Exelixis, Inc. (Nasdaq: EXEL) and Merck (NYSE: MRK), known as MSD outside of the United States and Canada, announced that the companies have entered into a clinical development collaboration to evaluate the combination of Exelixis’ investigational tyrosine kinase inhibitor (TKI) zanzalintinib with Merck’s anti-PD-1 therapy KEYTRUDA^® (pembrolizumab) in a Phase 3 pivotal trial for the treatment of patients with head and neck squamous cell carcinoma (HNSCC), and zanzalintinib with WELIREG^® (belzutifan), Merck’s oral hypoxia-inducible factor-2 alpha (HIF-2α) inhibitor, in a Phase 1/2 trial and two Phase 3 pivotal trials for the treatment of patients with renal cell carcinoma (RCC).

“This collaboration underscores our belief in zanzalintinib’s potential to drive patient benefit in combination with immunotherapy or targeted therapy in HNSCC and RCC indications that have unmet clinical need,” said Amy Peterson, M.D., executive vice president, product development & medical affairs, and chief medical officer, Exelixis. “KEYTRUDA and WELIREG are approved therapies that have led to improved outcomes for some cancer patients, and we are pleased to collaborate with Merck’s clinical development organization to evaluate the potential of these therapies in combination with zanzalintinib. This collaboration paves the way for further zanzalintinib development in RCC in a pragmatic manner.”

“We look forward to working with our colleagues at Exelixis to advance these clinical trials,” said Dr. Marjorie Green, senior vice president and head of oncology, global clinical development, Merck Research Laboratories. “Merck remains committed to building upon the progress made to-date by strategically evaluating the potential of new combination regimens to improve outcomes for more patients.”

Under the terms of the collaboration, Merck will supply KEYTRUDA for the ongoing, Exelixis-sponsored Phase 3 STELLAR-305 pivotal trial in previously untreated PD-L1 positive recurrent or metastatic HNSCC. In addition, Merck will sponsor a Phase 1/2 trial and two Phase 3 pivotal trials in RCC. Merck will fund one of these Phase 3 studies, and Exelixis will co-fund the Phase 1/2 trial and the other Phase 3 study, as well as supply zanzalintinib and cabozantinib. Exelixis maintains all global commercial and marketing rights to zanzalintinib.