Alternative Vaccination Schedules (0, 1, and 6 Months Versus 0, 1, and 12 Months) for a Recombinant OspA Lyme Disease Vaccine

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1 1260 Alternative Vaccination Schedules (0, 1, and 6 Months Versus 0, 1, and 12 Months) for a Recombinant OspA Lyme Disease Vaccine C. Van Hoecke, E. Lebacq, J. Beran, and D. Parenti From SmithKline Beecham Biologicals, Rixensart, and Clinique Notre- Dame de Grâce, Gosselies, Belgium; Purkyne Military Medical Academy, Hradec Kralové, Czech Republic; and SmithKline Beecham Pharmaceuticals, Collegeville, Pennsylvania, USA We have compared the immunogenicity profile of a recombinant lipoprotein outer-surface protein A (OspA) Lyme disease vaccine administered on schedules of 0, 1, and 6 months (group 1) or 0, 1, and 12 months (group 2) to 800 healthy subjects, aged years. One month after the second dosing, geometric mean titers of IgG antibodies to OspA were 1,309 ELISA units (EL.U)/mL in group 1 and 1,404 EL.U/mL in group 2. One month after the third dosing, the titers were 7,205 EL.U/mL and 10,659 EL.U/mL, respectively. Using bioequivalence methodology, we showed that the two vaccination schedules elicit an equivalent immune response 1 month after administration of dose 3: at that point, 91% 93% of all subjects had titers 1,400 EL.U/mL, proposed to be protective for one tick season. The vast majority of local and systemic symptoms were mild to moderate and of limited duration. The 0, 1, and 6 months vaccination schedule is a viable alternative to the 0, 1, and 12 months schedule and can provide protection against Lyme disease during one tick season. Lyme disease has become the most commonly reported tick- Lyme disease had IgG OspA antibody titers of õ400 EL.U/mL borne disease in the United States [1]. Since 1982, when the Centers at the onset of the disease (Marc Gillet, personal communication). for Disease Control initiated surveillance of Lyme disease, To increase the flexibility of dosing, we conducted a study to the number of reported cases has steadily increased and the disease evaluate whether LYMErix, on a 0, 1, and 6 months schedule, has spread geographically. Until recently, preventive measures would provide an acceptable safety profile and an immune response have included only personal protection such as avoiding tick-infested at least equal to that obtained in the pivotal field trial on areas, wearing light clothing, tucking pants into socks, and a 0, 1, and 12 months schedule. The results of the study and checking for ticks. These epidemiological aspects have stimulated implications for clinical use are presented herein. interest in the development of a safe and effective vaccine that would prevent Lyme disease. A recombinant vaccine consisting of a lipidated recombinant outer surface protein A (OspA) of Borrelia burgdorferi sensu Materials and Methods stricto (LYMErix; SmithKline Beecham Biologicals, Rixensart, Belgium) has been developed. In an extensive field trial involving Study Centers and Populations 10,936 participants aged years, three doses of LYMErix administered on a schedule of 0, 1, and 12 months were well The study was performed in two study centers, one in Bel- tolerated and provided 76% protective efficacy against definite gium and the other in the Czech Republic. Approval was Lyme disease due to B. burgdorferi and 100% protective efficacy granted by the ethics review committee of the Clinique Notreagainst asymptomatic infection [2]. In this efficacy trial, subjects Dame de Grâce (Gosselies, Belgium) and the medical faculty were vaccinated with two doses prior to the first tick season and of the University Hospital of Hradec Kralové (Czech Republic). received a third dose 1 year after the first. Each subject gave written informed consent prior to enrollment. The results of the statistical analyses demonstrated that a rela- The study was conducted in accordance with the provisions of tionship exists between antibody levels and protection, that vaccine the Declaration of Helsinki and the guidelines of good clinical failure and control groups could be discriminated, and that an practice. absolute cutoff titer can be proposed as a surrogate marker of Volunteers years of age were enrolled. Exclusion protection [3]. An IgG OspA antibody titer of 1,400 ELISA units (EL.U)/mL before the tick season should provide protection criteria included clinical signs of acute illness at the time of for Ç95% of the population. Nearly all vaccinees who contracted enrollment; history of significant and persisting hematologic, hepatic, renal, cardiac, or respiratory disease; any chronic treatment with immunosuppressive drugs, including corticosteroids; history of allergic disease or sensitivity to vaccine components; Received 21 August 1998; revised 28 January history of medically confirmed Lyme borreliosis or previous Reprints or correspondence: Dr. C. Van Hoecke, SmithKline Beecham Bio- vaccination with a candidate Lyme disease vaccine; simultanelogicals, Rue de l Institut, 89 B-1330, Rixensart, Belgium. ous participation in any other clinical trial; pregnancy; breast- Clinical Infectious Diseases 1999;28: feeding; and simultaneous administration of any other vac by the Infectious Diseases Society of America. All rights reserved /99/ $03.00 cine(s) during the study period.

2 CID 1999;28 (June) Lyme Disease Vaccination Schedules 1261 Vaccine 1 and 340 in group 2, were eligible for ATP immunogenicity analyses. All vaccines were developed and manufactured by Smith- ELISA for determination of total IgG OspA titer. IgG anti- Kline Beecham Biologicals. Each vaccine dose contained 30 bodies to OspA were measured in a direct ELISA as described mg of purified lipoprotein OspA antigen adsorbed onto 0.5 mg previously [4]. Titers were calculated relative to the reference of aluminum, as Al(OH) 3, with 2-phenoxyethanol as a preserwith use of four-parameter interpolation logistics [5] and were vative. Details of the expression and the purification are deexpressed as EL.U/mL. The assay cutoff was 20 EL.U/mL, and scribed elsewhere [4]. The final product was sterile and consubjects with titers 20 EL.U/mL were considered seropositive tained no appreciable DNA or endotoxin contaminants. and seroconverters if the baseline testing was negative. Geometric mean titers (GMTs) were determined by log-transformation Study Design of individual titers and use of the anti-log of the mean of these transformed values for seropositive subjects. GMTs of This was an open, randomized study. Eight hundred healthy antibodies and their confidence limits (95% CIs) were calcuadult volunteers (400 at each study center) were enrolled and lated for each time point. randomly allocated to receive two vaccine doses as intramuscular Comparison of the two vaccination schedules: 0, 1, and 6 injections in the deltoid region at 1-month intervals. After months vs. 0, 1, and 12 months. A bioequivalence approach receiving the second dose, the subjects were again randomized with use of the Anderson and Hauck [6] methodology was to receive a third dose of vaccine to complete either a 0, 1, used to demonstrate the equivalence of the two schedules in and 6 months schedule (group 1) or a 0, 1, and 12 months terms of immunogenicity 1 month following administration of schedule (group 2). Forty-six subjects declined to be given the dose 3. The equivalence of the vaccination schedules is based third dose. Blood samples were drawn at months 0 (prevaccination), on an acceptable relative difference in GMTs of 100% for IgG 2, and 7 (group 1) or 13 (group 2), for determination of antibodies to OspA in the ATP population. the titer of IgG antibodies to OspA. The null and alternative hypotheses for the bioequivalence Evaluation of reactogenicity. All volunteers who had re- test are as follows. The null hypothesis is that both schedules ceived at least one dose of vaccine were eligible for the reactogenicity are not equivalent in terms of immune response (the expected analysis. Reactogenicity was assessed by evaluation of local relative difference in GMTs is ú100%). The alternative hy- reactions (pain, redness, and swelling at the injection site) and pothesis is that both schedules are equivalent in terms of im- systemic reactions (fever, headache, malaise, rash, and arthral- mune response (the expected relative difference in GMTs is gia). After each vaccine dosing, subjects were observed by the not ú100%). investigator for at least 30 minutes, and all signs and symptoms Relative difference in GMT is defined as were recorded in case-report forms. Subjects were given diary GMT max 0 GMT min cards to record any solicited (asked-about) or unsolicited reactions they experienced in the evening following each injection min 1 100% GMT and during the 3 subsequent days (4-day follow-up). where GMT max stands for GMT in the group with the highest The volunteers returned the diary cards to the investigator GMT and GMT min for GMT in the group with the lowest GMT. at the next visit, and the information was checked and tran- The two vaccination schedules were considered equivalent if scribed into the case-report form by the investigator. Rash and there was a relative difference in GMTs of õ100% for IgG arthralgia were solicited throughout the study. When unsolic- antibodies to OspA. ited symptoms were reported, the subject was followed until 29 days after each vaccine dosing. Serious adverse events were recorded until study completion. None of the 46 subjects who Results withdrew before receiving the third dose did so because of the Demographics vaccination. The safety data for the two doses received by each The volunteers, 396 males and 404 females, were aged 14 of these 46 subjects are included in the data for group years at the time of first vaccination (mean { SD, 31.5 { Evaluation of immunogenicity: population. The ATP (ac- 9.8 years). There was no significant statistical difference in the cording to protocol) study cohort for the immunogenicity an- distribution of males and females between groups (P Å.944), alysis included subjects who conformed to the specific inclu- but a significant difference could be shown in the mean ages sion/exclusion criteria as described in the protocol and had an between sexes (32.5 years for males vs years for females; initially undetectable OspA antibody titer (prior to first vaccina- P Å.002); however, this difference was not clinically relevant. tion). A total of 800 subjects were enrolled in the study. Seven hundred and fifty-four subjects (94.3%) received the third vaccine dose. Seventy-eight subjects were eliminated from immunogenicity Safety and Reactogenicity analyses for protocol violations. Six hundred and The majority of adverse events (solicited and unsolicited) seventy-six subjects (84.5% of enrolled subjects), 336 in group reported in both groups were mild to moderate in intensity and

3 1262 Van Hoecke et al. CID 1999;28 (June) Table 1. Incidence of solicited symptoms in subjects who received Table 2. Geometric mean titers (GMTs) of IgG antibody to outersurface a recombinant outer-surface lipoprotein A vaccine against Lyme disease, lipoprotein A. administered on a schedule of 0, 1, and 6 months (group 1) or 0, 1, and 12 months (group 2). Group Timing* n GMT (95% CI) Number (%) of recipients reporting symptoms 1 PII (mo 2) 374 1,404 (1,240 1,589) PIII (mo 7) 340 7,205 (6,363 8,159) Group 1 (n Å 1,231*) Group 2 (n Å 1,122*) PIII (mo 13) 336 1,761 (1,544 2,007) PIII (mo 18) 172 1,211 (996 1,473) Symptoms Total Grade 3 Total Grade 3 2 PII (mo 2) 331 1,309 (1,133 1,512) PIII (mo 13) ,659 (9,320 12,191) Local Pain 864 (70.2) 9 (0.7) 797 (71.0) 16 (1.4) NOTE. Group 1 schedule Å 0, 1, and 6 months; group 2 schedule Å 0, Redness 286 (23.2) 41 (3.3) 236 (21.0) 32 (2.9) 1, and 12 months. Swelling 177 (14.4) 7 (0.6) 192 (17.1) 5 (0.4) * PII Å post second dosing; PIII Å post third dosing. The point at which the ELISA was performed is indicated in parentheses. Systemic ELISA units per ml. Arthralgia 19 (1.5) 0 (0.0) 19 (1.7) 0 (0.0) Fever 21 (1.7) 0 (0.0) 22 (2.0) 0 (0.0) Headache 147 (11.9) 1 (0.1) 134 (11.9) 4 (0.4) Malaise 120 (9.7) 1 (0.1) 127 (11.3) 1 (0.1) Rash 2 (0.2) 0 (0.0) 2 (0.2) 0 (0.0) test was performed to test the null hypothesis (schedules are not equivalent). The antibody titers at month 7 for group 1 * No. of administered doses. were compared to the antibody titers at month 13 for group 2. Grade 3 symptoms were those of clinical relevance (redness and swelling The point estimate of the relative difference in GMTs was of ú30 mm and persisting for ú24 hours; pain and systemic symptoms that prevented normal, everyday activities). 48% (95% CI, 27% 72%). Therefore, the null hypothesis is rejected (P value for bioequivalence, õ.001). Thus, the two vaccination schedules are equivalent in terms of immune response. This was further confirmed by the similar profiles of transient. All events resolved without sequelae except for one suicide (unrelated to vaccination). The number of subjects reafter three dosings (figure 1). the reverse cumulative distribution curves of the two schedules porting at least one symptom was similar in the two groups (76% vs. 78%). Most subjects reported local symptoms; 75% Persistence of immunity. The persistence of antibodies was in each group reported at least one local symptom, compared assessed 7 months and 1 year after administration of dose 3 with the 19% in each group who reported systemic symptoms. (months 13 and 18, respectively) in a subset of subjects in The incidence rates of local and systemic solicited events are shown in table 1. The reactogenicity profile was similar for the two groups. The most frequently reported local symptom was pain at the injection site. The incidence rates for the systemic events were õ2% except for headache and malaise. Symptoms of clinical relevance (grade 3: redness and swelling ú30 mm and persisting for ú24 hours; pain and systemic symptoms that prevented normal, everyday activities) were few and were reported at similar rates in both groups (table 1). There were no reports of fever, arthralgia, or rash that interfered with everyday activity. The vast majority of the unsolicited adverse events thought to be related or possibly related to vaccine were local events (for example, injection-site bruising), and 98% were mild or moderate in severity. There were no serious adverse events related to vaccination. Immunogenicity Figure 1. Reverse cumulative distribution curves of titers of IgG antibody to outer-surface lipoprotein A (OspA), by dosing schedule for Lyme disease vaccination. The vertical line indicates the protec- tive level of 1,200 ELISA units/ml; the solid line depicts titers at month 7, after three vaccine dosings at months 0, 1, and 6; and the dashed line depicts titers at month 13, after three vaccine dosings at months 0, 1, and 12. Basic immunity. The serological responses are shown in table 2. One month after the second dosing, GMTs of IgG antibodies to OspA were 1,309 EL.U/mL and 1,404 EL.U/mL for groups 1 and 2, respectively. GMTs 1 month after administration of dose 3 were 7,205 EL.U/mL and 10,659 EL.U/mL for groups 1 and 2, respectively. A bioequivalence

4 CID 1999;28 (June) Lyme Disease Vaccination Schedules 1263 EL.U/mL at the end of the tick season implies that the individual should have been protected throughout that season (Marc Gillet, personal communication). The percentages of subjects in the current study with titers 400 EL.U/mL or 1,400 EL.U/mL are shown in table 3. One month after administration of dose 3, 91% of the subjects in group 1 and 93% of those in group 2 had titers 1,400 EL.U/mL. Of subjects on the 0, 1, and 6 months schedule, 91% and 82% had titers 400 EL.U/mL at 7 months and 12 months, respectively, after receiving the third dose. Discussion This study compares the safety and immunogenicity of three doses of a lipoprotein OspA Lyme disease vaccine, LYMErix, administered according to two different vaccination schedules Figure 2. Reverse cumulative distribution curves for subjects on a (0, 1, and 6 months vs. 0, 1, and 12 months) to volunteers 0, 1, and 6 months dosing schedule for Lyme disease vaccination. aged years. Although the absolute differences in GMTs The vertical line indicates the protective level of 1,200 ELISA between the two groups seem large, we have demonstrated that units/ml; the solid line depicts titers at month 2, after two vaccine dosings at months 0 and 1; the dashed line depicts titers at month 7, the two vaccination schedules are equivalent in terms of the after three vaccine dosings at months 0, 1, and 6; the dotted line immune response, as assessed by IgG OspA antibody titers 1 depicts titers at month 13, after three vaccine dosings at months 0, month after the third dosing. The reverse cumulative curve 1, and 6; and the dotted/dashed line depicts titers at month 18, after data support the argument of no differences. three vaccine dosings at months 0, 1, and 6. In the field efficacy trial [2], 1 month after the third dosing, the subjects had attained an IgG OspA GMT of 6,006 EL.U/mL, and 90% had a titer 1,400 EL.U/mL. After two dosings, 52% had group 1 (table 2). At month 13 the GMT was 1,761 EL.U/mL, an IgG OspA titer of 1,400 EL.U/mL. In this study, after admin- which represented 25% of the GMT at month 7. One year after istration of two doses in both groups, 53% 55% of all subjects the third dosing (month 18), the GMT was 1,211 EL.U/mL, had antibody titers 1,400 EL.U/mL, which increased to 91% 69% of the GMT at month % after administration of dose 3. These results are similar to The reverse cumulative distribution curves for this cohort the findings of Steere et al. [2]. (figure 2) show that the immune responses 1 month after admin- Most subjects vaccinated according to the 0, 1, and 6 months istration of dose 3 (month 7) were better than at 1 month schedule remained seropositive, with high antibody titers 6 after administration of dose 2 (month 2) and that the immune months and 1 year after the third dosing and GMTs slightly responses at month 13 and month 18 were similar to the response higher or similar to those attained 1 month after the second at month 2. dosing (table 2). In this group, 1 month after they received Vaccine efficacy. The data from the efficacy trial [2] show dose 3, most subjects had titers high enough ( 1,400 that an IgG OspA antibody titer of 1,400 EL.U/mL ensures EL.U/mL) to expect protection against Lyme disease during a protection during a tick season [3] and that a titer of 400 tick season. Seven months after receiving dose 3, 91% of the Table 3. Percentage of subjects with IgG antibody to outer-surface lipoprotein A at titers 400 or 1,400 ELISA units (EL.U)/mL. Group Timing* n 400 EL.U/mL (95% CI) 1,400 EL.U/mL (95% CI) 1 PII (mo 2) ( ) 53.2 ( ) PIII (mo 7) ( ) 91.5 ( ) PIII (mo 13) ( ) 65.5 ( ) PIII (mo 18) ( ) 50.6 ( ) 2 PII (mo 2) ( ) 55.9 ( ) PIII (mo 13) ( ) 93.2 ( ) NOTE. Group 1 schedule Å 0, 1, and 6 months; group 2 schedule Å 0, 1, and 12 months. * PII Å post second dosing; PIII Å post third dosing. The point at which the ELISA was performed is indicated in parentheses.

5 1264 Van Hoecke et al. CID 1999;28 (June) subjects had titers 400 EL.U/mL, which is the proposed mini- ton for monitoring, Marc Gillet for statistical analysis, and Danny mum titer to ensure protection (Marc Gillet, personal communication). De Grave for technical assistance. The vaccine was well tolerated, and most reactions were mild to moderate in intensity and localized at the injection site, with similar incidence rates of symptoms in both vaccination- References schedule groups. 1. Centers for Disease Control and Prevention. Lyme disease United States, The results of this study demonstrate that vaccination of MMWR Morb Mortal Wkly Rep 1997;46:531. healthy subjects aged with three doses of the lipoprotein 2. Steere AC, Sikand VK, Meurice F, et al. Vaccination against Lyme disease OspA vaccine LYMErix (on a 0, 1, and 6 months or 0, 1, and with recombinant Borrelia burgdorferi outer surface lipoprotein A with 12 months schedule) is safe, well tolerated, and immunogenic. adjuvant. N Engl J Med 1998;339: Irrespective of the vaccine schedule, after three dosings, sero- 3. Parenti DL, Gillet M, Sennewald E, et al. Correlate of protection for positivity was 100% and at least 91% of subjects had titers Lyme disease (LD) using LYMErix, recombinant, adjuvanted Borrelia burgdorferi outer surface lipoprotein A (L-OspA) vaccine [abstract no 1,400 EL.U/mL, which is the titer estimated to be necessary 704]. Clin Infect Dis 1998;27:1053. at the beginning of the tick season to provide seroprotection 4. Van Hoecke C, Comberbach M, De Grave D, et al. Evaluation of the throughout the tick-transmission season. safety, reactogenicity and immunogenicity of three recombinant outer In summary, the two vaccination schedules are equivalent, surface protein (OspA) Lyme vaccines in healthy adults. Vaccine 1996; and irrespective of vaccination schedule, a high level of protec- 14: tion is attainable after administration of three doses. 5. Karpinski KF, Hayward S, Tryphonas H. Statistical considerations in Acknowledgments the quantitation of serum immunoglobulin levels using the enzyme linked immunosorbent assay (ELISA). J Immunol Methods 1987; 103: Anderson S, Hauck WW. A new procedure for testing equivalence in The authors thank Opokua Ofori-Anyinam and Norbert De comparative bioavailability and other clinical trials. Communication in Clercq for editorial assistance, Laurence Vigneron and Cécile Car- Statistics Theory and Methods 1983;12: