Evommune’s Phase 2b trial of EVO756 for chronic spontaneous urticaria (CSU) missed its primary endpoint, sending the stock down sharply and removing a potential challenger to Novartis in the CSU market. The study tested an oral MRGPRX2 antagonist across three doses versus placebo in 160 antihistamine-failed adults. Across the regimen, none of the EVO756 arms produced a statistically larger improvement than placebo on Urticaria Activity Score over seven days (UAS7) at Week 12. Evommune stated the doses were safe and well tolerated, but the lack of placebo-adjusted efficacy reduces confidence that the program can succeed in CSU. The setback leaves Novartis with fewer competitive concerns after its FDA approval of Rhapsido (BTK inhibitor) in CSU in September 2025. Evommune continues to test EVO756 in other itch-related areas, including an ongoing Phase 2b atopic dermatitis study expected to report data in the third quarter, and plans a Phase 2b migraine prevention trial. The outcome highlights how indicator specificity can be decisive in MRGPRX2 antagonism strategies, and how quickly investor expectations can reset after a clean negative readout.