Eisai Highlights E7386 in Collaboration with PRISM BioLab at ASCO 2025

TOKYO, May 23, 2025 /PRNewswire/ -- PRISM BioLab, Co. Ltd. ("PRISM"), a leading discovery and development biotechnology company designing small molecule inhibitors of protein-protein interaction (PPI) targets, today announced that the analysis of a combination study of E7386(*1), created through collaboration research with Eisai Co., Ltd. ("Eisai"), and Lenvatinib mesylate ("lenvatinib") (*2) will be presented by Eisai at the American Society of Clinical Oncology (ASCO) Congress 2025, held in Chicago, USA from May 30 to June 3, 2025. The abstract of the study has been released today.

To determine the optimal dose of E7386 in combination with Lenvatinib in the open-label Phase Ib study (NCT04008797(*3)), expansion cohort of advanced endometrial cancer patients progressed following platinum-based chemotherapy and anti-PD-(L)1 immunotherapy have been implemented by Eisai and the enrollment of 30 patients was completed. By data cutoff (Oct 22, 2024), with 9 patients remaining on treatment, 30% (9 patients) showed the confirmed response (decrease of tumor size > 30%) for an overall response rate of 30.0%. Furthermore, among patients without prior Lenvatinib treatment, the overall response rate was 42.9%.

Completing the enrollment of dose expansion cohort (n=30), the results confirmed promising preliminary antitumor activity of E7386 + Lenvatinib with a manageable safety profile. For the subsequent dose-optimization part for E7386 + LEN in advanced endometrial cancer, enrollment of patients had been initiated (NCT04008797).

(*1) E7386 : E7386 is an orally available small molecule CBP/ β-catenin inhibitor that inhibits protein-protein interactions between the transcription factor CBP and β-catenin, and regulates the Wnt signaling. E7386 achieved clinical POC (Proof of concept) in October 2021 and following clinical studies are ongoing including phase I for solid tumors as monotherapy, Phase Ib for solid tumors in combination with tyrosine kinase inhibitor Lenvatinib, Phase Ib/II for solid tumors in combination with pembrolizumab, the anti-PD-1 antibody from Merck & Co., Inc., Rahway, NJ, USA.

(*2) Lenvatinib : Lenvatinib is a multi-kinase inhibitor, discovered by Eisai and being co-developed and co-commercialized under a collaboration agreement with Merck & Co., Inc., Rahway, NJ, USA, which inhibits vascular endothelial growth factor receptors (VEGFRs),VEGFR1, VEGR2, VEGFR3 and fibroblast growth factor receptors (FGFRs), FGFR1, FGFR2, FGFR3, FGFR4, and other receptor tyrosine kinases, PDGFR-alpha, KIT, RET. Lenvatinib have been approved for thyroid cancer, hepatocellular carcinoma, thymic caner and renal cell carcinoma (in combination with Everolimus or pembrolizumab, the anti-PD-1 antibody from Merck & Co., Inc., Rahway, NJ, USA.). Lenvatinib is also approved for endometrium cancer in combination with pembrolizumab

(*3) NCT04008797: NCT04008797 is an open-label Phase Ib study of E7386 in combination with other anticancer drug, Lenvatinib for the patients with solid tumors. The study has been implemented by Eisai in Japan, Korea, Taiwan region, US, and France determine the safety and the recommended phase 2 dose (RP2D) and also to see the pharmacokinetics and efficacy of E7386 + Lenvatinib. Enrolment of each cohort of hepatic, colon, endometrial cancers are ongoing.

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