One year ago, on the eve of the yearly American Society of Clinical Oncology conference, a new class of drugs called IDO inhibitors seemed poised to become the next big thing in cancer care. They were a top choice to combine with the powerful but limited immunotherapies that have emerged this decade to fight many types of cancer. IDO inhibitors would broaden immunotherapy’s reach, the thinking went.
“Everything is starting to come together for these IDO inhibitors,” a University of California, San Francisco oncologist said at the time.
Now everything is coming apart. After immunotherapy leader Merck (NYSE: MRK) reported in April a failed Phase 3 melanoma study of its pembrolizumab (Keytruda) paired with an IDO inhibitor from Incyte (NASDAQ: INCY), several companies with billions of dollars invested have scaled back IDO-immunotherapy regimens or stopped them altogether. Merck, for example, canceled four more late-stage trials and downsized two others. Merck’s chief rival Bristol-Myers Squibb (NYSE: BMY) shuttered three Phase 3 studies.
[…]Additionally, experts interviewed by Xconomy also agreed: Don’t completely scrap IDO. “Too many people took that failure as, ‘Let’s just all drop IDO.’ The biology and the science say it’s an important target,” says Padmanee Sharma, co-director of the Parker Institute for Cancer Immunotherapy at MD Anderson Cancer Center in Houston. “Just go back to the drawing board and think about” running a different study, she says. “In oncology we’re used to failures.”