FDA Grants Orphan Drug Status to Mustang Bio's MB-108 for Malignant Glioma

Mustang Bio, Inc., a biopharmaceutical company in the clinical stage, has announced a significant achievement in their efforts to combat malignant glioma. The U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation for MB-108, a herpes simplex virus type 1 (HSV-1) oncolytic virus, aimed at treating malignant glioma. This designation is particularly important for drugs that address rare diseases, affecting fewer than 200,000 individuals in the United States. With this designation, Mustang Bio gains several benefits, including tax credits for clinical trial costs, waiver of prescription drug user fees, and seven years of market exclusivity upon approval, independent of intellectual property rights.

Mustang Bio's President and CEO, Dr. Manuel Litchman, expressed optimism about the Orphan Drug Designation for MB-108, as it may offer additional market exclusivity. The company is advancing a combined treatment approach using MB-108 alongside MB-101, an IL13Rα2-targeted CAR-T cell therapy, aiming to treat patients with malignant glioma, including recurrent glioblastoma and high-grade astrocytomas. These types of cancers historically have a median overall survival of just six months. The innovative strategy of combining MB-108 with MB-101 represents a potentially groundbreaking industry-sponsored trial for malignant glioma. Mustang Bio plans to seek a similar Orphan Drug Designation for MB-101 as well, reflecting their dedication to improving outcomes for patients with hard-to-treat cancers.

Preclinical data presented at the American Association for Cancer Research (AACR) Annual Meeting in 2022 highlighted the potential of this combination therapy in treating recurrent glioblastoma. The data suggested that MB-108 could alter the tumor microenvironment (TME), converting cold tumors to "hot," thereby potentially enhancing the effectiveness of MB-101 CAR-T cell therapy. Individual studies on MB-101 and MB-108 demonstrated that these therapies were well tolerated in patients with recurrent glioblastoma. Specifically, two patients who received only MB-101 showed significant responses, with complete remission lasting 7.5 and more than 31 months, respectively. These findings were particularly notable among patients with the most inflamed tumors before treatment, suggesting a potential link between tumor inflammation and treatment efficacy. Ongoing Phase 1 clinical trials for MB-101 at City of Hope and MB-108 at The University of Alabama at Birmingham continue to enroll participants.

The progression of Mustang Bio’s MB-109 program, which combines MB-101 and MB-108, depends on securing additional funding or forming strategic partnerships. The MB-109 treatment regimen leverages MB-108's ability to infect tumor cells and reshape the TME by recruiting endogenous CD8- and CD3-positive effector T-cells. This inflamed TME could allow MB-101 CAR-T cells to better infiltrate and activate within the tumor, enhancing the potential for tumor cell destruction.

Mustang Bio, Inc. is committed to translating contemporary medical breakthroughs in cell therapies into potential treatments for challenging cancers. The company seeks to acquire rights to advanced technologies through licensing or ownership, fund their development, and eventually bring these innovations to market. Collaborating with leading medical institutions, Mustang Bio focuses particularly on advancing CAR-T therapies. Founded by Fortress Biotech, Inc., Mustang Bio continues to make significant strides in the field of biopharmaceuticals, driven by their mission to improve patient outcomes.