Glaxo’s Potential Cure for “Bubble Boy Disease” One Step Closer
A potential cure for children born with a form of an extremely rare immune-system condition often referred to as “bubble-boy disease” has moved a step closer to approval after receiving the support of a European Union regulatory panel.
The treatment, which involves inserting a new gene into the patient’s stem cells, received a positive opinion from the European Medicines Agency’s advisory committee on Friday, paving the way for final approval in coming months.
It is aimed at children with a disease known as ADA-SCID, a rare condition in which a single genetic defect prevents sufferers from developing a robust immune system, leaving them very susceptible to infections. Without treatment, they rarely live for more than two years.
Currently, the best available option is a bone-marrow transplant, but success heavily depends on how well matched the donor is. For the one in four babies who have a well matched family member, a transplant can be an effective cure. But for the rest, success rates can be as low as 50%, according to Bobby Gaspar,professor of pediatrics and immunology at London’s Great Ormond Street Hospital.
The new therapy, called Strimvelis, was developed by a group of scientists and doctors based in Milan who have used it to treat 22 children over the past 14 years. All are still alive, most without needing any further treatment. In 2010, GlaxoSmithKline PLC struck a licensing deal for the rights to market the therapy.
If approved, it would be only the second gene therapy to be sold in Europe, after UniQure NV’s Glybera for a rare genetic condition in which the body can’t break down fat molecules. No gene therapies are approved for sale in the U.S.
The ADA-SCID gene therapy has moved at a cautious pace. Scientists tested an older form of gene therapy in children with the disease as early as 1990, but suffered a setback when, around 10 years later, several of those patients developed a leukemia-like condition.
“To be recognized as a licensed medicine shows gene therapy has come a long way forward,” Dr. Gaspar said.
One complication of administering Strimvelis: For now, it can be performed only in the Milan hospital where it was developed. The procedure involves removing some stem cells from the patient, applying the gene therapy outside the body and then reinjecting them, all of which must be done in quick succession to keep within the short “shelf life” of stem cells.
Parents will probably be willing to take their babies to Milan for treatment if it is considered the best option: Children from as far away as the U.S. and the Middle East came to Italy to take part in the clinical trial, according to Martin Andrews, head of the company’s rare-disease unit. Still, Glaxo aims to eventually make the therapy available in several “hubs,” and is working on methods to increase the shelf life of stem cells so that the procedure could be done remotely, by sending the child’s stem cells to a central facility for the gene therapy, he said. Glaxo also plans to seek approval from America’s Food and Drug Administration in 2017.
While Strimvelis is unlikely to move the needle for Glaxo in terms of revenue—around 14 babies are born with the condition every year in Europe—the company is betting that the technology can be used as the basis for several new treatments, Mr. Andrews said.
Rare diseases have drawn increasing interest from drugmakers in the past few years because the industry can command high prices for effective treatments in diseases with few other available therapies.
“If efficacy is demonstrated, payers are willing to reimburse [the companies],” said Mladen Tomich, head analyst for rare diseases at health-care consultancy Decision Resources Group. “While the price tag is high the overall expenditures are still limited due to the small patient population.”
Mr. Andrews didn’t disclose Glaxo’s pricing plans for the treatment but said it was considering flexible pricing models, including amortizing the payment over several years.