What happened

Shares of Agenus Inc (NASDAQ:AGEN), a biopharmaceutical company developing cancer therapies, had fallen about 14.5% as of 3:20 p.m. EST on Wednesday. Investors weren't too thrilled about its cancer vaccine's recent clinical trial failure.

So what

The Prophage G-200 vaccine involved using a patient's own cancer cells to direct a prolonged immune response against their brain tumors. Glioblastoma multiforme is a notoriously difficult-to-treat form of brain cancer, and earlier results suggested adding it to standard treatment would reduce a patient's risk of death compared to historical data.

Investor not happy about a sinking stock chart

Image source: Getty Images.

This was this little biotech's second most advanced candidate, but that's all over now. At a pre-scheduled interim analysis during a trial measuring Prophage plus Avastin versus Avastin alone, data monitors concluded there wasn't any chance the candidate would provide a statistically significant overall survival benefit.

Now what

Luckily, Agenus has several irons in the fire, or today's market thumping would have been more severe. Its QS-21 Stimulon technology is a component of two GlaxoSmithKline vaccine candidates approaching commercialization. Shingrix, a shingles vaccine, is expected to generate about $1.0 billion in annual sales by 2022, and the FDA is currently reviewing its application.

Further out, a collaboration with Incyte could eventually lead to substantial milestone and royalty payments. Earlier this month, Agenus stock surged when its big biotech partner amended their co-funded development-with-profit-and-loss-sharing agreement to a royalty-bearing collaboration. The amendment will ultimately reduce potential profits that Agenus might be able to earn from the collaboration, but it also shifts a great deal of risk to the larger partner.

While the failure of Agenus' Prophage cancer vaccine is deeply disappointing, there's still plenty for Agenus investors to look forward to.