Pompe drug wins orphan status

The US Food and Drug Administration (FDA) has granted orphan drug status to BioMarin Pharmaceutical's investigational therapy for Pompe disease, a rare lysosomal storage disorder that damages the heart and other muscles and is often fatal.

The drug, BMN-701, is a novel fusion of insulin-like growth factor 2 and alpha glucosidase (IGF2-GAA) that is expected to begin phase I/II clinical studies in the first quarter of 2011.

Orphan drug status confers a number of benefits, including tax breaks, extra advice and assistance from the FDA, and seven years of marketing exclusivity if the product is approved. It was designed to encourage the development of treatments for diseases that affect fewer than 200,000 patients in the US.

BioMarin noted that the FDA had determined that its Pompe drug was sufficiently different from Genzyme's alglusidase alfa (Myozyme/Lumizyme) to allow BMN-701 to have its own orphan designation. Had the federal agency decided that the two treatments were not sufficiently different, BioMarin would have had to prove clinical superiority over alglusidase alfa in order to win the seven years of marketing exclusivity granted through the programme.

BioMarin added the experimental Pompe treatment to its pipeline when it acquired the privately-held biotech company ZyStor in mid-August. In vitro studies suggest that the product, which uses ZyStor's proprietary Glycosylation Independent Lysosomal Targeting (GILT) technology, could deliver markedly higher levels of enzyme to the lysosomes of muscle cells in Pompe patients than Genzyme's product does, according to BioMarin.