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# Mustang Bio Positive Data on ‘Bubble Boy Disease’ Cure
- URL: https://www.fdaweb.com/mustang-bio-positive-data-on-bubble-boy-disease-cure/
- Published: 2019-04-18T12:00:00.000Z
- Updated: 2026-09-15T01:21:15.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5143904

Mustang Bio has reported positive data from a Phase 1/2 clinical trial of a lentiviral gene therapy for treating newly diagnosed infants under two years old with XSCID, also referred to as SCID-X1 and commonly known as “bubble boy disease.” Under a licensing agreement with St. Jude Children’s Research Hospital, Mustang says it will develop the lentiviral gene therapy for commercial use as MB-107\. Just-published data in the [*New England Journal of Medicine*](https://www.nejm.org/doi/full/10.1056/NEJMoa1815408?query=TOC&ref=fdaweb.com) show that: 

- Bone marrow harvest, busulfan conditioning and cell infusion were well tolerated.
- All patients cleared previous infections and are growing normally.
- Seven of eight infants treated have developed normal immunoglobulin M levels to date.
- Most patients were discharged from the hospital within one month.

"The results have been very good thus far," said St. Jude’s **Ewelina Mamcarz**. “We’ve been able to restore a full immune system pretty quickly.”