Micromet, Inc, a biopharmaceutical company developing novel, proprietary antibodies for the treatment of cancer, inflammation and autoimmune diseases, announced that the German Multicenter ALL Study Group (GMALL) presented phase-2 clinical data of the BiTE antibody blinatumomab (MT103) at the 14th Congress of the European Haematology Association (EHA) in Berlin, Germany, showing a high response rate in acute lymphoblastic leukaemia (ALL) patients with minimal residual disease (MRD). Blinatumomab is a novel therapeutic antibody that activates a patient's T cells to seek out and destroy cancer cells.

The patients included in this phase-2 clinical trial were in complete haematological remission following intense chemotherapy regimens, but retained a detectable level of ALL cancer cells in their bone marrow -- so called minimal residual disease (MRD). Various studies have confirmed that ALL patients with MRD following chemotherapy have a significantly worse prognosis than patients without MRD.

The primary endpoint of the phase-2 study is MRD response within four cycles of treatment. MRD response is defined as the elimination of ALL cancer cells in patients with MRD below the limit of detection. The achievement of the primary endpoint requires that at least 22 per cent of 21 patients have an MRD response. Currently, 13 of 16, or 81 per cent of evaluated patients have shown an MRD response, thus qualifying the trial as having met its primary endpoint before the completion of the study. Patients in all subgroups responded to treatment with blinatumomab, including bcr-abl positive patients after failure of treatment with bcr-abl inhibitors, and patients with t(4;11) translocations. Side effects were observed primarily in the first 24 to 48 hours with transient pyrexia and lympho-/leukopenia being the most frequent adverse events.

"Blinatumomab is one of the most active agents the GMALL has tested in the adult ALL consolidation setting," said Dr Ralf Bargou, principal investigator of the trial. "We are excited about the significant activity of blinatumomab in ALL and the favourable safety profile observed in this study. These results are particularly important for these patients who are in a disease stage with extremely poor prognosis and for which we lack treatment options except for patients eligible for allogenic stem cell transplantations."

"The ALL interim data showing an MRD response rate above 80 per cent significantly exceeds the rate which was considered to be clinically meaningful and was set as the hurdle for the achievement of the primary end point," said Micromet's senior vice president and chief medical officer, Carsten Reinhardt. "We are now looking forward to discussing a pivotal ALL programme with the regulatory authorities later this year."

Micromet is a biopharmaceutical company developing novel, proprietary antibodies for the treatment of cancer, inflammation and autoimmune diseases.