Generics drug firm Ranbaxy Laboratories said it has reached an agreement with GlaxoSmithKline resulting in a dismissal of US patent litigation regarding Glaxo’s herpes pill Valtrex (valacyclovir hydrochloride).

Under the agreement, Ranbaxy will be allowed to introduce its generic version of Valtrex in the US in late 2009 and will have 180 days of sales product exclusivity.

In early February 2007, Ranbaxy received a final approval from the FDA to market and manufacture valacyclovir hydrochloride tablets.

Glaxo’s Valtrex patent is set to expire in 2009 in the US and most of Europe. The drug was first introduced in 1995.

Total global sales of Valtrex were around $1.3 billion for 2006.