On Jul 27, 2018, District of Delaware delivered opinion in
Sensipar® Hatch-Waxman litigation & found Amneal, Piramal, Watson non-infringing
& Zydus infringing.
This is a consolidated patent infringement action in which
Amgen accuses multiple Defendants of infringing US 9,375,405 patent by filing
ANDA seeking FDA approval to manufacture, use and/or sell generic versions of
Sensipar®. These Defendants are Amneal, Piramal, Watson & Zydus. Court
bifurcated the infringement claims and invalidity counterclaims and held a
four-day bench trial on infringement beginning on March 5, 2018. The ’405
patent relates to “Rapid Dissolution Formulation of Calcium Receptor-Active
Compound”. For most of the asserted claims, the parties’ stipulated that a
finding of infringement would depend on the findings for claim 1 of the ’405
patent. Claim 1 recites a pharmaceutical composition combining specific
excipients in specific amounts with the active ingredient cinacalcet
hydrochloride.
Claim 1 of the ’405 patent specifically states:
A pharmaceutical composition comprising:
(a) from about 10% to about 40% by weight of cinacalcet HCl
in an amount of from about 20 mg to about 100 mg;
(b) from about 45% to about 85% by weight of a diluent
selected from the group consisting of microcrystalline cellulose, starch,
dicalcium phosphate, lactose, sorbitol, mannitol, sucrose, methyl dextrins, and
mixtures thereof;
(c) from about 1% to about 5% by weight of at least one
binder selected from the group consisting of povidone, hydroxypropyl
methylcellulose, hydroxypropyl cellulose, sodium carboxymethylcellulose, and
mixtures thereof; and
(d) from about 1% to 10% by weight of at least one
disintegrant selected from the group consisting of crospovidine (sic), sodium
starch glycolate, croscarmellose sodium, and mixtures thereof;
wherein the percentage by weight is relative to the total
weight of the composition, and wherein the composition is for the treatment of
at least one of hyperparathyroidism, hyperphosphonia, hypercalcemia, and
elevated calcium phosphorus product.
On February 27, 2018, court construed the Markush groups for
the binder and disintegrant elements as “closed to unrecited binders and
disintegrants.” Court concluded that “there could be no literal
infringement if the Defendants’ ANDA product contained an unrecited (or
unlisted) binder or disintegrant.” Amgen then opposed the court’s construction
of the Markush groups by filing a motion for reargument, which was later denied.
Amneal product:
Amneal’s ANDA contains Opadry
YS-1-7006 (“Opadry”) as binder. But claim 1 of the ’405 patent does not
list Opadry in the Markush group for binders, therefore there was not a clear
case of literal infringement. Amgen nonetheless attempted to prove literal
infringement by arguing that Opadry is a pseudonym for hydroxypropyl
methylcellulose (“HPMC”), which is a listed binder. Alternatively, Amgen argued
that infringement is established through the doctrine of equivalents. Court
disagreed with Amgen on both of these arguments. Court concluded that for
numerous reasons the Opadry is not literally HPMC. The excipients have
different chemical structures, physical characteristics, binding mechanisms,
and commercial sources. Amneal also does
not infringe the binder limitation under the doctrine of equivalents. Here,
Amgen’s expert, Dr. Davies, opined in conclusory fashion that only the HPMC
fraction of Opadry functioned as the binder, and “the polyethylene glycol … in
the Opadry doesn’t act as a binder.” Dr. Davies never explained it with
“function-way-result,” or “substantial/insubstantial differences” test. The court
is therefore not obligated to accept the conclusory assertions of an expert.
Thus, Dr. Davies’ opinion, given without explanation or corroborating evidence,
was not found persuasive.
Amneal’s ANDA discloses the use of the listed disintegrant crospovidone and the unlisted
disintegrant pregelatinized starch.
The ’405 patent lists “starch” in the Markush groups for diluents, and the
parties remaining in this litigation do not dispute that the term “starch” in
the ’405 patent covers pregelatinized starch. Accordingly, Amgen argued that
the pregelatinized starch in Amneal’s product is not functioning as a
disintegrant, but as a diluent. Amgen’s sole support for its argument is Dr.
Davies’ opinion that crospovidone is a super-disintegrant which destroys the
structure of a tablet so quickly that the pregelatinized starch does not have
the opportunity to act as a disintegrant. However, court did not find Dr.
Davies’ opinion, as applied to Amneal’s ANDA product, convincing. First, as Dr. McConville (Amneal’s
expert) testified, Amneal’s ANDA product does not appear to need another
diluent. Amneal’s ANDA product already includes two diluents—microcrystalline
cellulose and mannitol—in a large amount; specifically, 67.89% by weight of the
accused product. Second, Dr.
McConville persuasively testified that, with Amneal’s manufacturing process,
the crospovidone cannot usurp the disintegration function of the pregelatinized
starch. Here, Amneal uses pregelatinized starch as an intragranular
disintegrant and crospovidone as an extragranular disintegrant. And because the
pregelatinized starch is the only disintegrant inside the granules, it alone
acts as a secondary disintegrant. Third,
Amneal’s ANDA contains the results of testing which confirm that the
pregelatinized starch in its product functions as a secondary disintegrant.
Thus, Amgen has failed to show by a preponderance of the
evidence that Amneal’s accused product infringes the binder and disintegrant
limitations of the ’405 patent. For the foregoing reasons, Amneal does not
infringe claim 1 of the ’405 patent. This means, pursuant to the parties’
stipulation, Amneal does not infringe claims 2-4, 8-12, and 14-17.
Watson product:
Watson uses unlisted disintegrant, low substituted hydroxypropyl cellulose (“L-HPC”), which under
court’s claim construction order means there is no literal infringement. As a
result, Amgen argued that L-HPC infringes claim 1 under the doctrine of
equivalence. At trial, Amgen took the position that L-HPC is equivalent only to
crospovidone and only under the function-way-result test. However, in its
post-trial briefs, Amgen took two new positions: (1) L-HPC is equivalent to all
three listed disintegrants of claim 1 under the function-way-result test, and
(2) L-HPC is equivalent to crospovidone under the insubstantial differences
test. Watson correctly pointed out that Amgen did not fairly presented these
positions in expert discovery or at trial. For that reason alone, Amgen’s new
infringement theories should be disregarded as an unfair surprise. Court
however, still found why Amgen’s new theories under the function-way-result
test are not persuasive & explained why Amgen’s original theory also would
have failed.
Court said that Amgen should have presented through its
expert, Dr. Davies, particularized testimony regarding the function, way, and
result for each disintegrant to be compared. Dr. Davies, however, did not
identify at trial what he considered to be the function, way, or result of the
disintegrants being compared. Accordingly, Amgen failed to prove at trial that
L-HPC is equivalent under the function-way-result test to all three
disintegrants listed in claim 1. Also because L-HPC is not a superdisintegrant,
it does not perform substantially the same function as the disintegrants listed
in claim 1. In addition, Dr. Davies’ testimony on this point was unclear: He
also testified that “there are a number of different mechanisms by which
[superdisintegrants] work.” Amgen also argued that L-HPC is equivalent to
crospovidone under the insubstantial differences test. Amgen’s expert, Dr.
Davies, did not provide an opinion regarding the insubstantial differences
between L-HPC and crospovidone. Dr. Appel (Watson;s expert)identified several
differences between L-HPC and crospovidone, which were corroborated by
scientific literature.
Thus, Amgen has failed to prove by a preponderance of the
evidence that L-HPC is equivalent to all of the disintegrants listed in claim 1
under the function-way-result test or that L-HPC is equivalent to crospovidone
alone under the insubstantial differences test. Therefore, Watson does not
infringe claim 1 of the ’405 patent. This means, per the parties’ stipulation,
Watson does not infringe claims 2-4, 8-17, and 19-20.
Piramal product:
The parties disputed whether Piramal’s ANDA product
infringes the binder and disintegrant limitations of claim 1. Amgen argued that
the unlisted binder in Piramal’s ANDA product—pregelatinized starch—has two components; a native starch fraction
that actually functions as a diluent; and a cold water soluble fraction that
functions as a binder. Neither pregelatinized starch nor its cold water soluble
fraction are listed in the Markush group for binders, which under court’s claim
construction order means there is no literal infringement. Accordingly, Amgen
argued that cold water soluble fraction is equivalent to povidone. But court
found that Amgen is foreclosed by prosecution history estoppel from asserting
the doctrine of equivalents against Piramal’s use of pregelatinized starch as a
binder.
During prosecution, Examiner did not allow the claims in the
2014 Amendment which included specific 20-100 mg of cinacalcet. Instead, the
Examiner proposed the Examiner’s Amendment, which added the Markush groups
to the binder and disintegrant limitations. In addition, the Examiner
expressly stated that he was allowing the claims as set forth in the Examiner’s
Amendment because, inter alia, the closest prior art “fails to specifically
disclose or render obvious the combination of components and in the amounts
thereof.” For all of these reasons, court found that the Examiner’s
Amendment was adopted for substantial reasons related to patentability &
hence estoppel applies.
Thus, for the foregoing reasons, Amgen cannot prove that
Piramal’s product infringes claim 1 of the ’405 patent. Per the parties’
stipulation, Piramal also does not infringe claims 2-4, 8-17, and 19-20.
Zydus product:
Amgen’s dispute with Zydus comes down to the function of pregelatinized starch. Amgen took the
position that it functions as a diluent, as stated in Zydus’ ANDA. Zydus takes
the position that it functions as a binder. Zydus’ position adopts an
opinion Amgen’s expert has asserted against other defendants. In tablet
formulations, pregelatinized starch can, depending on the context, function as
a diluent, binder, or disintegrant. The ’405 patent, however, limited itself by
claiming pregelatinized starch only as a diluent. On the face of the ANDA,
Zydus’ product appears to literally infringe each and every limitation of claim
1. To avoid a finding of literal infringement, Zydus simply adopted Dr. Davies’
opinion that the cold water soluble fraction of pregelatinized starch functions
as an unlisted binder. Normally, where literal infringement is unavailable, a
patentee can still prove infringement by resorting to the doctrine of
equivalents. Here, however, court granted a motion in limine, which bars Amgen from asserting the doctrine of
equivalents against Zydus.
Court was not persuaded that Dr. Davies’ opinion regarding
pregelatinized starch is scientifically sound. Amgen claims that three
defendants literally infringe claim 1, because the fractions opinion applies to
Aurobindo and Piramal but not to Zydus. But Dr. Davies could not provide a
credible explanation for this variation in treatment. First, he said that the
pregelatinized starch in Zydus’ product functioned only as a diluent, because
that was how Zydus identified the pregelatinized starch in its ANDA. When it
was pointed out that Dr. Davies did not accept how pregelatinized starch was
identified in other defendants’ ANDAs, he agreed and said that was why he was
also asserting his fractions opinion against Zydus. This shift in infringement
theories does not place Amgen in a better position. Amgen acknowledges, Zydus
already uses 4.98% of hydroxy propyl cellulose as a binder. If the cold water
soluble fraction in Zydus’ product also acts a binder, then that is another
3.97% acting as a binder. Adding 4.98% of hydroxy propyl cellulose to 3.97% of
a cold water soluble fraction results in a total 8.95% of binder, which exceeds
the “about 5%” weight limitation in the ’405 patent. When Zydus raised this
point with Dr. Davies, he shifted infringement theories yet again, stating that
Zydus’ product literally infringed the binder limitation, because there was “at
least one” binder from the Markush group in Zydus’ product that was within the
about 1% to about 5% weight limitation: the 4.98% of hydroxy propyl cellulose.
This testimony is not consistent with the court’s controlling claim
construction. Ultimately, Dr. Davies consistently asserted, and other experts
agreed, that the particular function of pregelatinized starch in any given
formulation “depends on the context,” including the amount of pregelatinized
starch, the other excipients present, and the manufacturing process. When
evaluating the ANDA products for Amneal, Piramal, and Zydus, the percolation
theory provides the consistency lacking in Dr. Davies’ opinion. For example,
Amneal and Zydus use over 20% by weight of pregelatinized starch which is consistent
with the diluent function identified in their ANDAs. Piramal uses 11% of
pregelatinized starch which is consistent with the binder function identified
in its ANDA. Finally, the Example uses 33.378% of pregelatinized starch which
is consistent with a diluent function that would result in the ’405 patent
covering the Example.
Given all of the foregoing, Court found that Amgen has not
proven by a preponderance of the evidence that pregelatinized starch should be
artificially divided into two fractions, with each fraction alone serving a
different function. As a result, Zydus cannot defeat Amgen’s assertions of
literal infringement by adopting Dr. Davies’ opinion that the cold water
soluble fraction of pregelatinized starch functions as a binder. Zydus’ ANDA
product literally infringes claim 1 to the extent the claim is found valid and
enforceable. Court also found per the parties’ stipulation that Zydus’ ANDA
product literally infringes claims 2-4, 8-9, 15-17, and 19, to the extent each
claim is found valid and enforceable.