Corcept Therapeutics (CORT) announced in a regulatory filing that it received a Paragraph IV Notice Letter advising that Teva Pharmaceuticals (TEVA) submitted an Abbreviated New Drug Application to the FDA seeking authorization to manufacture, use or sell a generic version of Korlym in the United States. The Notice Letter contains Paragraph IV certifications against certain of Corcept’s patents related to Korlym, the company points out. The Notice Letter also alleges that the Korlym patents, the ‘348 patent with an expiration date in August 2028 and the ‘495 patent with an expiration date in August 2036, will not be infringed by Teva’s proposed product, are invalid and/or are unenforceable. “The Company intends to vigorously defend its extensive intellectual property rights related to Korlym,” Corcept stated. The stock in premarket trading is down 19%, or $4.53, to $18.90.