By Maggie Fick
LONDON (Reuters) -Shares in French drugmaker Sanofi fell more than 9% on Thursday after late-stage trial data for its experimental inflammatory disease drug amlitelimab disappointed Wall Street.
Sanofi is developing amlitelimab for atopic dermatitis, a severe form of eczema. Its blockbuster medicine Dupixent treats the same condition, and the company has billed amlitelimab as a potential complement or successor.
Sanofi said amlitelimab met all main goals in the Phase III study, showing statistically significant improvements in skin clearance and disease severity compared with placebo after 24 weeks.
But the data looked weak against Dupixent, Sanofi’s best-selling medicine, which is due to lose patent protection in 2031. Dupixent is approved not only for eczema but also for other immune-related conditions including severe asthma. With the patent expiry looming, Sanofi has doubled down on immunology, making amlitelimab a pillar of that effort.
Analysts at Jefferies said the Phase III results fell short of its earlier trial and of rival biologic drugs, though the drug’s safety profile and convenient 12-week dosing could still support its use.
JPMorgan said the data confirmed the drug is less effective than Dupixent, which brought in about 13 billion euros ($15.22 billion) in sales in 2024.
Ahead of the data release, investors had viewed amlitelimab as Sanofi’s lead pipeline asset to follow on from Dupixent for eczema treatment, Barclays analyst Emily Field told Reuters.
“That’s why we’re seeing a big reaction in the stock, because of the concern that Sanofi is not going to have enough in its pipeline to replace Dupixent after patent expiry,” Field said. “This is increasingly looked at as a cliff stock.”
Shares were down 10% at 0837 GMT, making Sanofi the biggest faller on Europe’s blue-chip STOXX 600 index.
($1 = 0.8542 euros)
(Reporting by Maggie Fick; Editing by Bernadette Baum, Jan Harvey and Muralikumar Anantharaman)
