What happened

After a whopping 41% drop yesterday, shares of the clinical-stage biotech Five Prime Therapeutics (NASDAQ:FPRX) are on the mend today as the result of an upbeat clinical update. Specifically, Five Prime provided an investor update this morning regarding the company's experimental pancreatic cancer drug, cabiralizumab, that's currently being assessed in combination with Bristol-Myers Squibb's (NYSE:BMY) immunotherapy Opdivo (nivolumab) in an early-stage study.

The key takeaway is that the combo produced a "durable clinical benefit" in 16% of the patients (5/31) enrolled in this study so far. Bristol and Five Prime also noted that the therapy has an acceptable safety safety profile when assessed across its broader clinical program for solid tumors, although there were three treatment-related deaths. Five Prime's shares ended the day up 17.7% as a result of this news.

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Image source: Getty Images.

So what

Yesterday, investors hit the panic button on Five Prime's stock largely because of these forthcoming results. The problem is that pancreatic cancer rarely responds to experimental therapies in general, and investors seemed to be anticipating that this combo would be yet another dead end.

However, a 16% durable response rate is actually quite respectable for this particular malignancy, and this result would probably even garner an approval from the U.S. Food and Drug Administration if this was a larger, pivotal-stage trial. Five Prime's investor update today appears to have gotten this point across based on today's double-digit move northward.   

Now what

Perhaps most importantly, Bristol and Five Prime announced in today's presentation that the two companies will advance this combination therapy's clinical program by enrolling an additional 30 patients in this ongoing early-stage trial. While there's no way to know if the therapy will have continued success in this extremely hard-to-treat malignancy, it is a product candidate well worth keeping an eye on going forward. An effective pancreatic cancer therapy, after all, could easily generate several hundred million in sales, if not billions. 

George Budwell has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.