Effect of Verapamil on the Pharmacokinetics of Pasireotide in Healthy Volunteers

Transcription

1 Drug Interactions Effect of Verapamil on the Pharmacokinetics of Pasireotide in Healthy Volunteers The Journal of Clinical Pharmacology 54(11) The Authors. The Journal of Clinical Pharmacology Published by Wiley Periodicals, Inc. on behalf of The American College of Clinical Pharmacology DOI: /jcph.325 Ruediger Kornberger, MD 1, Lillian S.L. Ting, PhD 2, Anadya P. Tripathi, Msc Health Statistics 3, Heidi Rodrigues, BA 2, Dalal Nesheiwat, PharmD 2, Vanessa Q. Passos, MD, PhD 2, and Ke Hu, PhD 2 Abstract We evaluated the drug-drug interaction between pasireotide SC and verapamil, a known P-glycoprotein inhibitor. Subjects received pasireotide SC (single dose, 600 mg) on day 1, and samples for pharmacokinetics evaluation were collected from days 1 to 8. Subjects received an oral dose of verapamil 240 mg/d for 10 days (days 15 24). On day 18, subjects also received pasireotide SC 600 mg. Pharmacokinetic sampling for pasireotide SC and verapamil was done during days 18 to 25 and days 15 to 21, respectively. Safety evaluations were performed throughout the study period, including a 30-day post-treatment follow-up. Pharmacokinetic profiles of pasireotide SC alone and in combination with verapamil sustained-release (SR) were superimposable with the geometric mean ratios (90% confidence interval [CI]) of 0.98 ( ) for C max, 0.97 ( ) for AUC last, and 0.98 ( ) for AUC inf. Exploratory analyses showed a 17% (90% CI, ) reduction in C trough and 31% ( ) reduction in C max (8 hours post-dose) for verapamil SR with pasireotide SC versus verapamil alone. Pasireotide SC with or without verapamil was well tolerated. In conclusion, there was no change in the rate of pasireotide absorption and elimination or extent of exposure following concomitant administration with verapamil. Keywords drug-drug interaction, pasireotide, P-gp inhibitor, verapamil, pharmacokinetics Pasireotide (SOM230), a second-generation, multireceptortargeted somatostatin analogue (SSA), exhibits a unique binding profile with higher binding affinity to four of the five known human somatostatin receptor subtypes sst 1,2,3 and sst 5. 1,2 Due to its unique binding profile, pasireotide has shown promising results in patients with gastroenteropancreatic neuroendocrine tumors, acromegaly, and Cushing s disease. 3 7 The pasireotide subcutaneous (SC) formulation is indicated in patients with Cushing s disease for whom pituitary surgery is not an option or surgery has not been curative, 8 and as of December 2013, it has been approved in 50 countries. In patients with Cushing s disease and acromegaly, pasireotide SC demonstrates a dose-proportional and time-independent pharmacokinetic (PK) profile at a dose range of 300 to 1200 mg. 5,8 11 Pasireotide SC has shown a linear PK with acceptable safety and tolerability within a dose range from 2.5 to 1500 mg in healthy volunteers. 8 The PK profile of pasireotide SC in healthy volunteers exhibits rapid absorption (T max, h), low clearance (CL/F, ~8 9 L/h), large volume of distribution (V z /F >100 L), and effective half-life (T 1/2 eff, ~12 hours, based on area under curve [AUC] accumulation ratio with once-daily dosing for 14 days) with favorable tolerability in a single- or multiple-dose regimen. 8 10,12 Results from human PK studies indicate that pasireotide, when administered subcutaneously, is mainly eliminated via the liver with a minimal renal contribution. 13 Pasireotide has low passive permeability and is likely to be a substrate of P-glycoprotein (P-gp). 8 Preclinical data indicate that pasireotide is a potential Abbreviations: AE, adverse event; AESI, adverse event of special interest; AUC, area under curve; AV, atrioventricular; BMI, body mass index; CI, confidence interval; CTCAE, Common Terminology Criteria for Adverse Events; CV, coefficient of variation; ECG, electrocardiogram; EDTA, ethylenediaminetetraacetic acid; IR, immediate release; LC/MS/MS, liquid chromatography-tandem mass spectrometry assay; LLOQ, lower limit of quantification; P-gp, p- glycoprotein; RIA, radioimmunoassay; SAE, serious adverse event; SC, subcutaneous; SR, sustained-release; SSA, somatostatin analogue; ULOQ, upper limit of quantification. 1 Parexel International GmbH, Berlin, Germany 2 Novartis Pharmaceuticals Corporation, East Hanover, NJ, USA 3 Novartis Healthcare Pvt. Ltd., Raheja Mind Space, Hitech City, Madhapur, Hyderabad, India This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. Submitted for publication 28 February 2014; accepted 18 March Corresponding author: Ke Hu, Novartis Pharmaceutical Corp, One Health Plaza, East Hanover, NJ, 07936, USA mike.hu@novartis.com Trial Registration: EudraCT no

2 1264 The Journal of Clinical Pharmacology / Vol 54 No 11 (2014) P-gp substrate the only transporter that is expected to be involved in the distribution and/or elimination of pasireotide. 14 Thus, when administered concomitantly, a drug-drug interaction between pasireotide and P-gp inhibitor is likely. If such an interaction occurs, then it would lead to an increased exposure of pasireotide following coadministration with a P-gp inhibitor. The potential for drug-drug interaction of pasireotide and P-gp inhibitors has not been examined previously in humans. Verapamil is a strong P-gp inhibitor and it has been demonstrated that concomitant administration of verapamil increases the exposure of the P-gp substrate. 15 Therefore, in the present study, we aimed to investigate the potential for drug-drug interaction when pasireotide SC is used in combination with oral verapamil, a known P-gp inhibitor. Methods This study was conducted in compliance with the ethical principles set out in the Declaration of Helsinki and with Good Clinical Practice. The study protocol and all amendments were reviewed and approved by the Independent Ethics Committee for the study center (Ethik-Kommission des Landes, Berlin, Germany). Written informed consent from each volunteer was obtained prior to any study-related screening. Study Population As per the study plan, a total of 21 healthy male volunteers were to be enrolled to obtain a minimum of 17 evaluable healthy volunteers to complete the study. Healthy male volunteers, aged 18 to 55 years, with normal vital signs (blood pressure, pulse rate, and body temperature) after 5 minutes at rest and measured in the supine position, and with a body mass index (BMI) between 19 and 29.9 kg/m 2 were eligible for the study. Volunteers had to be able to swallow the verapamil tablet, communicate well with the investigator, comply with the requirements of the study procedures, and provide written informed consent. Exclusion criteria included clinically important drug allergies; a history of cardiac arrhythmias, syncope or risk factors for torsades de pointes; a screening QTcF >450 ms; concomitant diseases or medications that could prolong the QT interval; significant illness or use of prescription (including CYP3A isozyme [cytochrome P450 system 3 A isoenzyme] inducers, CYP3A inhibitors, grapefruit juice, HMG CoA reductase inhibitors) or over-the-counter drugs (such as aspirin, St. John s wort) within 2 weeks of study drug dosing; participation in any clinical investigation within 4 weeks of dosing; donation or loss of 400 ml of blood within 8 weeks of dosing; surgical or medical conditions that may significantly alter the absorption, distribution, metabolism, or excretion of any drug; evidence of liver, gallbladder, gastrointestinal, or chronic bronchospastic disease; pancreatitis; type 1 or 2 diabetes mellitus; impaired glucose tolerance; or history of smoking and/or drug or alcohol abuse. Study Design This was a phase 1, open-label, single-sequence, crossover study. The primary objective was to determine the effect of daily 240 mg oral verapamil sustained-release (SR) tablet administered with food on the PK of a single dose of pasireotide 600 mg SC formulation in healthy male volunteers. The secondary objective was to assess the safety of pasireotide SC formulation when administered alone or concomitantly with the verapamil SR formulation. The exploratory study objectives were to assess the effect of pasireotide SC on the PK of verapamil SR and immediate release (IR) formulations, the effect of verapamil IR formulation on the PK of pasireotide SC, and the safety of pasireotide SC formulation when administered alone or with the verapamil IR formulation. This study enrolled only healthy male volunteers to avoid a potential sex effect and to be consistent with the majority of other phase 1 studies for the pasireotide SC formulation. 12,16 Under the original protocol, the IR formulation of verapamil (240 mg once daily) was administered. The rationale for selecting IR formulation was to achieve higher PK exposure (C max ) for verapamil and attain maximum inhibition of P-gp in the liver to evaluate potential drug-drug interaction between pasireotide SC and verapamil. However, the study was placed on hold because of high frequency of AV blocks observed with verapamil IR. After investigation, the protocol was amended to change the verapamil IR formulation to SR formulation. Following the change in verapamil formulation, an additional 21 volunteers were recruited, in addition to the 21 volunteers originally recruited in the study. Volunteers administered the IR or SR formulations are referred to as the IR cohort or SR cohort, respectively. All subjects were scheduled to participate in a screening phase (days 28 to 2), followed by a treatment phase of 24 days (Figure 1). On day 1, each subject received a single dose of pasireotide SC 600 mg (~30 minutes after breakfast, standard low-fat meal). PK samples were collected from days 1 to 8 at pre-specified time points. This 7-day sampling was appropriate to capture the complete PK profile in consideration of the long half-life of the terminal phase of PK profile following SC administration (32 66 hours for mg and hours for mg). 10,12 For pasireotide SC, the AUC contribution of the terminal phase to AUC inf was minimal, and has been reported in the range of 7% to 15%, 10,12 with an effective half-life of approximately 12 hours. 8,9 A washout period until day 14 was allowed after the

3 Kornberger et al 1265 Verapamil SR PK: 0 to 8 h Verapamil IR PK: 0 to 2 h (Days 15 to 21) Pasireotide PK: 0 to 168 h (Days 1 to 8) Pasireotide PK: 0 to 168 h (Days 18 to 25) Day -28 Day 1 Day 8 Day 15 Day 18 Day 21 Day 25 Day 55 Day 1: Pasireotide SC 600 µg single dose Day 18: Pasireotide SC 600 µg single dose Day 25: End of treatment Day 55: End of study Screening phase days -28 to -2 Washout period, days 9 to 14 Verapamil daily dose, days 15 to 24 Safety follow-up, days 25 to 55 Figure 1. Study design for a phase 1 evaluation of pasireotide SC administered alone or with verapamil SR (21 subjects) or IR (21 subjects). pasireotide PK sampling to ensure the complete elimination of pasireotide, and was considered sufficient because it represented more than five effective half-lives of pasireotide SC. 9,17 Following the washout period, verapamil (verapamil IR 120 mg two tablets once daily with 200 ml noncarbonated water in a fasting state for the IR cohort or verapamil SR 240 mg once daily ~30 minutes after breakfast for the SR cohort) was administered to the subjects for 10 days (days 15 24). For the verapamil tablet, subjects were instructed not to chew the medication and, instead, to swallow the tablet whole. Serial PK sampling was performed at pre-specified time points for both verapamil and norverapamil assessments. Subjects received verapamil alone on 3 days (days 15 17); on day 18, a single injection of pasireotide SC 600 mg was administered after verapamil dosing (within 5 minutes). From days 18 to 25, PK sampling for pasireotide SC was performed at pre-specified time points to determine the PK profile of pasireotide SC with verapamil coadministration. PK sampling for verapamil was also performed from days 15 to 21 to monitor verapamil trough and peak concentrations. The 3-day dosing with verapamil alone following the washout period was considered sufficient to reach steady state for verapamil, as the approximate halflife of verapamil is 2.8 to 7.4 hours (IR formulation) 18 or 8.6 to 10.6 hours (SR formulation). 19 On day 25, an end-of-treatment visit was performed for safety evaluations and pasireotide PK sampling. A 30-day safety follow-up was then performed on day 55, the endof-study visit. Besides the study drugs (pasireotide and verapamil), no other concomitant medication was allowed from 14 days prior to the first dose until the end-of-study evaluations, except for the treatment of adverse events (AEs). If subjects required treatment with a concomitant medication, the decision to discontinue the subject from the study was evaluated on a case-by-case basis. Pharmacokinetic Assessments For pasireotide, venous blood samples were collected from days 1 to 8 and days 18 to 25 at pre-dose and 0.25, 0.5, 1, 2, 4, 8, 12, 24, 48, 72, 96, 120, 144, and 168 hours post-dose. For verapamil, venous blood samples were collected at pre-dose (C trough ) and 2 hours post-dose (C max for the IR cohort) or 8 hours post-dose (C max for the SR cohort) from days 15 to 21. Blood samples were collected in ethylenediaminetetraacetic acid (EDTA) tubes and centrifuged within 20 minutes at approximately 1000g between 3 ºC to 5 ºC for 10 minutes for plasma separation. Soon after centrifugation, the plasma was transferred into a polypropylene screw-cap tube. All PK samples were stored at a temperature of 18 C or less. For time points when only pasireotide samples were collected (days 1 8), a minimum of a 2.5 ml blood sample was collected to yield 1 ml of plasma for analysis of pasireotide concentration. A 3 ml blood sample was obtained to yield approximately 1.5 ml of plasma where only verapamil samples were collected. For sample times when both pasireotide and verapamil were tested, a minimum of 5.5 ml of blood was collected to yield 2.5 ml of plasma. The plasma was stored in two separate tubes; one tube with a 1 ml aliquot plasma sample to be used for pasireotide analysis, and the remaining 1.5 ml aliquot for verapamil and norverapamil analysis. The clock time of dosing and the sample-collection date and time were recorded. The plasma concentration-time data were used to derive PK parameters by noncompartmental method using WinNonlin software (Phoenix version 6.2; Pharsight, Mountain View, CA). For pasireotide, the following PK parameters were calculated: AUC from time zero to the last measurable concentration sampling time (AUC last ); AUC from time zero to infinity (AUC inf ); maximum (peak) observed plasma concentration after single-dose administration (C max ); time to reach

4 1266 The Journal of Clinical Pharmacology / Vol 54 No 11 (2014) maximum (peak) plasma concentration after single-dose administration (T max ); terminal elimination rate constant (l z ); elimination half-life (T1/2); total body clearance of drug from the plasma (CL/F); and apparent volume of distribution during terminal phase (V z /F). C max and C trough (minimum [trough] observed plasma concentration after single-dose administration) for verapamil and its metabolite (norverapamil) were also reported. Analytical Methods Pasireotide plasma sample concentrations were analyzed by AtlanBio Laboratories (Saint-Nazaire Cedex, France) using a validated radioimmunoassay (RIA) with a lower limit of quantification (LLOQ) and upper limit of quantification (ULOQ) of 0.15 and 2.5 ng/ml, respectively. The observed precision (% coefficient of variation [%CV]) was in the range of 3.9% to 12.1%, with percentage accuracy in the range of 98.9% to 103.7%. Precision was within the acceptable limit of CV 30% on triplicate concentration value. Both verapamil and its metabolite, norverapamil, were analyzed by WuXi AppTec Co. Ltd. (Shanghai, China) by using a validated, liquid chromatography-tandem mass spectrometry assay (LC/MS/MS) with LLOQ and ULOQ of 10 and 500 ng/ml, respectively. Precision and the percentage bias for all the calibration standards during the validation for verapamil and norverapamil were within the acceptable range ( 20.0% of the LLOQ and 15.0% of the other concentration levels). For verapamil, the precision (%CV) was in the range of 1.4% to 2.9% with the percentage bias from 3.6% to 3.8%. During the calibration for norverapamil, precision (%CV) was observed in the range of 1.8% to 3.7% with the percentage bias in the range of 3.4% to 4.0%. Safety Assessments Adverse events were recorded as they occurred, with severity graded according to the Common Terminology Criteria for Adverse Events (CTCAE) version 3.0 (grade 1, mild; grade 2, moderate; grade 3, severe; grade 4, lifethreatening/disabling). 20 Safety assessments consisted of monitoring and recording AEs and serious AEs (SAEs) with their severity and relationship to study drug; physical examination; laboratory evaluations including hematology parameters, blood chemistry, coagulation tests, thyroid function tests; urine drug, alcohol, and cotinine screening; and cardiac assessments, electrocardiogram (ECG), and QT-related cardiology consultation or Holter monitoring. For cardiac assessments, ECGs were collected in triplicate and reevaluated on study days 1, 15, and 18. If QTcF of 500 ms or a change from baseline in QTcF of >60 ms was observed at any visit, triplicate ECGs were taken approximately 1 hour after the initial ECG, each 2 to 3 minutes apart. The subject was discontinued from the study if the mean QTcF of the triplicate ECGs was 500 ms or the change from baseline in the mean QTcF of the triplicate ECGs was >60 ms. If a QTcF >480 ms occurred but was not confirmed, no further action was taken. If a QTcF >480 ms was confirmed, a cardiologist performed a thorough examination (such as reviewing baseline ECG and concurrent medications and performing a cardiovascular examination, including at least a cardiac auscultation) to assess the subject for cardiovascular risk factors. The subject was allowed to continue with the study on confirmation of the absence of acute cardiovascular risk factors. Statistical Analyses Sample size was calculated using log-transformed PK parameters. As the data on estimates of intrasubject variability from healthy subjects studies are lacking, the intrasubject %CV from an earlier study of pasireotide was used (38.5 for C trough [Novartis, data on file]) to estimate intrasubject %CV for this study. Assuming a %CV of 38.5, with a sample size of 17, the precision of the 90% confidence interval (CI) on the log-scale extended by from the observed mean difference of log PK. With an estimated 20% dropout rate, 21 participants were to be recruited to achieve a minimum of 17 evaluable volunteers. Baseline demographic and PK parameters (including T max, AUC last, AUC inf, T1/2, T max, CL/F,V z /F) of pasireotide alone or in combination with verapamil were summarized. For each of the PK parameters, descriptive statistics included the number of volunteers, mean, geometric mean, median, standard deviation, CV% geo-mean, minimum, and maximum values. For T max, median, minimum, and maximum values were calculated. The PK profiles of pasireotide were presented graphically with and without coadministration of verapamil SR. The PK parameters of the pasireotide SC formulation (C max, AUC last, and AUC inf ) were analyzed using a mixed effects model that included treatment (with and without verapamil) as a fixed effect and volunteer as a random effect following log-transformation. A point estimate and corresponding 90% CI for the difference between the least squares mean with and without coadministration of verapamil was calculated. This value was exponentiated to obtain the point estimate and the two-sided 90% CI for the ratio of the geometric means on the untransformed scale. Results Demographics and Disposition of Participants A total of 42 subjects were enrolled in this study, with 21 subjects in each of the cohorts (SR and IR cohorts). The mean age of the subjects was 42 (range, 26 54) years in the SR cohort and 37 (20 55) years in the IR cohort. All subjects in both cohorts were Caucasians; mean BMI was

5 Kornberger et al (range, ) and 24.9 ( ) kg/m 2 for the subjects in the SR and IR cohorts, respectively. All 42 subjects in both cohorts received the first dose of pasireotide SC (on day 1). In the SR cohort, 19 of the 21 subjects received all verapamil doses on days 15, 16, and 17; eighteen subjects received the second dose of pasireotide SC (day 18), and these subjects also received all subsequent verapamil doses as per the protocol (last dose on day 24). Of the 21 subjects enrolled in the IR cohort, 11 received verapamil on days 15 to 17; eight subjects also received the second pasireotide SC dose on day 18. None of the subjects in the IR cohort received all planned doses due to the study hold to address the emergence of a higher-than-expected prevalence of cardiac AEs related to the verapamil IR formulation. Pharmacokinetic Analysis SR cohort. In the SR cohort, 17 (81.0%) of 21 subjects were included in the PK analysis (3 subjects had discontinued the study [2 due to consent withdrawal and 1 lost to follow-up before complete PK sampling for the first period] and 1 subject vomited on day 18 within 8 hours of verapamil administration). PK profiles of pasireotide SC 600 mg alone and in combination with verapamil SR 240 mg were superimposable with a similar absorption, distribution, and elimination phase and with a median T max of approximately 0.5 hour (Figure 2). The values of the three primary PK parameters of pasireotide were similar for pasireotide SC alone or pasireotide SC plus verapamil SR (Table 1) groups. The geometric mean ratios (90% CI) for C max (0.98 [ ]), AUC last (0.97 [ ]), and AUC inf (0.98 [ ]) were all close to unity. No significant differences were observed in the secondary PK parameters for pasireotide SC with or without coadministration of verapamil SR (Table 2). Pasireotide plasma concentration (ng/ml) Pasireotide alone Pasireotide + Verapamil Time (h) Figure 2. Mean (SD) plasma concentration vs time profiles of pasireotide SC formulation in 17 healthy male subjects by treatment (pasireotide SC 600 mg alone or in combination with verapamil SR tablet 240 mg once daily). Exploratory analyses assessing the effect of pasireotide SC on verapamil SR concentration showed a 17% (90% CI, ) reduction in C trough and 31% (90% CI, ) reduction in C max (8 hours post-dose) compared with verapamil alone. The pattern of change in norverapamil concentrations following coadministration of verapamil SR with pasireotide SC was similar to that of verapamil. Concentrations on the following day returned to the levels observed prior to pasireotide coadministration (Figure 3). IR cohort. The C max for pasireotide SC 600 mg alone or in combination with verapamil IR (240 mg, once daily) overlapped. The verapamil IR concentration showed a decrease in C max (2 hours post-dose; geometric mean [% CV]) when administered in combination with pasireotide (234 ng/ml [31%] after administration of verapamil alone on day 17 vs 142 ng/ml [59%] after administration of verapamil IR plus pasireotide SC on day 18). In the IR cohort, C trough of verapamil increased by 6% when coadministered with pasireotide SC. No PK collection of verapamil or norverapamil was made after day 18 for further evaluation as the administration of verapamil IR was not done after day 18 due to study hold. The PK data obtained from the IR cohort (n ¼ 8) were not optimal to evaluate the drug-drug interaction between pasireotide SC and verapamil IR. Safety No subject died or experienced an SAE during the study. The AEs suspected to be related to study drug are reported in Table 3. The incidence of grade 3 or 4 AEs was relatively low in the SR cohort (3 subjects [143%]; 1 subject had grade 4 increased blood creatinine phosphokinase, 1 subject had grade 4 increased lipase, and 1 subject had grade 3 neutropenia), and there was none in the IR cohort. None of the subjects in the SR cohort experienced an AE leading to study drug discontinuation. In the IR cohort, 2 subjects discontinued the study due to AEs (second degree AV block and nodal rhythm). In the SR cohort, the most frequent AEs (as reported in 10% of subjects), regardless of study drug relationship, were headache (57.1%), nausea (47.6%), dizziness (33.3%), vomiting (23.8%), nasopharyngitis (23.8%), diarrhea (14.3%), and fatigue (14.3%); in the IR cohort, these were nausea (57.1%), headache (19.0%), nodal rhythm (14.3%), and AV block second degree (14.3%). During the study, the majority of subjects in the SR cohort (69%) experienced AEs of special interest (AESI; AEs either associated with the therapeutic indication or with the gained knowledge on the properties and mechanismofactionofthestudydrugs)withpasireotidesc.inthe SR cohort the most common AESI with pasireotide SC included nausea (47.6%), vomiting (23.8%), diarrhea (14.3%), and injection site erythema (14.3%); and those

6 1268 The Journal of Clinical Pharmacology / Vol 54 No 11 (2014) Table 1. Summary of Primary PK Parameters of Pasireotide SC Formulation in Healthy Male Subjects by Treatment (Pasireotide SC 600 mg Alone or in Combination With Verapamil SR Tablet 240 mg Once Daily, SR Cohort) Treatment Statistics C max (ng/ml) AUC last (ng h/ml) AUC inf (ng h/ml) Pasireotide SC (600 mg) alone N Mean SD Geo-mean CV% geo-mean* Min Max Pasireotide SC (600 mg) þ verapamil SR (240 mg) N Mean SD Geo-mean CV% geo-mean* Min Max AUC last, area under the curve from time zero to the last measurable concentration sampling time; AUC inf, area under the curve from time zero to infinity; C max, maximum plasma concentration; CV, coefficient of variation; Max, maximum; Min, minimum; SD, standard deviation; SR, sustained-release; SC, subcutaneous. *CV% geo-mean ¼ (sqrt [exp (variance for log transformed data)-1]*100) in the IR cohort included nausea (57.1%) and AV block second degree (14.3%). Of these, 2 subjects experienced grade 3 or 4 AESI (one subject with lipase increase and another with neutropenia) in the SR cohort; none of the subjects had grade 3 or 4 AESI in the IR cohort. The overall profile for laboratory evaluations in the SR cohort did not reveal clinically significant abnormalities in hematologic, coagulation, or biochemical parameters. A slight decrease in median glucagon levels from baseline to end-of-study was observed in the SR cohort, which returned to normal on the end-of-study follow-up. No clinically significant changes in vital signs were noted from baseline to end-of-study. None of the subjects in the SR cohort had a newly occurring QTcF of >480 ms or a change from baseline in QTcF of >60 ms. PR >200 ms was noted in 38.9% of subjects in the pasireotide SC plus verapamil SR group versus 9.5% in the pasireotide SC alone group. A heart rate (HR) <50 bpm was noted in 44.4% of subjects in the pasireotide SC with verapamil SR group as compared with 28.6% in the pasireotide SC alone Table 2. Summary of Secondary Pharmacokinetic Parameters of Pasireotide SC Formulation in Healthy Male Subjects by Treatment (Pasireotide SC 600 mg Alone or in Combination With Verapamil SR Tablet 240 mg Once Daily) Treatment Statistics T max (h) T1/2(h) CL/F (L/h) V z /F (L) l z (1/h) Pasireotide SC (600 mg) alone N Mean N/A SD N/A Median Geo-mean N/A CV% geo-mean* N/A Min Max Pasireotide SC (600 mg) þ verapamil SR (240 mg) N Mean N/A SD N/A Median Geo-mean N/A CV% geo-mean* N/A Min Max CL/F, clearance; CV, coefficient of variation; Max, maximum; Min, minimum; SD, standard deviation; T max, time to maximum plasma concentration; T 1/2, elimination half-life; Vz/F, volume of distribution; l z, terminal elimination rate constant. *CV% geo-mean ¼ (sqrt [exp (variance for log transformed data)-1]*100)

7 Kornberger et al 1269 a Verapamil plasma concentration (ng/ml) b Norverapamil plasma concentration (ng/ml) Day Day Figure 3. Mean (SD) trough (pre-dose) and peak (8 h post-dose) plasma concentrations of a) verapamil (17 subjects) and b) norverapamil (17 subjects) on days 15 to 21 following a concomitant administration with pasireotide SC on day 18 (SR cohort). group. None of the subjects had abnormal findings in gallbladder imaging at screening, and 1 subject presented with new gallstones at end-of-study follow-up in the SR cohort. Five subjects in the IR cohort experienced AEs of grade 1 or 2 (that is, AV block second degree and/or nodal rhythm), which led to study drug discontinuation in 2 subjects. Of these 5 subjects, 3 withdrew consent prior to the second dosing of pasireotide SC. These events were considered as not related to pasireotide by the investigator. Discussion The results clearly demonstrate no change in the rate or extent of pasireotide SC bioavailability with coadministration of verapamil SR, and indicate that orally administered P-gp inhibitors do not impact the absorption, distribution, and elimination of pasireotide following SC administration. The PK profiles of pasireotide SC 600 mg given alone were similar to the profiles when given in combination with the P-gp inhibitor verapamil SR 240 mg, as indicated by the overlapping concentrationtime profiles. Geometric mean ratios and the 90% CI of primary PK parameters (C max,auc last, and AUC inf )of pasireotide based on a linear mixed effects model were all close to unity. The median T max of pasireotide remained at 0.5 hour post-dose, and the secondary PK parameters of pasireotide, including T1/2, CL/F, and V z /F, were also similar between treatments (pasireotide SC alone vs pasireotide SC plus verapamil SR). Previously, studies have suggested that the clinical relevance of P-gp drug interactions alone on pharmacokinetics is limited, even for the sensitive P-gp probe substrates such as digoxin It is recognized that P-gp interactions with a significant impact on pharmacokinetics are mostly limited to the gastrointestinal tract. Only a few interactions are observed in the liver and kidneys. If they occur, they are often confounded by inhibitions of cytochrome P450 enzymes. 22 Since pasireotide is administered subcutaneously and is mainly eliminated unchanged via the liver, the absence of any drug-drug Table 3. Drug-Related Adverse Events (With Frequency >5%) SR cohort (N ¼ 21) IR cohort (N ¼ 21) All subjects (N ¼ 42) Nausea, n (%) 10 (47.6) 12 (57.1) 22 (52.4) Headache, n (%) 11 (52.4) 4 (19.0) 15 (35.7) Dizziness, n (%) 6 (28.6) 2 (9.5) 8 (19.0) Vomiting, n (%) 5 (23.8) 1 (4.8) 6 (14.3) Fatigue, n (%) 3 (14.3) 1 (4.8) 4 (9.5) AV block, second degree, n (%) 0 3 (14.3) 3 (7.1) Nodal rhythm, n (%) 0 3 (14.3) 3 (7.1) Diarrhea, n (%) 3 (14.3) 0 3 (7.1) Feces discolored, n (%) 2 (9.5) 1 (4.8) 3 (7.1) Injection site erythema, n (%) 3 (14.3) 0 3 (7.1) Injection site pruritus, n (%) 2 (9.5) 0 2 (4.8) Dizziness postural, n (%) 2 (9.5) 0 2 (4.8) AV, atrioventricular.

8 1270 The Journal of Clinical Pharmacology / Vol 54 No 11 (2014) interaction with the P-gp inhibitor verapamil in the present study was in agreement with the former observation that clinically important interactions at the P-gp level are generally not expected. We observed lower verapamil exposure when it was coadministered with pasireotide SC. The change seen in verapamil and norverapamil concentrations is not likely to be clinically significant considering the higher observed variability of verapamil concentrations. A chronic administration of 120 mg verapamil exposure every 6 hours gives a bioavailability within the range from 20% to 35% (1.75-fold difference; due to rapid biotransformation of verapamil during first-pass metabolism) and a wide range of plasma levels of 125 to 400 ng/ml (a 3-fold difference). 18 The reported T max of verapamil SR is 7.7 hours, 18 but the variability in T max has also been observed in different studies (3 10 hours 19,24,25 ). Further, it is worth noting that only two time points (pre-dose and 8 hours post-dose) were measured in the current study; therefore, with a single concentration at 8 hours post-dose, the C max was an approximation and might not have been captured accurately. In addition, the relationship of verapamil concentration and prolongation of the PR interval disappears upon chronic administration, and no relationship has been established between verapamil concentrations and blood pressure reduction. 18 Therefore, modest changes in PK exposure, as observed in the present study, do not impact clinical outcomes of verapamil when administered concomitantly with pasireotide SC. Nevertheless, the impact of pasireotide SC on verapamil PK was not conclusively demonstrated, and should be interpreted with caution as this study was not designed to evaluate verapamil PK and the total exposure (ie, AUC) of verapamil could not be determined. If deemed necessary for clinical efficacy, a dosage uptitration for verapamil according to the product label could be considered to overcome the reduction of C min and C max following coadministration with pasireotide SC. 18 We investigated the impact of verapamil on pasireotide PK at the highest tolerable dose strength (240 mg), as verapamil is a reversible competitive inhibitor of P-gp and maximum inhibition depends on the peak concentration achieved. In the exploratory analysis of the IR cohort (where C max was approximately 2-fold higher than the SR formulation), no difference was observed for pasireotide PK with or without verapamil suggesting changes in pasireotide PK are unlikely with higher dosages of verapamil. However, the study did not evaluate an impact of verapamil dosage up-titration on pasireotide PK, and the results should be interpreted cautiously. Pasireotide SC, when administered alone and in combination with verapamil, was generally well tolerated by healthy participants. The overall safety results in this study were similar to the known safety profile of pasireotide, with no deaths or SAEs reported. The most frequent AEs in the SR cohort were headache, nausea, dizziness, vomiting, and nasopharyngitis. In the IR cohort, the most frequent AEs were nausea and headache. As the cardiac AEs in the IR cohort presented in a high frequency (5 out of 11 subjects), the study was put on hold and the protocol was amended to change the verapamil formulation. As PR-interval prolongation is correlated with verapamil plasma concentrations, a lower C max and smaller fluctuation in plasma verapamil concentration of the verapamil formulation would reduce the risk of AV block. It is known that the SR tablets of verapamil have a different absorption rate than the IR formulation and offer a narrower peak to trough ratio of verapamil. 18 Therefore, an SR formulation was used to reduce the risk of AE following an amendment to switch the verapamil formulation. No clinically significant abnormalities of hematologic, coagulation, or biochemical parameters were observed on laboratory evaluations in the SR cohort. None of the subjects in the SR cohort had clinically relevant changes in ECG from baseline. A higher incidence of ECG changes following coadministration of pasireotide SC and verapamil IR 240 mg once daily was observed and is suspected to have been related to verapamil due to the higher exposure with the IR formulation. Conclusions There was no change in the rate or extent of pasireotide exposure when administered with a P-gp inhibitor, verapamil. Pasireotide SC administered alone or in combination with verapamil SR was well tolerated in healthy subjects, and the safety findings were similar with the known safety profile of pasireotide. Declaration of Conflicting Interests This study was sponsored by Novartis Pharmaceuticals Corporation. Ruediger Kornberger has no disclosures to declare. Lillian S.L. Ting, Anadya P. Tripathi, Heidi Rodrigues, Dalal Nesheiwat, Vanessa Q. Passos, and Ke Hu are employees of Novartis. Lillian S.L. Ting, Vanessa Q. Passos, and Ke Hu also have stock/stock options with Novartis. Acknowledgments The authors acknowledge the contribution from Guoxiang Shen for QC of PK analysis, Wei Zhou for bioanalytical support, Joceyln Zhou for study design and protocol writing, and Anne Marie Cesario for protocol writing and start up. The authors also thank Bhavik Shah and Rohit Kachhadiya of Novartis Healthcare Pvt. Ltd. for providing medical editorial assistance with this manuscript.

9 Kornberger et al 1271 References 1. Schmid HA. Pasireotide (SOM230): development, mechanism of action and potential applications. Mol Cell Endocrinol. 2008;286(1-2): Horsmans Y, Hu K, Ruffin M, et al. Effect of hepatic impairment on the pharmacokinetics of pasireotide (SOM230): results from a multicenter phase I study. J Clin Pharmacol. 2012;52(4): Kvols LK, Oberg KE, O Dorisio TM, et al. Pasireotide (SOM230) shows efficacy and tolerability in the treatment of patients with advanced neuroendocrine tumors refractory or resistant to octreotide LAR: results from a phase II study. Endocr Relat Cancer. 2012;19(5): Oberg K, Astrup L, Eriksson B, et al. Guidelines for the management of gastroenteropancreatic neuroendocrine tumours (including bronchopulmonary and thymic neoplasms). Part I- general overview. Acta Oncol. 2004;43(7): Petersenn S, Schopohl J, Barkan A, et al. Pasireotide (SOM230) demonstrates efficacy and safety in patients with acromegaly: a randomized, multicenter, phase II trial. J Clin Endocrinol Metab. 2010;95(6): van der Hoek J, Lamberts SW, Hofland LJ. The role of somatostatin analogs in Cushing s disease. Pituitary. 2004;7(4): Boscaro M, Ludlam WH, Atkinson B, et al. Treatment of pituitarydependent Cushing s disease with the multireceptor ligand somatostatin analog pasireotide (SOM230): a multicenter, phase II trial. J Clin Endocrinol Metab. 2009;94(1): Signifor (pasireotide diaspartate) injection, for subcutaneous use [package insert]. Stein, Switzerland: Novartis Pharma Stein AG Beglinger C, Hu K, Wang Y, et al. Multiple once-daily subcutaneous doses of pasireotide were well tolerated in healthy male volunteers: a randomized, double-blind, placebo-controlled, cross-over, Phase I study. Endocrine. 2012;42(2): Golor G, Hu K, Ruffin M, et al. A first-in-man study to evaluate the safety, tolerability, and pharmacokinetics of pasireotide (SOM230), a multireceptor-targeted somatostatin analog, in healthy volunteers. Drug Des Devel Ther. 2012;6: Ma P, Wang Y, van der Hoek J, et al. Pharmacokineticpharmacodynamic comparison of a novel multiligand somatostatin analog, SOM230, with octreotide in patients with acromegaly. Clin Pharmacol Ther. 2005;78(1): Petersenn S, Hu K, Maldonado M, et al. Tolerability and dose proportional pharmacokinetics of pasireotide administered as a single dose or two divided doses in healthy male volunteers: a single-center, open-label, ascending-dose study. Clin Ther. 2012;34 (3): Lin TH, Hu K, Flarakos J, et al. Assessment of the absorption, metabolism and excretion of [(1)(4)C] pasireotide in healthy volunteers using accelerator mass spectrometry. Cancer Chemother Pharmacol. 2013;72(1): Signifor FDA Approval Package. Summary basis for approval of pasireotide (NDA ). Clinical Pharmacology and Biopharmaceutics Review(s) /Orig1s000 (February 17, 2012). 15. Mendell J, Zahir H, Matsushima N, et al. Drug-drug interaction studies of cardiovascular drugs involving P-glycoprotein, an efflux transporter, on the pharmacokinetics of edoxaban, an oral factor Xa inhibitor. Am J Cardiovasc Drugs. 2013;13(5): Petersenn S, Unger N, Hu K, et al. Pasireotide (SOM230), a novel multireceptor-targeted somatostatin analogue, is well tolerated when administered as a continuous 7-day subcutaneous infusion in healthy male volunteers. J Clin Pharmacol. 2012;52(7): Food and Drug Administration. Guidance for Industry: Bioavailability and Bioequivalence Studies for Orally Administered Drug Products - General Considerations Available at. fda.gov/downloads/drugs/../guidances/ucm pdf. 18. Isoptin 1 SR (verapamil HCl) Sustained-Release oral tablets [package insert]. Jacksonville, FL USA: Ranbaxy Laboratories Inc Rebello S, Leon S, Hariry S, Dahlke M, Jarugula V. Effect of verapamil on the pharmacokinetics of aliskiren in healthy participants. J Clin Pharmacol. 2011;51(2): Trotti A, Colevas AD, Setser A, et al. CTCAE v3.0: development of a comprehensive grading system for the adverse effects of cancer treatment. Semin Radiat Oncol. 2003;13(3): Fenner KS, Troutman MD, Kempshall S, et al. Drug-drug interactions mediated through P-glycoprotein: clinical relevance and in vitro-in vivo correlation using digoxin as a probe drug. Clin Pharmacol Ther. 2009;85(2): Lee CA, Cook JA, Reyner EL, Smith DA. P-glycoprotein related drug interactions: clinical importance and a consideration of disease states. Expert Opin Drug Metab Toxicol. 2010; 6(5): Eckermann G, Lahu G, Nassr N, Bethke TD. Absence of pharmacokinetic interaction between roflumilast and digoxin in healthy adults. J Clin Pharmacol. 2012;52(2): Hoon TJ, McCollam PL, Beckman KJ, Hariman RJ, Bauman JL. Impact of food on the pharmacokinetics and electrocardiographic effects of sustained release verapamil in normal subjects. Am J Cardiol. 1992;70(11): Conway EL, Phillips PA, Drummer OH, Louis WJ. Influence of food on the bioavailability of a sustained-release verapamil preparation. J Pharm Sci. 1990;79(3):