Israel’s Teva Pharmaceutical Industries, currently jostling with Sandoz for the top slot in the global generics sector, and US firm Ivax Laboratories have been granted final approval for two formulations of the antibiotic clarithromycin in the US, which is sold by Abbott Laboratories in the USA under the Biaxin brand name.

The companies have been given the green light to sell 250mg and 500mg immediate-release versions of the product. Andrx Corp and Roxane Laboratories have also received marketing approvals in the US for generic Biaxin.

The immediate-release formulations of Biaxin are no longer patent-protected in the US, and account for around $204 million dollars a year, out of total revenues for the brand of around $1.2 billion. Biaxin remains Abbott’s top-selling drug [[13/04/05d]].

Last month, Teva also won approval for a 500mg extended-release formulation of Biaxin, the most lucrative part of the franchise which accounts for three quarters of the product’s total turnover. Teva is locked in a patent infringement battle with Abbott over this product, the generic equivalent of Biaxin XL Filmtabs, which generates annual sales of around $284 million.

In April, Abbott said it had received an additional patent for Biaxin XL that it claimed effectively blocks generic competition on this compound. The patent covers the pharmacokinetic profile of the formulation. The earlier patents on this formulation expired in the USA on May 23. Other patents covering composition of matter, various formulations, manufacturing processes and crystal forms of clarithromycin extend until 2017, according to Abbott.