Daiichi Sankyo and Merck paused enrollment in the Phase III IDeate-Lung02 trial of an antibody-drug conjugate (I-DXd/ifinatamab deruxtecan) after a higher-than-anticipated incidence of grade 5 interstitial lung disease (ILD) events and reported patient deaths. Daiichi informed regulators and sponsors that the pause is voluntary while safety data are reviewed by the independent data monitoring committee and the U.S. FDA. The partial hold spans multiple European countries and an FDA-imposed partial clinical hold in the U.S. Regulators and the companies will analyze accumulated safety signals and determine next steps for trial conduct and patient monitoring. The companies have not disclosed the precise number of deaths. The pause highlights ongoing safety challenges for ADCs in certain lung indications and will influence risk assessments for ongoing and planned ADC programs across oncology portfolios.