United States: Mere Possibility Of Different Results From Different Measurement Techniques To Determine A Claimed Value Does Not Render A Claim Indefinite

In Takeda Pharmaceutical Co. v. Zydus Pharmaceuticals USA, Inc., No. 13-1406 (Fed. Cir. Feb. 20, 2014), the Federal Circuit affirmed the district court's finding that U.S. Patent No. 6,328,994 ("the '994 patent") was not invalid, and reversed the district court's finding of infringement.

Takeda Pharmaceutical Company Limited, Takeda Pharmaceuticals North America, Inc., Takeda Pharmaceuticals LLC, Takeda Pharmaceuticals America, Inc., and Ethypharm, S.A. (collectively "Takeda") own patents claiming the formulation of Prevacid® SoluTab".  When Zydus Pharmaceuticals USA, Inc. and Cadila Healthcare Limited (collectively "Zydus") filed an ANDA with the FDA seeking to manufacture a generic version of Prevacid® SoluTab", Takeda filed suit, alleging that Zydus's product infringed claim 1 of the '994 patent.  Zydus counterclaimed that claim 1 was invalid under 35 U.S.C. § 112.  Claim 1 of the '994 patent encompasses orally disintegrable tablets comprising lansoprazole, the active ingredient of the product marketed as Prevacid® SoluTab". 

The district court construed the claim term "fine granules having an average particle diameter of 400 µm or less" of claim 1 to include a deviation of ±10%, i.e., fine granules having an average particle diameter of 360 µm-440 µm.  Slip op. at 3.  Under that construction and based on its determination of how the average particle diameter was measured, the district court found that Zydus's ANDA product infringed claim 1 of the '994 patent.  The issue of infringement turned on whether the average particle diameter of the granules included measuring the agglomerated granules—granules fused together because of the coating process used to manufacture the granules—or whether the agglomerates were dissected individually before measurement.  The district court found that the '994 patent required measuring the average particle diameter regardless of whether or not they were present as agglomerates.  The district court further rejected Zydus's position that claim 1 was invalid under 35 U.S.C. § 112, and enjoined Zydus from manufacturing or selling its ANDA product until the '994 patent expired.

"However, we do not believe that the mere possibility of different results from different measurement techniques renders claim 1 indefinite.  Rather, the evidence established that both methods of measurement accurately report average particle diameter; the experts agreed that 'the correct but differing particle size results obtained using various instruments are all equally correct, but each simply may be expressing its correct results in different terms.'"  Slip op. at 11-12 (citation omitted).

On appeal, the Federal Circuit first held that the district court incorrectly construed the term "fine granules having an average particle diameter of 400 µm or less" to include a deviation of ±10%.  The Court found that there was no indication in the claim language itself, the specification, or the prosecution history to support a broader diameter range than actually claimed.  While Takeda argued that the word "about" was used in the specification to modify the term "average particle diameter of 400 µm or less," the Court found that those instances only referred to diameters lower than the claimed amount.  Id. at 8.  During prosecution, Takeda also distinguished the claimed invention over potentially invalidating art by arguing that the reference failed to teach or suggest an "average particle diameter of 400 µm or less."  Id.  The Court therefore concluded that "the inventors have consistently relied on 400 µm as the dividing line between granules that would avoid roughness in the mouth and those that would not—meaning those that were within the scope of the invention, and those that were not."  Id. at 9.  Accordingly, the Court found that the term should be limited to "fine granules having an average particle diameter of precisely 400 µm or less," and based on that construction, the Court found that Zydus's ANDA product, which has an average particle diameter of 412.28 µm, did not literally infringe claim 1 of the '994 patent.  Id. at 9-10 (citation omitted). 

The Federal Circuit then turned to the district court's finding that claim 1 of the '994 patent was valid.  The central issue as to indefiniteness revolved once again around the method used to measure the average particle diameter of the claimed granules.  While Zydus highlighted the failure of the '994 patent specification to provide sufficient information to determine which type of measurement technique could be used, the Court rejected the premise that "the mere possibility of different results from different measurement techniques [disclosed in the '994 patent's specification] renders claim 1 indefinite."  Id.  at 11-12.  The Court noted that expert testimony indicated that both methods of measurement accurately reported the average particle diameter and further concluded that "there is no evidence that the differences between these techniques are in fact significant."  Id. at 12.  Thus, the Court concluded that Zydus failed to establish, by clear and convincing evidence, that claim 1 of the '994 patent was invalid for indefiniteness.

The Court also rejected Zydus's argument that claim 1 of the '994 patent lacked written description because the specification only discussed measuring the diameter pretableting and failed to demonstrate how to ensure whether the granules were present in the claimed average particle diameter when in tablet form.  The Court concluded that Zydus's argument relied on there actually being an effect on particle size from the tableting process, and the evidence was to the contrary.  Relying on testing performed by Takeda's expert, which showed that the compression technique did not affect the average particle diameter, the Court explained that, "here, the evidence established only a hypothetical possibility that tableting could affect particle size in a relevant way."  Id. at 15.  Based on that evidence, the Court simply could not conclude that the district court committed clear error.

Finally, the Court rejected Zydus's argument that claim 1 of the '994 patent was invalid for lack of enablement because one of skill in the art would not be able to determine the average particle diameter using the coulter counter method of measurement without undue experimentation.  Here, the Court found that because the specification identified laser diffraction as a viable measurement technique, one of ordinary skill in the art would know how to measure particle diameter, which was sufficient to show enablement.  The Court noted, however, that if the district court had been correct in determining that the '994 patent required measuring the average particle diameter of each dissected agglomerate, the Court would have necessarily reached a different conclusion regarding enablement.  Because the Court determined that deagglomeration was not required prior to particle size measurement, the Court concluded that the '994 patent could not be found invalid for lack of enablement.

Thus, the Court reversed the district court's claim construction ruling and finding of literal infringement but affirmed the judgment of no invalidity, and remanded for further proceedings.

Judges: Prost (author), Plager, Chen

[Appealed from D.N.J., Judge Pisano]

This article previously appeared in Last Month at the Federal Circuit, March, 2014

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