Even an obvious solution does not render an invention obvious if the problem solved was previously unknown. Here, for example, even though the addition of the claimed “antioxidant” would have been an obvious solution for a formulation with known oxidation problems, the prior art failed to establish that a rivastigmine formulation of the type at issue was known to be susceptible to oxidative degradation. “Merely finding each of the claimed elements in the prior art does not prove a composite invention obvious, however, because ‘claimed discoveries almost of necessity will be combinations of what, in some sense, is already known.’” This would be a good case to consult and cite in response to an obviousness rejection in which the Examiner’s asserted motivation derives from a problem not known in the prior art.
Background / Facts: The patents being asserted here in response to a generic drug ANDA submission are directed to transdermal pharmaceutical formulations of rivastigmine for the treatment of dementia related to Alzheimer’s disease and Parkinson’s disease. Present in all asserted claims is an “antioxidant” limitation. The primary prior art reference disclosed all of the limitations of the asserted claims except the addition of an antioxidant, which was known to address the problem of oxidation-based instability in various compounds.
Issue(s): Whether one skilled in the art would have had a reason to add an antioxidant to the primary reference’s transdermal formulation.
Holding(s): No. “Although the addition of an antioxidant would have been an obvious solution for a formulation with known oxidation problems, here [the accused infringer] failed to prove that a rivastigmine formulation was known to be susceptible to oxidative degradation. … The references upon which [the accused infringer] primarily relies disclose rivastigmine formulations, but only with an antioxidant added either conditionally ([as in a first reference]) or indiscriminately across the board ([as in a second reference]), and, moreover, not in a transdermal patch. Merely finding each of the claimed elements in the prior art does not prove a composite invention obvious, however, because ‘claimed discoveries almost of necessity will be combinations of what, in some sense, is already known.’”