
Icosavax keeps up the excitement for its VLP 'soccer balls,' earning the RA Capital stamp of approval in $100M Series B
Roughly a year and a half since its last raise, Icosavax scored a fresh goal Wednesday morning in nabbing new funds for its soccer ball-like VLP vaccine tech. And the Seattle-based company is bringing in a high-profile set of new investors.
Icosavax unveiled a $100 million Series B, backed by Peter Kolchinsky’s RA Capital Management and Perceptive Advisors, among others. Kolchinsky scores a board seat with the raise, as the biotech plans to use its newfound cash to advance a handful of vaccine programs for SARS-CoV-2 and viruses that trigger pneumonia.

The big idea around Icosavax centers around its virus-like particle vaccine platform, developed out of the lab of Neil King at the University of Washington. King and his team built on years-old research of how some viral proteins could spontaneously assemble themselves, working out a design system for similar particles with software.
His research produces an end result of what’s essentially a particle shaped like a soccer ball — the “white” parts making up the structure and the “black” spots representing the displayed antigens. It’s the same technology King is using to develop a “super-seasonal” flu vaccine described in a new paper published just a few weeks ago, though Icosavax wasn’t involved in that research.
Originally, Icosavax had been working on a vaccine for respiratory syncytial virus. The company is still working on that candidate, which incorporates an antigen that has completed a Phase I study run by the NIH. Wednesday’s funds will be used for not only this program, known as IVX-121, but a newer candidate that aims to tackle two viruses at once, CEO Adam Simpson told Endpoints News.
One of the breakthroughs discovered at the NIH dealt with the nature of the RSV antigen itself. The virus, unbeknownst to researchers for years, is a shapeshifter — it presents differently after it invades cells. Historically, scientists had gone after the post-fusion form of the virus, but that didn’t stop the virus from causing infections.
But the NIH managed to stabilize an antigen representing the prefusion form of the virus, Simpson said, which is ultimately what Icosavax licensed.
In the 17 or so months following the last round, Icosavax has advanced its RSV program as intended, and is now also looking to make a dual vaccine to fight both RSV and human metapneumovirus. Both are prevalent causes of pneumonia from the viral side of things, as opposed to better-known pneumococcal bacteria.
“In this case we’ll have two different ‘soccer balls’ in one vial,” Simpson told Endpoints. The design could have featured a single soccer ball displaying both RSV and hMPV as well.
The plan, Simpson added, is to start with the RSV vaccine and then “layer” the hMPV antigens into the shot as development continues. IVX-121 is expected to enter another clinical trial later this year, and based on the data should enable the bivalent vaccine studies.
Icosavax’s Covid-19 program also got some love from the investor group, with some of Wednesday’s funds headed toward a Phase I trial launch for the candidate this year. This vaccine, dubbed IVX-411, has already received $10 million in backing from the Bill and Melinda Gates Foundation. Amgen is also chipping in on the manufacturing side, agreeing to produce a critical component of the compound and allowing for a more rapid transition into Phase I.
Simpson stayed mum on timelines for data readouts, noting that with the pandemic still raging enrollment rates can be difficult to predict. And despite the crossover nature of the round, he demurred about potential IPO plans, saying “we’re well aware of the market.”
RA Capital Management led the round, and Perceptive was joined by other new investors Janus Henderson Investors, Viking Global Investors, Cormorant Asset Management, Omega Funds, and Surveyor Capital. Icosavax’s existing investors also participated, including Qiming Venture Partners USA, Adams Street Partners, Sanofi Ventures, and ND Capital. A previously announced funding from Open Philanthropy was included in this round.