(Solid Tumors) Nature Medicine 2022: ARROW Trial Report on Pralsetinib in RET Fusion-Positive Solid Tumors

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This article is a summary of international medical information and is not medical advice; it cannot replace the diagnosis or treatment plan of your attending physician. The medical technologies, drug information and clinical data presented here are compiled from public literature and official statements of Japanese medical institutions; the applicability and outcome of any therapy vary with each patient and must be assessed individually by a qualified physician.

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Regulatory status in Japan (checked November 4, 2026): Pralsetinib is not approved in Japan; no Japanese marketing approval or Japanese package insert was found. This article only summarizes overseas research reports. It is not an assessment of the treatment and is not medical or treatment advice.

Originally posted: September 12, 2022

On August 12, 2022, Vivek Subbiah and colleagues at The University of Texas MD Anderson Cancer Center published results from the ARROW Phase 1/2 clinical trial (NCT03037385) in Nature Medicine. The analysis covered pralsetinib monotherapy in patients with advanced RET fusion-positive solid tumors other than non-small cell lung cancer and thyroid cancer.

Trial design

29 patients with 12 different tumor types who had received or were not candidates for standard therapies
Primary endpoint: objective response rate

Reported results (23 evaluable patients)

Objective response rate: 57% (95% CI, 35–77%)
Median duration of response 12 months, median progression-free survival 7 months, median overall survival 14 months
Most common grade 3 or higher treatment-related adverse events: neutropenia 31%, anemia 14%

Points to consider

This was an early-phase, single-arm trial without a control group and with few patients per tumor type, so it cannot be used to predict outcomes for individual patients. Pralsetinib is not approved in Japan.

Source: Subbiah V, et al. Nat Med. 2022;28(8):1640-1645. https://www.nature.com/articles/s41591-022-01931-y

Note: This article summarizes overseas clinical research for reference only and is not medical or treatment advice. Study data do not predict outcomes for individual patients. Please refer to the original source and discuss any treatment decisions with your physician.

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