Core Viewpoint - The experimental drug Itepekimab, developed by Sanofi and Regeneron for treating chronic obstructive pulmonary disease (COPD) in former smokers, has shown mixed results in late-stage trials, leading to significant stock price declines for both companies [1][2]. Group 1: Company Performance - Sanofi's stock price fell by 6.17% and Regeneron's stock price dropped by 13.77% following the announcement of the trial results [1]. - The late-stage trials for Itepekimab produced contrasting outcomes, with one trial showing a 27% reduction in disease worsening, while the other did not demonstrate the same efficacy despite initial positive results [1]. Group 2: Drug Development Insights - Analysts are closely monitoring the trial data for Itepekimab, especially as Sanofi's key drug Dupixent is nearing patent expiration, which has been a significant growth driver for the company [2]. - The mixed results of Itepekimab represent a major setback for Sanofi and Regeneron, potentially delaying the drug development process by at least three years [2]. - Other pharmaceutical companies, such as GlaxoSmithKline, are also developing treatments for COPD, with GlaxoSmithKline's Nucala recently approved for use in the U.S. [2].