Prima facie obviousness

In summary, Sanofi presented two superior and unexpected results, in the form of a highly significant combination of properties [associated with one enantiomer], as part of a point-by-point rebuttal of Apotex s arguments in its prima facie obviousness case. By doing so, Sanofi retained patent protection for Plavix. Superior and unexpected results can thus overcome a basic case of obviousness and confer patentability, even in the close case of an enantiomer compared to a racemate. 

FOCUSING THE OBVIOUSNESS INQUIRY PRIMA FACIE OBVIOUSNESS AND THE CHEMICAL INVENTION... 

When the applicant for patent is attempting to make a showing of unexpected results or benefits to rebut a prima facie case of obviousness, the question often comes up as to what prior art does the claimed invention need to be compared against. The short answer is the closest prior art. 56 However, the closest prior art does not need to be the same prior art that the patent examiner relied on but rather can be different prior art if that different prior art is in fact closer to the claimed invention. For example, in the appeal of Ex parte Humber, claimed 13-chloro substituted compounds were found prima facie obvious in view of prior art nonchlorinated compounds. Instead of making a showing over the prior art nonchlorinated compounds, the applicant showed unexpected results over more closely related 9-, 12- and 14- chloro substituted compounds this was deemed sufficient to rebut the prima facie case of obviousness.57... 

PRIMA FACIE OBVIOUSNESS BASED PRIMARILY ON SIMILARITY OF CHEMICAL STRUCTURE... 

Issues related to prior art enablement, prima facie obviousness and secondary considerations of nonobviousness often intertwine in obvious determinations during patent prosecution and litigation since their definitional boundaries are often not well demarcated. In the case Sterling Drug Inc. v. Watson,69 the USPTO rejected claims to various single enantiomer compounds,70 and this decision was appealed to the U.S. District Court for the District of Colombia. The claims in question—10,12, and 14—are presented in Figure 8.18 together with the claimed structures (L-arterenol is the neurotransmitter norepinephrine).71... 

In the instant case, the Court apparently did not find a prima facie case of obviousness because the Court believed that Mylan had failed to provide evidence that the prior art would have provided a reasonable expectation of success for levofloxacin. In this regard, the Court recited the exemplary properties of the compound and argued that those properties could not have been reasonably expected. The Court further explained that even if a prima facie case of obviousness did exist, the case would be effectively rebutted by the many secondary indicia of obviousness, including unexpected results, which are the subject of the rest of the case summary presented here. This interpretation of reasonable expectation of success by the District Court may have set the bar too high for establishing prima facie obviousness and has been criticized. See JJ. Sparrow, Stan. Tech. L. Rev. 2 (2007). 

In a subsequent rejection of the same claim upon reconsideration, the Court further provided that the Appellant apparently relies upon continuous operation to differentiate over the Jahjah batch process. It is, however, well within the expected skill of the technician to operate a process continuously. So from the case of In re Dilnot, we learn that changing from a batch addition of an ingredient to a continuous addition will probably not be sufficient to escape a prima facie obviousness rejection. Of course this does not mean such a process is not patentable, only that unexpected results relative to the prior art batch addition would need to be demonstrated. 

As we just learned, combining compounds or materials known in the art to be useful singly for the same purpose can be prima facie obvious. It is also instructive to consider the situation that occurs where one equivalent material or compound is substituted for another in a composition or process. In this context, it is important to not focus solely on the actual equivalence of the material being substituted but also to focus on whether one of ordinary skill in the art would appreciate this equivalency. These points are addressed in the case of Smith v. Hayashi, arising from an interference... 

This does not mean he is out of the woods yet with respect to the prior art. Potential issues of obviousness could still remain though, as we learned earlier, prima facie obviousness can be rebutted through secondary evidence, whereas a lack of novelty cannot. 

Composition of Matter Ciaims. Prior art compounds that are structurally similar to the claimed compound or drug may render the claimed compound obvious and therefore unpatentable. But [a]n assumed similarity based on a comparison of formulae must give way to evidence that the assumption is erroneous" (128). Recently, the Court of Appeals for the Federal Circuit reaffirmed this standard for prima facie obviousness as applied to composition of matter claims ... 

The court also affirmed that prima facie obviousness does not require, given structural similarity, the same or similar utility between the claimed compositions and the prior art composition(130). 

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