Outcomes of Patients with RET Fusion-Positive Non-Small Cell Lung Cancer Treated with First-Line Non-Molecularly...

The single-arm phase 1/2 LIBRETTO-001 trial demonstrated durable efficacy and a favorable safety profile with the selective RET inhibitor (RETi) selpercatinib in patients with RET fusion-positive non-small cell lung cancer (NSCLC), regardless of prior non-RET-selective treatment. The aim of this study (RECALIB-RET), comparison of outcomes with first-line (1L) non-RET-selective therapy in a real-world external control arm to the LIBRETTO-001 selpercatinib-treated population, was precluded by a small real-world sample size. Therefore, we report European benchmark data, reflecting physician's choice of 1L therapy and treatment availability in routine clinical practice.

The study population comprised data from adult patients with RET fusion-positive, locally advanced/metastatic NSCLC who received ≥ 1 prior line of systemic non-RET-selective therapy, pooled across chart reviews from four European countries. Patient characteristics, biomarker testing and treatment patterns, clinical outcomes, and safety events during 1L therapy are reported.

Patients in the RW benchmark population (n = 24) had a median age at 1L therapy initiation of 61.0 years (interquartile range 56.0-71.5); 58.3% were male and 41.7% were female, 95.8% had adenocarcinoma, and 91.7% had advanced-stage disease at diagnosis. Overall response and disease-control rates to 1L non-RET-selective therapy were 37.5% (95% confidence interval [CI] 18.8-59.4) and 58.3% (95% CI 36.6-77.9), respectively. Median progression-free survival was 5.4 months (95% CI 2.1-8.0). Median time between advanced disease diagnosis and biomarker testing (n = 21, 87.5%) was 17 days, with a median turnaround time for the results of 25 days; 70.8% (n = 17) initiated 1L treatment before receiving test results. Of 125 adverse events reported, 20 (16.0%) were grade ≥ 3.

Outcomes observed in the RECALIB-RET RW benchmark population reflect the limitations of non-selective RETi therapies in RET fusion-positive NSCLC, and reinforce the rationale for early use of targeted agents such as selpercatinib. Optimizing biomarker testing practices may enable earlier access to these therapies.