FDA Approval Summary: Selpercatinib for the Treatment of Advanced RET Fusion-Positive Solid Tumors.

On September 21, 2022, the FDA granted accelerated approval to selpercatinib (Retevmo, Eli Lilly and Company) for the treatment of adult patients with locally advanced or metastatic solid tumors with a rearranged during transfection (RET) gene fusion that have progressed on or following prior systemic treatment or who have no satisfactory alternative treatment options. The approval was based on data from Study LOXO-RET-17001 (LIBRETTO-001; NCT03157128), an international, non-randomized, multi-cohort clinical trial that included patients with advanced solid tumors harboring RET alterations. The overall response rate in 41 patients with locally advanced or metastatic RET fusion-positive solid tumors other than non-small cell lung cancer (NSCLC) or thyroid cancer was 44% [95% confidence interval (CI), 28%-60%], with median duration of response 24.5 months (95% CI, 9.2-not evaluable). Patients with 10 of 14 tumor types with a variety of fusion partners had objective responses, including patients with the following tumors: pancreatic adenocarcinoma, colorectal, salivary, unknown primary, breast, soft-tissue sarcoma, bronchial carcinoid, ovarian, small intestine, and cholangiocarcinoma. The recommendation for approval was supported by results from LIBRETTO-001 in patients with RET fusion-positive NSCLC and thyroid cancer, which formed the basis of prior approvals in these tumor types. The most common adverse reactions (>25%) were edema, diarrhea, fatigue, dry mouth, hypertension, abdominal pain, constipation, rash, nausea, and headache. This is the first tissue-agnostic approval of a RET-directed targeted therapy.

FDA Approval Summary: Cabozantinib for Differentiated Thyroid Cancer.

On September 17, 2021, the FDA approved cabozantinib (Cabometyx; Exelixis, Inc.) for the treatment of adult and pediatric patients 12 years of age and older with locally advanced or metastatic differentiated thyroid cancer (DTC) that has progressed following prior VEGFR-targeted therapy and who are radioactive iodine (RAI)-refractory or ineligible. This is the first approval for patients with RAI-refractory locally advanced or metastatic DTC who have progressed following prior therapy and the first approval in pediatric patients with DTC. The approval was based on data from COSMIC-311 (Study XL184-311, NCT03690388), an international, randomized, double-blind trial in which patients with locally advanced or metastatic RAI-refractory DTC that progressed during or following treatment with at least one VEGFR-targeting tyrosine kinase inhibitor were treated with either cabozantinib 60 mg orally once daily (N = 170) or placebo with best supportive care (N = 88). The primary efficacy outcome measures were progression-free survival (PFS) and overall response rate (ORR) by blinded independent central review per RECIST 1.1. The median PFS was 11.0 months [95% confidence interval (CI), 7.4-13.8] in the cabozantinib arm compared with 1.9 months (95% CI, 1.9-3.7) in the control arm, with an HR of 0.22 (95% CI, 0.15-0.31). The endpoint of ORR was not met. No new safety signals were identified with the exception of hypocalcemia, which was added as a warning in the product labeling.