Icosavax announces interim results from IVX-A12 trial

Icosavax announced topline interim results from its Phase 2 clinical trial of IVX-A12 against respiratory syncytial virus, or RSV, and human metapneumovirus, or hMPV, in older adults. Topline interim safety and immunogenicity data from this trial were generally consistent with the previously reported Phase 1 data for IVX-A12. Solicited local and systemic adverse events, or AEs, collected within seven days of vaccination were generally mild to moderate without severe events. No cases of fever were reported in any group. For unadjuvanted IVX-A12, the proportion of subjects experiencing any systemic AE within seven days was 32%, and similar to placebo. The most common local and systemic AEs were injection site tenderness, injection site pain, and myalgia. There were no vaccine related serious adverse events, or SAEs, clinical events or AEs of special interest, or AESIs, or AEs leading to discontinuation. IVX-A12 induced robust immune responses against both RSV and hMPV at Day 28 across both formulations with and without adjuvant. For unadjuvanted IVX-A12: IVX-A12 induced geometric mean titers, or GMTs, in RSV-A neutralizing antibody titers, or nAbs, of approximately 12,200 IU/mL compared to approximately 2,000 IU/mL for placebo at Day 28. IVX-A12 induced GMTs in RSV-B nAbs of approximately 5,500 IU/mL compared to approximately 1,300 IU/mL for placebo at Day 28. IVX-A12 induced GMTs in hMPV-A nAbs of approximately 1,600 assay units/mL compared to approximately 400 assay units/mL for placebo at Day 28. IVX-A12 induced GMTs in hMPV-B nAbs of approximately 15,300 assay units/mL compared to approximately 6,700 assay units/mL for placebo at Day 28. No standardized international units exist in the field for hMPV.