Micromet has presented promising new data from two clinical trials with its lead BiTE® antibody, blinatumomab, at the 53rd American Society of Hematology (ASH) Annual Meeting in San Diego, CA. 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. The compound is being developed for the treatment of leukemia and B cell lymhoma.
The data show that Micromet’s blinatumomab more than doubled the complete remission rate produced by current standard therapies used to treat adult patients with relapsed or refractory B-precursor acute lymphoblastic leukemia (ALL).
In a phase 2 single-arm dose-ranging trial, 68% of evaluable patients (17/25) across all tested doses and schedules achieved a complete response (CR) or complete response with partial hematologic recovery (CRh*) following treatment with blinatumomab. Of the 12 evaluable patients who received the selected dose and schedule 75% (9 of 12) achieved a CR or CRh*. Notably, all responders also achieved a molecular response, or in other words, had no evidence of remaining leukemic cells detectable in the blood or bone marrow.
A first interim analysis of the time impact of blinatumomab treatment was conducted for the initial 18 patients enrolled to the trial. The median survival had not been reached, with a median follow-up period of 9.7 months. With combination chemotherapy, median survival typically ranges from 3 – 6 months1-5. 12 of the initial 18 patients had a CR or CRh* with a median duration of response of 7.1 months. Based on the results of this study, the Company initiated a global phase 2 study in this patient population in November 2011.
Moreover, new findings from a phase 1 trial presented at the meeting demonstrate Micromet’s blinatumomab induces durable responses in patients with extensively pre-treated diffuse large B cell lymphoma (DLBCL).
Data focused on a cohort of 13 patients with DLBCL, of which 11 received the target dose and were evaluable for response. Of these 11 patients, 6 (55%) achieved an objective response following treatment with blinatumomab. 4 of 11 patients (38%) achieved a complete response. Patients were treated with a single course of blinatumomab induction therapy for up to eight weeks. As of October 2011, 5 of 6 patients had ongoing responses for up to 16.6 months. The median duration of response had not been reached with a median observation time of 7.1 months.
All patients enrolled in this study had received prior rituximab-containing regimens. Most had received three or more prior lines of therapy, including 8 of 13 patients with prior autologous stem cell transplant.