Sanofi reported mixed Phase 2 outcomes for lunsekimig, a bispecific nanobody targeting TSLP and IL-13, succeeding in asthma and chronic rhinosinusitis with nasal polyps but failing to meet primary goals in atopic dermatitis. In the Aircules Phase 2b study in moderate-to-severe asthma, lunsekimig reduced symptom flare-ups versus placebo in a statistically significant and clinically meaningful way. In Duet, for chronic rhinosinusitis with nasal polyps, the therapy reduced polyp size and severity and improved related congestion outcomes. However, in the Velvet Phase 2b eczema trial, lunsekimig did not meet the primary objective for skin-clearance threshold improvements compared with placebo. Sanofi said the program was generally well tolerated across trials, with serious adverse event and discontinuation rates similar to placebo. The conflicting readouts put pressure on differentiation strategies for lunsekimig in a biologics-heavy asthma market and raise questions about the breadth of the drug’s disease-modifying potential beyond respiratory indications.