GlaxoSmithKline said it will seek a preliminary injunction from a US court to prevent generic drugmaker Ranbaxy Laboratories from launching a cheaper version of its herpes, shingles and cold sore treatment Valtrex (valacyclovir).
Ranbaxy won approval for its version of the drug from the FDA Thursday and told Glaxo it intended to begin marketing the drug.
By filing the preliminary injunction, Glaxo prevents Ranbaxy from launching their Valtrex copy until the court rules on the injunction or decides a pending infringement case filed by Glaxo in 2003 against Ranbaxy. The suit alleges that Ranbaxy’s product would infringe a “composition of matter” patent that is due to expire in 2009. A trial date in that case has not yet been set.
Global sales of Valtrex in 2005 reached $695 million in 2005 and were set to reach almost $1 billion for 2006, according to published reports.