What were the biggest clinical trial flops of 2025?

Every clinical setback carries lessons. That’s why Fierce revisits major trial failures each year: not to dwell on disappointment, but to understand what went wrong and what it signals for the road ahead. The 2025 edition of Fierce Biotech’s clinical trial flops report highlights a familiar pattern. Large drugmakers account for a disproportionate share of high-profile misses, reflecting the reality that many of the industry’s most ambitious late-stage programs now sit inside big pharma portfolios. On this episode of "The Top Line," Fierce Biotech's James Waldron and Fierce Pharma's Fraiser Kansteiner discuss the failures that stood out in 2025 and what they suggest about the challenges facing drug development. To learn more about the topics in this episode:  2025's top 10 clinical trial flops Sanofi ousts Paul Hudson after 'bumpy ride,' enlists Merck KGaA CEO to lead the French pharma See omnystudio.com/listener for privacy information.