Pfizer and Tokyo-based Kyowa Hakko Kirin have entered into an agreement to explore the therapeutic potential of the combination of Pfizer’s PF-05082566, an investigational, fully humanized monoclonal antibody (mAb) that stimulates signaling through 4-1BB (CD-137), a protein involved in regulation of immune cell activation, proliferation and survival, with Kyowa Hakko Kirin’s anti-CCR4 antibody mogamulizumab, which suppresses some of the immune cells that shield the tumor from the immune system, in a phase Ib clinical study evaluating the safety and tolerability of the combination in patients with solid tumors.

Pfizer and Kyowa Hakko Kirin will co-fund the clinical study, which will be conducted by Pfizer. This study is expected to establish a recommended dose regimen and assess the safety and preliminary efficacy of the combination. This study is expected to begin in 2015 and the results will determine the future clinical development of the combination.

“With recent progress in the field of cancer immunotherapy, the combination therapy of mogamulizumab and Pfizer’s 4-1BB agonist has the potential to bring significant benefits to patients,” said Yoichi Sato, managing executive officer, vice president, head of R&D of Kyowa Hakko Kirin.