Icosavax (Nasdaq:ICVX) saw its stock skid 65.5% to $4.26 in mid-day trading after announcing interim results from an ongoing Phase 1/2 trial of IVX-411, a virus-like particle vaccine candidate against SARS-CoV-2.
After going public last July, the company’s stock hit a peak of $39.73 on September 3.
Initial data from IVX-411 was comparable or below human convalescent sera control in previously unvaccinated individuals.
Three weeks after receiving the second vaccine dose, participants’ responses were up to 154 IU/mL across dosage groups in the live virus neutralization assay and up to 592 BAU/mL across groups in the spike IgG assay. The corresponding human convalescent sera control figures were 281 IU/mL and 361 BAU/mL, respectively.
In previously vaccinated participants, an IVX-411 booster drove up neutralizing antibody titers 5x to 599 IU/mL for wild-type virus after 28 days. For the omicron variant, neutralizing antibody titers were as much as eight-fold lower than for the wild-type virus.
Icosvax chief medical officer Niranjan Kanesa-thasan noted in a news release that the immunologic response was “below our expectations.”
“We plan to investigate the potential causes of these discordant clinical results, including manufacture, shipment, and administration of the product,” said Icosavax CEO Adam Simpson.
The study recruited 84 SARS-CoV-2 naive individuals and 84 previously vaccinated adults.
Before going public, Icosavax announced that it had closed $100 million in Series B financing, which it set aside for the development of its SARS-CoV-2 vaccine candidate.