On Sep 06, 2018 Federal Circuit upheld a New Jersey court’s
decision that Supernus Pharmaceuticals Inc.’s patents related to its
anti-epilepsy drug (Oxtellar XR) are valid and infringed by ANDA filer Twi Pharmaceuticals
Inc.
Twi Pharmaceuticals, Inc. appealed from a decision of the
United States District Court for the District of New Jersey holding, after
bench trial, that Supernus Pharmaceuticals, Inc.’s U.S. Patent Nos.
7,722,898 (“the ’898 patent”), 7,910,131 (“the ’131 patent”), and 8,821,930
(“the ’930 patent) are not invalid and would be infringed. These patents
provide controlled-release oxcarbazepine formulations for once-a-day administration.
The asserted patents purport to achieve these objectives by (1) using matrix
polymers that comprise a homogeneous matrix structure, and (2)
“incorporat[ing] a combination of solubility-enhancing excipients
and/or release-promoting agents into the formulations to enhance
the bioavailability of oxcarbazepine and its derivatives.”
Representative claim 1 of the ’898 patent recites:
1. A pharmaceutical formulation for once-a-day administration
of oxcarbazepine comprising a homogeneous matrix comprising:
(a) oxcarbazepine;
(b) a matrix-forming
polymer selected from the group consisting of cellulosic polymers,
alginates, gums, cross-linked polyacrylic acid, carageenan, polyvinyl pyrrolidone,
polyethylene oxides, and polyvinyl alcohol;
(c) at least one
agent that enhances the solubility of oxcarbazepine selected from the group
consisting of surface active agents, complexing agents, cyclodextrins, pH
modifying agents, and hydration promoting agents; and
(d) at least one
release promoting agent comprising a polymer having pHdependent solubility
selected from the group consisting of cellulose acetate phthalate, cellulose
acetate succinate, methylcellulose phthalate, ethylhydroxycellulose phthalate,
polyvinylacetate phthalate, polyvinylbutyrate acetate, vinyl acetate-maleic
anhydride copolymer, styrene-maleic mono-ester copolymer, and Eudragit L100-55
(Methacrylic Acid-Ethyl Acrylate Copolymer (1:1)), and methyl
acrylate-methacrylic acid copolymers.
On Oct. 7, 2015, the district court held a Markman hearing
in related case (“Actavis”), during which it construed claim term “at
least one agent that enhances the solubility of oxcarbazepine” as “an
agent, other than oxcarbazepine, that enhances the solubility of oxcarbazepine,
which agent cannot also serve as the sole matrix-forming polymer in 1(b) or the
sole release promoting agent in 1(d) in claim 1,” and claim term “homogeneous
matrix” as a “matrix in which the ingredients or constituents are uniformly
dispersed.” The district court then held a four-day bench trial in this
litigation from April 3–6, 2017. In a decision dated August 15, 2017, the
district court concluded that the asserted patents are not invalid and would be
infringed by TWi’s proposed tablets. In particular, the district court found
that TWi’s proposed tablets satisfied the “homogeneous matrix” and the
solubility agent limitations under its constructions of those terms, and that
the common specification and prosecution histories of the asserted patents
demonstrate that the “homogeneous matrix” limitation is not indefinite and does
not lack adequate written description support. In making these determinations,
the district court, at times, referenced its decision in Actavis.
“On appeal, First, TWi contended that the district court
erred because it gave its decision in Actavis “de facto preclusive effect”
in this case. CAFC however, disagreed & said that district court did not
give its decision in Actavis de facto preclusive effect in this case. The
district court explicitly stated in its post-trial decision that its decision
in Actavis has “some relevance to this action,” but that its “findings of fact
and conclusions of law set forth are based upon the evidence and argument
presented in this litigation.”
Second, TWi argued that Supernus’s admissions in the common
specification preclude a finding that the accused agent satisfies the “solubility
agent limitation”. As described above, the asserted patents require both a
release promoting agent and a solubility agent. Twi argued that the accused
agent cannot satisfy the solubility agent limitation because the common
specification, at Table 1, characterizes a formulation that contains the
accused agent, but not a release-promoting agent, as a “non-enhanced”
formulation. CAFC said that “non-enhanced” formulations can include
formulations that do not contain either a solubility agent or a release
promoter. Applied to Table 1, the “non-enhanced” formulation containing the
accused agent does not preclude a finding that the accused agent is a
solubility agent. This is because it is entirely possible that the formulation
is “non-enhanced” solely because it lacks a release-promoting agent and not
because it lacks a solubility agent. Thus, the district court did not err in
finding that this statement in the specification does not amount to an
admission of non-infringement, nor did it err in ultimately concluding, based
on expert testimony, that the accused agent infringes the solubility agent
limitation.
Third, TWi also argued that the district court erred in
finding that the proposed tablets infringe the “homogeneous matrix”
limitation. Specifically, it contended that the district court changed its
construction of “homogeneous matrix” from a “matrix in which the ingredients or
constituents are uniformly dispersed,” as construed in the district court’s Markman order, to “no localization of
constituents,” as stated in its post-trial decision. CAFC said that district
court did not change the construction of the term in its post-trial decision,
but rather clarified what was already inherent in its construction, as
permitted. Supernus raised concerns that TWi may attempt to avoid infringement
by arguing that the asserted patents require complete uniformity, which
Supernus contends is unattainable. In response to Supernus’s concerns, the
district court stated that, in its view, the asserted patents do not require
any specific degree of uniformity, just some degree of uniformity. Thus, the
district court clarified that inherent in its construction of “homogeneous
matrix” is this understanding that, where the degree of uniformity is
irrelevant, “uniformly dispersed” necessarily implicates an absence of
localization.
Finally, TWi argued that the district court erred in finding
that the “homogeneous matrix” limitation was not indefinite and did not lack
written description support. CAFC disagreed to this also & held that the
specification, prosecution history, and expert testimony support the district
court’s conclusions. Thus, the district court did not err.
