GSK PLC (LSE:GSK, NYSE:GSK) has picked up another regulatory boost for its experimental cancer medicine risvutatug rezetecan, after the US Food and Drug Administration granted the treatment Orphan Drug designation for small-cell lung cancer.
The company said the decision was supported by early data from its phase-one ARTEMIS-001 study, where some patients with extensive-stage small-cell lung cancer, a form of the disease that has spread widely and is notoriously hard to treat, showed durable responses.
Orphan status is reserved for medicines aimed at rare or life-threatening conditions and offers benefits such as tax credits and potential market exclusivity if the drug is approved.
Small-cell lung cancer accounts for about 13% of all US lung cancer cases, with roughly 29,500 people expected to be diagnosed this year. Around 70% of those have extensive-stage disease.
Standard treatment options are limited, relapses are common and the five-year survival rate is roughly 3%. Once the disease returns, median overall survival is about eight months.
The new designation follows a similar move by the European Medicines Agency, which recently granted orphan status to the drug for pulmonary neuroendocrine carcinoma, a group of cancers that includes small-cell lung cancer.
It is the fifth regulatory designation for the medicine, which has also secured PRIME status in Europe and two Breakthrough Therapy Designations in the US for relapsed or refractory disease.
Risvutatug rezetecan is a B7-H3-targeted antibody-drug conjugate, a type of treatment that links a tumour-targeting antibody to a cancer-killing payload.
GSK licensed rights to the drug, outside mainland China and a small number of Asian regions, from Hansoh Pharma. A global phase III trial in relapsed extensive-stage small-cell lung cancer began in August 2025.