"Critical" ratio in claim does not get the benefit of the doctrine of equivalents

January 19, 2007
Post by Blog Staff

Today's lesson from the Federal Circuit: be careful not to make a claim limitation "critical," or you may lose the benefit of the doctrine of equivalents for that element. The court found that the claimed weight ratio of two drugs was critical in part because other claims recited a range of ratios, but the claim at issue simply recited a specific ratio, "about 1:5." The court stated that permitting infringement of the about 1:5 range under the doctrine of equivalents would vitiate the limitation, and thus no range of equivalents was available for this element. As a result, the court affirmed the grant of summary judgment of noninfringement for the defendant. More details of the case after the jump.The patent in Ortho-McNeil Pharmaceutical, Inc. v. Caraco Pharmaceutical Laboratories, Ltd. claimed pharmaceutical compositions comprising combinations of two analgesics, tramadol and acetaminophen. The patent states that at certain weight ratios, the combination of these two drugs has a synergistic effect. This patent covers Ortho's Ultracet® product. The only claim at issue, claim 6, required a ratio of tramadol to acetaminophen of "about 1:5." One other claim included a specific range, namely "about 1:1," and other claims claimed various ranges of ratios of the two drugs. First, the court affirmed the lower court's claim construction of "about 1:5." The court noted that because some of the claims included ranges of ratios but the claim at issue did not, one of ordinary skill would understand the scope of "about 1:5" to be relatively narrow. The court also relied, in part, on the testimony of expert witnesses who testified regarding the ratio range that would be statistically indistinguishable from 1:5. The court essentially adopted this range (1:3.6 to 1:7.1) as the literal scope of the claims. Because the defendant's product only used ratios of "no less than 1:7.5," there could be no literal infringement based on this claim construction. The court then held that Ortho could not claim infringement under the doctrine of equivalents. The court found the 1:5 ratio critical to the invention, partially because it was one of only two claims that claimed a specific ratio as opposed to a range of ratios. Also, during reissue, the asserted claim was the only claim that was not narrowed by changing the preamble from "comprising" to "consisting essentially of." As a result, the court stated that "having so distinctly claimed the 'about 1:5' ratio, Ortho cannot now argue that the parameter is broad enough to encompass, through the doctrine of equivalents, ratios outside the confidence intervals expressly identified in the patent. We agree with the district court that to do so would eviscerate the limitation." With no possibility of infringement under the doctrine of equivalents because of the doctrine of claim vitiation, summary judgment of noninfringement was affirmed. This case illustrates a potential pitfall in claim drafting when ranges are involved. If some claims contain ranges of an element and others claim specific values, courts may deem the specifically-claimed elements "critical," and deny application of the doctrine of equivalents for those elements. To read the full decision in Ortho-McNeil Pharm., Inc. v. Caraco Pharm. Labs., Ltd., click here.

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