Teva Pharmaceutical says it has gained a green light in the USA to market its copycat version of Procter & Gamble’s $1 billion a year osteoporosis drug Actonel (risedronate) in three different doses, 5 mg, 30 mg and 35 mg.

Specifically, Teva has been given clearance to market its tablets for treating and preventing postmenopausal and glucocorticoid-induced osteoporosis, as well as treatment of Paget's disease. The brand product had annual sales of approximately $1 billion in the USA for the twelve months ended June 30, 2007, based on IMS sales data.

The potentially imminent arrival of generic Actonel is the subject of patent litigation in a US court; a trial was held in November 2006, but a decision has not yet been reached. However, the Israeli firm has agreed – unusually - to provide 30 days’ notice to P&G of any launch activities. It has not yet provided such notice.

As the first to file a generic copy of Actonel, Teva has been awarded 180 days’ marketing exclusivity for this product, which will begin to run from the date of commercial marketing.

Analysts at Dresdner Kleinwort Benson comment in a research note today that it estimates around 50% of Actonel's profit is booked by partner Sanofi-Aventis. Though Teva could still launch at risk, DKB believes it will wait until the conclusion of the patent litigation case, with a decision imminent.

In the USA, the bisphosphonate class of drugs to which Actonel belongs is under review following post-marketing reports of a heart condition known as atrial fibrillation. The review is likely to take 12 months.