Idenix fires off a shot in patent battle over Gilead's sofosbuvir

As Gilead ($GILD) nears a virtually guaranteed FDA approval for the hepatitis C-fighting sofosbuvir, the biotech is facing intellectual property challenges from a bevy of competitors, most recently Idenix Pharmaceuticals ($IDIX), which claims the blockbuster hopeful infringes its patents.

In two lawsuits disclosed this week, Idenix alleges that Gilead violated three of its patents tied to nucleotide prodrugs, or "nucs," and the company is asking the court to invalidate a separate Gilead patent stemming from its $11 billion Pharmasset buyout. The latest squabble follows an ongoing suit-countersuit fight between the pair over two other sofosbuvir-related patents. Idenix remains confident in its position, general counsel Maria Stahl said.

"While we have attempted to resolve this matter with Gilead without resorting to infringement litigation, we intend to diligently and vigorously protect our patent rights for the benefit of our company and our shareholders and prevent infringing use by others," Stahl said in a statement.

If the Massachusetts biotech wants a piece of sofosbuvir, it'll have to get in line. In August, Gilead hit Merck ($MRK) with a preemptive lawsuit after the pharma giant laid claim to 10% of sofosbuvir's future sales, saying the drug cribbed from two of its patents. Meanwhile, Roche ($RHHBY) has stepped up with a claim of its own, arguing that a Pharmasset partnership from 2004 gives it an exclusive license on sofosbuvir. Gilead has swept that notion aside, pointing out Roche's deal ended long before its 2011 buyout.

Gilead didn't respond to a request for comment on the latest lawsuits, but the company has said it believes any claims on sofosbuvir to be without merit. Analysts have expressed little alarm over any of the suits filed so far. With peak sofosbuvir sales pegged at around $5 billion a year, the company will likely spare no expense in defending its exclusive right to sell the drug.

Meanwhile, Gilead's hep C hopeful is scheduled for a Dec. 8 final decision from the FDA. After picking up a unanimous co-sign from a panel of agency advisors in October, the drug is widely expected to win approval.

- read the statement