Selpercatinib Earns Full FDA Approval Status in RET+ Thyroid Cancer

The FDA has approved selpercatinib for patients with RET fusion-positive thyroid cancer.

The FDA has granted full approval to selpercatinib (Retevmo) as a treatment for patients 2 years and older with advanced or metastatic thyroid cancer that is RET fusion-positive, according to a press release from the agency.¹

Specifically, the agent is indicated for use in patients who are refractory to radioactive iodine.

Supporting data for the approval came from the phase 1/2 LIBRETTO-001 trial (NCT03157128). Among 41 previously treated patients with RET fusion-positive thyroid cancer, the overall response rate (ORR) was 85% (95% CI, 71%-94%) compared with 96% (95% CI, 79%-100%) among 24 patients who were naïve to systemic therapy. The median duration of response (DOR) in the previously treated and untreated patients, respectively, was 26.7 months (95% CI, 12.1-not evaluable [NE]) and NE (95% CI, 42.8-NE).

Additional findings supporting the full approval came from the phase 1/2 LIBRETTO-121 study (NCT03899792), in which investigators assessed treatment with selpercatinib among pediatric and young adult patients with advanced solid tumors harboring RET alterations. The ORR for this population was 60% (95% CI, 26%-88%), and responses of at least 12 months were reported in 83%.

Common adverse effects (AEs) reported with selpercatinib included edema, fatigue, diarrhea, dry mouth, hypertension, abdominal pain, constipation, rash, headache, and nausea. Grade 3/4 toxicities included lymphocyte decreases, alanine aminotransferase increases, and aspartate aminotransferase increases.

According to the FDA, the recommended dose of selpercatinib in this population is dependent on body surface area for patients between 2 and 12 years old and is based on weight for those 12 years and older.

The FDA previously granted accelerated approval to selpercatinib for adult and pediatric patients with advanced or metastatic RET fusion-positive thyroid cancer in May 2020 based on findings from the LIBRETTO-001 trial.²

The FDA granted accelerated approval to selpercatinib in pediatric patients 2 years and older with RET fusion-positive thyroid cancer in May 2024.³ The accelerated approval status was based on data from the LIBRETTO-121 trial.

References

1. FDA approves selpercatinib for RET fusion-positive thyroid cancer. News release. FDA. June 12, 2024. Accessed June 12, 2024. https://tinyurl.com/5n7uxtu8
2. FDA approves selpercatinib for lung and thyroid cancers with RET gene mutations or fusions. News release. May 8, 2020. Accessed June 12, 2024. https://shorturl.at/giten
3. FDA grants accelerated approval to selpercatinib for pediatric patients two years and older with RET-altered metastatic thyroid cancer or solid tumors. News release. FDA. May 29, 2024. Accessed June 12, 2024. https://shorturl.at/4Bduj