Mustang Bio Receives FDA Orphan Drug Designation for MB-101 to Treat Astrocytomas and Glioblastoma
Tuesday, July 08, 2025
Mustang Bio, Inc, a clinical-stage biopharmaceutical company focused on developing cell therapies for hard-to-treat cancers, has been granted Orphan Drug Designation by the U.S. Food and Drug Administration (FDA) for MB-101. This CAR T-cell therapy targets IL13Ra2 and is being developed for the treatment of recurrent diffuse and anaplastic astrocytoma (astrocytomas) and glioblastoma (GBM).
The FDA’s Orphan Drug Designation is intended to support the development of therapies for rare conditions affecting fewer than 200,000 people in the U.S. It provides several benefits, including tax credits for clinical trials, waivers for certain regulatory fees, and seven years of market exclusivity if the product receives approval.
This new designation for MB-101 builds on previous recognition of Mustang’s MB-108 programme. Mustang is exploring a combined approach using MB-101 with MB-108, an oncolytic virus therapy, as a possible treatment for malignant glioma, including recurrent GBM and high-grade astrocytomas. The combination is intended to improve the tumour’s immune environment, making it more receptive to CAR T-cell treatment. MB-108 is designed to convert "cold" tumours (which resist immune attack) into "hot" tumours (which attract immune cells), potentially improving the effectiveness of MB-101.
Preclinical data presented at the 2022 American Association for Cancer Research (AACR) meeting supported the potential of this combination. Individual studies of MB-101 and MB-108 have shown they were generally well tolerated in patients with recurrent GBM. A 2024 publication in Nature Medicine by City of Hope reported that two patients treated with MB-101 alone, who had high levels of tumour-infiltrating CD3+ T-cells prior to therapy, achieved complete responses lasting 7.5 and more than 66 months, respectively. These results were among the best in a group of 57 patients who were part of City of Hope’s Phase 1 trial.
Phase 1 trials for MB-101 and MB-108 are ongoing at City of Hope and The University of Alabama at Birmingham. Mustang’s development of the combination therapy, referred to as MB-109, will depend on securing further funding or forming a strategic partnership.
MB-109 combines MB-101, a CAR T-cell therapy licensed from City of Hope, and MB-108, an HSV-1 oncolytic virus licensed from Nationwide Children’s Hospital. MB-108 is administered first to infect tumour cells and trigger an immune response by attracting CD8+ and CD3+ T-cells to the site. This process aims to improve the tumour environment, allowing MB-101 CAR T-cells to penetrate the tumour, activate effectively, and destroy cancer cells.
Source: globenewswire.com
