NEW YORK – Blueprint Medicines on Wednesday said it will discuss with US regulators the latest data from the Phase I/II ARROW trial, which showed that its RET inhibitor pralsetinib (Gavreto) has a durable clinical benefit in patients with metastatic non-small cell lung cancer and other solid tumors with RET fusions.
Pralsetinib, which is being codeveloped by Blueprint and Genentech, received accelerated approval from the US Food and Drug Administration last year as a treatment for metastatic RET fusion-positive NSCLC and advanced thyroid cancers with RET fusions and mutations. The agency made its decision based on the data from the ARROW basket trial.
Updated data from the same study now further supports the earlier results seen in NSCLC and shows pralsetinib's activity in a variety of solid tumors. In patients with RET fusion-positive tumors that were not NSCLC or thyroid cancer, 53 percent responded to pralsetinib and the median duration of response was 19 months. Responses were seen in patients with cholangiocarcinoma, cancers of unknown primary, and pancreatic, colon, mesenchymal, salivary duct, sweat gland, thymus, and lung tumors other than NSCLC.
The company wants to discuss these data with the FDA and the possibility of broadly expanding pralsetinib's use as a treatment for RET fusion-positive solid tumors, Becker Hewes, Blueprint's chief medical officer, suggested in a statement.
The company also highlighted the drug's activity in treatment-naïve NSCLC lung cancer patients. The accelerated approval of pralsetinib in RET fusion-positive, metastatic NSCLC was based on an overall response rate of 70 percent in treatment-naïve patients. In updated analysis, the overall response rate was 79 percent in this patient subset and the median duration of response was not reached after a median nine months of follow-up.
The study initially restricted treatment-naïve patients to those who were ineligible for standard platinum-based chemotherapy, but researchers lifted the restriction to reflect real-world practice. In an exploratory analysis of the unrestricted treatment-naïve NSCLC patients, the overall response rate was 88 percent.
In NSCLC patients who had previously received platinum-based chemotherapy, the accelerated approval was based on an overall response rate of 57 percent. In the updated analysis, the overall response rate was 62 percent in this subset and the duration of response was 22.3 months.
"In treatment-naïve metastatic NSCLC, these results are particularly encouraging, with many patients remaining in response," Giuseppe Curigliano, associate professor of medical oncology at the University of Milano and an ARROW study investigator, said in a statement. "The data highlight the critical importance of identifying RET alterations before initiating treatment, so that more patients have the opportunity to benefit from targeted therapy."
Blueprint will present the results from the ARROW study in two posters at the American Society of Clinical Oncology's annual meeting in June.