Janssen Pharmaceuticals is suing Mylan over its bid to market a generic version of Janssen’s HIV drug Prezista.

Janssen claims that a generic of Prezista (darunavir) sought by Mylan’s ANDA in 75 mg, 150 mg, 300 mg, 400 mg and 600 mg doses would infringe the drug’s ‘829 patent. The patent expires in 2029, according to the complaint filed July 18.

Janssen and its predecessor, Tibotec, have spent years fending off generic challenges to Prezista’s various patents from generics firms such as Teva and Lupin. So far, the Orange Book lists Janssen as the only patent holder of Prezista’s active ingredient.

The current lawsuit also is Janssen’s second effort to protect Prezista from a Mylan generic. The parties are awaiting a decision on an earlier lawsuit alleging infringement by Mylan against Prezista’s ’411 patent, according to Janssen’s complaint.

Janssen parent Johnson & Johnson reported total Prezista sales of $1.7 billion in 2013. Mylan did not respond to a request for comment by press time. — Bryan Koenig

Originally appeared in Drug Industry Daily, the pharmaceutical industry’s number one source for regulatory news and information. Click here for more information.