RSV and hMPV Combo Vaccine Candidate Posts Positive Results

Icosavax, Inc. today announced positive topline interim results from its Phase 1 clinical trial of IVX-A12 against the respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) in older adults.

IVX-A12 comprises IVX-121, Icosavax’s RSV prefusion F protein VLP vaccine candidate, and IVX-241, Icosavax’s hMPV prefusion F protein VLP vaccine candidate.

“IVX-A12 is a potential first-in-class combination vaccine candidate designed to address an unmet medical need in older adults, and we believe these interim data for hMPV in an older adult population also break new ground in the field. Furthermore, as has been seen previously with prefusion F antigen approaches for RSV, we expect that a combination vaccine displaying prefusion F antigens for both hMPV and RSV, on our VLP technology, may translate into significant protection against two leading causes of pneumonia. Therefore, we plan to expeditiously proceed towards a Phase 2 trial for IVX-A12 in mid-2023 in older adults as we pursue our goal of developing a broader viral respiratory vaccine,” said Adam Simpson, Chief Executive Officer of Icosavax, in a press release on May 22, 2023.

In this Phase 1 trial, IVX-A12 induced robust immune responses against RSV and hMPV at Day 28 in older adults across dosage levels and with and without adjuvant.

When administered in combination, there was no evidence of immune interference between RSV and hMPV VLPs.

The IVX-121 (RSV) component of IVX-A12 (RSV/hMPV) previously demonstrated positive immunogenicity and tolerability results in a Phase 1/1b study, and a subset of these Phase 1b older adult subjects continue to be followed.

In December 2022, Icosavax reported positive durability data at six months, with twelve-month immunogenicity data expected in mid-2023.

Discovered in 2001, HMPV is in the Pneumoviridae family along with RSV, says the U.S. CDC.

Broader use of molecular diagnostic testing has increased the identification and awareness of HMPV as an important cause of upper and lower respiratory infections.

Other RSV vaccine candidate news is posted by Precision Vaccinations.