Eli Lilly & Co., Merck Sharp & Dohme Corp., and Amylin Pharmaceuticals, Inc. must face several hundred revived wrongful death suits in California alleging they failed to warn that their incretin-based diabetes drugs increased the risk of pancreatic cancer.

A California appeals court, in reinstating the cancer suits Nov. 6, followed the lead of the U.S. Court of Appeals for the Ninth Circuit in an opinion issued last December.

The federal appeals court reversed a federal trial judge’s...