LIBRETTO-001 (ClinicalTrials.gov identifier: NCT03157128) is a registrational phase I/II, single-arm, open-label trial of selpercatinib in RET-dependent cancers. With 19 months of additional follow-up, we report the final efficacy and safety results of selpercatinib in patients with RET fusion-positive non-small cell lung cancer (NSCLC) who had previously received platinum-based chemotherapy (N = 247) or were treatment-naïve (N = 69). The objective response rate (ORR) was 62% for pretreated patients and 83% for treatment-naïve patients. Duration of response (DoR) was 31.6 months for pretreated and 20.3 months for treatment-naïve patients (median follow-up approximately 38 months). Median progression-free survival (PFS) was 26.2 months for pretreated and 22.0 months for treatment-naïve patients (median follow-up approximately 40 months). Median overall survival was 47.6 months in pretreated patients and was not reached in the treatment-naïve group (median follow-up approximately 43 months). At the 3-year landmark estimate, 57% of pretreated and 66% of treatment-naïve patients were alive. Among 26 patients with measurable CNS metastases at baseline, the CNS-ORR was 85% with a CNS-DoR of 9.4 months and CNS-PFS of 11.0 months. The safety profile of selpercatinib was consistent with previous reports. With substantial additional follow-up, selpercatinib continued to show durable responses and intracranial activity, with a manageable safety profile in patients with RET fusion-positive NSCLC.
Gautschi et al. (Tue,) studied this question.