In an analysis of the phase I/II LIBRETTO-001 trial reported in the Journal of Clinical Oncology, Lori J. Wirth, MD, and colleagues provided the long-term outcomes of selpercatinib treatment among patients with RET-activated thyroid cancer.
Lori J. Wirth, MD
Study Details
The analysis included patients with RET-mutant medullary thyroid cancer (n = 324) and RET fusion–positive thyroid cancer encompassing different histologic subtypes (n = 66) who were treated with selpercatinib. The long-term outcomes include an additional 228 patients enrolled in the trial since initial reporting.
Key Findings
At data cutoff in January 2023, objective response rates were 82.5% among patients with cabozantinib/vandetanib–naive medullary thyroid cancer and 95.8% among patients with treatment-naive thyroid cancer. Median response duration was not reached (95% confidence interval [CI] = 51.3 months to not evaluable) in patients with cabozantinib/vandetanib–naive medullary thyroid cancer and not reached (95% CI = 42.8 months to not evaluable) in patients with treatment-naive thyroid cancer.
At a median follow-up of 42.4 months, median progression-free survival among cabozantinib/vandetanib–naive patients was not reached (95% CI = 53.1 months to not evaluable). At median follow-up of 44.0 months, median progression-free survival was 41.4 months (95% CI = 30.2 months to not evaluable) among patients with previously treated medullary thyroid cancer.
At median follow-up of 24.9 months, median progression-free survival was not reached (95% CI = 44.2 months to not evaluable) in treatment-naive patients with thyroid cancer. At a median follow-up of 30.4 months, median progression-free survival was 27.4 months (95% CI = 14.5 months to not evaluable) among patients with previously treated thyroid cancer.
The investigators concluded, “With an additional follow-up of 37 months and 228 more patients from the last disclosure, selpercatinib continued to provide durable and robust responses in treatment-naive and previously treated patients with RET-mutant medullary thyroid cancer and RET fusion–positive thyroid cancer.”
Philippe A. Cassier, MD, of Centre Léon Bérard, Lyon, France, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported by the National Cancer Institute and by Loxo Oncology, a wholly owned subsidiary of Eli Lilly and Company. For full disclosures of the study authors, visit ascopubs.org.
