TOKYO, May 16, 2025 - (JCN Newswire) - Eisai Co., Ltd. announced today that it has received notification from Japan’s Ministry of Health, Labour, and Welfare (MHLW) that the “all-case surveillance” post-marketing observational study condition required at the time of approval of anticancer agent “Remitoro® for Intravenous Drip Infusion 300μg” (Denileukin Diftitox (Genetical Recombination)) for the indications of T-cell Lymphoma has been cleared.

In March 2021, the MHLW approved “Remitoro” with the indications of “relapsed or refractory PeripheralT- cell Lymphoma (PTCL)” and “relapsed or refractory Cutaneous T-cell Lymphoma (CTCL)” , in Japan, with the following condition: “Because of the very limited number of subjects included in the Japanese clinical trials, the applicant is required to conduct a post-marketing observational study in all patients untildata from a certain number of patients is accumulated after its launch in the market, in order to identify thebackground information of patients treated with the product and collect safety and efficacy data on the product in the early post-marketing period, and thereby take necessary measures to ensure proper use of the product.”

Based on the safety data in 111 patients and efficacy data in 85 patients submitted to the MHLW as the results of analyses of this all-case surveillance, the MHLW has concluded that the all-case surveillancewas conducted properly and the necessary measures to ensure proper use of the product weresufficient to lift the condition.

Eisai will continually strive to promote the proper use of “Remitoro” and provide information about the product, thereby making further contributions to increase the benefits to patients and their families.

About Remitoro for Intravenous Drip Infusion 300μg (Denileukin Diftitox (Genetical Recombination))

This agent is a fusion protein consisting of interleukin-2 (IL-2) and partial sequence of diphtheria toxin. The antitumor effect of denileukin diftitox is believed to depend on specific binding to the IL-2 receptor on the surface of tumoral lymphocytes followed by intracellular delivery and release of diphtheria toxin fragment which inhibits proteinsynthesis and induce cell death.

Eisai retains exclusive development and marketing rights for the agent in Japan and Asia.

About Peripheral T-cell Lymphoma (PTCL)

PTCL is a type of T-cell non-Hodgkin's lymphoma that is classified as an intermediate-grade lymphoma. PTCL isoften detected in advanced stages, and has symptoms such as swelling and lumps in the lymph nodes, fever, heavy night sweats, and weight loss. Among PTCLs, Anaplastic Lymphoma Kinase (ALK)-positive anaplastic largecell lymphoma, which occurs in the 20s and 30s, has a favorable prognosis and is curable. However, other types ofPTCL often occur around the age of 60, and may have a poor prognosis or be difficult to treat. Therefore, PTCL is still a disease with extremely high-unmet medical need. It is estimated that the number of patients with PTCL in Japan is less than 7,000.1

About Cutaneous T-cell Lymphoma (CTCL)

CTCL is a type of non-Hodgkin's lymphoma of primary cutaneous disease with various other manifestations in additional sites like lymph nodes and peripheral blood. In CTCL, some of the T cells (a type of lymphocyte involvedin the immune system) become cancerous, causing skin lesions and reducing the patient's QOL (Quality of Life) due to pain and pruritus. CTCL is generally a low-grade lymphoma, with initial patch and plaque skin lesions, but itprogresses slowly and advances to the tumor stage over several years to over a dozen years. CTCL is still a diseasewith extremely high unmet medical need because it has a high malignancy when it reaches the tumor stage and hasa poor prognosis. It is estimated that the number of patients with CTCL in Japan is less than 4,000.1

About the results of “all-case surveillance” post-marketing observational study

The specified post-marketing observational study is conducted for the purpose of collecting and confirming sideeffect incidence by symptom, quality, efficacy and safety information in pediatric, geriatric, pregnant patients, patients with renal dysfunction, hepatic dysfunction, patients who use the drug for a long time or those patients withany limitations or conditions in drug use.

This study on Remitoro was conducted by central registration method to investigate the safety and efficacy of theagent, as well as factors that may affect them, in actual drug use under the approved conditions. The registered patients started administration of the drug for treatment within the period from May 2021 through September 2022 in86 medical facilities located in Japan. In the 111-safety analytical set, the common adverse drug reactions (ADRs)(incidence 10% or higher) were aspartate aminotransferase increased (22.5%), capillary leak syndrome (21.6%), alanine aminotransferase increased (21.6%), platelet count decreased (15.3%), hepatic function abnormal (14.4%)and pyrexia (13.5%).

With respect to efficacy, the overall response rate in the 85 evaluable cases (70 cases in PTCL and 15 cases inCTCL) was 15.7% in PTCL, 20.0% in CTCL, and 16.5% in overall.

(1) Vital Statistics/Patient Survey in 2023 (Health Statistics Office, Director-General for Statistics, Ministry of Health, Labour and Welfare, Japan.) (available in Japanese only)

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