Torcetrapib (2006)
Pfizer halted its CETP inhibitor torcetrapib after the ILLUMINATE trial showed a 58% increase in deaths among patients taking the drug. Pfizer had invested more than $800 million in the program.
Pfizer wrote off the program and its stock fell sharply.
The failure cast a shadow over the entire CETP class for a decade.
Torcetrapib's failure made regulators and investors wary of CETP inhibitors, which is why obicetrapib's approval took two decades.
