In re Langer

In re Langer
503 F.2d 1380
Bluebook cite
In re Langer, 503 F.2d 1380 (C.C.P.A. 1974).
503 F.2d 1380
Item Type
Appeal from decision of PTO Board of Appeals affirming rejection of claims. The invention at issue involved “compositions and methods using a new source of stannous tin for incorporation in dentifrices . . . i.e., compositions for introduction into the oral cavity as cleansing compositions.” Id. at 1382. The purpose of the compositions and methods was to reduce enamel solubility. The claims related to dentifrices, chewing gums, and methods to reduce enamel solubility.

The examiner rejected the claims, relying on a number of references to establish a prima facie case of lack of utility by showing that one skilled in the art would not accept the allegations that the invention would reduce enamel solubility. The patent applicant submitted the results of clinical tests to rebut the prima facie case, but both the examiner and the board held that the tests were not sufficient. The board held that “the examiner's references establish such a strong prima facie case for lack of utility (‘usefulness') in the entire claimed subject matter that the highest type of evidence (i.e.- clinical testing in humans) is required to rebut the prima facie case.” Id. at 1391.

The court modified the holding of the board, finding that the prima facie case for lack of utility had been overcome for some claims, but not others. The court disagreed with the board that clinical testing in humans was needed to rebut the prima facie case. Instead, the court stated that “{i}t is not proper for the Patent Office to require clinical testing in humans to rebut a prima facie case for lack of utility when the pertinent references which establish the prima facie case show in vitro tests and when they do not show in vivo tests employing standard experimental animals.” Id. at 1392-93. Thus, the court held that in vivo dental paste experiments performed on rats, the results of which were submitted in an affidavit by the applicant, were sufficient to rebut the prima facie case of lack of utility.

However, the dental paste experiments were only performed using the applicant’s preferred species of chelate (a chemical compound in the form of a ring that contains a metal ion attached by coordinate bonds to at least two nonmetal ions). The applicant submitted no evidence proving utility for other members of the chelate genus, including other claimed species. Since the court found instead “some evidence that appellant is in a technology largely based on empirical results-not on predictable factors,” the court reversed the decision of the board only for those claims which involved the specific species of chelate which had been tested.

Excerpts and Summaries

Tuesday 07 of October, 2008 14:19:28 GMT
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Tuesday 07 of October, 2008 15:51:15 GMT
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