This Phase 3 study will evaluate the consistency of the immune response to three different lots of GSK Biologicals' trivalent investigational MMR vaccine (referred to as INV_MMR vaccine, throughout this document) and compare its immunogenicity to the US standard of care comparator vaccine (M-M-R II, Merck and Co., Inc., referred to as COM_MMR throughout this document) in children during their second year of life.

The INV_MMR vaccine will be given as one of three consistency lots manufactured to target potencies designated as INV_MMR_L1, INV_MMR_L2, and INV_MMR_L3. The COM_MMR vaccine will be given as one of two lots designated COM_MMR_L1 and COM_MMR_L2 and will be analyzed as pooled lots within the study.

The MMR vaccine will be co-administered with Varivax (VV), Havrix (HAV), and (in the US sub-cohort only) Prevnar 13 (PCV-13), which are routinely administered to children of this age in the US.

Results

The Journal of the Pediatric Infectious Diseases Society published results for this clinical trial on April 30, 2020.

Results: Immunoresponses after vaccination with MMR-RIT were robust and non-inferior to those after vaccination with the MMR II. Immunogenicity of the 3 production lots of MMR-RIT was consistent; more than 97% of the children had a seroresponse to MMR components. The coadministered vaccines elicited similar immune responses in the MMR-RIT and MMR II groups. Both MMR vaccines resulted in comparable reactogenicity profiles, and no safety concerns were detected.

Conclusions: If licensed, the MMR-RIT could provide a valid option for preventing measles, mumps, and rubella in children in the United States and would reduce the potential risks of a vaccine shortage.