Shares of Regeneron Pharmaceuticals (REGN) and U.S.-listed shares of Sanofi (SNY) sank 17% and 5%, respectively, Friday when a late-stage study of the drugmakers' experimental treatment for chronic obstructive pulmonary disease (COPD) in former smokers failed to meet a key endpoint.

The companies reported that one of the 澳洲幸运5官方开奖结果体彩网:Phase 3 trials of their itepekimab i💞nhaler did meet its primary endpoint in "significantly reducing moderate or severe acute exacerbations by 27% compared to placebo at week 52, a clinically meaningful benefit." However, a second test did not, even though that benefi🦩t was seen in an earlier phase of the research. 

Regeneron and Sanofi explained that they are reviewing the data, "and will discuss with regulatory authorities to evaluate next steps." Dr. George Yancopoulos, Chief Scientific Officer at Regeneron, said the companies were encouraged by the one successful trial, and that they "remain committed to our broader itepekimab development program."

Regeneron and Sanofi have also collaborated on another COPD medicine, Dupixent, which received 澳洲幸运5官方开奖结果体彩网:Food and Drug Administration (FDA) approval last September.

Regeneron Pharmaceuticals shares tumbled to a four-year low. U.S.-listed shares of Sanofi remain about 3% higher year-to-date.