What happened

Investors were hoping that when an abstract for presentation at the upcoming American Society of Clinical Oncology was released today, it would show robust efficacy for JTX-2011, Jounce Therapeutics' (NASDAQ:JNCE) lead drug candidate. Unfortunately, the data underwhelmed investors, sparking a steep sell-off that wiped out 35.2% of the company's market value on Thursday.

So what

In collaboration with Celgene Corp. (NASDAQ:CELG), Jounce has JTX-2011 in phase 2 studies as a monotherapy and in combination with Opdivo for the treatment of various solid tumor cancers, including head and neck squamous cell cancer, non-small cell lung cancer, triple negative breast cancer, melanoma, and gastric cancer.

A man in dress clothes sits on the ground, holding his head in his hands, in front of a big monitor displaying a declining stock share price.


In March, Jounce Therapeutics revealed it had submitted some trial data, including one efficacy assessment, for presentation at ASCO; today, those results were unveiled.

Specifically, as of Jan. 27, one out of seven gastric cancer patients had a partial response, and two out of five patients with triple negative breast cancer had stable disease after JTX-2011 monotherapy. In the combination cohort, there were two partial responses and two patients with stable disease out of 19 patients. Also, one out of 15 triple negative breast cancer patients had a partial response. 

Now what

Jounce Therapeutics believes the data confirm that JTX-2011 has anti-tumor effects, but clearly, investors were less than impressed by the readout.

It remains to be seen, however, how the data will mature across the entire patient population, and that could make today's sell-off an overreaction. We'll have to wait for more data to parse before we can say for certain that the commercial opportunity for JTX-2011 is dashed. After all, patients in this trial are heavily pre-treated with few treatment options, so any response at all is welcome.

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.