Orphan drugs: legal aspects, current situation.

'Rare disorders' is the name given to those diseases, of very varied aetiology, whose common denominator is that they are low-prevalence diseases, and for the majority of which there is no treatment available. The World Health Organization defines a rare disorder as all pathological conditions affecting 0.65-1 out of every 1000 inhabitants. The European Union understands a rare disorder to be one with a prevalence of 5 : 10 000 Europeans; the USA defines it as an ailment affecting fewer than 200 000 Americans; Japan sets the limit at 50 000 Japanese patients; Australia at 2000 Australian patients. According to the aforementioned ratios, haemophilia, von Willebrand disease and other congenital coagulation disorders could be considered to be rare disorders. 'Orphan drugs' is the term given to those drugs intended for the treatment of rare disorders, because the number of patients affected is so small that it is not profitable to invest in research and development or to market them. Although the ratio of people affected by haemophilia means it could be classed as a rare disorder and its treatment could therefore be given orphan designation, haemophilia does have an established treatment, and research and development in this area proves profitable for the pharmaceutical companies. Haemophilia is therefore singular in that pharmaceutical companies can file an application for orphan designation with all the benefits deriving from this, while the treatment of haemophilia is profitable in its own right for companies carrying out research and development for the products involved.