What happened

Shares of the clinical-stage biotech Celldex Therapeutics (NASDAQ:CLDX) fell by 14.7% in October, according to S&P Global Market Intelligence. The good news -- if you can call it that -- is that Celldex's shares appear to have fallen simply because investors are tired of waiting for a major clinical update from the company's ongoing mid-stage trial assessing the antibody drug conjugate (ADC) glembatumumab vedotin, or glemba, in patients with triple negative breast cancer (TNBC). 

Chalkboard chart of a positive trend turning negative.

Image source: Getty Images.

So what

At the end of September, CEO Anthony Marucci gave a highly anticipated corporate update at the Cantor Fitzgerald Global Healthcare Conference that caused the company's shares to gain over 22% in just two days leading up to this presentation. Unfortunately, Marucci didn't really have all that much to say about glemba's progress in TNBC, which wasn't surprising since the trial isn't scheduled to readout until the first half of 2018. Even so, investors still decided to hit the exits.  

Now what

Celldex's near-term fate is heavily tied to glemba's forthcoming results in TNBC, especially since this trial could spark a regulatory filing if the drug can improve progression-free survival over standard chemotherapy. Patients with TNBC, after all, currently have few viable treatment options, implying that regulators might be open to approving a promising drug on an accelerated basis (i.e., without a large, randomized Phase 3 trial). Investors, though, shouldn't expect a major clinical update on glemba's progress in TNBC until perhaps the second quarter of next year at the earliest. And this lack of news flow may continue to weigh heavily on Celldex's shares in the interim. 

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.