Gemcitabine HCl for injection (Gemzar) 200mg base/vial and 1 g base/vial: District court invalidated method of use patent

Innovator Eli Lilly announced (in a press release Here ) that the U.S. District Court for the Eastern District of Michigan has granted a motion by Sun Pharmaceuticals for partial summary judgment against key patent covering method of use of Gemcitabine HCl for injection (Gemzar) 200mg base/vial and 1 g base/vial.

The following patents are listed in Orange Book for this product:

US4808614 (Patent Expiry: Nov 15, 2010): Which covers various nucleosides like Gemcitabine as product

US5464826 (Patent Expiry: May 7, 2013): Which covers a method of treating susceptible neoplasms in mammals comprising administering to a mammal in need of such treatment a therapeutically effective amount of Gemcitabine.

U.S. District Court for the Eastern District of Michigan has invalidated innovator Eli Lilly's method of use patent '826 patent. The court invalidated the said patent on the basis of obviousness type of double patenting. Innovator's coumpound patent '614 discloses use of Gemcitabine for the treatment of viral infection. Also, the said patent has disclosed use of Gemciatabine as anticancer drug. Later on, innovator got '826 patent, wherein, innovator claimed method of use of Gemcitabine for the traetment of cancer. Importantly, Sun pharma identified this important point and challenged '826 patent on double patenting grounds in the light of '614 disclosure. The court construed the claims of earlier and later patents and determined their diffrence. Finally, the court opined that claim 12 of '614 covers anticancer use of Gemcitabine and the claim 2, 6 and 7 of '826 patents have reclaimed the same use, accordingly, claims are not patentably distinct.

As per press release, innovator opined that Gemcitabine HCl for injection (Gemzar) compound patent (‘614) would remains in place until November 15, 2010, accordingly, no generic version of the drug will enter the U.S. marketplace until then.

"We strongly disagree with the Court's ruling granting summary judgment in favor of the generic challenger," said Robert A. Armitage, senior vice president and general counsel for Lilly. "We continue to believe that our Gemzar method-of-use patent is valid and will be upheld by the courts. We intend to pursue an appeal of this decision with the Court of Appeals for the Federal Circuit.