Traditional Approval Granted to Selpercatinib for Patients as Young as 2
The accelerated approval of selpercatinib for certain patients with thyroid cancer was converted to a full approval.
The U.S. Food and Drug Administration (FDA) has granted full approval to selpercatinib (Retevmo) for patients 2 years of age and older who have advanced or metastatic medullary thyroid cancer harboring a RET mutation and who need systemic therapy.
Selpercatinib is a targeted therapy that inhibits mutant forms of the RET tyrosine kinase, a protein that is commonly mutated in several cancer types and can cause tumors to grow faster. It received accelerated approval for this indication in May 2024 and is also approved for certain other adult and pediatric patients with RET-mutated thyroid cancer.
The conversion from an accelerated approval to a full approval was based on results from LIBRETTO-531, a randomized, multicenter, open-label phase 3 clinical trial that enrolled adult and adolescent patients with advanced or metastatic medullary thyroid cancer with RET mutations. Patients were randomly assigned (2:1) to receive selpercatinib or physician’s choice of either cabozantinib or vandetanib (Caprelsa).
Patients who received selpercatinib were 72% less likely to have experienced disease progression or death during the study than those who received cabozantinib or vandetanib. After a median follow-up time of 12.5 months, the median progression-free survival had not been reached for patients in the selpercatinib arm. In contrast, the median progression-free survival was 16.8 months for those in the cabozantinib/vandetanib arm after a median follow-up of 11 months.
For patients aged 2 to 12 years, the recommended dose of selpercatinib is based on body surface area and ranges from 40 mg three times daily to 160 mg twice daily. For patients 12 years of age and older, the recommended dose is 120 mg twice daily if the patient weighs less than 50 kg and 160 mg twice daily if the patient weighs more than 50 kg.
Thyroid cancer can occur in children and adults and arises in the thyroid, an organ that produces hormones. Approximately 40% to 70% of noninherited medullary thyroid cancers harbor RET mutations. According to federal statistics, it was estimated that 44,020 individuals in the United States would be diagnosed with thyroid cancer and 2,170 patients would die of the disease in 2024.
The FDA rendered its decision on September 27, 2024.
