GSK's Risvutatug Rezetecan Receives Orphan Drug Designation in Japan for Small-Cell Lung Cancer
GSK's antibody-drug conjugate risvutatug rezetecan has received Orphan Drug Designation in Japan for small-cell lung cancer, marking its sixth global regulatory designation. The decision was based on phase I trial data showing durable responses in extensive-stage SCLC patients. The drug is currently in phase III development for relapsed ES-SCLC.
GSK's B7-H3-targeted antibody-drug conjugate risvutatug rezetecan has received Orphan Drug Designation from Japan's Ministry of Health, Labour and Welfare for the treatment of small-cell lung cancer. The designation was supported by preliminary clinical data showing durable responses in patients with extensive-stage SCLC who were treated with the drug in the phase I ARTEMIS-001 clinical trial. This marks the sixth global regulatory designation for the investigational therapy.
The drug, also known as Ris-Rez, is being developed in a range of solid tumours, including lung, prostate and colorectal cancers. GSK's global phase III trial for Ris-Rez in relapsed extensive-stage SCLC began in August 2025.
Lung cancer is the second most common cancer in Japan, and SCLC makes up 10-15% of cases. Of patients with SCLC, 70% have extensive-stage disease, meaning the cancer has spread throughout one or both lungs and/or to other parts of the body. ES-SCLC is an aggressive and difficult-to-treat cancer with limited treatment options and poor long-term survival. Most patients with ES-SCLC relapse after initial treatment and the median overall survival with standard-of-care for these patients is approximately 8 months.
Risvutatug rezetecan is a novel investigational B7-H3-targeted antibody-drug conjugate composed of a fully human anti-B7-H3 monoclonal antibody covalently linked to a topoisomerase inhibitor payload. GSK acquired exclusive worldwide rights from Hansoh Pharma to progress clinical development and commercialisation of the drug.
Regulatory designations received for Ris-Rez to date include Orphan Drug Designations from the US Food and Drug Administration in SCLC and the European Medicines Agency in a category of cancer that includes SCLC, called pulmonary neuroendocrine carcinoma; Priority Medicines Designation from the EMA for relapsed or refractory ES-SCLC; and Breakthrough Therapy Designations for relapsed or refractory ES-SCLC and relapsed or refractory osteosarcoma from the US FDA.