Pfizer, Merck KGaA run into a severe setback as PD-L1 drug Bavencio fails in PhIII gastric cancer study

Pfizer $PFE and its partner Merck KGaA have run into a dead end in their race to expand the market for their PD-L1 checkpoint Bavencio (avelumab). Researchers today conceded that the checkpoint — one of 5 now scrambling to expand their market turf in the mega-blockbuster global oncology business — failed to significantly improve overall survival for advanced gastric cancer patients compared to best standard of care.

We won’t see the data until a later scientific conference to be decided on, but the JAVELIN Gastric 300 flop will put a definite hitch in their plans to expand sales for a key drug in both companies’ pipelines.

Luciano Rossetti, Merck KGaA

Merck KGaA R&D chief Luciano Rossetti put the failure down to their decision to test the drug against currently used chemo rather than a placebo. He noted:

“Gastric cancer in the third-line setting is a particularly hard-to-treat and heterogeneous disease, and importantly, this was the first trial conducted with a checkpoint inhibitor compared to an active chemotherapy comparator rather than placebo in a global patient population.”

The trial enrolled 371 patients from 147 sites in Asia, Australia, Europe, North America and South America. Gastric cancer counts as the third most common type of cancer killer.

Their misfortune is US Merck’s gain, as well as Bristol-Myers Squibb’s, which both earned third-line approvals after testing their drugs against a placebo.

Merck gained an accelerated OK from the FDA two months ago to use Keytruda, a PD-1 checkpoint, against advanced gastric cancer after laying out marginally successful response rates for patients whose tumors hit the mark on PD-L1 expression. And after looking over the data on overall survival for both approved therapies, Uber Raffat at Evercore ISI concluded that Pfizer and Merck KGaA faced tough odds from the start.

And the failure raises another issue, he says:

Immediately makes you wonder: is avelumab inferior on efficacy?  And does this tie into the broader PDL1 vs PD1 debate?

That debate centers on a heated discussion of whether PD-L1 is inherently weaker than PD-1, so you can expect to hear lots more about it.

This setback for Pfizer and Merck KGaA also underscores the series of stunning surprises that continues to advance some players while others are held back. Checkpoints, which removes a brake on an immune system response to cancer cells, are fast entering the standard of care in a wide range of oncology markets, both as a solo therapy as well as in combination. And there’s been a frenzied race to field new checkpoints, as we highlight in this recent piece noting 50 PD-1/L1 therapies in the clinic and 114 more in preclinical development.

Still in the pipeline is a Phase III study — JAVELIN Gastric 100 — which is testing the checkpoint as a frontline therapy for gastric cancer.

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VP Oncology Biology
Skyhawk Therapeutics Waltham, MA
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Elektroki Boston, MA
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