Incyte has taken an ax to its suite of late-phase epacadostat trials after digesting the implications of last month’s pivotal study blowup. The cull sees Incyte downgrade two pivotal epacadostat-Keytruda trials to phase 2 studies and back away from six other late-stage tests of its IDO inhibitor.

Having started April with nine closely watched phase 3 trials designed to assess epacadostat in combination with Merck’s Keytruda and Bristol-Myers Squibb’s Opdivo, Incyte enters May without a pivotal trial to its name. The most advanced clinical trial—a study of epacadostat and Keytruda in melanoma—came up short against its primary endpoint early last month. And the other eight were knocked over by the shockwaves from that setback.

Incyte’s reorganization of its portfolio of trials amounts to a major, although not quite total, retreat from epacadostat. A pair of studies of epacadostat and Keytruda in non-small cell lung cancer (NSCLC) that started late last year will continue as phase 2 trials, not the pivotal programs originally envisaged.

The six other pivotal studies are halting recruitment altogether and giving already-enrolled patients the option to switch to different treatments. Those trials include another four testing epacadostat with Keytruda in head and neck cancer, renal cell carcinoma and urothelial cancer. And two from Incyte’s collaboration with Bristol-Myers Squibb that are testing the IDO drug and Opdivo in patients with head and neck cancer or NSCLC.

News of the decision to stop enrollment in the epacadostat-Opdivo trials comes shortly after Bristol-Myers culled its own late-phase IDO activities. The Big Pharma was set to assess its in-house IDO drug and Opdivo in head and neck cancer and NSCLC—the same indications as the epacadostat studies—but backed out after learning of the failure of Incyte’s pivotal Keytruda trial.

RELATED: Bristol-Myers drops phase 3 trials of $800M IDO drug 

With NewLink also revising its IDO strategy in the wake of the Incyte data, what was one of the most anticipated drug classes in the industry pipeline has undergone a dramatic, rapid transformation. 

Incyte and its rivals could still write a second chapter on their IDO drugs by going back, dotting the Is and crossing the Ts and taking another run at pivotal studies armed with a better understanding of their drugs and the patients they are most likely to help. Some of that work got skipped amid the excitement about the class and under the competitive pressures that characterize immuno-oncology. 

Incyte went quickly into phase 3 on the back of data from a single-arm phase 1/2. Such development strategies are a feature of modern cancer R&D and can significantly cut the time and cost taken to get breakthrough drugs to patients. But opting against putting a drug through a randomized mid-stage trial before entering phase 3 raises the risk of nasty surprises later on.

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