ImmunoGen Presents Updated Findings from Phase 1/2 Study of IMGN632 in Blastic Plasmacytoid Dendritic Cell Neoplasm at ASH Annual Meeting

ImmunoGen Inc. (Nasdaq: IMGN), a leader in the expanding field of antibody-drug conjugates (ADCs) for the treatment of cancer, today announced that new safety and efficacy findings from the expansion phase of the Phase 1/2 study of IMGN632 in patients with relapsed/refractory blastic plasmacytoid dendritic cell neoplasm (BPDCN) were presented during an oral session at the 62^nd American Society of Hematology (ASH) Annual Meeting.

“Comprising the largest prospective study with a single agent in patients with relapsed/refractory BPDCN, the results presented at ASH build on the previous data reported for IMGN632 and reinforce the potential of this CD123-targeting ADC as a best-in-class treatment option for BPDCN,” said Anna Berkenblit, MD, Senior Vice President and Chief Medical Officer of ImmunoGen. “Given IMGN632’s favorable safety profile, demonstrated anti-tumor activity, and ease of administration via short infusion in an outpatient setting, we continue to enroll both frontline and relapsed/refractory BPDCN patients in this trial. In addition, the preclinical data presented by our partners at MD Anderson Cancer Center in relapsed/refractory AML further support the combination of IMGN632 with azacitidine and venetoclax, which we are actively enrolling in a Phase 1b/2 clinical trial.”

“BPDCN is a rare, aggressive hematologic malignancy that is characterized by historically low overall survival rates,” said Naveen Pemmaraju, MD, Associate Professor in the Department of Leukemia at MD Anderson Cancer Center. “Despite currently available therapies, outcomes for relapsed/refractory patients remain poor and there is an urgent need to develop better-tolerated treatment options in the frontline setting. These updated safety and efficacy findings for IMGN632 in patients with relapsed/refractory BPDCN are encouraging, and I look forward to advancing IMGN632 into pivotal development.”

IMGN632 MONOTHERAPY DATA IN BPDCN

Title: “Clinical Profile of IMGN632, a Novel CD123-Targeting Antibody-Drug Conjugate, in Patients with Relapsed/Refractory Blastic Plasmacytoid Dendritic Cell Neoplasm” (Abstract #167)

Oral Presentation Session: 616
Date: Saturday, December 5, 2020
Time: 12:30pm PT/3:30pm ET
Updated key findings include:

Safety

• IMGN632 demonstrated a favorable safety profile in 29 patients who received 0.045 mg/kg once every 3 weeks via a short (under 30 minutes) intravenous infusion, with limited grade ≥3 treatment-related adverse events (AEs) and no treatment-related deaths.
• The most common grade ≥3 AEs were febrile neutropenia, hyperglycemia, and thrombocytopenia (10% each).
• Grade ≥3 liver function test elevations were seen in one patient (3%).
• No capillary leak syndrome was reported.

Efficacy