Sanofi Hit With Shock As Flagship Drug Successor Disappoints Investors

Core Viewpoint - Sanofi's stock experienced a significant decline following the disappointing late-stage trial results for amlitelimab, which raised concerns about the company's ability to maintain its dermatology portfolio after the expiration of patent protections for Dupixent [1][5]. Group 1: Trial Results - The global COAST 1 phase 3 study demonstrated that amlitelimab met all primary and key secondary endpoints, showing statistically significant and clinically meaningful improvements in skin clearance and disease severity compared to placebo at Week 24 for patients aged 12 years and older with moderate-to-severe atopic dermatitis [2]. - Amlitelimab was well-tolerated, with no new safety concerns identified during the study [2]. - The EASI-75 results indicated that 35.9% and 46% of patients achieved a 75% or greater improvement in the eczema area and severity index total score at Q4W, compared to 19.1% on placebo, and 39.1% and 50.3% at Q12W versus 27.6% [3]. Group 2: Comparative Analysis - The validated investigator global assessment scale for atopic dermatitis (vIGA-AD) showed results of 21.1% and 22.5% for amlitelimab compared to 9.2% and 26.5% for placebo, depending on patient inclusion [4]. - Analysts noted that the Phase 3 results were weaker than those of Sanofi's existing drug Dupixent and rival biologic drugs, although the safety profile and convenient 12-week dosing of amlitelimab could still support its use [6]. Group 3: Market Reaction - Following the trial results, Sanofi's stock price fell by 8.52%, trading at $45.64 during the premarket session [6]. - Investors had previously viewed amlitelimab as a key pipeline asset and potential successor to Dupixent, which is set to lose patent protection in 2031 [5].