"About 1.5" Weight Ratio Construed by Extrinsic Statistical Evidence and Reissue to Between 1:3.6 and 1:7.1

In Ortho-McNeil Pharmaceutical, Inc. v. Caraco Pharmaceutical Laboratories, Ltd. (January 19, 2007), the U.S. Court of Appeals for the Federal Circuit construed the numerical limits of a claim requiring a "tramadol . . . to acetaminophen . . . weight ratio of about 1:5." According to the opinion by Chief Judge McKinney, sitting by designation from the U.S. District Court for the Southern District of Indianna:

This court has looked at the meaning of the term "about," and similar qualifying words or phrases, in other cases and has developed an approach to the interpretation of such terms:

[T]he word "about" does not have a universal meaning in patent claims, . . . the meaning depends upon the technological facts of the particular case.
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The use of the word "about," avoids a strict numerical boundary to the specified parameter. Its range must be interpreted in its technological and stylistic context. We thus consider how the term . . . was used in the patent specification, the prosecution history, and other claims. It is appropriate to consider the effects of varying that parameter, for the inventor’s intended
meaning is relevant. Extrinsic evidence of meaning and usage in the art may be helpful in determining the criticality of the parameter . . . .

Pall Corp. v. Micron Separations, Inc., 66 F.3d 1211, 1217 (Fed. Cir. 1995) (citations omitted). See also Modine Mfg. Co. v. United States Int’l Trade Comm’n, 75 F.3d 1545, 1554 (Fed. Cir. 1996) (stating that "the usage [of the term ‘about’] can usually be understood in light of the technology embodied by the invention"); Conopco, Inc. v. May Dep’t Stores Co., 46 F.3d 1556 (Fed. Cir. 1994) (discussing the criticality of the claimed ratio to the invention and whether or not one of ordinary skill in the art would have read the modifier "about" expansively in light of the intrinsic evidence).

We must focus, then, on the criticality of the 1:5 ratio to the invention in claim 6 of the ’691 patent. The intrinsic evidence points to a meaning for the term "about 1:5" that is narrow because the 1:5 weight ratio, along with the 1:1 weight ratio, is distinctly claimed and distinguished from other broader weight ratio ranges in the patent. There are fifteen claims in the ’691 patent, all of which use the term "about" to modify the weight ratio or weight ratio ranges of tramadol to acetaminophen.4 ’691 Patent, cols.11-12. There are two claims, claim 4 and disputed claim 6, that claim a single weight ratio; the other claims distinctly point out ranges of weight ratios. For example, independent claim 1 reads: "A pharmaceutical composition comprising a tramadol material and acetaminophen, wherein the ratio of the tramadol material to acetaminophen is a weight ratio from about 1:1 to about 1:1600." Id. col.11 ll.19-22. This leads to a conclusion that one of ordinary skill in the art would understand the inventors intended a range when they claimed one and something more precise when they did not. The criticality of the "about 1:5" parameter to the claimed invention is also supported by other intrinsic evidence. As noted, in the specification, the inventors disclose the following:

The [acetaminophen] and the tramadol material are generally present in a weight ratio of tramadol material to [acetaminophen] from about 1:1 to 1:1600. Certain ratios result in a composition which exhibits synergistic analgesic effects. For example, in a composition comprising a tramadol material and [acetaminophen], the ratio of tramadol material: [acetaminophen] is preferably from about 1:5 to 1:1600; and more preferably, from about 1:19 to 1:800.

The most preferred ratios are from about 1:19 to 1:50. Compositions of tramadol material and [acetaminophen] within these weight ratios have been shown to exhibit synergistic analgesic effects. In addition, the particular compositions wherein the ratio of the components are [sic] about 1:1 and about 1:5 are encompassed by the present invention. Id. col.3 l.63 to col.4 l.8.

These paragraphs suggest that the qualifier "about" is narrow because to find otherwise would allow the scope of the more specifically identified ratio, 1:5, to encompass a range of ratios that could potentially render meaningless another claim’s limitation, namely the 1:1 limitation.

Furthermore, the data points from the experiments described in the specification support a conclusion that the more specifically identified ratio of 1:5 was meant to encompass compositions very close to that ratio. The experiments disclosed in the specification show data points for ratios of tramadol to acetaminophen in the lower ratio quadrant of 1:1, 1:3, 1:5, 1:5.7, and 1:15. ’691 Patent, col.7 l.49 to col.8 l.68; id. Fig. 1 & Table 1. Yet, the patentees chose to specifically claim ratios of 1:1 and 1:5. If the data suggested to the inventors that a range of ratios in this lower ratio quadrant was desirable, they could easily have claimed a ratio range of "about 1:1 to about 1:5," or even a ratio range of "about 1:3 to about 1:5," but they did not. Instead, they chose a specific data point for claim 6 of precisely 1:5. Moreover, the identification of the 1:5 ratio in both claim 6 and the specification is especially important when the only other specifically identified ratio is close to it, 1:1, and the other claims point to a broad range of ratios. This dichotomy between the specific ratio of 1:5 and the broader ratio ranges of the other claims points to a narrow scope for the "about 1:5" limitation.

As discussed above, the district court relied in part upon Ortho’s expert evidence to arrive at its claim construction. Ortho’s expert, Dr. Stanski, noted that the data in the patent shows a synergistic analgesic effect for many ratios tested. In addition, he noted that the patent discloses statistical variability in the measured responses for each ratio. Dr. Stanski stated that "[b]ased on that statistical variability and [his] expertise, [he] can use statistical analyses to determine confidence bounds for the data in the patent, and [is] thus able to determine an upper bound and lower bound for the 1:5 weight ratio." Dr. Stanski concluded that "the ratio of ‘about 1:5’ would not be statistically different from a ratio up to and including 1:7.1 and a ratio down to and including 1:3.6." In other words, Dr. Stanski opined that "about 1:5" means "about 1:5, which includes a ratio up to and including 1:7.1."

Considering the intrinsic and extrinsic evidence in this case, we see no error in the district court’s construction of the term "about 1:5" to mean "approximately 1:5, encompassing a range of ratios no greater than 1:3.6 to 1:7.1."

Ortho had also applied for reissue of the ’691 patent. Other than being rewritten in independent form, the claim asserted here, claim 6, survived reissue unchanged. Likewise, the relevant portions of the specification remain unchanged. Designated Circuit Judge McKinney went on to explain that the criticality of the ration, and cancelling of other claims in the reissue application prevented any broader claim construction under the Doctrine of Equivalents:

As discussed above in connection with claim construction, the 1:5 parameter was critical to the invention. Moreover, the ’691 patent points out the 95% confidence levels and makes them relevant to determining the scope of the invention. An infringement analysis that stretches the bounds of the "about 1:5" limitation beyond those confidence intervals directly conflicts with the patent’s express claim to both the 1:1 and the 1:5 ratios. The patent specification distinctly identifies the 1:5 ratio versus all the other ratios or ratio ranges. Under this circumstance, whether or not the 1:5 ratio’s analgesic response is statistically different from that of other ratios is of no moment. The intrinsic evidence points to the desirability, and thus the criticality, of the 1:5 ratio versus other ratios.

Also relevant is the prosecution history of the ’691 patent and the ’221 reissue patent, described above. Ortho admitted that it claimed more than it was entitled to claim in the ’691 patent when, in its reissue application, it cancelled the broader "comprising" claims, except for claim 6. In sum, 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 of the confidence intervals expressly identified in the patent.

We agree with the district court that to do so would eviscerate the limitation. The intrinsic evidence in this case points to the criticality of the "about 1:5" parameter, which necessitates a narrow claim construction and range of equivalents that does not encompass Caraco’s product. Similarly, we do not find Ortho’s other arguments persuasive.

. . . For these reasons, we conclude that the district court properly granted summary judgment of non-infringement in favor of defendant, Caraco Pharmaceutical Laboratories, Ltd., and against plaintiff, Ortho-McNeil Pharmaceutical, Inc.