US biotechnology group Genentech, part of Roche, is handing back rights to NewLink Genetics’ IDO inhibitor GDC-0919 (navoximod), an investigational cancer treatment.

Genentech gained rights to navoximod, which is designed to harness multiple parts of the immune system to fight cancer, in October 2014 as part of a partnership on solid tumor therapies. The deal had an upfront payment of $150 million and could have been worth more than $1 billion, including milestones, for NewLink.

As a consequence of Genentech’s decision, NewLink will pay the US company a low single-digit royalty on any sales of GDC-0919 if it decides to develop and commercialize the drug. Genentech will continue to supply the drug for one year after the agreement’s termination.

The end of the collaboration also came about a week after NewLink admitted that a Phase II trial of indoximod plus taxane chemotherapy for breast cancer had failed to meet its primary endpoints. The company said it would present full results at an (unspecified) upcoming academic meeting.

However, NewLink’s CEO, Charles Link, said: “We remain committed to advancing our IDO pathway inhibitor indoximod, which continues to generate exciting data in combination with anti-PD-1 agents, cancer vaccines, and chemotherapy in multiple cancer types including melanoma, prostate cancer, acute myeloid leukaemia, and pancreatic cancer.”

NewLink confirmed that its research collaboration with Genentech for the discovery of next generation IDO/TDO (tryptophan 2,3-dioxygenase) inhibitors continues.