The US Food and Drug Administration has approved the first ever ‘follow-on biologic’ medicine, Sandoz’ Omnitrope, but the development should not be read as an opening up of the marketplace for this type of product, according to a spokesman for the company.

The FDA acceded to pressure by a US court, which last month ordered it to deliver a verdict on Sandoz’ application to market Omnitrope, which had been languishing at the agency since July 2003 as it tried to work out a way to handle what could loosely be described as ‘biogenerics’, copycat versions of the first wave of biologic drugs to reach the market that have now lost patent protection.

But Omnitrope has been cleared under existing legislation - the so-called 505(b)(2) pathway of the Hatch-Waxman Act - which is only really suitable for approving small, simple follow-on biologics, said a Sandoz spokesman. For more complex applications a brand new regulatory route will have to be mapped out by the FDA, he said, and industry observers have suggested this is not likely to occur until 2009.

The main problem for the agency has been the lack of a defined regulatory route to approval for these products, mainly because it is not possible to make a biologic by one production process that is completely identical to another using a different process. And because the agency’s position is that there is a close relationship between the product's manufacturing process and its clinical attributes, classical notions of bioequivalence - which underpin the conventional generic drug market - do not apply.

In a statement, Sandoz said it believes that while “rigorous scientific criteria should be consistently applied to the approval process for all follow-on biotechnology medicines ... the unnecessary or unethical duplication of animal studies and human clinical trials should be avoided so that resources are not wasted that could otherwise be invested in innovation and continuous improvement.”

“These types of medicines should be approved and produced once patents have expired without specific reference to the trade secrets and confidential commercial information of innovators.”

Omnitrope has been cleared for the treatment of growth disorders in children and adults in the USA and is equivalent to Pfizer’s Genotropin (somatropin) product, the leading hGH product in both Europe and the USA. The US market for hGH products was around $600 million in 2005, according to IMS data.

Omnitrope was cleared in the European Union on April 19, and launched onto the market in Germany soon after with other introductions planned over the remainder of 2006. It debuted in Australia last November.

Sandoz’ spokesman said the company was developing five other follow-on biologics – or biosimilard as they are known in Europe – at ‘various stages of development’. He would not divulge their identity for commercial reasons, but other first-generation biologics that have lost patent protection include interferon alfa, insulin, erythropoietin and colony stimulating factors.

Datamonitor estimates that biologics with annual sales of around $20 billion are out of patent and vulnerable to generic competition.