Mustang Bio, Inc. announced that interim Phase 1/2 data from Mustang's multicenter clinical trial of MB-106, a CD20-targeted, autologous CAR-T cell therapy for patients with relapsed or refractory B-cell non-Hodgkin lymphomas (NHL") and chronic lymphocytic leukemia (CLL"), have been selected for a poster presentation at the 65 American Society of Hematology (ASH") Annual Meeting, taking place December 9-12, 2023 in San Diego. MB-106 is being developed in a collaboration between Mustang and Fred Hutchinson Cancer Center (Fred Hutch"). The abstract posted on the ASH Annual Meeting website reported on four patients who received MB-106 at dose level 1 (DL1"), 3.3 10 cells/kg: two patients with follicular lymphoma (FL") who achieved complete response as demonstrated by both PET-CT and bone marrow biopsy, one patient with Waldenstrom macroglobulinemia (WM") who achieved a very good partial response (VGPR"), and one patient with transfusion-dependent hairy cell leukemia variant (HCL-v") who continued to have stable disease with decreased bone marrow disease and who achieved complete transfusion independence which is ongoing at 6 months.

All patients displayed MB-106 expansion, with peak levels between 7-14 days post-infusion, and CAR-T cell persistence is ongoing at 6 months. From a safety perspective, 3 patients experienced Grade 1 cytokine release syndrome and no occurrences of immune effector cell-associated neurotoxicity syndrome were reported. Dose-limiting toxicities (DLT") were monitored through day 28, and no DLTs were observed at DL1.

Because of this favorable safety profile, MB-106 is infused in the outpatient setting if allowed by the institution, except for the first patient in each DL cohort, who is kept for overnight observation after MB-106 administration.