Another day, another cancer immunotherapy pact, and this time it’s Pfizer and Merck & Co joining forces to research the potential of another combination of two of their drugs.

The firms said they will explore the therapeutic potential of marrying Pfizer’s Xalkori (crizotinib) with Merck’s high-profile anti-PD-1 antibody pembrolizumab in a Phase Ib clinical study assessing safety and tolerability in patients with ALK-positive advanced or metastatic non-small cell lung cancer (NSCLC).

Pfizer will conduct the multi-center, open-label study, which is expected to begin sometime next year, but further specifics of the deal were not disclosed.

“Understanding the effects of combining one drug, Xalkori, which inhibits an abnormally activated enzyme in patients with ALK-positive metastatic lung cancer, with the investigational drug, pembrolizumab, which harnesses the body’s immune system to fight cancer, is vital if we are to continue to advance the care of lung cancer patients,” said Mace Rothenberg, chief medical officer for Pfizer Oncology, commenting on the deal.

This is not the first time the companies have announced such an agreement: pembrolizumab in combination with Pfizer’s small molecule kinase inhibitor Inlyta (axitinib) is to be evaluated in patients with renal cell carcinoma, while, separately, pembrolizumab plus Pfizer’s PF-05082566 (PF-2566), an investigational immuno-oncology agent that targets the human 4-1BB receptor, will be tried across multiple cancer types, with enrolment for these studies expected to begin later this year.

The announcement also came hot on the heels of news from yesterday that Merck has signed an immunotherapy pact with Advaxis for prostate cancer involving pembrolizumab.