Eisai Co., Ltd. announced today that it has submitted in Japan a marketing authorization application of the anticancer agent denileukin diftitox (genetic recombinant) (generic name, development code: E7777) for relapsed or refractory Cutaneous T-cell Lymphoma (CTCL) and Peripheral T-cell Lymphoma (PTCL).

This application is based on data from a multicenter, open-label, single-arm Phase II clinical study (study 205) conducted in Japan for patients with relapsed or refractory CTCL or PTCL to evaluate the efficacy and safety of this agent.

This study achieved the primary endpoint and exceeded a predetermined threshold with statistical significance: the objective response rate (ORR) of CTCL and PTCL patients in total (n=36) was 36.1% (95% confidence interval (CI): 20.8-53.8). The ORRs of each subtype were 31.6% (95% CI:12.6-56.6) for CTCL (n=19) and 41.2% (95%CI: 18.4-67.1) for PTCL (n=17).

The five most frequent adverse events observed in this study were increased aspartate aminotransferase (AST) (89.2%), increased alanine aminotransferase (ALT) (86.5%), hypoalbuminaemia (70.3%), lymphopenia (70.3%), and pyrexia (51.4%).

Denileukin diftitox (genetic recombinant) is a fusion protein of the receptor-binding portion of interleukin-2 (IL-2) and diphtheria toxin that specifically binds to the IL-2 receptor on the surface of tumoral lymphocyte. The antitumor effect of denileukin diftitox depends on the intracellular delivery of diphtheria toxin which inhibits protein synthesis and induces cell death. The agent has been evaluated as a drug with high medical need by the "Study Group for Unapproved Drugs/Off-Label Drugs for High Medical Needs"(1), and Eisai has been requested to develop it by the Ministry of Health, Labour and Welfare.

Eisai positions oncology as a key franchise area and aims to create innovative drugs that act towards curing cancer. Eisai aims to make continuous efforts to meet the diversified needs of and increase the benefits provided to patients with cancer, their families, and healthcare professionals.

(1) The Study Group set up within the Ministry of Health, Labour and Welfare with the purpose of contributing to enhancing the development of drugs and indications that have not been approved in Japan (unapproved drugs/off-label drugs) by pharmaceutical companies. In addition to evaluating the medical needs of unapproved drugs/off-label drugs, their responsibilities include evaluating the applicability of the drug to an Application with Public Knowledge, and the adequacy of additional clinical studies that need to be conducted for filing applications for approval, and so on.