Merck and Daiichi look beyond small cell with ifinatamab

Daiichi Sankyo and Merck & Co are to start a pivotal trial of the B7-H3-targeting ADC ifinatamab deruxtecan in oesophageal cancer, adding to ongoing efforts in small-cell lung cancer. The latest trial, Ideate-Esophageal01, will test ifinatamab-dxd against investigator’s choice chemo in oesophageal squamous cell carcinoma patients who’ve progressed after platinum and checkpoint inhibitors, according to a recently unveiled listing on clinicaltrials.gov. A clue about ifinatamab-dxd’s potential here could come from the phase 1/2 Ideate-Pantumor01 study, which found an ORR of 21% among 28 oesophageal patients with a median of four prior lines of therapy. Keytruda and Opdivo chemo combos are approved in first-line oesophageal cancer, with ORRs of around 45%, but look set to be restricted to PD-L1 expressers. The Ideate-Pantumor01 results could also give an indication of where Merck and Daiichi might go next: the companies have also reported results in late-line castration-resistant prostate cancer and squamous NSCLC. Meanwhile, in SCLC, the groups are now testing a combination of ifinatamab-dxd and the DLL3-targeting T-cell engager MK-6070 – something that looked likely since August, when they teamed up on this asset. MK-6070 was originally developed by Harpoon, which Merck acquired for $680m earlier this year.

Notable trials of ifinatamab deruxtecan

Notes: all trials global and sponsored by Daiichi, except HPN328-4001, sponsored by Merck. ESCC=oesophageal squamous cell carcinoma; SCLC=small-cell lung cancer. Source: OncologyPipeline & clinicaltrials.gov.