Sanofi Shares Drop 9% on Weak Phase 3 Eczema Drug Results

Sanofi's experimental eczema drug amlitelimab met the primary and key secondary endpoints in its phase 3 trial, showing statistically significant improvements in skin clearance and disease severity compared to placebo after 24 weeks. However, the efficacy results were weaker than expected and fell short of analyst projections, with response rates notably lower than those seen with Sanofi’s blockbuster Dupixent, which is due to lose patent protection in 2031. This has raised concerns among investors about Sanofi's ability to replace Dupixent's substantial revenue, driving the company's shares down by around 7% to 10% in early trading. Analysts noted that although amlitelimab’s safety profile and convenient dosing schedule could support its use, the drug's diminished efficacy reduces its commercial potential. The trial's outcome has intensified worries about a potential revenue cliff for Sanofi, as amlitelimab was viewed as a key pipeline asset to sustain growth post-Dupixent patent expiry. Overall, the market reaction reflects heightened sensitivity due to the looming generic competition and limited late-stage drug alternatives in Sanofi's pipeline.