The U.S. Food and Drug Administration ordered a partial clinical hold and froze enrollment in MacroGenics’ Phase 2 lorigerlimab trial after a patient death and multiple life‑threatening adverse events. The company disclosed the hold following the safety signal, and regulators have demanded additional safety data before allowing enrollment to resume. MacroGenics paused dosing and is engaging with the FDA to define next steps; the hold affects the company’s development timeline and investor outlook. The agency’s action highlights heightened scrutiny of immune‑modulatory oncology agents, particularly when severe immune‑related toxicities occur in mid‑stage studies. Biotech sponsors will view this event as a reminder to prioritize comprehensive safety monitoring and to prepare for rigorous FDA engagement when unexpected severe events arise in immuno‑oncology trials.