Celldex reported that its experimental barzolvolimab met primary endpoints in two Phase 3 trials for chronic spontaneous urticaria, but safety questions emerged due to two life-threatening anaphylaxis cases. The mixed result complicates the risk-benefit narrative as the company weighs next regulatory and development steps. The readout is likely to influence trial and regulatory discussions around dosing, patient selection, and mitigation strategies. For investors, it reinforces that late-stage autoimmune success can still hinge on rare but high-severity adverse events.