Rare diseases are a growing focus for drug companies, with prices for some treatments for ultra-rare conditions running into hundreds of thousands of dollars a year.
The following are among the top-selling treatments for extremely rare disorders:
Soliris, Alexion Pharmaceuticals (ALXN.O)
- Treatment for a progressive disease that destroys red blood cells and a second condition that damages the kidney and other vital organs.
Forecast 2012 sales: $1.1 billion.
Cerezyme, Sanofi (SASY.PA)
- Drug to help break down fatty clumps that build up in cells in patients with Gaucher disease, damaging the liver, spleen and bones.
Forecast 2012 sales: $830 million
- Treats Pompe disease, an inherited neuromuscular disorder that causes progressive muscle weakness.
Forecast 2012 sales: $580 million
Elaprase, Shire (SHP.L)
- Treatment for Hunter syndrome, a genetic disease that primarily affects males, causing serious physical and mental problems.
Forecast 2012 sales: $495 million
- Fabry disease treatment designed to counter damaging symptoms including kidney failure, heart problems and stroke.
Forecast 2012 sales: $352 million
Cinryze, ViroPharma VPHM.O
- Prevents dangerous swelling and painful attacks in people with hereditary angioedema.
Forecast 2012 sales: $330 million
- Treatment for Gaucher disease.
Forecast 2012 sales: $310 million
Kalydeco, Vertex Pharmaceuticals (VRTX.O)
- For treating a rare form of the lung disease cystic fibrosis in patients with a particular genetic mutation.
Forecast 2012 sales: $260 million
Naglazyme, Biomarin Pharmaceutical (BMRN.O)
- Treatment for Maroteaux-Lamy syndrome, which causes short stature, stiff joints and breathing problems.
Forecast 2012 sales: $233 million
Source: sales figures based on analyst forecasts compiled by Thomson Reuters
(Reporting by Ben Hirschler; editing by David Stamp)