Bristol-Myers Squibb has signed a clinical trials pact with Nektar Therapeutics that will test a combination of the firms' immunotherapy drugs across a range of cancer indications.

The firms will assess the potential of combining BMS' PD-1 checkpoint inhibitor Opdivo (nivolumab) in combination with Nektar's experimental immuno-stimulator NKTR-214.

Opdivo is designed to overcome immune suppression, while NKTR-214 is designed to expand specific cancer-fighting T cells and natural killer cells directly in the tumour micro-environment and increase expression of PD-1 on these immune cells.

"The combination of checkpoint inhibition with T cell growth could lead to synergistic effects that may provide a new treatment option for patients," said Howard Robin, president and chief executive of Nektar.

Phase I/II clinical trials will evaluate potential for the combination to show improve and sustain efficacy and tolerability above the current standard of care in melanoma, kidney, colorectal, bladder and non-small cell lung cancer patients. An initial dose-escalation trial is already underway.

Under the terms of the deal, the companies will equally share costs of the combined therapy trials, and Nektar will maintain its global commercial rights to NKTR-214.