By Jason Rantanen
SkinMedica Inc. v. Histogen Inc. (Fed. Cir. 2013)
Download SkinMedica v Histogen
Panel: Rader (dissenting), Clevenger, Prost (author)
The written descriptions of the '494 and '746 patents explain that a novel and important aspect of their invention is the difference between growing cells in two-dimensions and growing cells in three-dimensions.
Claim 1 of the '494 patent:
1. A method of making a composition comprising:
(a) culturing fibroblast cells in three-dimensions in a cell culture medium sufficient to meet the nutritional needs required to grow the cells in vitro until the cell culture medium contains a desired level of extracellular products so that a conditioned medium is formed;
(b) removing the conditioned medium from the cultured cells; and
(c) combining the conditioned medium with a pharmaceutically acceptable carrier to form the composition.
(emphasis added by court). At issue was the phrase "culturing...cells in three-dimensions." The district court construed this phrase to mean "growing...cells in three dimensions (excluding growing in monolayers or on microcarrier beads." Following claim construction, the district courted summary judgment of noninfringement for Histogen as it was undisputed that Histogen grew its cells on microcarrier beads.
Limits on Ordinary Meaning: On appeal, the Federal Circuit affirmed the district court's claim construction. The court first agreed with SkinMedica that "the ordinary meaning of “culturing . . . cells in three-dimensions” would reach the use of beads." However,
If the specification reveals “a special definition given to a claim term by the patentee that differs from the meaning it would otherwise possess[,] . . . the inventor’s lexicography governs.”.... And if the specification reveals “an intentional disclaimer, or disavowal, of claim scope by the inventor,” the scope of the claim, “as expressed in the specification, is regarded as dispositive.”
In the written description, the patentees plainly and repeatedly distinguished culturing with beads from culturing in three-dimensions. They expressly defined the use of beads as culturing in two-dimensions. And they avoided anticipatory prior art during prosecution by asserting that the conditioned medium produced by two-dimensional cultures was inferior and chemically distinct from the conditioned medium produced by three-dimensional cultures. Because none of the evidence called to our attention by SkinMedica would reasonably lead to a different reading of the intrinsic evidence, we find that the inventors clearly redefined the scope of “culturing . . . cells in three dimensions” by disclaiming the use of beads—which would otherwise be included in the ordi- nary meaning of that phrase.
Id. at 15. In support of this conclusion, the majority opinion walks through a lengthy discussion of the text of the specification and prosecution history, addressing language such as "beads, as opposed to cells grown in three dimensions and the use of "i.e." The result was a disavowal of beads from the scope of the claim term at issue:
"In sum, although the inventors never explicitly redefined three-dimensional cultures to exclude the use of beads, their implicit disclaimer of culturing with beads here was even “so clear that it equates to an explicit one. Without fail, each time the inventors referenced culturing with beads in the specification, they unambiguously distinguished that culture method from culturing in three-dimensions."
Id. at 27.
Incorporation by Reference: One of SkinMedica's counter arguments was that the written description incorporated a voluminous technical treatise, Cell & Tissue Culture: Laboratory Procedures ("Doyle") in its entirety and that Doyle describes three-dimensional culturing with beads. Among the majority's bases for rejecting SkinMedica's argument was the lack of any specific reference to Doyle:
Third, even if we assume that the passage from Doyle discusses what one of ordinary skill in the art might understand to be three-dimensional culturing with beads, the inventors’ general citation of Doyle does not indicate any reliance on that particular passage to define “culturing in three-dimensions” and to abandon the otherwise clear disclaimer of beads in the specification. When discussing cell culture methods, the patentees make the following reference to Doyle:
The cells may be cultured in any manner known in the art including in monolayer, beads or in three-dimensions and by any means . . . . Methods of cell and tissue culturing are well known in the art, and are described, for example, in [Doyle], supra; Freshney (1987), Culture of Animal Cells: A Manual of Basic Techniques, infra.
’494 patent col. 10 ll. 2–6.
It is clear from that passage that the inventors did not refer to Doyle in order to define what they meant by “three-dimensional culturing” in their patent. They did not indicate their reference to Doyle was for that purpose; nor did they even refer with any detailed particularity to the passages in Doyle that, according to SkinMedica, may have discussed three-dimensional culturing with beads. When the inventors wanted to use Doyle to explain the potential scope of terms they used, they did so specifically....We see no reason for such a non-specific reference to trump the clear disclaimer in the specification of culturing with beads.
Slip Op. at 35-36.
Judge Rader's Dissent: Writing in dissent, Judge Rader disagreed that the patentee had met the "heavy presumption" in favor of the ordinary meaning of claim language. Central to Judge Rader's opinion was the distinction between growing cells "on beads" and growing cells in three-dimensions using beads.
Deference battle? Judge Rader's dissent also relied on testimony by SkinMedica's technical expert, Dr. Salomon. The majority agreed with district court's decision to give Dr. Salomon's testimony "no weight"; in Judge Rader's eyes, "Dr. Salomon's testimony, when viewed as a whole, deserves great weight and respect." Slip Op. at 47.