count , Pos Bac Res=Positive Bacteriologic Response; Obs Rate=Observed Rate; LS =Least Squares; CI=Confidence Interval * Difference (1200 mg-600 mg); ** Cochran-Mantel-Haenszel statistic (based on Ridit scores); *** derived from t-test based on mixed effect model; + sterilization is based on one negative culture; ++ change from baseline in MAC colony count (log base 10), with baseline counts of approximately 2.0 cfu/ml in each group; +++ observed rate based on number of subjects -235-

37 Page 37 Clinical Endpoints 1) Satisfactory Response + Rates and 2) Change in Weight (kg) from Baseline -- Week 6 Azithromycin 600 mg Azithromycin 1200 mg Evaluable Subgroup Analysis Endpoint N Obs Rate (%) N Obs Rate (%) 95% CI on Difference* CMH** p-value Sponsor Assessment , Investigator Assessment , Fever , Night Sweats , N LS Mean (kg) N LS Mean (kg) 95% CI on Difference* p-value*** Weight Loss**** , Intent-to-Treat Analysis Endpoint N Obs Rate (%) N Obs Rate (%) 95% CI on Difference* CMH** p-value Sponsor Assessment , Investigator Assessment , Fever , Night Sweats , N LS Mean (kg) N LS Mean (kg) 95% CI on Difference* p-value*** Weight Loss**** , Obs Rate=Observed Rate (% subjects); LS=Least Squares; CI=Confidence Interval + Complete/partial response (sponsor/investigator 4-point assessments) and normal/improved (fever, night sweats); * Difference (1200 mg-600 mg); ** Cochran-Mantel-Haenszel (CMH) statistic (based on Ridit scores); *** t-test based on mixed effect model; **** Change in weight (kg) from baseline Safety Results: Azithromycin Number of subjects with: 600 mg 1200 mg Treatment-emergent side effects (a/c)* 24/39 (4) 37/47 (4) Treatment-emergent side effects (t/r)** 21/39 (4) 32/47 (2) Clinically significant laboratory test abnormalities 25/36 (1)** 32/45 (1) * a/c = all causality, t/r = treatment-related; ( ) = Resulting in discontinuation of study ** actual discontinuation based on the potassium value for the subject being low at baseline Summary and Conclusions: In the evaluable subgroup, the observed rates of sterilization (one negative blood culture) were not statistically significantly different between the randomized 600 mg and 1200 mg azithromycin groups at any timepoint. Similarly, the observed mean rates of a positive bacteriologic response, the mean MAC colony counts (log base 10), and the mean changes from baseline in colony counts (log base 10) were not statistically significantly different between the two azithromycin groups at any timepoint. Results from the intent-to-treat analyses of these endpoints were comparable. In an analysis of sterilization by race, there were too few subjects within each racial group to draw meaningful conclusions. The MIC90 of baseline isolates was 64 µg/ml. In the evaluable subgroup analysis of the sponsor s assessment of clinical response, subjects experiencing a satisfactory clinical response were not statistically significantly different between the two azithromycin groups at any timepoint. At week 6, 23.5% (4 of 17) of subjects in the 600 mg group and 15.8% (3 of 19) subjects in the 1200 mg group were completely cured (95% CI -33.8, 18.3, p=1.000). In the investigator s assessment, satisfactory response rates overall tended to be greater than in the sponsor s assessment, but statistically similar between the 600 mg and 1200 mg groups. Additionally, satisfactory response rates for fever and night sweats, as well as mean weight losses from baseline, were not statistically significantly different between the two azithromycin groups. Results from the intent-to-treat analyses of these endpoints were generally comparable. Overall, the strongest positive clinical effect was seen with fever and night sweats; there was no positive effect on weight loss

38 Page 38 Following daily oral doses of 600 mg or 1200 mg azithromycin, serum concentrations from most subjects fell within or above the range of concentrations anticipated from serum concentrations in normal subjects following single doses. The results suggest that absorption in HIV-positive subjects with MAC is generally not decreased by the disease state and will not result in unexpectedly low concentrations. In the 600 mg group, 9.8% (4 of 41) of subjects discontinued for reasons considered by the investigator to be related to study treatment (all due to side effects), compared to 6.4% (3 of 47) of subjects in the 1200 mg group (2 side effects, 1 lack of efficacy). The incidence of subjects with one or more treatment-emergent side effects was lower in the 600 mg group (61.5%) compared to the 1200 mg group (78.7%). The investigator considered the majority of these to be related to study treatment (53.8% of subjects in the 600 mg group, 68.1% of subjects in the 1200 mg group). Related side effects of the digestive system predominated. In the 600 mg group, 10 of 13 digestive system side effects were mild and 3 moderate in severity. In the 1200 mg group, 11 of 26 digestive system side effects were mild, 13 moderate, and 2 severe (both diarrhea). Discontinuations for treatment-related side effects were reported for 9.8% (4) of subjects receiving 600 mg and 4.3% (2) of subjects receiving 1200 mg. Two other subjects in the 1200 mg group discontinued for side effects considered unrelated to study treatment. Temporary discontinuations/reductions in dose for side effects were more frequent in the 1200 mg group (29.8%) than the 600 mg group (7.3%). Intercurrent illness was reported for 58.5% of subjects receiving 600 mg and 61.7% of subjects receiving 1200 mg. The incidence of subjects with one or more clinically significant laboratory test abnormalities was 69% in the 600 mg group and 71% of subjects in the 1200 mg group. Hematologic and liver function tests were most common. Overall, the incidences of specific test abnormalities were generally similar between groups, except for somewhat greater incidences of decreased hemoglobin, hematocrit, lymphocytes, and potassium in the 600 mg group versus the 1200 mg group. One subject per group discontinued the study for laboratory test abnormalities the investigator considered unrelated to study drug. Overall, 43 cases of serious adverse events (including deaths) were reported for 34 subjects; the investigator considered two in each azithromycin group probably or possibly related to study drug. Overall, 11 subjects in the 600 mg group and 7 in the 1200 mg group died. Of these, ten deaths occurred during or within 35 days of the end of therapy. No deaths were attributed to study drug by the investigator, but most to progression of AIDS and associated conditions and opportunistic diseases, including MAC. Overall, four of all deaths were the cause for discontinuing the study. In conclusion, azithromycin, at either dose, showed bacteriologic and clinical efficacy against MAC. A single 600 mg daily dose of azithromycin was equally efficacious, but better tolerated, than a single 1200 mg dose when administered chronically for six weeks for treatment of disseminated MAC infection in subjects with AIDS. H.3.B.3 Supportive Compassionate Use Studies Protocol 162/162X/148B (U.S.) Study Objectives: The purpose of study 162/162X/148B was to evaluate the efficacy and safety of azithromycin when administered chronically for the treatment of M. avium bacteremia in patients failing or intolerant of currently available MAC therapy -237-

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40 Page 40 Duration Indefinite based on clinical response and quantitative blood cultures. Efficacy and Safety Evaluations: Both microbiological and clinical intent-to-treat efficacy analyses were performed. Two types of efficacy analyses were performed to address missing data, i.e., last observation carried forward (LOCF) analysis and observed cases (OC) analysis, for both the primary sterilization endpoint and the investigator s assessment of clinical response. All other analyses were OC only. Microbiological endpoints included sterilization (primary, defined as one negative MAC blood culture), time to sterilization (defined as time from baseline to first negative MAC blood culture), change in colony count (cfu/ml, log base 10) since baseline, and colony count (cfu/ml, log base 10). Subjects who had a negative MAC blood culture at baseline were excluded from these analyses. In addition, time to first positive MAC blood culture after sterilization (based on data from 162/162X/148B) was also examined. Clinical endpoints included overall assessment of clinical response, change in weight since baseline and time to death in addition to other specific signs and symptoms. Laboratory parameters utilized as indicators of efficacy included CD4 count, alkaline phosphatase and hemoglobin. Safety was assessed by incidences of side effects, laboratory test abnormalities, intercurrent illnesses, median changes from baseline in selected laboratory tests and serious adverse events including deaths. Statistical Methods: Subjects were categorized into two groups based on the route of administration, Oral only and IV with or without Oral. Efficacy and safety data were summarized for each of these two categories. Bacteriologic and clinical endpoints were assessed by summarization across time. For time-to event-endpoints, Kaplan-Meier plots and summary statistics were provided. Efficacy Results: In general, both bacteriologic and clinical assessments of efficacy were indicative of beneficial responses to azithromycin. However, due to the duration of the study and the nature of the subject population, the number of evaluable subjects declines throughout the study. Consequently, assessments of efficacy must be made with care due to the potential effects of a declining subject pool. All bacteriologic endpoints indicated a favorable therapeutic response to azithromycin. Both the OC and LOCF analysis of blood culture sterilization revealed that sterilization often occurred relatively rapidly, i.e., within the first month, and rates continued to improve for up to three months of therapy. Overall, approximately 40%-60% of all subjects had a favorable response. Median time to sterilization for all subjects was 57 days with an observed sterility rate of 48.2%. The beneficial response was durable, i.e., median time for all subjects combined to first positive culture after sterilization was 259 days while the rate of relapse was 32.6%. Colony counts and changes in colony counts followed this same general pattern. Clinical endpoints often indicated a beneficial therapeutic response also. Investigator assessments of clinical response categorized approximately one-half to two-thirds of all subjects as slightly, moderately or markedly improved during the first three to six months of the study. This favorable response then appears to diminish. During the first portion of the study approximately 10%-15% of the subjects are categorized as slightly, moderately or markedly deteriorated. This deterioration affects 20-30% of the subjects during the latter part of the study. Approximately one quarter of the subjects are categorized as having no change in status throughout the study. The incidence rate for fever (>100.5 F) declined throughout the study from approximately 15% to less than 6 %. Both mean and median hemoglobin increased throughout the duration of the study by approximately 1 G/DL

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