ESMO I-O: Keytruda shines among KRAS-mutated patients in Merck's latest lung cancer analysis

GENEVA—With all the buzz about KRAS these days, Merck’s been fielding its fair share of questions about whether lung cancer patients with KRAS mutations respond as well to Keytruda as other previously untreated patients do. So the New Jersey drugmaker set out to answer them.

Its findings? Pitted against chemo, Keytruda reduced the risk of death by 58% among patients with any KRAS mutation and by 72% among patients with a KRAS G12C mutation, Merck said in a Thursday presentation at the The ESMO Immuno-Oncology Congress.

“The effect of Keytruda was really preserved very well. The effect sizes were really quite dramatic,” said Roy Baynes, M.D., Merck SVP and head of global clinical development. “I think the bottom line is that, directionally, the responses are very, very consistent whether you have a RAS mutation or not.”

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The data help put aside “a question that has been asked a number of times,” especially as interest in KRAS—and candidates targeting KRAS, one type of RAS mutation—has mounted. Amgen’s investors have been eagerly following along all year as the Big Biotech rolled out promising data for its AMG510 in non-small cell lung cancer; about 20% of patients with the disease harbor KRAS mutations.

The new analysis also begs the question of what results might look like for patients receiving a combination of Keytruda and a RAS-targeting drug, Baynes said, noting that “that’s an important area to consider.” He didn’t comment on what Merck’s got going in the RAS arena, but Amgen, for its part, has said it’s looking to test its prospect alongside checkpoint inhibitors.

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Meanwhile, it’s not the first time in recent months that the New Jersey pharma giant has turned to its treasure trove of trial data to silence Keytruda’s doubters. Back in September, a similar analysis dispelled the myth that Keytruda’s performance was linked to patients’ levels of investigational biomarker TMB, or tumor mutational burden.

“We have this very rich database, so we can obviously answer these questions quite quickly—and that’s exactly the point," Baynes said.