The following article features coverage from the American Society of Clinical Oncology 2020 meeting. Click here to read more of Cancer Therapy Advisor‘s conference coverage.

Pralsetinib appears to be promising among patients with RET fusion-positive non-small cell lung cancer (NSCLC), according to safety trial data presented at the ASCO20 Virtual Scientific Program.

RET, a proto-oncogene, has oncogenic fusions present in up to 2% of NSCLC cases. Pralsetinib, an oral selective RETkinase inhibitor, targets both RET fusions and alterations.

For the ARROW study ( identifier: NCT03037385), researchers are recruiting patients with RET fusion­-positive NSCLC to determine the safety and efficacy of pralsetinib in this patient population. During the ASCO virtual program, the researchers presented safety and efficacy data for patients who received the the recommended phase 2 dose of 400 mg once daily.

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Of 354 patients in the safety population, 132 had RET fusion-positive disease and were included in the intent-to-treat population. Among these patients, the median age at baseline was 60 years, 48% of patients were male, and 42% had brain metastases; the RET fusion partner was KIF5B in 71% of cases. Ninety-two patients had received prior platinum therapy and 29 were treatment naive.

Among the 116 patients with evaluable response data, the overall response rate (ORR) was 65%, with a complete response (CR) rate of 6% and a partial response (PR) rate of (59%). Twenty-eight percent of patients had stable disease, and 7% of patients had disease progression.

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Among 80 patients who had received prior therapy and 26 who were treatment naive, the response rates were, respectively, 61% and 73% for ORR, 5% and 12% for CR, and 56% and 62% for PR. Three of 9 patients with measurable central nervous system metastases had an intracranial complete response, with a 56% overall response rate in this subgroup.

The median duration of response was not reached (95% CI, 11-3-not reached), with 75% of responders still on treatment.

In the overall cohort of 354 patients, the most common grade 3 or worse adverse events were neutropenia (10%), hypertension (10%), and anemia (8%).

Read more of Cancer Therapy Advisor‘s coverage of the ASCO 2021 meeting by visiting the conference page.


Gainor JF, Curigliano G, Kim DW, et al. Registrational dataset from the phase I/II ARROW trial of pralsetinib (BLU-667) in patients (pts) with advanced RET fusion+ non-small cell lung cancer (NSCLC). Presented at: ASCO20 Virtual Scientific Program. J Clin Oncol. 2020;38(suppl):abstr 9515.