Blueprint Medicines Announces Proof-of-Concept Data for Highly Selective RET Inhibitor BLU-667 from Phase 1 ARROW Clinical Trial in Patients with RET-Altered Solid Tumors
The data from the dose escalation portion of the ARROW trial showed broad and robust clinical activity for once-daily (QD) dosing of BLU-667 across multiple tumor types and RET genotypes, including in patients whose disease had progressed on prior multi-kinase inhibitor therapy. As of the data cutoff date of
"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
Data from the Ongoing Phase 1 ARROW Clinical Trial
As of the data cutoff date of
Pharmacokinetic (PK) data across all QD dose levels demonstrated rapid absorption of BLU-667 and a mean half-life greater than 12 hours, supporting a QD dosing regimen.
Preliminary Safety Data:
As of the data cutoff date, QD dosing of BLU-667 was observed to be well-tolerated. The maximum tolerated dose (MTD) for BLU-667 was determined to be 400 mg QD using a Bayesian optimal interval design. At QD dose levels up to and including the MTD, the majority of AEs reported by investigators were Grade 1 or 2. AEs reported by investigators (≥20 percent) most commonly included constipation (24 percent), increased alanine aminotransferase (ALT) (22 percent) and increased aspartate aminotransferase (20 percent). Investigators reported treatment-related Grade 3 AEs in eight patients (16 percent). Treatment-related Grade 3 AEs occurring in two or more patients included hypertension and neutropenia. There were no treatment-related Grade 4 or 5 AEs.
Across all QD dose levels up to 600 mg QD, seven patients experienced dose-limiting toxicities. Only one patient discontinued treatment with BLU-667 due to a dose-limiting toxicity (Grade 3 ALT increase). An additional 11 patients discontinued treatment, including eight patients due to progressive disease, one patient due to an AE unrelated to BLU-667 and one patient due to non-compliance. One patient passed away, and the death was deemed unrelated to BLU-667. Among all 53 enrolled patients, 41 patients (77 percent) remained on BLU-667 as of the data cutoff date. Duration of treatment ranged from 0.3 to 11.5 months.
Preliminary Clinical Activity Data:
As of the data cutoff date, 40 patients with RET-altered tumors were evaluable for response assessment, including 14 patients with NSCLC, 25 patients with MTC and one patient with papillary thyroid cancer (PTC). CT and MRI imaging was used to measure clinical activity by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. Of the remaining 13 enrolled patients who were not evaluable for response assessment, two patients did not have RET-altered tumors, one patient died due to an AE unrelated to BLU-667 prior to any response assessment and 10 recently enrolled patients had not been evaluated for response by the data cutoff date.
Across all evaluable patients, the preliminary ORR was 45 percent. Responses were observed in patients previously treated with multi-kinase therapy, immunotherapy and chemotherapy.
- 85% of NSCLC patients with measurable target lesions had radiographic tumor reductions.
- Seven patients achieved a partial response (PR) (five confirmed, two pending confirmation), representing a preliminary ORR of 50 percent.
- Responses were observed in patients with the most common RET alterations in NSCLC, including RET-KIF5B and RET-CCDC6 fusions.
- Preliminary evidence of anti-tumor activity in the brain was observed in metastatic NSCLC.
- 83% of MTC patients with measurable target lesions had radiographic tumor reductions.
- One patient achieved a confirmed complete response, nine patients achieved a PR (five confirmed, four pending confirmation), representing a preliminary ORR of 40 percent.
- Responses were observed in patients with the most common activating RET mutations in MTC, including the RET-M918T mutation.
Other RET-altered solid tumors
- One patient with RET-altered PTC achieved a PR (pending confirmation).
Based on the favorable tolerability and encouraging clinical activity observed for BLU-667 to date,
Investor Event and Webcast Information
About the Phase 1 ARROW Clinical Trial of BLU-667
ARROW is a Phase 1 clinical trial of BLU-667 designed to evaluate the safety and tolerability of BLU-667 in multiple ascending doses in adults with RET-altered NSCLC, MTC and other advanced solid tumors. The trial consists of two parts: a dose escalation portion and an expansion portion. Enrollment in the dose escalation portion is complete, and the expansion portion has been initiated and is actively enrolling patients in four defined cohorts at the MTD of 400mg QD: (1) RET-altered NSCLC patients previously treated with a tyrosine kinase inhibitor (TKI), (2) RET-altered NSCLC patients who have not previously received any TKI treatment, (3) patients with medullary thyroid cancer, and (4) patients with other RET-altered solid tumors. Trial objectives include assessing response, pharmacokinetics, pharmacodynamics and safety.
Patients and physicians interested in the ARROW trial can contact the
About RET-Altered NSCLC, MTC and Other Solid Tumors
RET activating fusions and mutations are a key disease driver in multiple cancers, including NSCLC and MTC. RET fusions are implicated in approximately 1-2% of patients with NSCLC, while RET mutations are implicated in approximately 60% of patients with MTC. In addition, genomic analyses published by scientists at Blueprint Medicines have identified RET fusions at low frequencies in colon and breast cancer. Currently, there are no approved therapies that selectively target RET-driven cancers, though there are several approved multi-kinase inhibitors with RET activity being evaluated in clinical trials. Thus far, clinical activity attributable to RET inhibition has been uncertain for these inhibitors, likely due to insufficient inhibition of RET and off-target toxicities.
BLU-667 is an orally available, potent and highly selective inhibitor designed to target RET fusions, mutations and predicted resistance mutations.
Blueprint Medicines is developing a new generation of targeted and potent kinase medicines to improve the lives of patients with genomically defined diseases. Its approach is rooted in a deep understanding of the genetic blueprint of cancer and other disease driven by the abnormal activation of kinases.
Cautionary Note Regarding Forward-Looking Statements
This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including, without limitation, statements regarding plans and timelines for the clinical development of BLU-667, including plans and timelines for advancing the expansion portion of the Phase 1 ARROW trial; expectations regarding the safety and efficacy of BLU-667 and the potential benefits of BLU-667 in treating patients with RET-altered cancers; plans to advance a QD dosing regimen for BLU-667; plans and timelines for activating additional clinical sites in the Phase 1 ARROW trial; expectations regarding enrollment in the expansion portion of the Phase 1 ARROW trial; and
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Kristin Hodous, 617-714-6674, KHodous@blueprintmedicines.com; Jim Baker, 617-844-8236, JBaker@blueprintmedicines.com