NEW ORLEANS, LA—GlaxoSmithKline’s investigational combined measles, mumps, and rubella (MMR) vaccine (GSK_MMR) “demonstrated an acceptable immune response” that was non-inferior to Merck & Co., Inc.’s MMR vaccine (MRK_MMR), a multinational, randomized, Phase 3A, controlled, observer-blinded study reported at IDWeek 2016 has shown.

In addition, “no safety concerns were identified,” with “reactogenicity profiles very similar between the 2 vaccines,” reported Nicola P. Klein, MD, PhD, of the Kaiser Permanente Vaccine Study Center in Oakland, CA, and coauthors.

Merck’s MMR vaccine (MRK_MMR), first licensed in the United States in 1971, is the only combination vaccine on the market. GSK’s MMR vaccine, which is undergoing non-inferiority studies in its path to U.S. licensure, was first approved outside the U.S. in 1997 and, to date, more than 400 million doses have been administered worldwide.

The study evaluated consistency of 3 lots of GSK_MMR; the immunogenic non-inferiority of pooled lots of GSK_MMR to Merck’s MRK_MMR; acceptable immune response of GSK_MMR; and reactogenicity of GSK_MMR.

The researchers enrolled 5,003 healthy children aged 12–15 months to receive hepatitis A vaccine and varicella vaccine and, among U.S. children, pneumococcal 13-valent conjugate vaccine. Participants were then randomly assigned at a 3:1 ratio to receive one of 3 different lots of GSK_MMR or 2 different lots of MRK_MMR (the controls).

Blood was sampled at Day 0 and Day 42 and anti-MMR antigen antibodies noted. Solicited symptoms were recorded at 4 days after vaccination for the injection site, 15 or 43 days for general symptoms, and 5–12 days post-vaccination for fever (≥38°C).

A total of 1,239 children were randomly assigned to the GSK_MMR lot 1 study group, 1,232 to the GSK_MMR lot 2 group, and 1,243 to the GSK_MMR lot 3 group.

The according-to-protocol (ATP) cohort for immunogenicity included 4,498 participants. At Day 42, “All success criteria for GSK_MMR lot-to-lot consistency were met,” said Dr. Klein.

In addition, non-inferiority of GSK_MMR pooled lots was demonstrated to MRK_MMR for both seroresponse rate and geometric mean concentration, including for anti-measles, anti-mumps, and anti-rubella. Pooled lots showed GSK_MMR met the success criterion for seroresponse rate.

Among the total vaccinated cohort, “solicited symptoms occurred at a similar frequency in recipients of GSK_MMR and MRK_MMR,” she said. This included pain, 25.9% vs 28.1%; redness, 24.5% vs 25.2%; and swelling, 8.9% vs 10.7%, at the injection site, respectively. Fever was 19.7% vs 18.2% Days 5–12 post-vaccination.

The general symptoms of drowsiness, irritability/fussiness, and loss of appetite Day 0–14 post-vaccination were also similar between the GSK_MMR and MRK_MMR cohorts.

Reactogenicity for MMR-specific solicited symptoms at Days 0–42 post-vaccination—febrile convulsion, parotid gland swelling, and rash, localized or generalized—was similar between the GSK_MMR and MRK_MMR pooled lots.

The study was funded by GlaxoSmithKline Biologicals SA.