Pan-cancer efficacy of pralsetinib in patients with RET fusion-positive solid tumors from the phase 1/2 ARROW trial

Pharmacodynamics; Prognostic markers; Target validation Farmacodinámica; Marcadores pronósticos; Validación de objetivos Farmacodinàmica; Marcadors pronòstics; Validació d'objectius Oncogenic RET fusions occur in diverse cancers. Pralsetinib is a potent, selective inhibitor of RET receptor tyrosine kinase. ARROW (NCT03037385, ongoing) was designed to evaluate pralsetinib efficacy and safety in patients with advanced RET-altered solid tumors. Twenty-nine patients with 12 different RET fusion–positive solid tumor types, excluding non-small-cell lung cancer and thyroid cancer, who had previously received or were not candidates for standard therapies, were enrolled. The most common RET fusion partners in 23 efficacy-evaluable patients were CCDC6 (26%), KIF5B (26%) and NCOA4 (13%). Overall response rate, the primary endpoint, was 57% (95% confidence interval, 35–77) among these patients. Responses were observed regardless of tumor type or RET fusion partner. Median duration of response, progression-free survival and overall survival were 12 months, 7 months and 14 months, respectively. The most common grade ≥3 treatment-related adverse events were neutropenia (31%) and anemia (14%). These data validate RET as a tissue-agnostic target with sensitivity to RET inhibition, indicating pralsetinib’s potential as a well-tolerated treatment option with rapid, robust and durable anti-tumor activity in patients with diverse RET fusion–positive solid tumors. The authors would like to thank the patients, their families and all investigators involved in this study. V.S. is an Andrew Sabin Family Foundation Fellow at The University of Texas MD Anderson Cancer Center. V.S. acknowledges support of the Jacquelyn A. Brady Fund. V.S. is supported by US National Institutes of Health grants R01CA242845 and R01CA273168. MD Anderson Cancer Center Department of Investigational Cancer Therapeutics is supported by the Cancer Prevention and Research Institute of Texas (RP1100584), the Sheikh Khalifa Bin Zayed Al Nahyan Institute for Personalized Cancer Therapy (1U01 CA180964), a National Center for Advancing Translational Sciences grant (UL1 TR000371) and the MD Anderson Cancer Center Support grant (P30 CA016672). Medical writing support, including assisting authors with the development of the outline as well as initial draft and incorporation of comments, was provided by N. Tracey and W. Wheddon; editorial support, including submission, was provided by E. Sims and T. Taylor, all of Paragon (Knutsford, United Kingdom), supported by Blueprint Medicines, according to Good Publication Practice guidelines. The sponsor was involved in the study design and collection, analysis and interpretation of data, as well as data checking of information provided in the article. However, ultimate responsibility for opinions, conclusions and data interpretation lies with the authors. E.G. is supported by the Caixa Research Advanced Oncology Research Program (supported by Fundació La Caixa, LCF/PR/CE07/50610001). E.N. is supported by the Carlos III National Health Institute grant (PI21/00789) and Horizon 2020 (H2020-SC1-2019-Single-Stage-RTD). M. Schuler is supported by the Oncology Center of Excellence Grant/German Cancer Aid (70112273) and the German Cancer Consortium, partner site: University Hospital Essen (BMBF 613-71043-1). G.C. is supported by an OPTIMA (optimal treatment for patients with solid tumors in Europe through artificial intelligence) grant (101034347). The ARROW study (NCT03037385) was supported by Blueprint Medicines and F. Hoffmann-La Roche.