Nektar Therapeutics announced it has entered into a new oncology clinical collaboration with Merck KGaA, Darmstadt, Germany and Pfizer Inc. to evaluate the maintenance regimen of NKTR-255, Nektar's interleukin-15 (IL-15) receptor agonist, in combination with avelumab, a PD-L1 inhibitor, in patients with locally advanced or metastatic urothelial carcinoma (UC) in the Phase II JAVELIN Bladder Medley study. NKTR-255 is wholly owned by Nektar and is currently being evaluated in two separate clinical studies in both liquid and solid tumors. The novel IL-15 agonist is designed to activate the IL-15 pathway to expand both natural killer (NK) cells and memory CD8+ T cell populations.1 Avelumab, which is marketed in the U.S. as BAVENCIO, is co-developed and co-commercialized by Merck KGaA, Darmstadt, Germany and Pfizer Inc. Under the new collaboration, Merck KGaA, Darmstadt, Germany and Pfizer Inc. will include the combination of NKTR-255 plus avelumab in the new JAVELIN Bladder Medley study. The study is a recently designed global, multi-center Phase II umbrella trial evaluating different avelumab-based combinations, compared with avelumab monotherapy, as potential maintenance therapy regimens for patients with locally advanced or metastatic UC that has not progressed with a first-line platinum-containing chemotherapy regimen. Nektar will supply NKTR-255 for the trial. Nektar and the Merck KGaA, Darmstadt, Germany-Pfizer alliance will each maintain existing global commercial rights to their respective medicines. The study is expected to begin enrolling patients in the first quarter of 2022. BAVENCIO® (avelumab) is indicated in the U.S. and Europe for the maintenance treatment of patients with locally advanced or metastatic urothelial carcinoma that has not progressed with first-line platinum-containing chemotherapy. NKTR-255 is an investigational agent in clinical development and is not approved alone or in combination with avelumab (or any other agent) for use in any country.