What: Shares of Chimerix (NASDAQ:CMRX), a clinical-stage biopharma focused on antiviral drugs, rose more than 13% as of 11:15 a.m. ET. 

So what: There doesn't appear to be any news today to justify the strong share price move, so it's likely that shares are just recovering from their more than 80% plunge in late December. Shares collapsed after the company announced that brincidofovir, its lead product candidate, failed to deliver on its primary endpoint in its phase 3 SUPPRESS 3 trial. The trial was reviewing brincidofovir as a potential preventative treatment for cytomegalovirus infection in patients undergoing hematopoietic cell transplantation.

During the recent J.P. Morgan Healthcare Conference, its management team provided investors with an update on its plans for the year ahead, which included releasing more clinical data from the SUPPRESS trial in February. Chimerix confirmed that it is still working with both the Food and Drug Administration and European Medical Authority to see if a regulatory pathway for brincidofovir as a treatment for cytomegalovirus and kidney transplants still exists.

Now what: When the market is pricing a clinical-stage biopharma for great clinical news and the results come up short, it's common to see shares tank. Just ask shareholders of Esperion Therapeutics (NASDAQ:ESPR). Esperion Therapeutics shares were flying high last year but were then crushed on a less-than-perfect clinical update on its experimental hypercholesterolemia treatment, ETC-1002. The results were good enough to continue moving ETC-1002 down the regulatory pathway, but the FDA urged Esperion Therapeutics to launch a cardiovascular outcomes study as part of the drug's late-stage assessment. The FDA wanted the outcomes study completed before it could be submitted for regulatory review, and news of the delay caused shares to drop dramatically

Chimerix is in a worse position than Esperion Therapeutics as the results from the SUPPRESS trial brings serious questions to the market about the future of brincidofovir. While Chimerix is also studying brincidofovir as a potential treatment in helping Adenovirus and smallpox, its failure in one late-stage trial could mean that more are coming. Even after today's pop, the market is pricing the company for failure, as its current market cap of roughly $350 million is lower than its reported cash balance on Sept. 30 of $378 million.

Chimerix's stock is far riskier today that it was even just a few short months ago. I'd advise staying far away from this stock until we get a closer look at the details from the SUPPRESS trial to see if brincidofovir has a future.

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.