Pfizer Inc. and 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.

Under the terms of the agreement, 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.

PF-05082566 is an investigational, fully humanized mAb that targets 4-1BB (CD-137), a protein expressed in many immune cells. In pre-clinical models, it has shown anti-tumor activity by enhancing T-cell mediated immune responses. Pfizer is currently evaluating PF-05082566 in a Phase I study as a single agent in multiple tumor types, as well as in several combination studies, including a clinical study of PF-05082566 in combination with rituximab in non-Hodgkin lymphoma patients. PF-05082566 is not approved for any indications in any markets.

Mogamulizumab is a novel, humanized mAb directed against CC chemokine receptor 4 (CCR4). Engineered by Kyowa Hakko Kirin’s Potelligent technology, the antibody is designed to kill its target cells through potent antibody-dependent cellular cytotoxicity. Mogamulizumab was launched in Japan in May 2012 for the treatment of patients with relapsed or refractory CCR4-positive adult T-cell leukemia-lymphoma (ATL). The drug was approved for indication expansion and was granted marketing authorization in Japan for the treatment of patients with relapsed or refractory CCR4-positive, peripheral T-cell lymphoma (PTCL) and cutaneous T-cell lymphoma (CTCL) in March 2014. Clinical trials with mogamulizumab in ATL, PTCL, and CTCL are ongoing in the US, EU and other countries.

Source: Pfizer