Benzinga | May 12, 2021 12:46PM EDT

Mustang Bio Announces MB-106 CD20-Targeted CAR T Data Selected For Presentation At European Hematology Association 2021 Virtual Congress

Mustang Bio, Inc. ("Mustang") (NASDAQ:MBIO), a clinical-stage biopharmaceutical company focused on translating today's medical breakthroughs in cell and gene therapies into potential cures for hematologic cancers, solid tumors and rare genetic diseases, today announced that interim data from the ongoing Phase 1/2 clinical trial investigating the safety and efficacy of MB-106 CD20-targeted CAR T for high-risk B-cell non-Hodgkin lymphomas ("B-NHL") and chronic lymphocytic leukemia ("CLL") has been selected for an e-poster presentation at the European Hematology Association 2021 Virtual Congress ("EHA2021"). MB-106 is being developed in a collaboration between Mustang and Fred Hutchinson Cancer Research Center ("Fred Hutch").



In the abstract posted today on the EHA2021 website, Fred Hutch reported on 12 patients treated with MB-106, which underwent a major cell manufacturing modification after treating the first 7 patients as previously reported at the 62nd Annual American Society of Hematology meeting in 2020. The 12 patients treated under the new manufacturing process were treated at dose levels ("DL") ranging from 3.3x105 to 1x107 CAR T cells/kg, and clinical responses were observed at all DLs with no dose-limiting toxicities. Cytokine release syndrome occurred in 3 patients (25%): 2 patients with grade 1 and 1 patient with grade 2. Only 1 patient required tocilizumab and dexamethasone, and no immune effector cell-associated neurotoxicity syndrome of any grade was observed. Overall response rate ("ORR") was 92% (11/12) with a complete response ("CR") rate of 58% (7/12). In 9 patients with follicular lymphoma, ORR and CR were 89% (8/9) and 67% (6/9), respectively. The patient with CLL had a PET-negative CR and undetectable measurable residual disease in peripheral blood and bone marrow by flow cytometry (10-4) (uMRD4) on day 28. Among patients who received the highest two dose levels, DL3 (3.3x106 CAR T cells/kg; n=4) and DL4 (1x107 CAR T cells/kg; n=1), CR rate was 100% (5/5). All 7 patients who achieved a CR remain in remission at a median follow-up of 4 months. CAR T expansion was robust, with median peak blood levels of CAR+ T cells of 122 CAR+ cells/?l (range 0.27-2024), corresponding to 19% (range 0.15 - 65%) of all CD3+ cells. Updated data will be presented at EHA2021.

Manuel Litchman, M.D., President and Chief Executive Officer of Mustang, said, "We are pleased that Fred Hutch will present interim data from the ongoing Phase 1/2 trial of MB-106 at EHA2021. The data thus far indicate that MB-106 has a highly favorable safety profile at all dose levels when compared to commercially available CAR T cell therapies targeting CD19. We look forward to the continued progression of this CD20-targeted CAR T cell therapy program for patients with relapsed or refractory B-cell non-Hodgkin lymphomas and CLL."

Details of the MB-106 e-poster presentation are as follows:

Topic: 25. Gene therapy, cellular immunotherapy and vaccination -- Clinical

Abstract Code: EP731

Title: Immunotherapy Using a 3rd Generation CD20 Targeted CAR T-Cell (MB-106) for Treatment of B-Cell Non-Hodgkin Lymphoma (B-NHL) and Chronic Lymphocytic Leukemia (CLL)

Presenter: Mazyar Shadman, M.D., M.P.H., Fred Hutchinson Cancer Research Center, Seattle, WA, USA

Date and Time: All e-posters will be available for viewing on June 11, 2021 at 09:00 Central European Summer Time (CEST) / 3 a.m. ET

A copy of the abstract can be viewed online through the EHA2021 website at https://ehaweb.org.