"The 'ends' - commercialization of a very successful cancer drug - do not justify the 'means' of Cancer Research Technology," the judge wrote.
"Something was awry, insofar as not a single piece of data was provided to the patent office in over 11 years, despite over a decade's worth of research on the technology," she said.
In 1999, the Food and Drug Administration granted Schering approval for Temodar, also known as temozolomide, which treats two types of brain cancers: newly diagnosed glioblastoma multiforme and refractory anaplastic astrocytoma.
Schering sued after Barr applied to the FDA to sell a lower-cost generic copy.
Robinson heard the case last year in a four-day nonjury trial.
"We are very disappointed with the court's ruling," said Bruce N. Kuhlik, Merck executive vice president and general counsel. "We continue to believe the patent for Temodar in the United States is valid and enforceable" through February 2014.
The court's decision "reflects a step in the lengthy patent-litigation process," Kuhlik said, adding that Merck, with major pharmaceutical operations in West Point, Montgomery County, will appeal the decision.
Merck is seeking a "stay of the court's judgment and will seek an immediate appeal," spokesman Ron Rogers said.
Israel-based Teva, with North American headquarters in North Wales, said its application to sell temozolomide capsules is awaiting final FDA approval.
Teva was the first generic manufacturer to file with the FDA to market a generic version of the chemotherapy drug and will receive 180-day marketing exclusivity, if its product is approved. The 180 days is when a generic manufacturer can sell a product without competition from rival generic companies.
Generic drugs are chemically equivalent versions of brand-name medicines that typically sell for much less.
Temodar had annual U.S. sales in 2008 of $348 million, Merck said. U.S. sales for the first nine months of 2009 were $285 million. Next month, Merck will report full-year 2009 sales. Worldwide Temodar sales in 2008 were about $1 billion. For the first nine months last year, global sales were $781 million.
Contact staff writer Linda Loyd at 215-854-2831 or email@example.com.