A U.S. federal appeals court today invalidated the patent on Altace, a widely prescribed drug to treat high blood pressure. This clears the way for low-cost generic versions of the drug to hit the market immediately. King Pharmaceuticals, the company that makes Altace, is asking for a rehearing, but in the meantime it may lose its window of opportunity to “upgrade” Altace patients to a reformulated (and newly patented) version it was it planning on introducing in 2008. [Reuters]