New Delhi: In what could be a huge relief for India’s largest drug maker, Ranbaxy Laboratories Ltd has launched its generic version of GlaxoSmithKline Plc’s (GSK) herpes drug Valtrex in the US in time to take advantage of a marketing exclusivity.

Huge relief: Ranbaxy Laboratories MD and CEO Atul Sobti. Ramesh Pathania / Mint

A Ranbaxy spokesperson confirmed the development, adding the drug was launched on 25 November in the US in 500mg and 1g tablets.

Valtrex (valacyclovir) had sales of $2.2 billion (Rs10,186 crore) in the US in 2008. Ranbaxy was expected to make $150-200 million from its copy of Valtrex. Ranbaxy won the 180-day marketing exclusivity after a settlement with GSK in 2007.

Ranbaxy shares closed 1.79% up at Rs430.05 each in a weak Mumbai market.

“People had doubts about Ranbaxy’s first to file (FTF) pipeline being secure due to the FDA issues. Valtrex being launched on time means that they are well in control of (the) situation. It restores confidence in their FTFs since previously their FTF launch of generic Imitrex was delayed by five months," said an analyst with a foreign brokerage.