Regeneron Stock Drops On Mixed Results For Smoker’s Lung Treatment

Regeneron Pharmaceuticals (REGN) shares dropped nearly 10% in premarket trading Friday after mixed results from late-stage trials of Itepekimab, an experimental treatment for chronic obstructive pulmonary disease (COPD) or “smoker’s lung.”

Developed in partnership with Sanofi, the drug was evaluated in two Phase 3 studies involving former smokers with moderate to severe COPD.

In the AERIFY-1 trial, Itepekimab met its primary endpoint. Patients receiving the treatment every two or four weeks experienced a statistically significant 27% reduction in moderate or severe exacerbations after 52 weeks compared to those on placebo. The result is considered a clinically meaningful benefit.

However, the second trial, AERIFY-2, did not meet the same target. While some benefit was observed at the 24-week mark, the drug failed to maintain statistical significance through the full 52 weeks.

Both trials were conducted during the COVID-19 pandemic, a factor the companies said may have influenced outcomes. Fewer-than-expected exacerbations were recorded across both studies, potentially reducing the trials’ power to detect differences between treatment and placebo groups.

Across both studies, patients received subcutaneous injections of Itepekimab every two or four weeks, in addition to standard-of-care inhaled therapies. AERIFY-1 enrolled 1,127 participants, while AERIFY-2 included 953.

The safety profile of Itepekimab was consistent with earlier studies. Rates of adverse events and serious infections were comparable between treatment and placebo groups.

Regeneron and Sanofi said they will continue evaluating the results and plan to engage with regulators on potential next steps. Itepekimab remains under investigation in other respiratory indications, including chronic rhinosinusitis and non-cystic fibrosis bronchiectasis.

Regeneron’s stock has fallen 16% this year and 37% over the past 12 months. 

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