June 25, 2015 Judges LORA M. GREEN, ZHENYU YANG, and ROBERT A. POLLOCK denied Institution of Apotex IPR against Merck’s US 5,691,336 which claims Fosaprepitant Dimeglumine.
IPR was filed by Apotex on Dec 11, 2014 against Merck’s US 5,691,336 A which claims Fosaprepitant Dimeglumine and also listed in OB for Fosaprepitant Dimeglumine.
US ‘336 was filed by Merck on Sep 8, 1995 claiming Fosaprepitant Dimeglumine generically which was issued on Nov 25, 1997. US ‘336 is set to expire on March 4, 2019 (including patent term extension of five years).
Fosaprepitant Dimeglumine is a prodrug of Aprepitant and it is a P/neurokinin 1 (NK1) receptor antagonist which is developed and patented (US 5,691,336) by Merck. Fosaprepitant Dimeglumine is approved in US on Nov 12, 2010 which is marketed under the brand name EMEND. The structure of Fosaprepitant is shown below:
Apotex challenged the validity of claims of US ‘336 as it is obvious over the the following documents:
i) Dorn’s US 5,637,699 which discloses Aprepitant and its use as Tachykinin receptor antagonist.
ii) Murdock’s US 5,070,082 which teaches the use of phosphoramidate moiety in the preparation of prodrugs with enhanced aqueous solubility.
Apotex argued that an ordinary skilled person will modify Aprepitant which is well known from Dorn ‘699 with the teachings of Murdock ʼ082 to derive Fosaprepitant. However, on June 25, 2015 Patent Trial And Appeal Board rejected Apotex requisition for an inter partes review of US ’336, stating that Petitioner has failed to sufficiently explain why, at the time of the ’336 patent invention, a skilled artisan would have chosen compound 96 of Dorn ’699 to further develop its prodrug, which is the subject matter of the challenged claims. Therefore, it is concluded that Petitioner has not established a reasonable likelihood it would prevail in showing any of the challenged claims would have been obvious over Dorn ’699 and Murdock ’082.
Finally, the board concluded that Petitioner has not established a reasonable likelihood it would prevail in showing any of the challenged claims would have been obvious on either of these grounds. So the IPR is dismissed.
Thanks to Harshavardhan.K for suggesting me and helping me to post this article.