# ARROW (thyroid cohorts)

Source: https://onco.cc/trials/arrow-thyroid/  
OnCo record `arrow-thyroid` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

ARROW is the single-arm study behind the second RET inhibitor's thyroid approvals.

## Summary

ORR 71% in treatment-naive RET-mutant MTC and 60% after prior cabozantinib/vandetanib; 89% in RET-fusion thyroid cancer. Accelerated approval December 2020; the MTC indication was later withdrawn in the US (2023) when the confirmatory trial was not pursued, leaving selpercatinib as the RET-selective option for MTC.

## Fields

- Kind: Trial
- Status: positive
- Last checked: 2026-09-07
- Registry id: NCT03037385
- Phase: 1/2
- Setting: RET-mutant medullary and RET-fusion thyroid cancer: pralsetinib
- Sponsor: Blueprint Medicines
- Result: ORR 71% (naive MTC), 89% (RET-fusion thyroid).
- Outcomes: Objective response rate, treatment-naive RET-mutant MTC: Pralsetinib 71%
- Replication: LIBRETTO-001/531 with selpercatinib show the same RET-selective effect.

## Notes

- ARROW also enrolled a lung cohort. Of 233 patients with RET fusion-positive non-small-cell lung cancer enrolled between March 2017 and May 2020, 92 who had had platinum chemotherapy and 29 who were treatment-naive received pralsetinib 400 mg daily before the efficacy cutoff. Overall response was recorded in 53 of 87 previously treated patients with centrally adjudicated measurable disease (61 percent, 95 percent confidence interval 50 to 71), including five complete responses (Lancet Oncology 2021). NICE TA812 (3 August 2022) does not recommend pralsetinib for this indication in England.

## Sources

- ClinicalTrials.gov NCT03037385: https://clinicaltrials.gov/study/NCT03037385
- Lancet Diabetes & Endocrinology 2021: https://www.thelancet.com/journals/landia/article/PIIS2213-8587(21)00120-0/fulltext
- ARROW lung cohort (Lancet Oncology 2021): https://doi.org/10.1016/S1470-2045(21)00247-3
- NICE TA812: pralsetinib for treating RET fusion-positive advanced non-small-cell lung cancer (not recommended): https://www.nice.org.uk/guidance/ta812

## Connected records

- cancers: [Lung cancer (all types)](https://onco.cc/cancers/lung-cancer/), [Non-small-cell lung cancer](https://onco.cc/cancers/nsclc/), [RET fusion-positive non-small-cell lung cancer](https://onco.cc/cancers/ret-fusion-nsclc/), [Thyroid cancer](https://onco.cc/cancers/thyroid/)
- technologies: [Small-molecule kinase inhibitors](https://onco.cc/technologies/kinase-inhibitors/)
- targets: [RET](https://onco.cc/targets/ret/)
- drugs: [Pralsetinib](https://onco.cc/drugs/pralsetinib/)
- companies: [Blueprint Medicines](https://onco.cc/companies/blueprint-medicines/)
- trials: [A Study of Selpercatinib (LOXO-292) in Participants With Advanced Solid Tumors, RET Fusion-Positive Solid Tumors, and Medullary Thyroid Cancer (LIBRET](https://onco.cc/trials/nct03157128/), [LIBRETTO-431](https://onco.cc/trials/libretto-431/)
- terms: [Basket trial](https://onco.cc/terms/basket-trial/), [Single-arm trial](https://onco.cc/terms/single-arm/)

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JSON: https://onco.cc/api/v1/entities/arrow-thyroid.json