By Chris Wack

ALX Oncology Holdings Inc. said Tuesday it is collaborating with Merck & Co. to evaluate the combination of ALX148 and Keytruda for treating patients with a certain type of head and neck cancer.

Under the terms of the agreement, ALX Oncology will conduct two Phase 2 studies. The first will evaluate the efficacy of ALX148, an investigational next generation CD47 blocker, in combination with Merck's drug to treat patients with PD-L1 expressing metastatic or unresectable, recurrent head and neck squamous cell carcinoma.

The second study will evaluate ALX148, Keytruda and standard chemotherapy to treat patients with metastatic or unresectable, recurrent HNSCC.

ALX Oncology owns worldwide commercial rights to ALX148.

Write to Chris Wack at chris.wack@wsj.com