Daiichi Sankyo paused enrollment in the phase III IDeate-Lung02 study of the antibody-drug conjugate ifinatamab deruxtecan following a higher-than-anticipated incidence of fatal interstitial lung disease (grade 5 ILD) events. The company reported the pause across numerous European sites and the FDA placed a partial clinical hold while it, Daiichi Sankyo and an independent data monitoring committee review safety data. The action underscores continued regulatory scrutiny of ADC safety signals and will trigger formal data reviews that could affect dosing, label strategies, or trial design. Sponsors and CROs running ADC programs are likely to reassess monitoring plans and risk mitigation measures in ongoing studies.