AACR: One year after mammoth lung cancer win, Merck's Keytruda holds its own in tough-to-treat subgroups

Merck unveiled a new Keynote-189 analysis at this year's AACR annual meeting in Atlanta. (Pixabay)

ATLANTA—At last year’s American Association for Cancer Research annual meeting, Merck’s Keytruda-chemo combo stole the spotlight with stellar lung cancer data. And this year, the company was back to show the regimen's results held up in historically tough-to-treat patient groups.

Among previously untreated non-small cell lung cancer (NSCLC) patients with liver and brain metastases who participated in Merck’s Keynote-189 trial, the Keytruda-chemo pairing significantly cut the risk of death compared with solo chemo, a new analysis showed. Sixty-six patients with liver metastases saw their risk of death shrink by 38%, and that number was even higher—59%—among 73 patients with brain metastases.

As Roy Baynes, Merck senior vice president and head of global clinical development, put it, “the effect size is convergent with what we saw in the parent trial.”

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In that trial, presented at AACR last April, the chemo combo slashed the risk of death by a whopping 51%. And the benefit held across patients with high levels of biomarker PD-L1, low PD-L1 levels and those who were PD-L1 negative.

“It really just speaks to the notion that it is inordinately active across subgroups and obviously the whole study,” Baynes said.

The new data will help cement Keytruda’s lead in the first-line lung cancer market, though the lead is already pretty solid. Merck snagged its chemo combo approval—its second for Keytruda in front-line NSCLC—back in May of 2017, and it didn’t get any immuno-oncology competition until Roche secured an FDA green light for its Tecentriq-Avastin-chemo cocktail in December.

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And in that time—especially since the Keynote-189 data made their debut—uptake of Keytruda “has been really quite dramatic,” Baynes said.

Meanwhile, competitors haven’t fared nearly as well. Last year, AstraZeneca’s Imfinzi-tremelimumab combo failed to show a benefit in the first-line setting, and Bristol-Myers Squibb earlier this year withdrew its seemingly doomed Opdivo-Yervoy FDA filing, citing a need for more data.