Investors didn't have to wait long to get good news about a potential increase in Barr Labs' (NYSE:BRL) revenue for this year. Less than a week after it announced guidance, the company won an important patent battle that could give it a near-term revenue boost.

A judged ruled on Monday that the patent on Bayer's birth-control pill Yasmin was invalid because the product was obvious. Apparently, the outcome of the ruling wasn't quite so obvious to Bayer, which inherited the drug and the patent lawsuit when it bought Schering AG in 2006. Bayer could appeal the decision, but I'd guess that Barr will take the risk and launch this year, regardless of Bayer's decision; appeals are generally harder to win than the initial cases are.

The generic-drug maker was certainly hoping that the court would rule in its favor, but it didn't include any sales of generic Yasmin in its 2008 guidance. The drug, which had about $488 million in U.S. sales last year, could have a substantial impact on the $2.7 billion to $2.8 billion in revenue that Barr is projecting this year.

The Stock Advisor pick will have six months of exclusive marketing, since it was the first to file an Abbreviated New Drug Application (ANDA) for Yasmin, but it could benefit beyond that time as well. Oral contraceptives are notoriously hard to copycat, so the surprise ruling could result in other generic-drug makers such as Teva Pharmaceuticals (NASDAQ:TEVA) or Novartis (NYSE:NVS) taking longer to provide additional competition.

The patent ruling could also affect Bayer's Yaz, which is a low-dose version of Yasmin, although Bayer claims to have the exclusive distribution to Yaz until March of next year. Next up on the docket for Barr are patent rulings on another birth-control pill, Johnson & Johnson's (NYSE:JNJ) Tri-Cyclen Lo, Boehringer Ingelheim Pharmaceuticals' restless leg syndrome drug Mirapex, and J&J's Alzheimer's treatment Reminyl. Let's hope that investors see more bumps in revenue growth from another win or three later in the year.

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