Eli Lilly and Company (NYSE: LLY) announced that its drug Retevmo demonstrated an 83% reduction in the risk of disease recurrence or death in patients with early-stage RET fusion-positive non-small cell lung cancer, according to results from the Phase 3 LIBRETTO-432 clinical trial.

The study evaluated Retevmo (selpercatinib) as adjuvant therapy versus placebo in 151 patients with stage IB-IIIA RET fusion-positive NSCLC following surgery or radiation treatment. Patients were randomized to receive either selpercatinib 160mg twice daily or placebo for up to three years.

At a median follow-up of 24 months, the primary analysis population of 109 patients with stage II-IIIA disease showed investigator-assessed event-free survival significantly favored selpercatinib with a hazard ratio of 0.17. The 24-month event-free survival rate was 92% for selpercatinib compared to 61% for placebo. Median event-free survival was not reached for selpercatinib versus 31.8 months for placebo.

The most common Grade 3 or higher adverse events were increased alanine aminotransferase occurring in 17% of selpercatinib patients versus 1% in placebo, and increased aspartate aminotransferase in 19% versus 3% respectively. These events were manageable with dose modifications according to the company.

The results will be published in the New England Journal of Medicine and presented at the 2026 ASCO Annual Meeting in Chicago. This marks the first randomized Phase 3 study to evaluate a selective RET kinase inhibitor as adjuvant therapy in this patient population.

Lilly plans to submit the LIBRETTO-432 results to global health authorities for regulatory review.