BRIEF—RMAT designation from FDA for Mustang Bio's 'bubble boy disease' candidate

Mustang Biotech and St Jude Children’s Research Hospital have announced that MB-107, a lentiviral gene therapy for the treatment of X-linked severe combined immunodeficiency, also known as bubble boy disease, has been granted the Regenerative Medicine Advanced Therapy (RMAT) designation by the US Food and Drug Administration.

Under the terms of the RMAT designation, the FDA will help facilitate the program’s expedited development and review and provide guidance on generating the evidence needed to support the approval of MB-107 for XSCID.

RMAT designation was granted to MB-107 based on positive Phase I/II clinical data for infants with XSCID under the age of 2 (ClinicalTrials.gov Identifier: NCT01512888), which were published in the New England Journal of Medicine in April 2019.

This is not a ‘first’ for bubble boy disease.

UK pharma major GlaxoSmithKline developed and started marketing its Strimvelis (autologous CD34+ cells transduced to express ADA) for the treatment of this disease, but in April last year, along with its rare disease portfolio, parceled the drug off to British start-up Orchard Therapeutics.