Barr challenges key US patents for Oxytrol
This article was originally published in Scrip
Barr Laboratorieshas initiated a challenge to patents listed by Watson Laboratoriesin connection with Oxytrol (oxybutynin transdermal system). The ANDA contains a paragraph IV certification stating that the patents are invalid, unenforceable, or will not be infringed. Barr believes it is the first to file an application with the agency with a paragraph IV challenge. On October 23rd, Watson filed suit in the US District Court for the District of Delaware, alleging infringement of eight patents and triggering the 30-month stay of approval. The patents listed in the Orange Book for the product expire between 2010 and 2015, and most are method-of-use patents. Oxytrol has annual US sales of about $39 million, Barr said.