Genzyme drugs take four spots among the most expensive in a Forbes survey (chart). The developer's rare disease treatments Myozyme, Fabrazyme, Cerezyme and Aldurazyme all cost over $200,000 per year. But the Cerezyme price is likely to head south following last week's FDA approval of Shire's Gaucher treatment, velaglucerase alfa for injection. Alexion Pharmaceuticals takes the top spot for the world's most expensive drug, Soliris. The therapy costs $409,500 per year. Chart | Article | Genzyme release