On Friday, the European Medicines Agency for the first time recommended approval for a gene therapy medicine. Glybera, made by Dutch company uniQure, corrects a rare genetic deficiency of the lipoprotein lipase (LPL), a protein that helps breakdown fats. Patients with this disease repeatedly suffer severe pancreatitis attacks and must follow a very restrictive low fat diet.
Gene therapy uses genetic engineering technology to insert a new gene into a patient that can compensates for a defective gene causing the disease. The use of gene therapy for clinical applications initially met with much enthusiasm but serious problems with a few early trials dampened much of the early enthusiasm. Recent trials, however, have produced some promising results in the last fews years.
Glybera consists of an functional LPL gene packaged in an adeno-associated virus--a type of virus often used for gene therapy. After injection of the drug into muscle, the virus invades the cells and integrates the functional LPL gene into the DNA. Following a single treatment, the patient's cells then make a working version of the LPL protein which enters the blood stream to carry out its function of breaking down fats.
China was the first country to approve a medicine made using gene therapy when it approved Gendicine in 2004 for the treatment of head and neck cancer. Subsequently, in 2005, China approved Oncorine, another gene therapy medicine, for similar cancers. Also, at the end of last year, Russia approved Neovasculgen a gene therapy to deliver vascular endothelial growth factor (VEGF) to treat peripheral arterial disease.
A therapy for a form of severe combined immunodeficiency (SCID)--a genetic disease that results in a severely compromised immune systems that is sometimes referred to as the "bubble boy" syndrome--may be the next for approval in Europe. Unlike Glybera, this SCID treatment is not directly injected into patients but rather, bone marrow cells are taken out of the patient, the virus is added, then the cells are reimplanted. It would be the first gene therapy drug to use this ex vivo protocol. GlaxoSmithKline is working with San Raffaele Telethon Institute and MolMed in Italy to bring this treatment to market.