VACCINE REPORTS The Pediatric Infectious Disease Journal •฀ Volume฀31,฀Number฀5,฀May฀2012 www.pidj.com | 487 Safety, Reactogenicity and Immunogenicity of the Human Rotavirus Vaccine in Preterm European Infants: A Randomized Phase IIIb Study Felix Omenaca, MD, PhD,* Jean Sarlangue, MD, MSc,† Leszek Szenborn, MD,‡ Marta Nogueira, MD,§ Pemmaraju V. Suryakiran, MSc,¶ Igor V. Smolenov, MD, PhD,¶ Htay H. Han, MB BS,¶ and ROTA-054 Study Group Background: Rotavirus disease is more severe in preterm infants than in full-term infants. This study assessed the safety, reactogenicity and immu- nogenicity of a human rotavirus vaccine, RIX4414, in European preterm infants. Methods: A total of 1009 preterm infants were randomized (2:1, vaccine:placebo) and stratified into 2 groups: 20% of early (27–30 weeks, group 1) and 80% of late (31–36 weeks, group 2) gestational age preterm infants in each group. Two doses of RIX4414/placebo were administered to these preterm infants according to the recommended chronologic age for full-term infants with an interval of 30–83 days between doses. Seri- ous adverse events were recorded throughout the study period. Solicited and unsolicited adverse events were recorded for 15 and 31 days post-each dose. Antirotavirus IgA concentrations (enzyme-linked immunosorbent assay cutoff 20 U/mL) and geometric mean concentration were deter- mined pre-dose 1 and 30–83 days post-dose 2 in a subset of 300 infants. This study is registered with ClinicalTrials.gov, number NCT00420745 (eTrack106481). Results: Serious adverse events were reported at a similar frequency in both groups (P 0.266). Fifty-seven infants reported at least 1 serious adverse event (5.1% [3.5–7.0] in the RIX4414 group and 6.8% [4.3–10.0] in the placebo group). During the 15-day postvaccination follow-up period, diarrhea, vomiting and fever occurred at a similar frequency in both groups; fever could have been due to concomitant vaccines. Five cases (RIX4414 3, Placebo 2) of rotavirus gastroenteritis were reported. The onset of rotavirus gastroenteritis in the RIX4414 group was 1–5 days after vaccination (vaccine strain identified in all cases) and in the placebo group it was 3–4 days after receiving placebo (wild-type rotavirus identi- fied from both cases). Antirotavirus IgA seroconversion rates at 30–83 days post-dose 2 were 85.7% (79.0–90.9) in the RIX4414 group and 16.0% (8.8–25.9) in the placebo group. Geometric mean concentrations were 202.2 U/mL (153.1–267.1) in the RIX4414 group and 20 U/mL in the placebo group. Seroconversion rate in groups 1 and 2 in RIX4414 recipients were 75.9% (95% confidence interval [CI]: 56.5–89.7%) and Accepted for publication December 30, 2011. From the *La Paz Hospital, Madrid, Spain; †Hôpital des Enfants, CHU Bor- deaux, France; ‡Department of Pediatric Infectious Diseases, Medical Uni- versity, Wroclaw, Poland; §Maternidade Alfredo da Costa, Lisbon, Portugal; and ¶GlaxoSmithKline Biologicals, Rixensart, Belgium. This study was sponsored and funded by GlaxoSmithKline Biologicals, Rix- ensart, Belgium. The sponsor was involved in all stages of the study, that is, from study design to data analysis and writing of the report, and also performed rotavirus enzyme-linked immunosorbent assay testing. The cor- responding author had full access to all the data in the study and had final responsibility for the decision to submit for publication. P.V.S., H.H.H. and I.V.S. are employed by the GlaxoSmithKline Group of Com- panies. H.H.H. and I.V.S. have stock ownership. J.W., H.C., F.O., X.C., J.R-C., E.R., J.D-D., D.M-P., J.M.M., F.C., J.C., J.A., J.C.T., J.S. and L.S. received honoraria/paid expert testimony/travel grants from GlaxoSmithK- line Biologicals. E.R. and J.A. received consulting fees. The authors have no other funding or conflicts of interest to disclose. Address for correspondence: Felix Omenaca, MD, PhD, Paseo de la Castellana 261, 28046 Madrid, Spain. E-mail: fomenaca.hulp@salud.madrid.org. Copyright © 2012 by Lippincott Williams & Wilkins ISSN: 0891-3668/12/3105-0487 DOI: 10.1097/INF.0b013e3182490a2c 88.1% (95% CI: 80.9–93.4%), respectively; the geometric mean concen- trations in the respective groups were 110.2 U/mL (95% CI: 56.1–216.5) and 234.8 U/mL (95% CI: 173.4–318.0; exploratory analysis). Conclusions: Two doses of RIX4414 were immunogenic and well-tolerated in European preterm infants. Key Words: gastroenteritis, gestational age, transplacental antibody transfer (Pediatr Infect Dis J 2012;31: 487–493) R otavirus disease continues to claim the lives of thousands of children 5 years of age, with the rate of hospital admission being highest in the 12- to 18-month age group (42.5 admissions per 10,000 children). 1 Worldwide, rotavirus accounts for 25 million clinic visits, 2 million hospitalizations and 527,000 deaths each year. 2,3 A live-attenuated, oral human rotavirus vaccine RIX4414, developed from the parent G1P[8] 89-12 vaccine strain for the immunization of infants 4 has been found to be highly efficacious in 2 doses in various phase III studies conducted on full-term infants across Europe, Latin America and Asia in preventing severe rotavi- rus gastroenteritis. 5–7 Effectiveness of RIX4414 against G2P[4] has been demonstrated in a Latin American study. 8 Earlier studies have shown that preterm infants are at an increased risk of hospitalization due to gastroenteritis 9 but are less likely to receive vaccination in a timely manner due to complica- tions related to preterm births. 10,11 Currently, the American Acad- emy of Pediatrics and the Advisory Committee on Immunization Practices recommend that all preterm infants regardless of their gestational age receive rotavirus vaccination along with all other childhood vaccines at the same chronologic age as the full-term infants. 12,13 The present study assessed the safety, reactogenicity and immunogenicity of the 2 oral doses of RIX4414 vaccine as compared with placebo in preterm infants across 4 European countries. MATERIALS AND METHODS Subjects and Study Design This phase IIIb, randomized (2:1, vaccine:placebo), double- blind placebo-controlled trial was conducted in 4 European coun- tries—France, Portugal, Poland and Spain between January 2007 and March 2008. Vaccine doses were supplied by GlaxoSmithKline Biologicals (Rixensart, Belgium) based on a computer-generated randomization list. A block randomization system in the ratio of 2:1 (vaccine:placebo) was used to ensure balance between the treatment arms; vaccine doses were supplied to each participating country with respect to the randomization block size. The infants were also stratified based on their gestational age (20% of preterm