Here’s why BeyondSpring shares are up more than 25% on Monday

Shares of BeyondSpring Inc (NASDAQ: BYSI) gained more than 200% in August as the pharmaceutical company said its candidate drug (Plinabulin) improved life expectancy for patients with advanced lung cancer.

This morning, however, the stock tanked over 25% as STAT (American health-oriented news website) published an article that said “issues with the conduct and analysis of the clinical trial” invoked a debate on the authenticity of the company’s claim.

Why the U.S. FDA could object to BeyondSpring’s Plinabulin trial

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BeyondSpring is expected to seek authorization for Plinabulin from the U.S. Food and Drug Administration (FDA) in early 2022.

The STAT article also said that the regulator could object to the company’s clinical trial based on demographics as only 20% of the participants came from U.S. hospitals. The study, therefore, might not reflect a “typical American population”.

Was Plinabulin’s effect on overall survival clinically meaningful?

On top of that, BeyondSpring’s Plinabulin trial only demonstrated its post-chemo effect, with just 15% of the 559 subjects having failed PD-(L)1 blockade. Defending the result, the U.S. firm’s chief medical officer Ramon Mohanlal said last month:

Even if we have only a relatively small number of patients who had had a prior PD-(L)1 inhibitor, the claim still holds that this is a treatment for second and third line generally, irrespective of what patients had before.

Mohanlal, however, refrained from calling Plinabulin’s effect on overall survival (OS) of patients with lung cancer clinically meaningful – another factor that investors might now be seeing as a red light.