05:35 AM EDT, 09/08/2025 (MT Newswires) -- Merck ( MRK ) said Sunday that results from its IDeate-Lung01 phase 2 trial evaluating ifinatamab deruxtecan in patients with previously treated extensive-stage small cell lung cancer showed clinically meaningful response rates.

The company said patients who received ifinatamab deruxtecan in both parts of its trial, dose optimization and single-arm expansion, displayed an objective response rate of 48.2% as assessed by blinded independent central review.

The company said the latest data demonstrate a median progression-free survival of 4.9 months and a median overall survival of 10.3 months.

Ifinatamab deruxtecan is a type of antibody drug conjugate being jointly developed by Daiichi Sankyo and Merck ( MRK ), the company said.