Trial deaths frustrate Merck's bid to pair Keytruda with Celgene's myeloma stars

New Keytruda image
Merck says the risks of adding Keytruda to Celgene meds Pomalyst or Revlimid outweigh the potential benefits.

After reviewing deaths in two Keytruda trials, the FDA put both Merck studies on clinical hold and stopped Keytruda dosing in a third, thwarting Merck's hopes for combining Keytruda with Celgene's big-selling myeloma meds Pomalyst and Revlimid.

All patients in Keynote-183 and Keynote-185as well as the Keytruda combo arm in Keynote-023will discontinue Keytruda treatment, Merck said Wednesday. All three trials pair the company’s immuno-oncology star with dexamethasone and either Celgene’s Pomalyst (pomalidomide) or Revlimid (lenalidomide).

“Data available at the present time indicate that the risks of Keytruda plus pomalidomide or lenalidomide outweigh any potential benefit for patients with multiple myeloma,” the New Jersey drugmaker said in a statement.

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The news follows Merck's mid-June notice that an independent data monitoring committee had flagged an imbalance in patient deaths in the active arms of Keynote-183 and Keynote-185. The company said it had halted enrollment, though it wouldn’t say much elseincluding anything about the number of patients who had died.  

With info still scarce, Credit Suisse analyst Vamil Divan said in a client note that he and his colleagues “hesitate to draw any significant conclusions at this time.” He did point out, however, that he sees Keytruda’s overall potential as “underappreciated, even with the termination of these studies.”

RELATED: In unexpected blow, Merck halts Keytruda myeloma trial enrollment to probe patient deaths

Barclays’ Geoff Meacham echoed that sentiment, writing in his own research note that “we see today’s announcement as a modest setback for Merck, but note that MM was never a key driver of our Keytruda sales forecasts.”

“Initial data presented at last month’s ASCO had been incremental at best, and we did not expect the indication to be a significant stock-mover for Merck,” he added.

At the same time, however, the stumble could be an opportunity for the pharma giant’s immuno-oncology rivals, which are racing with one another to rack up indications in various tumor types. Key competitors Bristol-Myers Squibb and AstraZeneca each started up their own myeloma trials within a year of Merck’s, and “it will be very interesting to see the fate” of those studies, Evercore ISI analyst Umer Raffat wrote to investors.