(Reuters) - A U.S. appeals court has upheld drugmaker Shire's (>> Shire PLC) patents for its top-selling drug Vyvanse, blocking five generic drug makers from launching cheaper versions of the drug to treat attention deficit hyperactivity before 2023.

The U.S. Federal Circuit Court of Appeals on Thursday rejected the generic manufacturers' claims that Shire's patents were invalid, leaving in place a ruling from a New Jersey federal court last year.

The generic drugmakers - Amneal, Mylan (>> Mylan NV), Allergan's (>> Allergan, Inc.) Actavis unit, Novartis's (>> Novartis AG) Sandoz unit and Roxane Laboratories, which Hikma Pharmaceuticals (>> Hikma Pharmaceuticals Plc) recently agreed to acquire from Boehringer Ingelheim - had all sought U.S. Food and Drug Administration approval for generic versions of Vyvanse. That prompted Shire to file a series of lawsuits in 2011 and 2012.

In June 2014, Shire won summary judgment in the U.S. District Court for the District of New Jersey that its 16 patents on the drug were valid and would be infringed by the planned generics, prompting the generic drugmakers to appeal.

"We are extremely pleased that the Federal Circuit affirmed the District Court's ruling that the patents are valid, which further confirms that Shire has strong patents protecting Vyvanse," said Mark Enyedy, Shire's interim general counsel, in a press release.

Representatives of Roxane and Amneal declined to comment. The other generic drugmakers did not immediately return requests for comment.

Vyvanse is approved by the FDA to treat ADHD and binge eating disorder. The drug brought Shire $841.6 million in revenue in the first half of 2015, about 28 percent of its total revenue.

The case is Shire LLC et al v. Amneal Pharmaceuticals LLC et al, U.S. Court of Appeals, Federal Circuit, No. 2014-1736.

(Reporting By Brendan Pierson in New York; Editing by Frances Kerry)

By Brendan Pierson