Much excitement has greeted the news that European regulators have finally recommended approval of Glybera, which should make it the first gene therapy to be approved in the western world.

The European Medicines Agency's Committee for Medicinal Products for Human Use issued a positive opinion on Glybera (alipogene tiparvovec) as a treatment for lipoprotein lipase deficiency (LPLD). LPLD is an ultra-rare inherited disorder estimated to affect no more than one or two people per million.

Due to a defective gene, patients with this disorder cannot produce enough LPL, an enzyme responsible for breaking down fats. So far, sufferers could only reduce their dietary fat to less than 20% of the daily caloric intake and many patients experience life-threatening pancreatitis attacks.

Glybera was developed by Amsterdam Molecular Therapeutics, which repeatedly submitted  the therapy to the EMA without success. The cost of these rejections meant that AMT, which could not raise funds on the open capital markets or find a partner, was forced to sell up in February to fellow Dutch group, UniQure which said that Glybera is the first gene therapy in the west (one is approved in China) to reach an "important regulatory approval milestone, culminating 40 years of research".

Backed for 'exceptional circumstances' use

The CHMP recommendation only covers "exceptional circumstances" and the EMA notes that UniQure will be required to provide data from a registry set up to monitor outcomes in patients treated with Glybera. Tomas Salmonson, acting chair of the CHMP, said that “our established ways of assessing the benefits and risks of Glybera were challenged by the extreme rarity of the condition and also by uncertainties associated with data provided". Now, "we have worked out a way to ensure robust and close follow-up of the quality, safety and efficacy" of the therapy he added.

Glybera has been tested in three studies with 27 LPLD participants. In all three, it was well tolerated, with no relevant safety issues observed and the data indicate that a single dose administration of Glybera resulted in a long-term biological activity of the LPL protein.

UniQure chief executive Joern Aldag, who held the same post at AMT, said the recommendation "represents a major breakthrough for both LPLD patients and for medicine as a whole". He noted that the company is developing treatments for a number of orphan diseases as well, such as acute intermittent porphyria and Sanfilippo B, "but the potential of gene therapy stretches far beyond rare diseases".

Mr Aldag added that haemophilia patients treated with the company's proprietary gene "are showing a sustained clinical effect over several years, which has allowed prophylaxis treatment to be stopped". He said UniQure is advancing programmes in degenerative diseases such as Parkinson’s and "we believe that just like antibodies, gene therapy will one day be a mainstay in clinical practice".

UniQure is now preparing to apply for regulatory approval in the USA, Canada, and other markets.