What happened

Shares of Icosavax (ICVX) were soaring 28.3% as of 11:22 a.m. ET on Thursday. The big gain came after the biopharmaceutical company provided its fourth-quarter update following the market close on Wednesday.

Investors weren't focused very much on Icosavax's Q4 financial results. The company didn't generate any revenue and posted a net loss of $18.2 million.

However, Icosavax gave a couple of reasons to be cautiously optimistic after its announcement of disappointing interim results last week from a phase 1/2 study of experimental COVID-19 vaccine IVX-411. The company expects to soon release interim results from a phase 1 study of respiratory syncytial virus (RSV) vaccine candidate IVX-121. It also reported a cash position of $280.7 million, enough to fund operations at least through 2024.

So what

To be sure, Icosavax's latest update doesn't make up for the bad news for IVX-411. The vaccine stock is still down close to 70% year to date even with today's jump. But investors are hopeful that better days lie ahead.

Icosavax CEO Adam Simpson fueled those hopes with his comments about RSV vaccine candidate IVX-121. Simpson noted, "RSV represents a significant commercial opportunity." He added that the upcoming data readout in the second quarter of 2022 could provide "a near-term potential milestone that may also serve as clinical proof of concept for our VLP [virus-like particle] platform."

A scientist looking at a monitor showing a virus.

Image source: Getty Images.

Now what

There's an even bigger reason for investors to eagerly anticipate the interim phase 1 results for IVX-121. Icosavax plans to begin a phase 1 study of its first combination vaccine candidate, IVX-A12, targeting both RSV and human metapneumovirus in the second half of this year if the data for IVX-121 are positive.