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Vaccines and Related Biological Drug Products Advisory Committee Meeting February 20, 2008. Rotarix™ (rotavirus vaccine, live, oral) GlaxoSmithKline Biologicals Paul Kitsutani, MD, MPH (Steven Rosenthal, MD, MPH) CBER/FDA. Product Information - Rotarix ™.
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Vaccines and Related Biological Drug Products Advisory Committee MeetingFebruary 20, 2008 Rotarix™ (rotavirus vaccine, live, oral) GlaxoSmithKline Biologicals Paul Kitsutani, MD, MPH (Steven Rosenthal, MD, MPH) CBER/FDA
Product Information - Rotarix™ • Live, attenuated, oral, human monovalent RV vaccine • Derived from human 89-12 strain which belongs to G1P[8] type • Prepared as a lyophilized formulation • End-of-shelf-life potency of ≥ 106.0 median Cell Culture Infective Dose (CCID50) per dose after reconstitution with liquid diluent • Contains no preservatives
Proposed Indication and Administration • Prevention of RV gastroenteritis (GE) caused by G1 and non-G1 types (including G2, G3, G4, and G9) • Orally administered as a 2-dose series to infants 6 to 24 weeks of age • First dose beginning at 6 weeks of age • Second dose by 24 weeks of age • Interval of at least 4 weeks between doses
Regulatory History – Rotarix™ • Rotarix™ under U.S. IND since July 2000 • Non-IND studies conducted thereafter outside the U.S., including pivotal efficacy and safety studies submitted to BLA • Pre-BLA meetings held from July to September 2006 • Based on FDA-sponsor agreement,10 of the completed Phase II and III studies were to be submitted in BLA • Additional Phase III immunogenicity study in U.S.(Rota-060) was to be submitted to BLA after completion • BLA submitted on June 1, 2007
Question 1 • Are the available data presented adequate to support the efficacy of Rotarix™ in preventing rotavirus gastroenteritis caused by serotypes G1, G2, G3, G4, and G9, when the first dose of vaccine is administered beginning 6 weeks of age, followed by a second dose separated by at least 4 weeks? • If not, what additional information should be provided?
Question 2 • Are the available data presented adequate to support the safety of Rotarix™ when used in a 2 dose series beginning with the first dose at 6 weeks of age, followed by a second dose separated by at least 4 weeks? • If not, what additional information should be provided?
Question 3 • Are there additional issues that should be addressed in post-marketing studies beyond the applicant’s proposed U.S. post-licensure safety study
Presentation Overview - Rotarix™ • Clinical overview • Efficacy – Pivotal Studies • Safety – Serious Adverse Events • Co-administration of Rotarix™ with routine childhood vaccines • Post-marketing commitments • Questions for the Advisory Committee
Clinical Overview – Rotarix™ • Complete results of 11 clinical studies submitted to BLA • 2 pivotal Phase III efficacy studies: Rota-023, Rota-036 • 2 supportive Phase II efficacy studies: Rota-004, Rota-006 • 1 Phase III concomitant childhood vaccination study: Rota-060 • 1 Phase III lot-to-lot consistency study: Rota-033 • Safety and RV immunogenicity evaluated in all studies • Rota-023 also considered pivotal safety study for IS • All studies randomized, double-blinded, placebo-controlled
Clinical Overview – Rotarix™ • From the BLA 11 studies: • 40,614 Rotarix™ and 34,739 placebo recipients received at least one study dose • 78,980 Rotarix™ and 67,349 placebo doses given • 37,214 infants received Rotarix™ at the potency, formulation, and storage conditions intended for commercial use (≥ 106.0 median CCID50 per dose, lyophilized, buffered, stored at 2° to 8°C) • Across studies, 90.5-99.1% of Rotarix™ and 90.3-100% of placebo recipients received 2 study doses
Efficacy – Pivotal Studies • Vaccine efficacy measured in 2 pivotal Phase III studies: • Rota-023 (Latin America) • Rota-036 (Europe) • Year 1 According to Protocol (ATP) efficacy cohort used for primary efficacy analyses in each study • Vaccination with 2 doses of Rotarix™ or placebo • No RV other than vaccine strain in GE stool samples between Dose 1 and 2 weeks post-Dose 2 • Entry into Year 1 efficacy follow-up period
Efficacy – Pivotal Studies Year 1 ATP efficacy cohort
Pivotal Efficacy Studies - Demographics Year 1 ATP efficacy cohort
Pivotal Efficacy Studies – Inclusion Criteria • Free of obvious health problems • Parents/guardians able to comply with study procedures • Age range at Dose 1 • Rota-023: 6 to 12/13 weeks • Rota-036: 6 to 14 weeks • Birth weight > 2000 grams (Rota-036)
Pivotal Efficacy Studies – Exclusion Criteria • History of chronic GI disease or other serious medical condition • Immunocompromised condition, including HIV • >14 days on immunosuppressive drugs
Pivotal Efficacy Studies – Other Characteristics • No feeding restrictions • Co-administration of infant vaccines allowed in Rota-023, except OPV which was administered 2 weeks apart from study vaccination • Choice of vaccines determined according to national recommendations in each country • DTwP, DTaP, HBV, IPV, OPV, MMR
Pivotal Efficacy Studies – Other Characteristics • Co-administration of infant vaccines allowed in Rota-036 • DTaP-Hib-HepB-IPV: Czech Republic, Finland, Germany, Italy, Spain • DTaP-Hib-HepB-IPV (Dose 1, 3), DTaP-Hib-IPV: France • Meningococcal group C conjugate: Spain • Prevnar®: France, Germany
Pivotal Efficacy Study – Rota-023 • Primary efficacy objective • Determine if 2 doses of Rotarix™ can prevent severe wild-type RV GE during Year 1 efficacy period (2 weeks post-Dose 2 to 1 year of age) • Secondary efficacy objectives: • Determine Year 1 efficacy of Rotarix™ against • Severe G1 wild-type RV GE • Severe non-G1 wild-type RV GE, pooled • Severe non-G1 wild-type RV GE, by individual type • Severe RV GE (Vesikari scale case definition)
Pivotal Efficacy Study – Rota-036 • Primary efficacy objective: • Determine efficacy of 2 doses of Rotarix™ given with childhood vaccines against any wild-type RV GE during Year 1 efficacy period (2 weeks post-Dose 2 until end of 1st RV season) • Secondary efficacy objectives: • Determine Year 1 efficacy of Rotarix™ against • Severe wild-type RV GE • Any/severe G1 wild-type RV GE • Any/severe non-G1 wild-type RV GE • Hospitalization for RV GE • Any medical attention for RV GE
Pivotal Efficacy Studies – Case Definitions • Diarrhea:≥ 3 looser than normal stools within a day • Vomiting: ≥ 1 episode of forceful emptying of partially digested stomach contents ≥ 1 hour after feeding within a day • Gastroenteritis (GE): diarrhea with or without vomiting • Medical attention: medical provider contact, advice or visit; emergency room contact or visit or hospitalization
Pivotal Efficacy Studies – Case Definitions • RV GE:an episode of GE in which RV other than vaccine strain identified in a stool sample collected no later than 7 days after GE symptom onset • Severe RV GE (Rota-023):an episode of RV GE requiring hospitalization and/or re-hydration therapy (equivalent to WHO plan B or C) in a medical facility • Severe RV GE (Vesikari scale, Rota-036): an episode of RV GE with a Vesikari score of ≥ 11 points
Pivotal Efficacy Studies – RV GE Case Ascertainment • Rota-023 • Hospitals and other medical facilities in study areas contacted at least twice a week • Subjects also contacted or visited at least every 4 days to identify severe cases not picked up by routine medical facility surveillance • Rota-036 • Subjects contacted weekly (by telephone) from 1 week post-Dose 1 until the end of the 1st RV season (end of May 2005) • Diary cards collected temperature, stool, emesis data
Pivotal Efficacy Studies – Stool Collection & Laboratory Diagnosis • Parents instructed to collect, label, store, and submit stool samples for each GE episode • All collected stools tested for RV antigen by ELISA at applicant’s laboratory in Belgium • RV antigen-positive stools analyzed for G and P type by RT-PCR followed by Reverse Hybridization Assay or optional sequencing (Delft Diagnostic Laboratory, the Netherlands)
Pivotal Efficacy Studies – Vaccine Efficacy Calculation Vaccine Efficacy = 1 – Relative Risk = 1 – (ARV/ARU) ARV = attack rate in Rotarix™ group = # subjects with at least one episode of RV GE endpoint ÷ total # subjects in Rotarix™ group ARU = attack rate in placebo group = # subjects with at least one episode of RV GE endpoint ÷ total # subjects in placebo group
Efficacy Results – Rota-036 ATP efficacy cohort, Year 1 N= total number of subjects in ATP efficacy cohort, Year 1 n= number of subjects reporting at least one clinical endpoint event caused by circulating wild-type RV
Efficacy Results – Rota-036 VE against any RV GE, ATP efficacy cohort, Year 1
Efficacy Results – Rota-036 VE against severe RV GE, ATP efficacy cohort, Year 1
Efficacy Results – Rota-036 ATP efficacy cohort, Year 1
Efficacy Results – Rota-023 ATP efficacy cohort, Year 1
Efficacy Results – Rota-023 VE against severe RV GE (main definition), ATP efficacy cohort, Year 1
Efficacy Results –FDA Analysis • FDA considers it more appropriate to use the “time-to-first-episode” analysis than using attack rates in each arm • Time-to-event approach accounts for differential follow-up of subjects, while the latter approach does not • FDA inclined to place more importance on efficacy results based on the Cox proportional-hazards model • Using the Cox-proportional-hazard model, VE against • Severe RV GE (Rota-023): 84.8%; 95% CI=72.0, 91.7% • Any RV GE (Rota-036): 87.4%; 95% CI=80.3, 91.9%
Intussusception (IS) Study – Rota-023 • Primary safety objective: • Determine the safety of Rotarix™ with respect to intussusception (IS) within 31 days (Days 0 to 30) after each dose • Primary safety endpoint: • Occurrence of definite IS within 31 days after each dose • The Brighton Collaboration IS Working Group case definition for IS used
IS Study – Rota-023 • The Brighton Collaboration IS Working Group case definition for “Definite IS”
IS Study – Rota-023 • To capture all IS events, IS cases reported irrespective of whether they met the Brighton case definition • Clinical Events Review Committee (CEC) performed blinded objective reviews of all IS cases occurring from Dose 1 to Visit 3* • CEC consisted of physicians acting as consultants who were not study investigators or medical care providers to study subjects *Visit 3 = 1-2 months post-Dose 2 or 2-4 months post-Dose 1
IS Study – Rota-023 • Rota-023 specifically designed and powered to assess the risk of IS following Rotarix™ vaccination • 31,673 subjects vaccinated with at least 1 dose of Rotarix™ • 31,552 subjects vaccinated with at least 1 dose of placebo • Original criterion for meeting primary safety objective • UL of 90% CI of IS risk difference (Rotarix™ minus placebo) less than 2/10,000 subjects • Criterion based on consensus estimate of Rotashield® attributable risk of 1/10,000 vaccinees
IS Study – Rota-023 • 9 months after study initiation, blinded overall IS incidence rate 31 days post-vaccination was 2-4/10,000 • Exceeded anticipated rate of 0.3/10,000 in placebo group • UL of 90% CI exceeded 2/10,000 • Background incidence rate of 5/10,000 calculated from concurrent, prospective, multi-center epidemiologic study in the same countries
Intussusception Study – Rota-023 • Criteria for meeting primary safety objective revised • UL of 95% CI of risk difference for definite IS < 6/10,000 (limit based on IS incidence of 3-5/10,000 in placebo group and 30,000 subjects in each group) • LL of 95% CI of the risk difference < 0 • Study had >86% power to meet primary objective if the risk difference was truly 0
IS Study Results– Rota-023 Definite IS diagnosed 31 days (Days 0 to 30) post-vaccination N = # subjects in the cohort; n = # subjects with definite IS
IS Study Results– Rota-023 • Applicant noted that when original criterion for primary safety objective used (UL of 90% CI of risk difference < 2/10,000), objective still met • UL = 1.71/10,000 • 25 definite IS cases diagnosed from Dose 1 until Visit 3 • Rotarix™ = 9, placebo = 16 • Risk difference = -2.23/10,000 (95% CI: -5.70, 0.94) • RR = 0.56 (95% CI: 0.25, 1.24)
IS Study Results– Rota-023 (FDA analysis) • One definite IS case had onset on Day 29 but diagnosed on Day 31 • Analysis of IS risk within 31 days after any dose based on onset date rather than diagnosis date • Rotarix™ = 7, placebo = 7 • Risk difference = -0.008/10,000 (95% CI: -2.63, 2.61) • RR = 0.996 (95% CI: 0.36, 2.72)
IS Study Results– Rota-023(FDA analysis) Definite IS by onset interval after each dose
IS Study Results– Rota-023(FDA analysis) Definite IS by onset interval after each dose
IS Study Results– Rota-023 (FDA analysis) • Criteria to meet the primary safety objective was revised during the conduct of the study • Such change while the trial is ongoing could potentially compromise the integrity of the study • Because FDA did not discuss this change with applicant (study was not performed under US IND), more detailed information has been requested to ensure that proper procedure was followed
Safety – Integrated Safety Summary (ISS) • Integrated Safety Summary (ISS) analyses conducted • Based on Total Vaccinated Cohort (TVC) data from 10 studies • Involved pooling of subjects into Core ISS and Supplementary ISS analysis groups • Core ISS analysis group: pooled subjects who received Rotarix™ at potency of ≥ 106.0 CCID50 per dose or placebo • Supplementary ISS analysis group: pooled subjects who received Rotarix™ at potency of < 106.0 CCID50 per dose or placebo
Safety – ISS Analyses • Core ISS analysis group • 36,755 Rotarix™ subjects (71,320 doses) • 34,454 placebo subjects (66,765 doses) • 8 studies • Supplementary ISS analysis group • 3076 Rotarix™ subjects (6037 doses) • 1613 placebo subjects (3177 doses) • 5 studies • For studies included in both ISS analysis groups, the same numbers of placebo subjects used