Retevmo Improves RET-Mutant Thyroid Cancer Outcomes

Retevmo (selpercatinib) improved progression-free survival (time from treatment until death or disease worsens) for patients with metastatic RET-mutant medullary thyroid cancer compared to primary physician’s choice of multikinase inhibitors like Cabometyx (cabozantinib) or vandetanib, according to findings from the LIBRETTO-531 trial that were announced by Eli Lilly, the manufacturer of Retevmo.

LIBRETTO-531, is a randomized phase 3 trial evaluating Retevmo versus Cabometyx or vandetanib. The trial is focused on measuring the safety and effectiveness of Retevmo, a highly selective RET-kinase inhibitor versus multikinase inhibitors.

The study involved 291 patients with metastatic RET-mutant medullary thyroid cancer. Two-thirds were randomly assigned to receive Retevmo, while the other third were assigned to receive physician’s choice of either Cabometyx or vandetanib. Treatment failure-free survival (absence of relapse, death or the addition of another therapy), overall response rate (percentage of patients whose disease shrinks or disappears as a result of treatment), duration of response and overall survival (time from treatment until death of any cause) were analyzed within the study as well, according to Eli Lilly and Company.

"These data from the LIBRETTO-531 trial confirm the importance of selectivity in targeting RET-driven cancers and suggest Retevmo should be considered the preferred first-line treatment for people with advanced RET-mutant medullary thyroid cancer. Taken together with the recent positive Retevmo phase 3 LIBRETTO-431 announcement in lung cancer, these results underscore the importance of timely and broad-based genomic testing to ensure patients who could potentially benefit receive targeted therapies. We look forward to sharing detailed data with the oncology community,” explained Dr. David Hyman, chief medical officer, Loxo@Lilly.

This trial gives insight into more data about thyroid cancer treatment, as LIBRETTO-001 stands as the largest clinical trial for patients with RET-driven cancers treated with an RET inhibitor. This trial analyzed responses of tumor types within patients with RET-driven cancers, according to Eli Lilly and Company.

Retevmo, a RET kinase inhibitor, is active within the central nervous system.

Side effects could occur, as warnings and precautions explain on its label, including hepatotoxicity, interstitial lung disease, pneumonitis, hypertension, QT interval prolongation, hemorrhagic events, hypersensitivity, tumor lysis syndrome, impaired wound healing risk, hypothyroidism and embryo-fetal toxicity, according to Eli Lilly and Company.

Results from the LIBRETTO-531 will be released at an upcoming medical meeting, accessed in a peer reviewed journal and sent to health authorities, according to Eli Lilly and Company.

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