Takeda Pharmaceuticals cancer treatment – Velcade – has been ruled valid by a US Appeals Court this week, meaning generic drug makers will be prevented from launching lower-cost versions of the drug in the USA until 2022.

More than a dozen generic drug companies including Teva, Mylan, and Sandoz filed complaints at the U.S. Court of Appeals that Takeda’s patent was obvious and should not have been granted for exclusivity. The drug in question, Velcade, is used to treat multiple myeloma (blood cancer) and had $1.13 billion in sales in North America in 2016. Outside of the US, Johnson & Johnson market the brand.

The ruling this week reversed the decision of a US Judge in Delaware in 2015 who claimed that the patent was invalid as it was an “inherent result of an obvious process”. The unanimous decision this week that the lower court “clearly erred” and the patent is valid, allows Takeda to exclusively sell the product until the expiration date of the patent in 2022.  Amy Atwood, a spokesman for Takeda, said the company was pleased with the decision.