The Safety, Tolerance, and Immunogenicity of MAS-1-Adjuvanted Seasonal Inactivated Influenza Vaccine (MER4101)

Summary

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Description

The study is a Phase 1A, 1B and 1B extension, randomized, double-blind, single-center, clinical trial, in healthy adults (18-49 years old) and ambulatory elderly subjects (aged 65 years and older). Phase IA evaluated the safety, tolerability and hemagglutination inhibition assay (HAI) antibody respo...

The study is a Phase 1A, 1B and 1B extension, randomized, double-blind, single-center, clinical trial, in healthy adults (18-49 years old) and ambulatory elderly subjects (aged 65 years and older). Phase IA evaluated the safety, tolerability and hemagglutination inhibition assay (HAI) antibody response to MER4101 at each of four escalating doses of seasonal inactivated influenza vaccine (IIV) hemagglutinin (HA) antigen with a fixed dose of a water-in-oil emulsion adjuvant MAS-1 (Mercia Adjuvant System-1), compared with licensed, unadjuvanted, standard dose (SD) of licensed inactivated trivalent influenza virus vaccine (IIV). Phase IB evaluated the optimal dose of IIV in MAS-1 selected under phase IA for safety, tolerability and HAI antibody response (from Phase 1A known to be 9 µg of HA antigen in 0.3 mL dose of MAS-1 adjuvanted emulsion) in ambulatory elderly subjects compared to high dose (HD) IIV. The Phase 1B extension will evaluate if the increased dose volume of MAS-1 (0.5 mL vs 0.3 mL) at the same 9 µg/HA adjuvanted IIV vaccine is safe, well tolerated and immunogenic, and then whether the increased dose of 15 µg/HA in 0.5 mL MAS-1 is safe, well tolerated and still more immunogenic in elderly subjects. The ability of standard dose (SD) IIV to protect against seasonal influenza virus infection in the elderly is less than vaccine efficacy observed in healthy young adults. The MAS-1-adjuvanted influenza virus vaccine offers the potential for higher seroconversion and seroprotection rates, hemagglutination inhibition (HAI) antibody titers relative to pre-vaccination HAI titers (GMFI), hemagglutinin (HA) antigen dose-sparing and cross-protection against antigenically divergent viral strains, and importantly, prolonged duration of protective immunity lasting up to at least 6 months post-vaccination in both the general adult population and the elderly, thereby providing potentially protective immunity throughout the influenza season. This study will determine if the adjuvanted vaccine formulated with one or more of the reduced HA antigen doses is safe. The study will also determine if it is likely to induce an improved HA antibody response (HAI) when compared to SD IIV in healthy adults and HD IIV in elderly subjects. This trial will inform future clinical trials in at-risk populations of older patients.

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