The FDA has granted breakthrough therapy designation to IMGN632, a CD123-targeting antibody drug conjugate, for the treatment of patients with relapsed or refractory blastic plasmacytoid dendritic cell neoplasm (BPDCN).
This decision was based on initial findings from the BPDCN cohort of a phase I/II study of IMGN632 in patients with hematologic malignancies, which were presented by Naval Daver, MD, from MD Anderson Cancer Center, at the 2019 American Society of Hematology (ASH) Annual Meeting.
In this trial, 74 patients (67 with AML and 7 with BPDCN) received IMGN632 across nine dose-escalation cohorts on two different schedules. The most common treatment-emergent AEs included diarrhea (30%), febrile neutropenia (27%), and nausea (26%). Three dose-limiting toxicities occurred at IMGN632 dose levels ≥0.18 mg/kg; these included one prolonged case of neutropenia and two reversible cases of veno-occlusive disease. The drug also demonstrated single-agent activity in this phase I/II trial and in supporting preclinical studies.
Updated data will be presented virtually as part of the 2020 ASH Annual Meeting in December.
Sources: ImmunoGen press release, October 5, 2020; ClinicalTrials.gov NCT03386513.