Last week, a child in Europe became the second individual to receive a commercial gene therapy, according to GlaxoSmithKline (GSK). The treatment, called Strimvelis, claims to provide a cure for a rare inherited immune deficiency by editing a patient's genetic makeup.

The therapy is for severe combined immune deficiency, a genetic disorder that leaves children helpless against infection. It is the same condition that forced David Vetter to live his life in a protective plastic sphere, depicted in the documentary "The Boy in the Bubble."

Without treatment, children suffering from the disorder die before the age of 2. But a single administration of GSK's Strimvelis kept 100% of patients alive after three years in a small clinical trial. That was enough to convince European regulators to approve it in May 2016.

A cheaper option compared to conventional treatments

The treatment however costs USD665,000, which the Italian Medicines Agency agreed to reimburse as it was a cheaper option compared to the conventional treatment of bone marrow transplants or enzyme replacement therapies that cost USD4 million over the course of a decade.

But GSK and other gene therapy developers such as Spark Therapeutics who seeks approval for a blindness treatment this year, will need to convince payers to make a one-time investment in these treatments whose long-term effects are still unknown.

The child has been treated since March - nearly a year since Strimvelis was approved for sale in Europe. The nationality of the patient and how the treatment was paid for was not disclosed.

And whilst gene therapy has been widely explored in clinical trials and experimental medical studies, its commercial potential has been largely untested. For Strimvelis, it is mainly due to cross-border European reimbursement as the treatment is only offered at a single centre in Milan, Italy.

Commercial success remains to be seen

The commercial fate of Strimvelis is closely monitored as several new gene-therapy treatments are edging towards the market. The price tags of the genetic therapy are usually the concern as many patients will not be able to afford them.

In addition, Glybera, the first commercialised gene therapy approved in Europe in 2012 was a commercial failure after reimbursement agencies refused to hand over USD1 million.

UniQure, the company that invented it, eventually gave up for a US application and sold Glybera's marketing rights to another firm.

"It's definitely a bad sign for patients" that sorting out reimbursement took so long, says Casey Quinne, a health economist at the MIT Centre for Biomedical Innovation who specialises in European drug pricing. "It remains to be seen whether this represents some kind of watershed, or it will take just as long to go from one [patient] to two?"

Limiting factors such as a "specialised environment" hinders commercial success

Lucia Monaco, chief scientific officer of Fondazione Telethon, the research organisation that originally developed the therapy and sold rights to GSK, says administering Strimvelis required a "specialised environment" therefore they are only offering it at the Ospedale San Raffaele in Milan.

The gene therapy involves the removal of bone marrow cells before it is modified outside the body with an engineered virus that contains the ADA gene - responsible for producing the enzymes. The repaired cells are then returned to the patient via an infusion drop into a vein.

GSK is not expecting Strimvelis to be profitable as ADA-SCID only affects an estimated 15 children per year in Europe. What is uncertain is whether companies can successfully commercialise hospital-based gene-therapy treatments for rare diseases at all.

Now, GSK is working on cryogenically freezing and transporting patients' cells so the company could provide Strimvelis across Europe and patients would not need to travel to Milan for treatment. They hope to roll out the technology within two years. MIMS

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