All issued United States patents are presumed valid but this presumption is rebuttable with clear and convincing evidence. When submitting previously considered evidence, it is generally more difficult to overcome the presumption of validity. The following case explains and illustrates how to treat evidence that was previously considered by the Patent Office during prosecution of the patent application.
In Sciele v. Lupin, the patent owner Shinogi obtained allowance for some but not all of its claims for an extended-release pharmaceutical product. During prosecution, the patentee cancelled the rejected claims so that the allowed claims would mature into a patent. To the patentee’s surprise, the Government Printing Office made a mistake and included both the rejected and cancelled claims in the issued patent.
The defendant attempted to market a competitive pharmaceutical formulation alleged to infringe the rejected claims which made its way into the issued patent. During litigation, the defendant argued that the claims at issue were invalid due to the prior art already considered by the examiner during prosecution of the patent application. The Federal Circuit held that regardless of whether the evidence submitted to rebut the presumption of a patent’s validity was previously considered by the Patent Office, the standard to rebut the presumption of validity always remains at the same level, namely, the clear and convincing standard. What changes is the weight of the evidence. If evidence was already considered by the Patent Office, then the trier of fact should afford this previously considered evidence less weight. But, if it was not considered, then the trier of fact is allowed to afford more weight to the evidence in rebutting the presumption.
In the present case, the prior art references were already considered by the Patent Office and is given less weight. Nonetheless, the Federal Circuit held that in light of the prosecution history and the Examiner’s finding that these prior art references established obviousness of the claims, the presumption of validity of the patent at issue was rebutted. Thus, the government printing errors did not save the validity of claims that the Examienr found were unpatentable.
Based on the foregoing, it is useful to review the file history of a patent to determine the history of each claim to determine the scope of patent protection afforded under a patent. Mistakes and public statements by the patent owner that conflict with arguments made in procuring the patent may exist which can be used against the patentee.