Mustang Bio Receives FDA Orphan Drug Designation for MB-101 to Treat Brain Cancers
Tuesday, July 08, 2025
Mustang Bio, a clinical-stage biopharmaceutical company, has been granted Orphan Drug Designation by the US Food and Drug Administration (FDA) for its investigational therapy MB-101.
MB-101 and MB-108 are currently being studied in Phase 1 clinical trials at City of Hope and The University of Alabama at Birmingham, respectively. Further development of the MB-109 programme will depend on securing additional funding or strategic partnerships.
MB-101 forms part of a broader therapeutic strategy under development by Mustang Bio. The company is exploring the potential of combining MB-101 with MB-108, an oncolytic virus therapy, under the combined programme MB-109. This approach is designed to enhance treatment outcomes in patients with malignant glioma by modifying the tumour microenvironment (TME). MB-108 is administered first to stimulate immune activity within the tumour, which may in turn increase the effectiveness of MB-101.
The treatment targets IL13Ra2 using CAR T-cell technology and is intended for use in patients with recurrent diffuse and anaplastic astrocytoma and glioblastoma (GBM).
Orphan Drug Designation is awarded to therapies aimed at treating rare conditions affecting fewer than 200,000 individuals in the United States. The designation provides a range of benefits, including tax credits for clinical trials and a waiver of certain regulatory fees. It also offers seven years of market exclusivity following approval, separate from any patent protection.
Preclinical and early clinical data suggest that this combination could be particularly effective in patients with “hot” tumours — those already showing signs of immune activation. Notably, earlier research showed that two patients with such tumours responded exceptionally well to MB-101 alone, achieving complete responses lasting several months to years.
The company continues to focus on developing innovative therapies for hard-to-treat cancers, with the aim of improving outcomes in rare and aggressive brain tumours.
Source: mustangbio.com
