Blinatumomab, administered in a stepwise, dose-escalated regimen with prophylactic dexamethasone, induced responses in patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL), according to a report published in Blood.
The phase II study included 25 patients who were refractory to their last treatment, had relapsed after autologous hematopoietic stem cell transplant (HSCT), or had relapsed disease and were ineligible for autologous HSCT.
In a previous phase I study that did not use a dose-escalated regimen, neurological adverse events were dose limiting at a maximum tolerated blinatumomab dose of 60 mcg/d. The current study used a 14-day stepwise dose escalation and corticosteroid premedication to minimize adverse events: blinatumomab was given at 9 mcg/d in the first week, 28 mcg/d in the second week, and 112 mcg/d thereafter.
Patients had received a median of three prior therapies. In total, 17 of 25 patients ended in cycle 1 (induction) because of disease progression, adverse events, or physician decision; 7 ended in cycle 2 (consolidation), and 1 ended in retreatment.
Among the 21 evaluable patients who received at least 1 week of blinatumomab at the target dose of 112 mcg/day or who discontinued treatment earlier because of progressive disease, the overall response rate was 43% (9/21) and the complete response rate was 19% (4/21). “At least 1 week of treatment at the target dose of 112 mcg/d appears to be required for efficacy,” wrote Dr. Andreas Viardot of the department of internal medicine III, University Hospital Ulm (Germany) and colleagues (Blood. 2016;127(11):1410-16).
The most common adverse events of grade 3 or higher were thrombocytopenia (17%) and leukopenia (17%). Grade 3 neurologic events included encephalopathy (9%) and aphasia (9%); no grade 4 or 5 neurologic events were reported. Cytokine release syndrome or cytokine storm were not reported.
Blinatumomab (Blincyto) is a bispecific T-cell engager antibody approved for the treatment of Philadelphia chromosome-negative relapsed or refractory B-cell precursor acute lymphoblastic leukemia. Blinatumomab transiently links CD3-positive T cells to CD19-positive B cells, which activates T cells and leads to T cell–mediated lysis of tumor cells and concomitant T-cell proliferation.
The study was supported by Amgen, the maker of Blincyto. Dr. Viardot reported having financial ties with Amgen and several other drug companies.