Immuno-Oncology Resource Center
Immuno-Oncology Resource Center
July 25, 2019
2 min read

Mustang Bio’s CAR T-cell therapy receives orphan drug designation for AML

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The FDA has granted orphan drug designation to MB-102, an investigational chimeric antigen receptor T-cell therapy for patients with acute myeloid leukemia.

MB-102 (Mustang Bio) is a CAR T-cell therapy that targets the CD123 antigen developed by researchers at City of Hope. The investigational agent was previously given orphan drug status in December 2018 for the treatment of blastic plasmacytoid dendritic cell neoplasm (BPDCN).

“We are pleased that MB-102 has received orphan drug designation in two indications, AML and BPDCN. AML most commonly occurs in senior adults, many of whom have to forgo chemotherapy due to other health conditions,” Manuel Litchman, MD, president and CEO of Mustang Bio, said in a press release.

“MB-102 has the potential to be an important new treatment for these and other patients, and to potentially address multiple areas of high unmet medical need.”

Litchman said his company anticipates starting a phase 1/2 multicenter trial in the coming months that will include patients with AML, BPDCN and high-risk myelodysplastic syndrome.

A first-in-human, phase 1 dose-escalation trial of MB-102 is currently being conducted at City of Hope to determine its safety and efficacy for patients with relapsed or refractory AML and BPDCN.

Initial safety and efficacy data from the phase 1 trial were presented at last year’s AACR Special Conference on Tumor Immunology and Immunotherapy. Five patients with AML received a higher dose (200M) of CD123 CAR T-cells; two patients had complete responses and three patients had stable disease at follow-up.

No patient experienced greater than grade 3 cytokine release syndrome or neurotoxicity during the dose-escalation portion of the trial. CRS and neurotoxicity were reversible and well managed, according to Mustang Bio. The investigators established that infusions up to 200M CD123 CAR T cells were safe for treatment of patients.

The FDA Office of Orphan Products Development grants orphan drug designation to novel drugs and biologics that are intended for the safe and effective treatment, diagnosis or prevention of rare diseases or disorders that affect fewer than 200,000 people in the United States. The designation allows manufacturers to qualify for various incentives, including tax credits for qualified clinical trials and — upon regulatory approval — 7 years of market exclusivity.


Mustang Bio. Mustang Bio receives orphan drug designation for MB-102 (CD123 CAR T) for the treatment of acute myeloid leukemia. Available at: Accessed July 25, 2019.

Mustang Bio. Mustang Bio receives orphan drug designation for MB-102 (CD123 CAR T) for the treatment of blastic plasmacytoid dendritic cell neoplasm. Available at: Accessed July 25, 2019.