Regeneron’s IL-33 “win” looks like bad news for Anaptysbio

Regeneron and Sanofi have claimed a win in the first proof-of-concept trial with their anti-IL-33 MAb REGN3500 (SAR440340), a potential successor to Dupixent. However, REGN3500 merely beat placebo in the phase II asthma trial. The study also included the anti-IL-4/IL-13 MAb Dupixent, which numerically beat the newcomer, while a combination of the two agents did not outperform Dupixent alone. The data raise questions about whether further development of REGN3500 is worthwhile but, perhaps more importantly, look like bad news for Anaptysbio, whose lead project, etokimab, also hits IL-33. Anaptysbio, which is awaiting readout of the Atlas trial in atopic dermatitis, saw its stock open down 15% today. The latest data suggest that IL-33-targeting drugs could at best be similar to Dupixent. If this is borne out in Atlas etokimab would find it difficult to compete in what are crowded sectors. As well as atopic dermatitis the company is taking aim at asthma, where Dupixent is already approved, and nasal polyps, where it soon could be. Glaxosmithkline might also want to re-evaluate its anti-IL-33 contender, GSK3772847, which it previously highlighted as its most promising respiratory project.