Mustang Bio Provides an Update on its IND Application for MB-207, a Lentiviral Gene Therapy for Treatment of X-linked Severe Combined Immunodeficiency (“XSCID”) in Previously Transplanted Patients - Seite 2

Manuel Litchman, M.D., President and Chief Executive Officer of Mustang, said, “We appreciate the FDA’s support and guidance as we pursue the advancement of MB-107 and MB-207 as potential treatment options for XSCID, a life-threatening, rare genetic disorder with limited treatment options available. We hope to efficiently expedite the development of both critically needed treatments for newly diagnosed infants with XSCID who are between two months to two years of age and for children with XSCID who have previously received HSCT and require re-treatment. We look forward to initiating our multi-center pivotal Phase 2 clinical trial of MB-107 under a Mustang-sponsored IND in newly diagnosed infants with XSCID who are between two months to two years of age in the third quarter of 2022. In light of our positive experience managing the prior MB-107 CMC hold, and our ability to secure FDA clearance to proceed with that program, we believe that our CMC team is well positioned to address the Agency’s concerns around MB-207 once additional clarification of the hold becomes available. Furthermore, we remain fully committed to the success of the pivotal Phase 2 MB-207 clinical trial for children with XSCID who have previously received HSCT and require re-treatment.”

The lentiviral gene-therapy method employed in MB-207 was co-developed by scientists at the National Institute of Allergy and Infectious Diseases (“NIAID”), part of the National Institutes of Health (“NIH”), and St. Jude Children’s Research Hospital (“St. Jude”). MB-207 has been studied at NIAID since 2012 and continues to be assessed in an NIAID-supported Phase 1/2 clinical trial for XSCID in patients over the age of two who have received prior HSCT as infants and have subsequently been noted to be experiencing declining immune function with symptomatic infections.

About X-linked Severe Combined Immunodeficiency (“XSCID”)
X-linked severe combined immunodeficiency is a rare genetic disorder that occurs in approximately 1 per 225,000 births. It is characterized by the absence or lack of function of key immune cells, resulting in a severely compromised immune system and death by 1 year of age if untreated. Patients with XSCID have no T-cells or natural killer cells. Although their B-cells are normal in number, they are not functional. As a result, XSCID patients are usually affected by severe bacterial, viral or fungal infections early in life and often present with interstitial lung disease, chronic diarrhea and failure to thrive. Among patients who receive HSCT, many are unable to establish adequate T-cell immunity or lose T-cell immunity over time. Further, approximately two-thirds of patients who receive HSCT lack sufficient B-cell immunity and need lifelong immunoglobulin replacement therapy.