 Genzyme pays a 39.5% - 50% royalty quarterly on worldwide net product sales to BioMarin.A portion of this royalty is considered to be product transfer royalties, meaning that if any Aldurazyme goes unsold, BioMarin merely retains the product transfer royalty, while not receiving any further royalties.Only in the case of defective product is Genzyme reimbursed for Aldurazyme product.