ASCO26: Lilly's Retevmo aces early-stage lung cancer trial

Eli Lilly looks set to extend the reach of its RET inhibitor Retevmo in RET-mutated tumours, as the LIBRETTO-432 trial shows its value in an adjuvant lung cancer setting.

The LIBRETTO-432 trial showed an 83% reduction in the risk of cancer recurrence with Retevmo (selpercatinib) when given as an adjuvant treatment for patients with early-stage (1b to 3a), RET fusion-positive non-small cell lung cancer (NSCLC), positioning Lilly's drug as a potential new standard of care in this setting.

The trial compared the RET inhibitor with placebo over three years in 151 patients who had undergone potentially curative surgery or radiotherapy and, in some cases, also received adjuvant chemotherapy.

A secondary presented at ASCO focused on a group of stage 2 to 3A patients, on the edges of early, localised cancer to more complex, locally advanced disease. In this group, after two years of follow-up, 92% of patients on Retevmo were alive and cancer-free compared to 61% who were on placebo, a result described as "striking" by lead investigator Dr Jonathan Goldman of the University of California, Los Angeles (UCLA).

The median event-free survival (EFS) was not reached for Retevmo in the study, and came in at 31.8 months for the control group.

"One of the major challenges for patients with early-stage lung cancer is that despite potentially curative surgery or radiation, many remain at high risk of cancer recurrence over the following five years," said Goldman.

"These results highlight the importance of testing for specific gene changes at the time of diagnosis so that patients can be started on the most appropriate therapy."

RET fusions are found in 1% to 2% of lung cancer cases, and are seen more often in younger patients with little or no smoking history.

Retevmo already has full FDA approval for first-line treatment of advanced, RET-positive lung cancer and thyroid cancer, along with an accelerated approval for any solid tumour with a RET mutation, but moving up the treatment pathway into the adjuvant setting would make it an option earlier on for a larger patient population.

Since its first approval in 2020, the drug has become the dominant brand in the RET inhibitor market, with a series of label extensions driving sales to $456 million last year that far outstripped Rigel's Gavreto (pralsetinib), currently the only other approved drug in the class, which made $42 million in 2025.

Lilly acquired Retevmo as part of its $8 billion buyout of Loxo Oncology in 2019, a deal that also gave it fast-growing BTK inhibitor Jaypirca (pirtobrutinib) for blood cancers.