After 7 years leading Merck Research Laboratories, Roger Perlmutter will retire at the end of 2020. Under his leadership, Merck has achieved some 100 regulatory approvals for treatments, including medicines for cancer and diabetes. Perlmutter will be succeeded by Dean Li, currently head of discovery sciences and translational medicine. And after 8 years at Sanofi, Chief Scientific Officer Gary Nabel is leaving. His replacement is Frank Nestle, who was named head of Sanofi’s immunology and inflammation programs this summer.