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Regeneron shares slide on mixed trial data for smoker's lung drug
By Sriparna Roy - 5/30/2025
By Sriparna Roy
(Reuters) -Regeneron shares fell nearly 18% on Friday after its experimental drug for patients with a type of lung condition commonly called "smoker's lung" failed a late-stage trial, although it succeeded in another.
Regeneron and partner Sanofi were studying the drug, which some analysts expect could bring in peak sales of as much as $5 billion, for treating chronic obstructive pulmonary disease (COPD).
Investors had pinned their hopes on the drug, itepekimab, which targets a broader population, to potentially drive growth beyond Regeneron and Sanofi's blockbuster Dupixent, which is also approved for the condition, as its patent expiry looms.
"Today's update likely represents a 2-3 year delay to market," said J.P. Morgan analyst Chris Schott for Regeneron's itepekimab.
The drug showed a significant reduction in exacerbations or flare-ups in the condition by 27% compared to placebo at 52 weeks in a 1,127-patient study.
But the second study - which had enrolled fewer former smokers compared to the first - did not meet its goal, although a benefit was seen earlier in the trial.
"Given the mixed results, the regulatory path is murky," said HSBC analyst Rajesh Kumar.
At least four analysts said the companies may need to conduct additional studies for a potential approval for the drug.
Shares of Regeneron, which have already fallen 15% this year, were down at $497.01, while U.S.-listed shares of French drugmaker Sanofi fell more than 7% to $48.65 in morning trading.
Regeneron's price-to-earnings ratio, a common benchmark for valuing stocks, was 16.15, compared with 13.62 for Gilead and 7.29 for Bristol Myers Squibb.
Itepekimab binds to and inhibits interleukin-33, a type of protein that causes inflammation in COPD.
The common lung disease causes restricted airflow and breathing problems. It typically affects smokers, but can also be caused by pollutants.
(Reporting by Sriparna Roy in Bengaluru; Editing by Shinjini Ganguli)