King Pharmaceuticals, Inc reported that the US District Court for the Eastern District of New York in the case of King Pharmaceuticals, Inc, et al. v. Eon Labs, Inc., Case No. 04-cv-5540 (DGT), issued an Order invalidating United States Patent Nos. 6,407,128 and 6,683,102, two patents relating to Skelaxin (metaxalone).

The company plans to appeal the order, which was issued in response to Eon's motion for summary judgment without the benefit of a hearing. Furthermore, the Order is unrelated to the company's pending litigation against Sandoz, Inc, successor to Eon, in the US District Court for the District of New Jersey regarding United States Patent No. 7,122,566, an additional patent relating to Skelaxin which is listed in the US Food and Drug Administration's Approved Drug Products With Therapeutic Equivalence Evaluations (Orange Book). Importantly, Sandoz does not currently have an Abbreviated New Drug Application approved by the US Food and Drug Administration to market a generic version of Skelaxin.