The California Supreme Court ruling in T.H. v. Novartis expands the liability innovator pharmaceutical companies may face in California courts, explain attorneys Andrew L. Bab, Maura K. Monaghan, Paul D. Rubin, and Jacob W. Stahl. The authors say the ruling creates the possibility that innovator pharmaceutical companies may face ‘‘liability in perpetuity— even after they have stopped manufacturing a drug or sold all of its rights.’’