Daiichi Sankyo and Merck’s phase III program testing an antibody‑drug conjugate (I‑DXd/ifinatamab deruxtecan) in small‑cell lung cancer was placed on partial clinical hold after a higher‑than‑anticipated incidence of fatal interstitial lung disease events. Daiichi halted enrollment and will collaborate with the FDA and an independent data monitoring committee to review safety data. At the same time, industry coverage shows renewed investor and developer interest in ADC targets such as B7‑H3 (CD276). Multiple preclinical programs and newly raised VC‑backed startups are advancing B7‑H3 ADCs, and larger pharma players are reported to be accelerating programs, signaling both therapeutic promise and the need for careful safety profiling in ADC development. The twin developments emphasize a sector‑wide tension: ADCs' potent therapeutic payloads create both high upside and serious safety risks, prompting regulators and sponsors to scrutinize pulmonary toxicity signals and target selection more closely.