Overview

• The COAST 1 study met all primary and key secondary endpoints at week 24, showing improved skin clearance and disease severity versus placebo.
• Efficacy was judged below expectations and softer than earlier Phase 2 results as well as leading IL‑13/4 therapies such as Dupixent, according to analysts.
• Sanofi shares declined roughly 8% to 10% on Thursday following the readout.
• Sanofi emphasized the potential for only four doses per year, with reported low rates of pyrexia and chills compared with Amgen’s OX40 program.
• Several analysts expect OX40/OX40L drugs to be used mainly as second‑line treatments, and the results have intensified scrutiny of the pathway’s competitiveness.