About a Phase III Clinical Study of Cancer-Specific Peptide Vaccine S-588410 in Patients with Esophageal Cancer

OSAKA, Japan, July, 16, 2021 - Shionogi & Co., Ltd. (Head Office: Osaka, Japan; President and CEO: Isao Teshirogi, Ph.D. ; hereafter “Shionogi”) has completed a Phase III clinical study of the cancer peptide vaccine S-588410 in patients with esophageal cancer (“the study”). The drug is licensed under an agreement with OncoTherapy Science, Inc. (Head Office: Kanagawa, Japan, President and CEO Jae-Hyun Park, hereafter “OTS”).


This is a Phase III, randomized, double-blind, placebo-controlled study to assess the efficacy of S-588410 as a postoperative adjuvant therapy in patients with esophageal cancer. After evaluation of recurrence free survival (RFS), which is the time to cancer recurrence, which is the primary endpoint, no significant prolongation of RFS was found in the S-588410 group as compared with the placebo group. Regarding the secondary endpoint, induction of cytotoxic T lymphocytes (CTL), a high induction rate was found after administration of S-588410. The main adverse reaction was a skin reaction at the injection site, but no cases of serious skin reaction were observed.


Following the results of the study and various additional analyses, Shionogi will determine the future development policy for S-588410 after consultation with OTS.