On May 08, 2019, Federal Circuit affirmed district court’s
decision that Sandoz’s biosimilar products do not infringe Amgen’s patents.
Amgen owns & markets filgrastim (Neupogen®) and
pegfilgrastim (Neulasta®) products for treating neutropenia, a deficiency of
white blood cells. Sandoz submitted BLA application to USFDA to market
biosimilar version of Amgen’s product. Amgen then
sued Sandoz for infringement. The court construed claims of U.S. Patents 6,162,427 and 8,940,878
and granted summary judgment of non-infringement of claim 7 of the ’878 patent
to Sandoz. The ’878 patent discloses methods of protein purification by adsorbent
chromatography. Claim 7 of US’878 patent relates to method of purifying a
protein with sequential steps. The ’427 patent discloses methods of treating
“diseases requiring peripheral stem cell transplantation.” Claim 1 of US’427
requires first administering G-CSF & thereafter disease treating effective
amount of at least one chemotherapeutic agent.
The district court construed “disease treating-effective
amount of at least one chemotherapeutic agent” in claim 1 of the ’427 patent as
limited to “[a]n amount sufficient to treat a disease for which at least one
chemotherapeutic agent is prescribed.” The court thereby rejected Amgen’s
argument that the amount must be “sufficient to enhance the mobilization of
stem cells.” Amgen thereafter stipulated to noninfringement of the ’427 patent
contingent upon its right to appeal from the district court’s claim construction
order. With respect to the ’878 patent, the district court construed
limitations (f) and (g) of claim 7 (the “washing” and “eluting” steps) as
separate steps and further clarified that the eluting step “must occur after
the step of ‘washing the separation matrix.’ Since it is undisputed that
Sandoz’s process only involves one step—applying the refold solution to the
matrix, with no separate washing or eluting steps—the district court granted
summary judgment that neither Zarxio® nor Sandoz’s proposed pegfilgrastim
biosimilar infringes claim 7 of the ’878 patent.
US’878 patent
Claim 7 reads:
7. A method of purifying a protein expressed in a non-native limited
solubility form in a non-mammalian expression system comprising:
(a) expressing a protein in a non-native limited solubility form in a
non-mammalian cell;
(b) lysing a non-mammalian cell;
(c) solubilizing the expressed protein in a solubilization solution
comprising one or more of the following: (i) a denaturant; (ii) a reductant;
and (iii) a surfactant;
(d) forming a refold solution comprising the solubilization solution
and a refold buffer, the refold buffer comprising one or more of the following:
(i) a denaturant; (ii) an aggregation suppressor; (iii) a protein stabilizer;
and (iv) a redox component;
(e) directly applying the refold solution to a separation matrix under
conditions suitable for the protein to associate with the matrix;
(f) washing the separation matrix; and
(g) eluting the protein from the separation matrix, wherein the
separation matrix is a non-affinity resin selected from the group consisting of
ion exchange, mixed mode, and a hydrophobic interaction resin.
Upon appeal Federal Circuit reviewed district court’s claim
construction de novo. Amgen contended
that the district court misconstrued the “washing” and “eluting” claim
limitations in both its claim construction and summary judgment decisions as
requiring distinct solutions added to the matrix at different times. Instead,
Amgen argued, the claims cover any number of solutions or steps as long as the
functions of washing and eluting happen in sequence. Sandoz responds that the
claim logically requires a series of steps & process claim is properly
limited to a certain order of steps “‘when the claim language requires that the
steps be performed in the order written, or the specification directly or
implicitly requires’ an order of steps. Federal Circuit agreed with Sandoz
& district court. It held that the washing and eluting steps of claim 7
require discrete solutions. Second, washing and eluting are consistently
described in the specification as separate steps performed by different
solutions.
Amgen next argued that the district court erred by rejecting
its argument that Sandoz’s process infringes claim 7 through the doctrine of
equivalents. Specifically, Amgen argued that Sandoz’s one-step, one-solution
process is insubstantially different from the claimed three-step,
three-solution process because it “achieves the same functions (washing and
eluting), in substantially the same way (binding protein preferentially
compared to contaminants, and then raising salt concentration to reverse
protein binding) to achieve the same result (protein purification).” Sandoz
responded that the district court properly analyzed Amgen’s argument and found
that Sandoz’s one-step, one-solution process accomplishes purification in a
different way from the claimed method and, as a result, is not equivalent.
Federal Circuit again agreed with Sandoz and concluded that the district court
correctly held that Sandoz’s one-step, one-solution process does not function
in the same way as the claimed process. District court correctly held that, the
claim recites a sequence of steps requiring application of “refolding,”
“washing,” and “eluting” solutions, and our precedent prohibits us from
overriding the natural language of claim 7 to extend these limitations to cover
nearly any type of adsorbent chromatographic separation. The doctrine of
equivalents applies only in exceptional cases and is not “simply the second
prong of every infringement charge, regularly available to extend protection
beyond the scope of the claims.” London
v. Carson Pirie Scott & Co., 946 F.2d 1534, 1538 (Fed. Cir. 1991). Accordingly,
the district court was correct to grant summary judgment that Sandoz does not
infringe claim 7 under the doctrine of equivalents.
US’427 patent
Claim 1 reads:
1. A method of treating a disease requiring peripheral stem cell
transplantation in a patient in need of such treatment, comprising
administering to the patient a hematopoietic stem cell
mobilizing-effective amount of G-CSF;
and thereafter administering to the patient a disease
treating-effective amount of at least one chemotherapeutic agent.
Amgen argued that the district court misconstrued the
limitation of “disease treating-effective amount” of a chemotherapeutic agent
in claim 1 of the ’427 patent as “an amount sufficient to treat a disease for
which at least one chemotherapeutic agent is prescribed.” Specifically, Amgen
asserted that the phrase only limits the amount of the chemotherapeutic agent
administered and that the method of claim 1 encompasses “situations where the
chemotherapeutic agent is prescribed only for stem cell mobilization rather
than treatment of an underlying disease.” Sandoz responded that Amgen’s
construction would read disease treatment out of the claim and collapse the
claim’s textual distinction between a “stem cell mobilizing-effective amount”
of G-CSF and a “disease treating-effective amount” of the chemotherapeutic agent.
Federal Circuit agreed with Sandoz & held that “disease treating” requires
that the chemotherapeutic agent be administered to treat an underlying disease.
The claimed method therefore must be performed to treat an underlying disease.
As the claim itself states, the “disease treating-effective amount” of a
chemotherapeutic agent does precisely that. Court further said that Amgen’s
construction would broaden claim 1 to cover administration of G-CSF and a
chemotherapeutic agent solely for the purpose of mobilizing stem cells. Such a
conclusion would require interpreting “disease treating” as “stem cell
mobilizing,” but “[o]ur precedent instructs that different claim terms are
presumed to have different meanings.” Finally, Federal Circuit held that the district
court did not err in construing claim 1 of the ’427 patent & affirmed the
Summary Judgment decision.
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