Retevmo (selpercatinib), an orphan lung cancer drug that remains non-benefit in Korea, is drawing attention for its efficacy as a first-line standard of care in patients with RET fusion-positive non-small cell lung cancer (NSCLC) in East Asia, including Korea.

At the 2024 American Society of Clinical Oncology (ASCO) Breakthrough meeting in Yokohama, Japan, from Aug. 8-10, new subgroup analyses from the LIBRETTO-431 study, a phase 3 trial of Retevmo, will be presented.

The LIBRETTO-431 study is a randomized, controlled, phase 3 trial evaluating Retevmo monotherapy vs. conventional platinum-based chemotherapy ± Keytruda (pembrolizumab) in patients with RET fusion-positive NSCLC. The new data are from a progression-free survival (PFS) analysis in a cohort of 116 patients in East Asia, including China, Hong Kong, Japan, Korea, and Taiwan.

According to an abstract published Tuesday, Retevmo improved PFS compared to control in East Asian patients with RET fusion-positive NSCLC, confirming its potential as a safe and effective treatment for them.

Of the 116 East Asian patients included in the analysis, 75 received Retevmo and 41 received platinum-based chemotherapy with or without Keytruda.

After a median follow-up of 19.4 months in the Retevmo group and 21.2 months in the control group, the median PFS had not reached yet in the Retevmo group, compared to 11.1 months in the control group.

The share of patients whose cancer had not progressed after 12 months was 72.8 percent in the Retevmo arm and 41.7 percent in the control arm. In addition, the overall response rate (ORR) was 86.7 percent in the Retevmo arm and 61 percent in the control arm.

These results were consistent across the entire patient population in the LIBRETTO-431 study, supporting Retevmo as a preferred first-line standard of care for patients with RET fusion-positive NSCLC.

Lung cancer is the second most commonly diagnosed cancer worldwide and the leading cause of cancer deaths. Typically, about 80 percent of lung cancer diagnoses are NSCLC and only about 1-2 percent of these patients are RET fusion-positive.

While RET fusion-positive NSCLC is a rare form of lung cancer, the significance of the findings can be inferred from the fact that more lung cancer is diagnosed in Asia than anywhere else in the world, experts noted.

The results of the East Asian subgroup analysis are more meaningful as Retevmo remains uncovered by health insurance in Korea.

After receiving approval for Retevmo from the Ministry of Food and Drug Safety in March 2022, Eli Lilly Korea attempted to enter the payroll through the approval-reimbursement linkage system. Still, it failed to pass the first gateway, the Cancer Disease Review Committee (CDRC).

Lilly tried again and passed the CDRC in November 2022 and even crossed the threshold of the Pharmaceutical Reimbursement Evaluation Committee (PREC) in May 2023 but failed in the subsequent drug price negotiations with the National Health Insurance Service.

Retevmo is the only RET inhibitor available to patients in Korea. With the withdrawal of rival drug Gavreto (pralsetinib) from the Korean market due to global ownership issues, Retevmo's reimbursement has become even more critical.

Experts are watching with interest to see if Lilly will try again to get insurance benefits for Retevmo based on data from East Asians, including Koreans.