Posted: Thursday, June 10, 2021
FF-10101-01, a selective and irreversible FMS-like tyrosine kinase 3 (FLT3) inhibitor, showed activity in patients with relapsed or refractory acute myeloid leukemia (AML), including those with FLT3 mutations resistant to other FLT3 kinase inhibitors. Mark J. Levis, MD, PhD, of the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins University, presented these findings on behalf of his colleagues at the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 7008).
This phase I dose-escalation trial enrolled 52 patients who had AML with or without FLT3 mutations. This cohort received oral FF-10101-01 once or twice daily until unacceptable toxicity was observed or there was no further clinical benefit. Doses ranged from 10 to 225 mg daily or 50 to 100 mg twice a day.
Patients in this trial had relapsed on a median of three prior therapies, and 82% of patients with known FLT3 mutations had received prior FLT3 inhibitors. Patients remained in the study for a median of 5.7 weeks. The composite complete remission rate was 13% (4 of 30 patients evaluable for response). There was one complete remission at 75 mg twice a day, one complete remission with incomplete platelet counts at 100 mg twice a day, and two complete remissions with incomplete hematologic recovery at 50 mg twice a day. In addition, four patients achieved a partial response at doses of 50 to 150 mg daily. The median time to overall response was 13.3 weeks. At doses higher than 75 mg twice daily, trough plasma concentrations were greater than 90 ng/mL and were associated with more than 90% inhibition of FLT3 phosphorylation.
FF-10101-01 was generally well tolerated with doses lower than 150 mg. The most common treatment-related adverse events included nausea, diarrhea, elevations in creatinine kinase, vomiting, and increased aspartate aminotransferase. Doses higher than 200 mg were associated with limiting cardiac toxicity.
Disclosure: For a full list of authors’ disclosures, visit coi.asco.org.