CHICAGO — Merck wowed the immuno-oncology market early this year with the headline news that its pivotal KEYNOTE-189 study demonstrated a clear success for Keytruda combined with chemo in treating frontline lung cancer cases. And at AACR in Chicago today, its investigators spelled out the promising results — demonstrating that the combo reduced the risk of death by half with a hazard ratio of 0.49 — as Merck looks to hold back a wave of major league competitors as it carves out a bigger share of the blockbuster lung cancer market.
In the first look at hard data for nonsquamous non-small cell lung cancer — which will be carefully compared with the data from Bristol-Myers — researchers say that their combo clearly beat out chemo alone on overall survival, though the final OS rate for the combination has not yet been reached.
The greatest benefit among these patients was among the high PD-L1 expressers, but chief investigator Leena Gandhi at the Perlmutter Cancer Center at NYU Langone Health also says that the survival benefit could be seen across the board on PD-L1 expression.
Merck’s pivotal data from the -189 study are crucial to their campaign to be the leader in checkpoint inhibition. Approved by the FDA for frontline cases on Phase II data — but rejected in Europe — Merck says that physicians have been slow to change the way they treat lung cancer. Now Merck believes this data should resolve any doubts as Keytruda becomes the standard of care in this critically important setting.
At 12 months, Gandhi tells me, 69.2% of the combo arm was still alive, compared to 49.4% in the control arm.
According to Merck, patients in the drug arm were 51% less likely to die than the control group, and those in the highest PD-L1 score group were 58% less likely to die. The rates held up despite a high number of patients who crossed over to the combo after their disease progressed.
“The greatest benefit was seen in those with high levels of PD-L1 expression, suggesting that PD-L1 does have some predictive value even in this combination setting,” Gandhi said.
Median PFS was 8.8 months for the pembrolizumab arm, versus 4.9 months for the control group.
Some analysts have been waiting to see if the benefits for the combo leaned primarily to high PD-L1 expressers, leaving rivals an opening in divvying up the market on the rest. But Gandhi says the survival advantages are clear regardless of PD-L1 status. That marks a trend that many are seeing, where new therapeutic approaches are delivering enhanced results for the high-PD-L1 group while retaining promising results for the full field.
“There was no group that didn’t get a survival benefit in this study,” Gandhi says, with the results offering a practice-changing set of results. She also says she wants to fully consider the final data from Checkmate-227 (Bristol-Myers) and IMpower-150 (Roche) as she ponders the changing scene for practitioners.
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