Groundbreaking LVV Gene Therapy Cures ‘Bubble Baby’ Disease in Pivotal Long-Term Study

LOS ANGELES – October 15, 2025 – A revolutionary gene therapy, developed through an international collaboration between UCLA, University College London, and Great Ormond Street Hospital, has demonstrated unparalleled, durable success in restoring immune function in children with adenosine deaminase severe combined immunodeficiency (ADA-SCID), often called “bubble baby” disease.

The long-term follow-up data, published in the New England Journal of Medicine, validate the experimental treatment as a potential curative therapy for this rare, life-threatening genetic disorder.

Durable Immune Restoration Confirmed
The study tracked 62 children treated between 2012 and 2019, accumulating an unprecedented 474 cumulative patient-years of observation.

→ Success Rate: 59 of the 62 patients experienced successful, long-term restoration and maintenance of immune function, eliminating the need for high-risk bone marrow transplants or lifelong enzyme replacement therapy.

→ Durability: The cohort includes five children living healthy, unrestricted lives more than a decade after their single treatment, confirming the stability and persistence of the gene-modified immune cells.

→ Safety: Researchers reported no serious adverse events attributable to the gene therapy itself. All recorded adverse effects were mild or moderate and linked to preparatory procedures.

ADA-SCID is caused by mutations in the ADA gene, leading to a profound impairment of the immune system and typically resulting in death within the first two years of life without intervention.

Method: Correcting Cells with a Lentiviral Vector
The therapy uses a sophisticated approach:

Harvesting: Hematopoietic stem cells are collected from the patient’s own blood.

Gene Correction: A genetically engineered lentiviral vector is used ex vivo to introduce a corrected, functional copy of the ADA gene into these precursor cells.

Re-infusion: The modified cells are re-infused into the patient, where they engraft in the bone marrow and progressively mature over 6 to 12 months into a fully functional immune system.

Logistical Breakthrough Expands Global Access
A key advancement is the validation of cryopreservation techniques.

→ Accessibility: More than half of the children received gene-corrected stem cells that had been frozen, performing equivalently to freshly infused cells. This breakthrough allows the cellular product to be manufactured at centralized facilities and shipped globally, significantly expanding access and simplifying logistics regardless of a patient’s geographic location.

→ Regulatory Pathway: The therapy has been licensed to Rarity PBC to establish commercial-grade production. FDA market authorization is anticipated within the next two to three years, paving the way for the broad clinical adoption of this precision medicine.

The long-term success of this gene therapy, exemplified by a patient now thriving a decade after treatment, represents a paradigm shift in the management of inherited immune disorders and validates the principles of cellular engineering for curative medicine.