What happened

Agenus (NASDAQ:AGEN), a small-cap immunotherapy company, saw its stock gain a healthy 51% during the month of May, according to data from S&P Global Market Intelligence. The biotech's shares perked up late last month in response to a positive clinical update for its cancer immunotherapy pipeline presented at the American Society for Clinical Oncology (ASCO) annual meeting.  

So what

The big draw for investors last month was the news that Agenus' experimental checkpoint inhibitor AGEN1181 may turn out to be a best-in-class product. In an early-stage trial, AGEN1181 produced a 70% clinical benefit in patients with various solid tumors.

Cells undergoing division.

Image source: Getty Images.

What's more, the therapy reportedly produced a more-favorable safety profile versus similar anti-cancer antibodies, such as Bristol Myers Squibb's Yervoy. That's a big deal because Yervoy is currently a blockbuster product (greater than $1 billion in annual sales). So Agenus may have a game-changer on its hands from a value creation standpoint.   

Now what

Agenus plans on accelerating AGEN1181's development as a treatment for a host of solid tumors, including advanced skin and lung cancer. The key take-home point is that this anti-cancer therapy may now have a real shot at generating blockbuster sales. To put this potential revenue figure into the proper context, Agenus' market cap presently stands at just $653 million, so this small-cap biotech stock, in turn, may be a diamond in the rough. If you're the aggressive type, it might be worthwhile to grab a few shares soon.  

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.