Case 1:20-cv-00692-ADA Document 475 Filed 01/10/24 Page 1 of 4
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`IN THE UNITED STATES DISTRICT COURT
`FOR THE WESTERN DISTRICT OF TEXAS
`WACO DIVISION
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`RAVGEN, INC.,
` Plaintiff
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`-vs-
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`NATERA, INC. AND NSTX, INC.,
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` Defendants.
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`1:20-CV-00692-ADA
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`MEMORANDUM OPINION AND ORDER
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`Before the Court is Defendants Natera, Inc. and NSTX, Inc.’s (“Natera’s”) Motion for
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`Summary Judgement of Non-Infringement of Claims 125 and 132 of U.S. Patent No. 7,332,277.
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`Dkt. 332. The Court heard the parties’ arguments during the final pretrial conference held on
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`December 11, 2023, and orally denied the motion. Consistent with the Court’s earlier oral ruling,
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`and omnibus order at Dkt. 458, the Court DENIES Natera’s Motion and further explains its
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`reasoning below.
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`Natera moves for summary judgement based on an interpretation of the asserted claims in
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`which the claims are limited to only one agent that inhibits cell lysis, and thus, according to Natera,
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`the accused products cannot infringe if they include multiple agents that may inhibit cell lysis. In
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`particular, Natera asserts the accused products include a preservative called IDU, twenty percent
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`of IDU is allantoin, and allantoin is also a cell lysis inhibitor. Dkt. 358 at 2-3. Natera’s motion,
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`however, is based on an improper construction of the claims and is thus denied.
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`Claim 132 is illustrative. Claim 132 depends from Claim 55 among others:
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`A method comprising determining the sequence of a locus of interest on free fetal
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`DNA isolated from a sample obtained from a pregnant female, wherein said sample
`comprises free fetal DNA and an agent that inhibits lysis of cells, if cells are present,
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`Case 1:20-cv-00692-ADA Document 475 Filed 01/10/24 Page 2 of 4
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`wherein said agent is selected from the group consisting of membrane stabilizer, cross-
`linker, and cell lysis inhibitor.
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`132. The method of claim 60, wherein said cell lysis inhibitor is selected from
`glutaraldehyde, formaldehyde and formalin.
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`Claim 55 includes both open language (“comprising”) and closed language (“consisting of”). The
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`claim recites a sample that comprises (i.e., includes) free fetal DNA and an agent that inhibits cell
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`lysis. That agent is selected from the group consisting of membrane stabilizer, cross-linker, and
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`cell lysis inhibitor. This claim language, which is known as a Markush group, limits the agent to
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`only one of the recited options: membrane stabilizer, cross-linker, and cell lysis inhibitor
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`(hereinafter the “Markush options”).
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`The flaw of Natera’s argument is that the claim is not limited to only one agent that inhibits
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`cell lysis. In accordance with the plain and ordinary meaning of “comprising,” the sample can
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`include more than one agent. Thus, a sample with an agent that inhibits cell lysis selected from
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`the Markush options is within the scope of the claims even if the sample includes other agents that
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`inhibit cell lysis. As a simple example, a sample with free fetal DNA and a first cell lysis inhibitor
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`(e.g., glutaraldehyde) is with the scope of the claims because the sample includes free fetal DNA
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`and a cell lysis inhibitor agent. If a second cell lysis inhibitor agent (e.g., allantoin) is added to the
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`sample, it is still within the scope of the claims because the open language of the claims (“said
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`sample comprises”) allows the sample to include additional components, including a second cell
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`lysis inhibitor agent.
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`Natera accuses Ravgen of using the “comprising” language to reopen the closed Markush
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`group. Dkt. 425 at 1. Instead, Natera is using the closed Markush group to close the open
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`“comprising” language. Under the proper construction, the Markush group is closed (i.e., at least
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`Case 1:20-cv-00692-ADA Document 475 Filed 01/10/24 Page 3 of 4
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`one agent is limited to one of the Markush group options) while the components that compromise
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`the sample are open (i.e., can include more than one agent).
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`The Federal Circuit considered a similar issue in Amgen, Inc. v. Amneal Pharm. LLC, 945
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`F.3d 1368 (Fed. Cir. 2020). The claim at issue recited a pharmaceutical composition comprising
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`a Markush group of binders and a Markush group of disintegrants. See id. at 1371. The Court
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`found the Markush groups to be closed but the “comprising” portion of the claim to include
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`additional binders and disintegrants. See id. at 1378-79. “The term ‘comprising’ is the standard
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`transition term used to make clear that the claim does not preclude the presence of components or
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`steps that are in addition to, though not inconsistent with those recited in the limitations that
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`follows.” Id.
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`Natera’s reliance on Multilayer Stretch Cling Film Holdings, Inc. v. Berry Plastics Corp.,
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`831 F.3d 1350 (Fed. Cir. 2016) and Shire Development, LLC v. Watson Pharmaceuticals, Inc., 848
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`F.3d 981 (Fed. Cir. 2017) is misplaced. In Amgen, the Federal Circuit distinguished those cases
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`because the decisions were based the interpretation of the Markush groups alone “without any
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`reliance on the ‘compromising’ language of the general transition phrase.” Amgen, 945 F.3d at
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`1378. The Multilayer and Shire cases are not inconsistent with the Court’s holding that the
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`Markush groups in Claims 125 and 132 are closed while the components that compromise the
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`sample are open.
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`Natera also argues the holding in Amgen was based on the claim language “at least one”
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`rather than “comprising.” The Markush groups at issue in Amgen recited “at least one binder
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`selected from the group consisting of …” and “at least one disintegrant selected from the group
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`consisting of ….” Amgen, 945 F.3d at 1371. Thus, those Markush groups covered one or more of
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`the recited Markush options but the Markush group in the asserted claims is limited to only one of
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`Case 1:20-cv-00692-ADA Document 475 Filed 01/10/24 Page 4 of 4
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`the Markush options. While the Amgen court discussed both the “at least one” and “comprising”
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`language, the holding applies to claims with “comprising” alone. As the Federal Circuit held,
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`“Amgen’s use of the ‘comprising’ transition phrases reinforces the conclusion that the language of
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`those limitations is best construed not to foreclose such additional binders and disintegrants.” Id.
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`at 1379.
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`For the above reasons, the Markush groups of the asserted claims are closed, but the claims
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`do not exclude a second agent, whether or not the second agent falls within the claimed Markush
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`group. See id. (a closed Markush group “does not forbid infringement of the claim if an additional
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`component is present functionally similar to the component identified in the Markush group
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`limitation … .”). Thus, even if the accused products include allantoin and allantoin inhibits cell
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`lysis, the mere presence of allantoin does not result in non-infringement.
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`For these reasons, the Court DENIES Natera’s Motion for Summary Judgement of Non-
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`Infringement (Dkt. 332).
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`SIGNED this 10th day of January, 2024.
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`ALAN D ALBRIGHT
`UNITED STATES DISTRICT JUDGE
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