A US District Court held that certain claims of the patents protecting Shire blockbuster ADHD drug Vyvanse were both infringed and valid, giving a boost to the drugmaker as it contends with a takeover bid by AbbVie.

In agreeing with Shire, Judge Stanley Chesler’s summary judgment ruling did more than just block five ANDA-filers from launching Vyvanse copies until as late as 2023, which is the year Shire’s Vyvanse patents expire (although they could still appeal and win).

He also gave Shire ammunition as it tries to prove that it’s worth more than the $46 billion AbbVie recently offered for the Ireland-based drugmaker, Reuters points out today. AbbVie is eying a deal to cut its tax bill and to grab a foothold in the rare-disease space, and it isn’t ruling out going hostile if need be, warned AbbVie CEO Richard Gonzalez, as reported today by Bloomberg.

Shire CEO Fleming Ornskov is willing to help broker a sale, if the price is right. Vyvanse, his firm’s top drug, had US revenue of $1.8 billion last year.

There’s one caveat to the patent win: Shire’s summary judgment motion did not include every patent claim in the litigation, so Shire isn’t completely out of the woods. According to Shire, the Court must decide whether to conduct a trial on the remaining patent claims, or allow the defendants to immediately appeal this ruling to the Federal Circuit.