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Pralsetinib
Source: Thyroid Cancer Treatment (PDQ®)–Health Professional Version, National Cancer Institute.
Source updated: May 9, 2025 · Captured 2026-09-09.
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Pralsetinib is an oral RET-targeted therapy. In December 2020, the FDA approved pralsetinib for patients aged 12 years and older and for adults with advanced or metastatic RET-altered medullary thyroid cancer (MTC) or RET fusion–positive RAI-refractory differentiated thyroid cancer.
Evidence (pralsetinib):
A phase I/II, multicenter, open-label study (ARROW [NCT03037385]) evaluated the efficacy and safety of pralsetinib.[38]
A phase I/II, multicenter, open-label study (ARROW [NCT03037385]) evaluated the efficacy and safety of pralsetinib.[38]
At data cutoff, 147 patients had RET-altered MTC and 22 patients had RET fusion–positive differentiated thyroid cancer. A total of 142 patients with RET-altered MTC or RET fusion–positive differentiated thyroid cancer initiated the phase II dose of pralsetinib at 400 mg once daily.
A phase I/II, multicenter, open-label study (ARROW [NCT03037385]) evaluated the efficacy and safety of pralsetinib.[38]
There were 61 patients with RET-altered MTC who had previously received cabozantinib, vandetanib, or both, and 23 patients were treatment-naïve.
A phase I/II, multicenter, open-label study (ARROW [NCT03037385]) evaluated the efficacy and safety of pralsetinib.[38]
In patients with RET fusion–positive differentiated thyroid cancer, the overall response rate was 89% (95% CI, 52%–100%), all of which were partial responses. Duration of response was not reached after a median follow-up of 9.5 months. Median PFS was not reached (95% CI, NE), with an estimated 1-year PFS rate of 81% after a median follow-up of 12.9 months. Median OS was also not reached, with an estimated 1-year OS rate of 91% (95% CI, 74%–100%) after a median follow-up of 15.8 months.
A phase I/II, multicenter, open-label study (ARROW [NCT03037385]) evaluated the efficacy and safety of pralsetinib.[38]
The most frequent all-cause adverse events were anemia (45%), musculoskeletal pain (45%), constipation (44%), increased AST (42%), and hypertension (40%). Grade 3 to 4 treatment-related adverse events included hypertension (17%), neutropenia (13%), lymphopenia (12%), and anemia (10%). Serious adverse events were reported in 15% of patients; the most frequently reported serious adverse event was pneumonitis (4%).
A phase I/II, multicenter, open-label study (ARROW [NCT03037385]) evaluated the efficacy and safety of pralsetinib.[38]
Of note, in patients with RET-altered MTC previously treated with cabozantinib, vandetanib, or both, the overall response rate was 60% (95% CI, 46%–73%). One patient (2%) had a complete response. However, in 2023 pralsetinib was withdrawn from FDA approval for this indication.[39]
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