A Phase 2 Trial of a Respiratory Syncytial Virus and Human Metapneumovirus Combination Virus-Like Particle Vaccine IVX-A12 in Adults ≥60 Years of Age
Temitope Oyedele, Lawrence D Sher, Kelly Morales, Craig Shapiro, Elizabeth Adams, Margaret MacDonald, Judy Wen, John A Pura, Kathryn Shoemaker, Jennifer Price, Ami Shah Brown, Anastasia A Aksyuk, Taylor S Cohen, Lee-Jah ChangAbstract
Background
Older adults (≥60 years) are susceptible to severe outcomes from infection with respiratory syncytial virus (RSV) or human metapneumovirus (hMPV). IVX-A12 is an investigational vaccine that uses virus-like particles (VLPs) to elicit an immune response against RSV and hMPV.
Methods
This Phase 2 trial (NCT06481579) randomized (1:1) adults ≥60 years of age to receive a single dose of IVX-A12 (150 µg RSV/150 µg hMPV) or the licensed RSV vaccine RSVPreF3 120 µg with AS01E adjuvant. Safety and immunogenicity were evaluated through 180 days post-vaccination.
Results
Overall, 143 participants received IVX-A12 (n = 71) or RSVPreF3 (n = 72). Solicited adverse reactions were reported through 7 days post-vaccination (IVX-A12, 25 [35.2%]; RSVPreF3, 36 [50.0%]). Unsolicited adverse events (AEs) were collected through Day 29 (IVX-A12, 5 [7.0%]; RSVPreF3, 11 [15.3%]). Serious AEs (IVX-A12, 2 [2.8%]; RSVPreF3, 1 [1.4%]) and medically attended AEs (IVX-A12, 1 [1.4%]; RSVPreF3, 9 [12.5%]) were documented through Day 181. There were no AEs of special interest and AEs leading to study discontinuation. At Day 29, IVX-A12 and RSVPreF3 administration increased RSV A neutralizing antibody (nAb) levels with geometric mean fold rise (GMFR) of 3.4 and 6.5, and RSV B nAb levels with GMFR of 2.9 and 5.4, respectively. IVX-A12, but not RSVPreF3, also increased hMPV A (GMFR 3.0) and hMPV B (GMFR 2.9) nAb levels.
Conclusions
IVX-A12 and RSVPreF3 were well tolerated and elicited nAb responses against their targeted pathogens. Given the neutralizing antibody response following IVX-A12, further investigation of an RSV-hMPV VLP combination vaccine is warranted.