Eisai and PRISM BioLab Announce Clinical Proof-of-Concept for E7386, a CBP/β-Catenin Inhibitor, and File Prospectus for Next-Stage Development

TOKYO, Nov. 12, 2021 /PRNewswire/ -- Eisai Co., Ltd. (Headquarters: Tokyo, CEO: Haruo Naito, "Eisai") and PRISM BioLab Co., Ltd. (Headquarters: Kanagawa, President and CEO: Dai Takehara, "PRISM") announced that E7386, a medium-sized compound discovered through collaborative research between Eisai and PRISM as an inhibitor of CREB-binding protein (CBP)/β-catenin, has achieved clinical Proof of Concept (POC).

Eisai is currently conducting a Phase I clinical study of E7386 monotherapy for the treatment of solid tumors and a Phase Ib clinical trial of E7386 in combination with Lenvatinib Mesylate (Product Name: LENVIMA®/Lenvima®, "Lenvatinib"), an orally administered multi-targeted tyrosine kinase receptor inhibitor originally developed by Eisai for solid tumors, including hepatocellular carcinoma. According to the collaborative research agreement between Eisai and PRISM BioLab, Proof of Concept (POC) will be confirmed based on data such as antitumor activity and biomarker changes observed in the clinical trials.

Based on the POC results, Eisai launched a Phase Ib/II clinical trial (Study 201) in Japan to evaluate E7386 in combination with the anti-PD-1 therapy pembrolizumab for the treatment of solid tumors.

Eisai Senior Vice President and Oncology Business President Dr. Takashi Owa stated, "With the confirmation of the POC results, we are confident about the future of providing E7386 as a cancer treatment to patients. E7386 may overcome resistance to lenvatinib or pembrolizumab through combination therapy with lenvatinib or pembrolizumab. Eisai will accelerate clinical trials of E7386 in combination with lenvatinib or pembrolizumab and make every effort to create new treatments for cancers with unmet medical needs."

PRISM President and CEO Dai Takehara said, "The clinical POC results of E7386 demonstrate that PRISM's drug discovery platform is an effective option for targeting what are considered challenging new drug targets. We appreciate Eisai driving this development forward. We will continue to take on challenges, aiming at more new targets to provide novel treatment options for as many patients as possible."