Expanded Access Program Pralsetinib in Advanced Non-Small Cell Lung Cancer with Rearranged during Transfection (RET) Gene Rearrangement

Purpose Rearranged during transfection (RET) gene rearrangement is a well-known driver event in non-small cell lung cancer (NSCLC). Pralsetinib is a selective inhibitor of RET kinase and has shown efficacy in oncogenic RET-altered tumors. This study evaluated the efficacy and safety of expanded access program (EAP) use of pralsetinib in pretreated, advanced NSCLC patients with RET rearrangement. Materials and Methods Patients who received pralsetinib as part of the EAP at Samsung Medical Center were evaluated through a retrospective chart review. The primary endpoint was overall response rate (ORR) per the Response Evaluation Criteria in Solid Tumors (RECIST) ver. 1.1 guidelines. Secondary endpoints were duration of response, progression-free survival (PFS), overall survival (OS), and safety profiles. Results Between April 2020 and September 2021, 23 of 27 patients were enrolled in the EAP study. Two patients who were not analyzed due to brain metastasis and two patients whose expected survival was within 1 month were excluded from the analysis. After a median follow-up period of 15.6 months (95% confidence interval [CI], 10.0 to 21.2), ORR was 56.5%, the median PFS was 12.1 months (95% CI, 3.3 to 20.9), and the 12-month OS rate was 69.6%. The most frequent treatment-related adverse events (TRAEs) were edema (43.5%) and pneumonitis (39.1%). A total of 8.7% of patients experienced extra-pulmonary tuberculosis. TRAEs with a common grade of three or worse were neutropenia (43.5%) and anemia (34.8%). Dose reduction was required in nine patients (39.1%). Conclusion Pralsetinib presents a clinical benefit when used in patients with RET-rearranged NSCLC, consistent with a pivotal study.