Scott Daniels | September 3, 2009
This past May, the PTO granted a request for reexamination of Merck’s U.S. Patent No. 5,565,473 (see archive report of May 20, 2009), identifying substantial new questions of patentability based on seven prior art references. The ‘473 patent covers Merck’s well-known allergy drug SINGULAIR®.
The PTO has now issued a non-final rejection of each of the claims under reexamination, finding that claims 1, 7, and 18-22 are unpatentable for nonstatutory obviousness-type double patenting over the claims of U.S. Patent No. 5,428,033 in view of U.S. Patent No. 5,104,882.
Significantly, however, the PTO also found that the ‘473 claims under reexamination were patentable despite the seven prior art references relied upon in the request for reexamination and the notice of reexamination. The PTO stated that each of the references “alone or in combination, fails to provide reasons that would have led one of ordinary skill in the art to modify the prior art compound via multiple changes in a particular manner to establish prima facie obviousness of the claimed invention.”
The ‘473 patent is the subject of two patent infringement suits, so-called “Singulair® I” and “Singulair® II.” Judge Garrett Brown issued a permanent injunction against Teva in the first case on August 19 and in the second case on September 1, 2009. Teva has filed a notice of appeal in both cases.