Blueprint Medicines has reported positive proof-of-concept results from the ongoing ARROW clinical trial, a Phase I open-label study of BLU-667 to treat patients with RET-altered solid tumours.
The ARROW trial aims to analyse the safety and tolerability of BLU-667 in multiple ascending doses in adults with RET-altered Non-Small Cell Lung Cancer (NSCLC), Medullary thyroid cancer (MTC) and other advanced solid tumours.
It features a dose escalation portion and an expansion portion.
Results from the dose escalation portion of the trial demonstrated improved clinical activity for once-daily (QD) dosing of BLU-667 across multiple tumour types and RET genotypes, including in patients whose disease had progressed on prior multi-kinase inhibitor therapy.
Until the data cut-off date of 6 April, the results demonstrated radiographic tumour reductions in 84% of patients with RET-altered solid tumours with measurable target lesions.
In patients evaluable for response, preliminary overall response rates (ORR) were found to be 50% in patients with NSCLC and 40% in patients with MTC.
From the data cut-off date, once-daily (QD) dosing of BLU-667 was reportedly well-tolerated, and investigators recorded Grade 1 or 2 most adverse events (AEs) during the dose-escalation portion of the trial that involved the treatment of 53 patients.
Blueprint has completed patient enrolment in this phase and started enrolling patients for the expansion portion of the trial.
Objectives of the ARROW trial include evaluating response, pharmacokinetics, pharmacodynamics and safety.
Blueprint Medicines chief medical officer Andy Boral said: “The data announced today reveal the broad clinical potential of BLU-667, a potent and highly selective RET inhibitor, and further demonstrate the power and reproducibility of Blueprint Medicines' proprietary drug discovery platform.
“We believe the safety, clinical activity and pharmacodynamic results from the dose escalation portion of the Phase I ARROW trial demonstrate compelling proof-of-concept for BLU-667.”
The University of Texas MD Anderson Cancer Center has led the ARROW trial.