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A Claim Reciting a Single Weight Ratio of “About 1:5” Is Limited to Encompass a “Range of Ratios No Greater Than 1:3.6 to 1:7.1”

06-1102
January 19, 2007

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Last Month at the Federal Circuit - February 2007

Judges: Schall, Gajarsa, McKinney (author, sitting by designation)

[Appealed from: E.D. Mich., Judge Steeh]

In Ortho-McNeil Pharmaceutical, Inc. v. Caraco Pharmaceutical Laboratories, Ltd., No. 06-1102 (Fed. Cir. Jan. 19, 2007), the Federal Circuit affirmed the district court’s grant of SJ of noninfringement of claim 6 of U.S. Patent No. 5,336,691 (“the ’691 patent”).

Ortho-McNeil Pharmaceutical, Inc. (“Ortho”) owns the ’691 patent directed to pharmaceutical compositions comprising certain weight ratios of two known drugs, tramadol and acetaminophen. Both of these drugs act as pain relievers. The ’691 patent discloses that at certain weight ratios, the pharmacological effects of the compositions are superadditive or synergistic. Claim 6 of the ’691 patent is directed to a pharmaceutical composition comprising a tramadol material and acetaminophen in a weight ratio of “about 1:5.”

The defendant, Caraco Pharmaceutical Laboratories, Limited (“Caraco”), filed an ANDA indicating its intent to make and sell a composition containing tramadol and acetaminophen with an average weight ratio of 1:8.67. The ANDA expressly requires that Caraco’s formulation have a weight ratio of no less than 1:7.5. In response to Caraco’s ANDA, Ortho filed suit for infringement of claim 6 of the ’691 patent. The sole issue before the district court was infringement because both parties agreed to be bound by the outcome of other pending litigations on all issues relating to the validity and enforcement of the ’691 patent. Caraco moved for SJ of noninfringement.

The district court granted Caraco’s motion. At issue was the claim construction of the term “about 1:5,” and whether under a proper claim construction Caraco’s ANDA infringed either literally or under the DOE. The district court relied upon intrinsic and extrinsic evidence to construe 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.” Slip op. at 5. Under this claim construction, the district court concluded that Caraco’s ANDA-defined product did not literally infringe the ’691 patent. In addition, the district court found that there was no infringement under the DOE because such a finding would render meaningless the “about 1:5” limitation under the doctrine of claim vitiation.

On appeal, the Federal Circuit reviewed the district court’s construction of the term “about 1:5,” particularly the meaning of “about.” The Court explained that “about” does not have a universal meaning in patent claims; rather, its meaning depends on the technological facts of a particular case. To determine the meaning of the term “about 1:5,” the Court focused on the criticality of the 1:5 ratio to the invention in claim 6 of the ’691 patent. They looked first to the intrinsic evidence in the ’691 patent and then to extrinsic evidence, and found that the term “about 1:5” has a narrow meaning and that the limitation is critical to the invention.

The intrinsic evidence that the Federal Circuit considered in its claim construction included the language of the claims and specification. First, the Court noted that the ’691 patent included fifteen claims, all of which use the term “about” to modify the claimed weight ratio or weight ratio ranges of tramadol to acetaminophen. Of these fifteen claims, only two of the claims claim a single weight ratio, while the other thirteen claims distinctly point out ranges of weight ratios. From this language, the Court concluded that one of ordinary skill in the art would understand that the inventors intended a range when they claimed one, and something more precise when they did not.

Next, the Federal Circuit looked to the specification, where the inventors disclosed a broad range of weight ratios, and then the most preferred range of weight ratios. In addition to ranges of weight ratios, the inventors specifically disclosed two single weight ratios of “about 1:1” and “about 1:5.” Again, the Court found that the qualifier “about” is narrow because to find otherwise would allow the scope of the specifically identified ratio, i.e., 1:5, to encompass a range of ratios that could potentially render meaningless the other specifically identified ratio of 1:1.

The Federal Circuit then looked to the data points from experiments described in the specification to support their conclusion that the term “about 1:5” was meant to be narrow. The Court noted that the specification showed data points for several ratios of tramadol to acetaminophen, yet the patentees chose to specifically claim ratios of 1:1 and 1:5.

The Court thus concluded that the inventors intended to claim compositions very close to these ratios.

The Federal Circuit also credited the extrinsic evidence provided by Ortho’s expert regarding the confidence bounds of the data. The expert used statistical analyses to determine that the ratio of “about 1:5” would not be statistically different from ratios from 1:3.6 to 1:7.1. Considering both intrinsic and extrinsic evidence, the Court concluded that the district court made no error in construing 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.” Id. at 12.

The Federal Circuit agreed with the district court that there could be no literal infringement because Caraco’s formulation must have a weight ratio of no less than 1:7.5, which is not encompassed by Ortho’s claim. Additionally, the Court agreed with the district court’s holding that a finding of infringement under the DOE would impermissibly vitiate the “about 1:5” limitation of the claim. Having distinctly identified the 1:5 ratio versus all other ratios or ratio ranges, the Court concluded that Ortho could not now argue through the DOE that the parameter is broad enough to encompass ratios outside of the confidence intervals expressed in the ’691 patent.