Merck is buying into a budding idea in immuno-oncology

Immunotherapies like Keytruda work really well for a minority of cancer patients. Figuring out how to mix and match treatments to extend those benefits has been an expensive and often disappointing process for the drug industry, but one emerging idea is beginning to show promise.

Yesterday, Merck bought a private company called Tilos Therapeutics to get its hands on some drugs that target TGF-beta proteins. Those proteins play a role in the process by which the immune system decides to either attack cancerous growths or let them pass idly by. Block TGF-beta, the thinking goes, and checkpoint inhibitors like Keytruda will be better at doing their jobs.

Merck, which happens to manufacture Keytruda, is not the first to see this promise. Sanofi, Genenetch, and Merck KGaA have all invested millions in TGF-beta research, and the startup Scholar Rock raised $75 million in a 2018 IPO on the strength of its work in the field.