Orphan drugs have the potential to generate as much lifetime revenue as treatments used for more common health conditions, according to a study published by Thomson Reuters.

The report compared the total value of orphan drugs from 1990 to 2030 and found that government incentives, shorter clinical trials and high rates of regulatory success make top orphan drugs as economically viable as non-orphan ones. Current estimates indicate that 250 new rare diseases are identified annually and a number of orphan drug therapies are already achieving blockbuster status.

Thomson Reuters claims that Roche and Biogen Idec's Rituxan (rituximab), which has garnered significant sales for the treatment of two rare diseases - chronic lymphocytic leukemia and non-Hodgkin’s lymphoma - as well as for the non-orphan indication rheumatoid arthritis. has a lifetime revenue potential (LRP) of $154 billion, second only to Pfizer's cholesterol blockbuster Lipitor (atorvastatin), with LRP of $197 billion.

The study notes that the orphan drug market was worth just over $50 billion globally at the end of 2011, and spending on such treatments currently makes up 6% of total pharmaceutical sales, assuming a total market value of $880 billion. The compound annual growth rate (CAGR) of the orphan drug market between 2001 and 2010 was 25.8%, compared to only 20.1% for a matched control group of non-orphan drugs.

Thomson Reuters says that this data, combined with the increasing number of orphan drug approvals, suggests that the CAGR of launched rare drugs "will outshine that of the non-orphan control drugs over the next 30 years". Kiran Meekings, life sciences consultant at Thomson Reuters and co-author of the report, said the figures give "economic validity to the importance of targeting rare diseases in the global pharmaceutical market".

He added that "not only does such focus help those affected by rare diseases, of which there are 25 million people in the USA alone, it also furthers the aim of precision medicine". It also "substantiates the envisioned high returns on the R&D investment, particularly for drugs with multiple orphan disease approvals.”