Mustang Bio presents updated Phase 1/2 data for MB-106

Mustang Bio announced updated safety and efficacy data from Mustang’s multicenter Phase 1/2 clinical trial of MB-106, a CD20-targeted, 3rd-generation autologous CAR T-cell therapy for patients with relapsed or refractory B-cell non-Hodgkin lymphomas and chronic lymphocytic leukemia. The data were presented during a poster session on December 9th at the 65th American Society of Hematology Annual Meeting and build upon previously reported data from a single-institution Phase 1/2 clinical trial conducted at Fred Hutchinson Cancer Center. MB-106 is being developed in a collaboration between Mustang and Fred Hutch. “All nine patients have responded clinically to treatment in this multicenter trial and the safety and efficacy profile of MB-106 appears to be consistent with the original single-institution trial. It is especially encouraging that complete responses were observed in all patients with follicular lymphoma in this multicenter trial,” said Mazyar Shadman, M.D., M.P.H., Study Chair, Innovators Network Endowed Chair at Fred Hutch, Associate Professor and physician at Fred Hutch and University of Washington. “One patient with follicular lymphoma who had six prior treatments including CD19-targeted CAR T-cell therapy experienced a complete response for the first time with no cytokine release syndrome or immune effector cell-associated neurotoxicity syndrome.” Highlights from the data include: All patients responded clinically to treatment with MB-106; 100% overall response rate for patients with follicular lymphoma and Waldenstrom macroglobulinemia; 100% of patients with FL had a complete response; 1 very good partial response and 2 partial responses were observed in WM patients; and the hairy cell leukemia variant patient experienced stable disease, with prolonged, ongoing independence from blood transfusions; Complete responses observed in patients previously treated with CD19-targeted CAR T-cell therapy; MB-106 has a tolerable safety profile in patients with indolent NHL, with no occurrence of CRS above grade 1, and no ICANS of any grade, despite not using prophylactic tocilizumab or dexamethasone; Outpatient administration was allowed and found to be feasible; MB-106 CAR T-cell expansion and persistence in patients was demonstrated. No related serious adverse events reported, apart from Grade 1 CRS. No prophylactic tocilizumab or dexamethasone was administered. The data reported on nine patients from the indolent lymphoma arm of the multicenter clinical trial, including five patients with follicular lymphoma, three patients with Waldenstrom macroglobulinemia, and one patient with transfusion-dependent hairy cell leukemia variant. The patients had been treated with a median of 4 lines of prior therapy, including 2 patients who had received prior CD19-directed CAR T-cell therapy and 1 patient who had received prior autologous stem cell transplant. The patients received one of two dose levels: dose level 1, 3.3106 CAR T-cells/kg body weight, or dose level 2, 1.0107 CAR T-cells/kg.