Micromet, Inc. (NASDAQ: MITI) today announced the initiation of a phase 2 trial of the Company's lead product candidate blinatumomab (MT103) in adult patients with relapsed or refractory B-precursor acute lymphoblastic leukemia (ALL). Blinatumomab is the first of a new class of agents called BiTE® antibodies, designed to harness the body's T cells to kill cancer cells.
“Existing treatment options for relapsed/refractory ALL fail to produce durable remissions in the majority of patients”
This phase 2, single-arm study is intended to evaluate the efficacy, safety and tolerability of blinatumomab in 20 adult patients with B-precursor ALL who are resistant or intolerant to standard chemotherapy. Patients will receive blinatumomab daily for 28 days followed by two weeks off therapy over a six week treatment cycle, for up to five treatment cycles. Patients will receive starting doses of blinatumomab of 15 micrograms per meter squared, with dose escalation in subsequent cohorts based on tolerability. The primary endpoint of the study is objective response rate. Secondary endpoints include duration of response and overall survival.
"Existing treatment options for relapsed/refractory ALL fail to produce durable remissions in the majority of patients," said Christian Itin, Ph.D., Micromet's President and Chief Executive Officer. "This trial will enable us to validate blinatumomab's potential utility in patients with ALL with more advanced disease, and, if successful, would be the basis for potential pivotal studies in relapsed/refractory ALL."
Blinatumomab Clinical Experience in ALL
Results from a phase 2 trial reported at the 2010 Congress of the European Hematology Association demonstrated that blinatumomab induced a prolonged hematologic relapse-free survival in patients with MRD-positive ALL and was well tolerated. Of 20 evaluable patients treated, 80% (16 out of 20) achieved a complete MRD response. As of June 2010, seven out of 11 evaluable non-transplanted patients were in hematologic remission with a median of nearly 18 months and ranging up to 23 months. Eight of the patients in the study received an allogeneic stem cell transplant after blinatumomab treatment, all of whom were alive and in remission, ranging up to 21 months. Overall, blinatumomab was well-tolerated. The most common adverse events (any grade) were fever, chills, decreases in immunoglobulins and headache.