UK regulators have awarded Orchard Therapeutics’ experimental ‘bubble baby’ disease therapy OTL-101 Promising Innovative Medicine status, pushing the drug closer to being accepted onto the Early Access to Medicines Scheme.

The adenosine deaminase severe combined immunodeficiency, also commonly known as ADA-SCID, is a rare inherited disorder of the immune system currently estimated to occur in between one in every 200,000 to 1,000,000 live births.

The disease is caused by mutations in the gene encoding for the adenosine deaminase enzyme, which result in a severe deficiency in white blood cells and life-threatening infections.

OTL-101 is an autologous ex-vivo lentiviral gene therapy being developed in collaboration with University College London/Great Ormond Street Hospital and the University of California.

To date, more than 40 ADA-SCID patients have been treated with OTL-101 in London and the US. All patients have survived with follow-up up to five years, and the treatment has been shown to restore patients’ immune function, with a favourable safety profile, according to the firm.

The Medicines and Healthcare products Regulatory Agency’s Promising Innovative Medicine designation, the first step of a two-stage process to complete for entry onto the EAMS, indicates that OTL-101 is likely to offer major clinical benefits to patients, Orchard noted.

In stage two, the Agency will issue an EAMS Scientific Opinion if the quality, safety and efficacy data provided in support of the application is sufficient to support a positive benefit/risk balance and added clinical value, opening the door to its use in the UK while a decision on its approval in the European Union is pending.