September 12, 2017
Mylan and other generic manufacturers petitioned the Patent Trial and Appeal Board (PTAB) to institute an inter partes review of AstraZeneca’s patent claiming compositions including saxagliptin. AstraZeneca markets saxagliptin as Onglyza® and Kombiglyze® XR for diabetes.
Case IPR2015-01340 / Patent RE44,186 E
The PTAB’s Administrative Patent Judges (APJ) decided that the petitioners did not show with preponderance of the evidence that the claims of Reissue RE44,186 of U.S. Patent No. 6,395,767 would have been obvious to a skilled artisan. Particularly, saxagliptin was not obvious over “compound 25.”
Saxagliptin:
Saxagliptin Structure
Prior art: “Compound 25”
Structure of “Compound-25”
State of the Art:
Experienced medicinal chemists (Persons of Ordinary Skill in the Art [PHOSITA]) knew saxagliptin bound to DP 4. But they did not have detailed knowledge of DP 4’s active site for guidance in designing inhibitors because DP 4’s crystalline structure was unknown. At the time of invention, knowledge of DP 4’s binding requirements came from structure-activity relationship (“SAR”) studies.
Lead Compound Analysis:
Petitioners cited a publication by Ashworth containing Compound-25, which they argued would have been selected as a lead compound. (Ashworth et al., 2-“Cyanopyrrolidides as Potent, Stable Inhibitors of Dipeptidyl Peptidase IV,” 6(10) Bioorganic &Med. Chem. Lett., 1163–66 (1996)).
“Compound-25” would not have been selected as a lead compound
The PTAB reasoned that a medicinal chemist would not have selected compound 25 as a lead compound because, among other reasons, (i) Compound 25 was only one of several other similar compounds (ii) Compound 25 only had in vitro data obtained using non-physiological conditions, (ii) there were two much more advanced compounds in clinical trials (i.e., NVP-DPP728 & P32/98) and (iii) Ashworth’s subsequent publication focused on different series of compounds.
Clinical Compounds NVP-DPP728 & P32/98
The PTAB’s analysis could have ended there. But even accepting Petitioners’ assertion that a skilled artisan would have chosen compound 25 as a lead compound, the PTAB determined that the Petitioners didn’t demonstrate that a skilled artisan would have had reason to modify compound 25 with a reasonable expectation of success to arrive at the claimed saxagliptin.
Check out PatentDocs’s Post for further discussion:
http://www.patentdocs.org/2017/09/mylan-pharm-v-astrazeneca-ab-ptab-2017.html
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