On Thursday, Replimune (REPL 1.73%) had a crucial meeting with federal regulators regarding one of its leading drug candidates. While the outcome of the event wasn't necessarily negative, it left the future of the drug up in the air, and investors didn't like that uncertainty. As a result, they assertively traded out of the clinical-stage biotech's stock, leaving it with a nearly 40% loss on the day.

A fateful meeting?

The meeting was conducted with U.S. Food and Drug Administration (FDA) officials, and it took place on Tuesday. The subject of discussion was Replimune's RP1, a cancer drug being trialed as a combination therapy with pharmaceutical sector mainstay Bristol Myers Squibb's Opdivo to treat advanced melanoma.

Healthcare professional inspecting charts.

Image source: Getty Images.

In June, the regulator sent Replimune a complete response letter regarding RP1, a type of missive informing a drug developer that a given product will not be approved. That caught the company and many of its shareholders by surprise, as the drug had shown notable promise in clinical testing.

The Replimune/FDA summit took the form of a Type A meeting, described by the health agency as one that's "needed to help an otherwise stalled product development program proceed."

"The company is evaluating the feedback from the FDA provided during the meeting to determine next steps," Replimune wrote in its press release on the matter. "At this time, a path forward under the accelerated approval pathway has not been determined."

Uncertain fate

Clearly, investors took this to mean that the RP1 program will be discontinued. While we shouldn't necessarily jump to conclusions, Replimune's rather tepid and neutral statement on the future of the drug didn't strike a note of confidence.