Merck’s favezelimab is latest Lag3 to falter

Investors got another reminder on Wednesday that expanding anti-Lag3 antibodies out of melanoma is hard, with the failure of Merck’s favezelimab/Keytruda combo in colorectal cancer. The phase 3 Keyform-007 study was testing a fixed-dose combination in previously treated patients with microsatellite-stable disease; Merck said it hadn’t shown a benefit on overall survival versus Stivarga or Lonsurf, but didn’t give details. Bristol Myers Squibb’s Opdualag flunked a similar study, Relativity-123, last year. Merck has other shots with favezelimab: the next big readout will be in Hodgkin’s lymphoma, a setting where Bristol’s phase 1/2 Relativity-069 trial is also under way. Many of Merck’s favezelimab efforts involve early-stage basket studies, suggesting that the company is taking a more cautious approach than Bristol, which recently took Opdualag into phase 3 in first-line NSCLC despite failing the mid-stage Relativity-104 study. Favezelimab plus Keytruda has disappointed in NSCLC, but Merck still listed the disease among the potential indications for its Lag3 contender in its second-quarter earnings presentation. Meanwhile, Regeneron is largely focused on melanoma with its Lag3 contender fianlimab, although phase 2 data are expected in first-line NSCLC this year.

Mid-to-late-stage trials of favezelimab

Note: MK-4280A=fixed-dose favezelimab/pembrolizumab. Source: OncologyPipeline.