The Business Intelligence firm La Merie SL reported that market and R&D activities in the interferon field are predominantly related to interferon alpha although total interferon alpha sales of more than US$ 2.1 bn in 2005 were lower than those of interferon beta (more than 3.8 bn). The interferon alpha field is characterized by more than 25 marketed products in industrialized and off-patent countries and more than 36 ongoing corporate R&D projects as compared with only 18 products and R&D projects for interferon beta.
As the conversion from first generation interferon alpha to pegylated interferon alpha nearly is completed, biogeneric activities are limited. New research is focused on finding novel subtypes or variants of interferon alpha with improved pharmacodynamic and safety properties. Numerous biosimilar interferon alpha products are produced and marketed for viral hepatitis in off-patent countries such as Argentina, Cuba, South Korea, China and India, but only one product was submitted for European centralized marketing authorization.
Clinical stage interferon alpha projects in the Western countries are longer acting interferon alpha molecules achieved by fusion with large molecules or drug delivery systems. Interferon alpha projects approaching clinical testing are obtained by genetic engineering of the native molecule, use of other subtypes of interferon alpha, additional pegylation or combinations thereof. Several clinical studies are ongoing to evaluate the efficacy of oral low dose interferon or of intradermal delivery.
Although the interferon beta market in multiple sclerosis is the biggest and has the single best selling product among the interferons (Avonex with US$ 1.5 bn in 2005), biogeneric activities are clandestine or make use of aerosol delivery to treat viral exacerbations of asthma. Preclinical R&D activities are focused on prolonging the half-life by pegylation, drug delivery systems or genetic engineering. Interferon beta gene therapy currently is being explored in two early stage clinical trials in cancer. Non-viral delivery systems may open the way of gene therapy with interferon beta for treatment of multiple sclerosis.