In a move that will help Ranbaxy [Get Quote] boost its revenues from the US in the next six months, the company has launched the generic version of GlaxoSmithKline's [Get Quote] blockbuster medicine Valtrex (valacyclovir hydrochloride) in the United States.

Daiichi-controlled Ranbaxy enjoys the first-to-file status for the drug and, therefore, has a six-month exclusive marketing right to the medicine. During the period, Ranbaxy will be the only company, other than the innovator GSK [Get Quote], to market the product in the US. Ranbaxy has confirmed that the drug was launched on November 25.

Analysts feel the company's earnings from the drug during the exclusivity period could be over $200 million (over Rs 933 crore). Ranbaxy has approvals to market two strengths -- 500 mg and 1 gm -- of the anti-herpes drug in the world's largest medicine market. Analysts have been apprehensive of the launch of the product due to the ongoing regulatory issues Ranbaxy has with the US drug regulator -- United States Food and Drugs Administration.

The USFDA had banned the supply of all medicines from two of Ranbaxy's Indian manufacturing plants, including the Dewas facility from which valacyclovir was to be supplied initially.

Since then, the company has managed to get valacyclovir manufactured from the production facility of its US subsidiary, Ohm Laboratories, thereby salvaging the six-month exclusive marketing opportunity.

Ranbaxy had reached a patent settlement agreement with GSK on the drug in 2007 and was pinning a lot of hopes on revenues from it. Ever since the USFDA clamped on the two main production facilities of Ranbaxy, the company has seen a decline in its US revenues.

During the three months ended September 30, the company had registered sales of $44 million (over Rs 205 crore) -- 53 per cent lower than its sales during the comparable quarter in 2003.