The lower burden of proof associated with inter partes reviews should make IPRs attractive to generic pharmaceutical companies, but even with that lower burden, success is not guaranteed, as illustrated by IPR2015-01340.  Mylan Pharmaceuticals challenged AstraZeneca’s patent RE44,186 on saxagliptin, the active ingredient in Onglyza® (used to treat type 2 diabetes).  Mylan’s petition argued the structure of the drug would have been obvious.  The Board disagreed, determining that the prior art did not provide sufficient motivation to modify the lead compound chosen by Mylan.  The Board denied review.

The Board started with the legal standard for this sort of issue:  “A determination of whether a new chemical compound would have been obvious over the prior art typically follows a two prong inquiry considering first, whether one of ordinary skill would have selected one or more lead compounds for further development and, second, whether the prior art would have supplied sufficient motivation to modify a lead compound to arrive at the compound claimed with a reasonable expectation of success.”

Here, the Board accepted Petitioner’s proposed lead compound, but found the record did not support the second prong of the test, modification of the lead compound to arrive at the claimed invention.  The Board analyzed the two aspects of the modification argument, stability and potency, and found both lacking.  As to stability, Petitioner argued that the person of ordinary skill would have been motivated to change one group on the lead compound to a more stable adamantyl group (as one would expect, the more stable group is also on the claimed compound).  The problem, though, was that the lead compound was noted for its stability, and the Board found the record was insufficient to establish a person of ordinary skill in the art would have been motivated to make it even more stable.  As to potency, Petitioner argued for a second substitution of a different group, which combined with the first substitution would yield the claimed compound.  The Board found the record failed to show that the proposed substitution would have been expected to increase potency.

The Board thus denied review.