Celldex’s barzolvolimab landed two Phase 3 chronic spontaneous urticaria wins but triggered new safety scrutiny after reports of life-threatening anaphylaxis cases associated with treatment. The company said the program met primary endpoints in both studies, even as the safety signals complicate the regulatory picture. The situation highlights the ongoing risk-benefit balancing in immunology drug development, where rapid systemic allergic reactions can carry meaningful labeling and monitoring implications. Clinicians and regulators will likely demand clearer characterization of who is at risk, dosing considerations, and mitigations before any marketing authorization decision. The market reaction suggests investors are weighing efficacy against potential regulatory friction.