Clinical Study With Blinatumomab in Patients With Relapsed/Refractory B-precursor Acute Lymphoblastic Leukemia (ALL)

Relapsed/refractory B-precursor ALL in adult patients is an aggressive malignant disease with dismal prognosis. Several studies have reported long term survival to be below 10%. Major prognostic factors are duration of first complete remission (CR1) and age. With current salvage chemotherapy, complete remission (CR) rate is low (20 to 30%) in patients in first salvage with short duration (\< one year) of first remission, patients relapsed after first salvage, or patients aged 60 years and older. Duration of CR is usually very short (median disease free survival \[DFS\]: 2.0-7.5 months). Allogeneic hematopoietic stem cell transplantation (HSCT) may provide a curative treatment option for patients in CR with a satisfactory donor and appropriate clinical status including age, organ function, and remission status. Allogeneic HSCT is not an option in most elderly patients with relapsed ALL. Additional therapeutic approaches are urgently needed. Blinatumomab is a bispecific single-chain antibody derivative against CD (cluster of differentiation)19 and CD3, designed to link B cells and T cells resulting in T cell activation and a cytotoxic T cell response against CD19-expressing cells. In vitro data indicate CD19+ lymphoma and leukemia cell lines to be extremely sensitive to blinatumomab-mediated cytotoxicity. Blinatumomab has the potential to provide meaningful therapeutic benefits to patients compared with existing treatments for this patient population. This study consists of a screening period, a treatment period and a follow-up period. Participants receive one to five treatment cycles of blinatumomab at a target dose of 28 μg/day. In the first cycle, the initial dose is 9 μg/day for the first seven days of treatment, escalated to 28 μg/day starting from Week 2 of treatment. Participants who achieve remission within two cycles of treatment can receive up to three additional cycles of consolidation treatment or proceed to allogeneic HSCT. In the event of progression or relapse within the treatment period, treatment will be terminated. Participants with hematological relapse during the efficacy or safety follow-up period may receive up to three additional cycles of blinatumomab (retreatment) for a maximal total of eight cycles at the investigator´s discretion. Thirty days after end of the last treatment, participants have an end-of-core-study visit. Following this, there are efficacy follow-up visits at 3, 6, 9, 12, 18 and 24 months at the most after treatment start. Once efficacy follow-up is complete, information on survival collected at least every six months until death or at least until three years after treatment start, whichever occurs earlier (survival follow-up).