FDA Approval Summary: Pralsetinib for the Treatment of Lung and Thyroid Cancers With RET Gene Mutations or Fusions

The FDA granted accelerated approval for pralsetinib on September 4, 2020 for non-small cell lung cancer (NSCLC) and December 1, 2020 for thyroid cancer, for: (i) adult patients with metastatic RET fusion-positive NSCLC, (ii) adult and pediatric patients >= 12 years of age with advanced or metastatic RET-mutant medullary thyroid cancer who require systemic therapy, and (iii) adult and pediatric patients >= 12 years of age with advanced or metastatic RET fusion-positive thyroid cancer who require systemic therapy and who are radioactive iodine refractory (if radioactive iodine is appropriate). Approval was based on the results of a multicenter, open-label, multi-cohort clinical trial (ARROW, NCT03037385), demonstrating substan- tial overall response rates (ORR) and durable responses in patients with RET-altered tumors. ORRs within the approved patient populations ranged from 57% [95% confidence interval ( CI), 46-68] in patients with RET fusion- positive NSCLC previously treated with platinum chemotherapy to 89% (95% CI, 52-100) in patients with RET fusion-positive thyroid cancer, with response duration of at least 6 months in most responders. The product label includes warnings and precautions for pneumonitis, hypertension, hepatotoxicity, hemorrhagic events, tumor lysis syndrome, risk of impaired wound healing, and embryo- fetal toxicity. This article summarizes the major considerations during FDA review leading to the approval of pralsetinib.