On Apr 27, 2020, Delaware court found Eagle pharmaceuticals patents valid & infringed by ANDA filers.
Plaintiffs (Teva, Cephalon and Eagle Pharmaceuticals) sued
Defendants (Apotex, Fresenius Kabi, Mylan, and Slayback Pharma) as they sought
to bring to market generic versions of Plaintiffs' Bendeka®, a drug indicated
for the treatment of chronic lymphocytic leukemia (CLL) and indolent B-cell
nonHodgkin lymphoma (NHL). Plaintiffs alleged infringement of U.S. Patent Nos.
9,265,831, 9,572,797 (formulation patents) and
9,144,568, 9,597,399, 9,572,887 (administration patents). Defendants
mostly stipulated to infringement of the asserted claims (except two) and
argued that all asserted claims are invalid.
Obviousness:
1. Formulation patents:
The main components of the asserted formulation are: a
non-aqueous liquid composition that contains (1) bendamustine (or a
pharmaceutically acceptable salt thereof); (2) about 5% to about 10% by volume
of the solvent propylene glycol (PG); (3) the solvent polyethylene glycol
(PEG); (4) one of the following ratios of PEG to PG: about 95:5, about 90:10,
about 85:15, about 80:20, and about 75:25; and (5) a stabilizing amount of an
antioxidant. Two claims also specify components and quantities: (1) claim 11 of
the #797 patent requires that "the antioxidant is thioglycerol or
monothioglycerol," and (2) claim 5 of the #831 patent requires that
"the bendamustine concentration is from about 25 mg/mL to about 50
mg/mL." Certain claims also recite stability limitations such as
"less than or equal to 0.11 % PG esters at about 1 month of storage at
about 5°C.
Bendamustine is prone to degradation because of two
functional groups (a nitrogen mustard group and a carboxylic acid group).
Because water causes bendamustine to degrade at its nitrogen mustard group, the
prior art bendamustine formulations used a lyophilized (freeze-dried) form of
bendamustine that required a human operator to reconstitute it using water
shortly before administering it to a patient. But this reconstitution by human
manipulation had two known disadvantages: it increased the risk of
contamination and, because bendamustine is a cytotoxic compound, it posed a
potential danger to the operator. Inventor of the asserted patents overcame
this problem by providing stable non-aqueous bendamustine composition which
contains appropriate quantities of PG & PEG solvents.
Defendants argued that five prior art references would have
motivated a POSITA to arrive at the asserted formulation claims with a
reasonable expectation of success: Olthoff, Drager, Alam, Rowe, and Boylan.
Olthoff (1983) – discloses non-aqueous, ready to use bendamustine
formulation (25 and 100 mg/mL) in polyols such as PG & PEG. Olthoff's
examples did not use an antioxidant.
Drager (2008) – discloses stable liquid pharmaceutical
formulations comprising bendamustine.But Drager determined that the
"results described in [Olthoff] were not reproducible." Drager' s
data showed that bendamustine in 99% PG degraded almost completely after eight
weeks at 25°C and more than 20% at 5°C after one year. The reason for that degradation, according to
Drager, was that (1) PG causes bendamustine to degrade at the nitrogen mustard
group and (2) PG's OH groups cause bendamustine to degrade at the carboxylic
acid group through esterification. As a solution to the degradation problem,
Drager disclosed the use of aprotic solvents (DMA). Drager also taught that
protic solvents-i.e., solvents, including PEG and PG, that have OH groups-are
acceptable to use with bendamustine but only when combined with aprotic
solvents.
Alam (1989) - disclosed stable liquid formulations of
cyclophosphamide, a compound that, like bendamustine, has a nitrogen mustard
group & tested its stability in 3 polyols (PG, PEG & glycerols). Alam
disclosed using PG at a ratio of from about 10% to about 90% and PEG at a ratio
of from about 90% to about 10%.
Rowe - Rowe's
Handbook of Pharmaceutical Excipients disclosed that PEG is susceptible to
oxidation and that one can use an antioxidant to prevent such oxidation.
Boylan - Boylan disclosed a list of "some of the most
commonly used antioxidants in pharmaceutical injectable formulations"
including monothioglycerol.
Defendants argued that Olthoff, Drager, and Alam would have
motivated a POSITA to use PEG and PG with bendamustine. Court, however, said
that Drager teaches away from Olthoffs teaching of using polyols. Specifically,
Drager determined that the results described in [Olthoff] were not reproducible
& bendamustine degrades completely in PG after 8 weeks. Drager, therefore,
suggested use of aprotic solvent as major component. Drager specifically showed
that a formulation containing 66% DMA and 34% PG is stable. Drager, thus,
teaches away from the use of only protic solvents (PG & PEG). Therefore,
Drager would not have motivated a POSA to replace DMA with a low-OH protic
solvent. POSA would have given more weightage to Dragger over Olthoff because
data is more reliable in Dragger since it used HPLC & Olthoff used TLC
method. Moreover, in the decades between Olthoffs publication in 1983 and the
priority date in 2010, Olthoffs formulations were never used, suggesting that
POSA generally did not rely on Olthoff. Third reference, Alam is related to
cyclophosphamide & the structural differences between bendamustine &
cyclophosphamide would have discouraged POSA because degradation pathway would
be different. Therefore, POS A would not have viewed cyclophosphamide as a
relevant comparator for bendamustine reactions, and would not have considered
Alam in formulating a stable bendamustine formulation. In sum, Defendants have
not proven by clear and convincing evidence that Olthoff, Drager, and Alam
would have motivated a POSITA to use PEG and PG to create a non-aqueous liquid
bendamustine formulation.
Since, POSA would not have motivated to use PG & PEG,
the other claimed limitations such as PEG:PG ratio, use of antioxidant,
bendamustine concentration, stability limitations would not have been obvious.
With respect to only argued secondary consideration - “commercial success”, court said that the evidence of $2 billion
sales of Bendeka does not support a
finding of nonobviousness. First, Bendeka® sells at a lower price than the
prior art lyophilized Treanda® product. Second, Plaintiffs' cluster of
exclusivities has blocked others from entering the market. Court finally held
that although the evidence of commercial success does not support a finding of
nonobviousness, Defendants have not shown by clear and convincing evidence that
the prior art they cited would have motivated a POSIT A to reach the claimed
formulations.
2. Administration patents:
The asserted administration claims recite methods of
treating CLL or NHL with a liquid bendamustine composition. Certain claims
require administering the bendamustine composition on days one and two of a
21-day cycle for NHL, or on days one and two of a 28-day cycle for CLL. One
claim requires a bendamustine dose of"about 25 mg/m2 to about 120 mg/m2”.
The asserted administration claims also specify administration times, the longest
time being "about 15 minutes or less”.They also specify administration
volumes that are all 100 mL or less. Finally, certain claims specify post
dilution bendamustine concentrations ranging from 0.05 mg/mL to 12.5 mg/mL.
Defendants argued that eight prior art references would have
motivated a POSIT A to combine the elements of the claimed administration with
a reasonable expectation of success: Palepu 2011 (Formulation patents as
discussed above), the Treanda® Label, Preiss 1985 (PK study with 3 minutes of administration
of bendamustine with 280 to 375 mg dose), Preiss 1998 (MTD study with 3 to 10
minutes of administration of bendamustine with 54 to 226 mg/m2 dose), Schoffski
2000a (administration of bendamustine over 30 minutes and compared its results
to the three-to-ten-minute infusions disclosed in Preiss 1998), Schoffski 2000b
(Schoffski 2000b administered 60 to 80 mg/m2 of bendamustine in 30 minutes),
Barth (suggested administering bendamustine in a solvent volume of 100 to 250
mL), and Glimelius (disclosed the administration of 5-Fluorouracil to treat
colorectal cancer as an infusion lasting ten to 20 minutes using a 50 to 100 mL
mini-bag).
Court said that prior arts would have motivated a POSA to
reach the claimed formulation, dose, and dosing schedule. But, the prior arts
would not have motivated a POSA to reach the remaining claim limitations
(Administration Times, Volumes, and Post-Dilution Concentrations), and thus the
claims as a whole are not obvious. All asserted claims require administering
bendamustine in 15 minutes or less, with some requiring ten minutes or less.
All asserted claims also require administering bendamustine in a volume of 100
mL or less, with some claims requiring about 50 mL. Finally, all but one of the
asserted administration claims require post-dilution bendamustine
concentrations ranging from 0.05 to 12.5 mg/mL. Defendants argued that the
Preiss studies support a finding that the claimed administration times,
volumes, and concentrations are obvious. Court, however,found that Preiss
studies would not have motivated a POSA to reach the claimed administration
times, volumes, or concentrations because (1) a POSA would not have relied on
the Preiss studies to determine a safe and effective infusion time, volume, or
concentration for bendamustine because those studies were not designed to
evaluate safety, (2) subsequent prior art taught away from Preiss's
three-to-ten-minute infusions, instead, it would have considered later prior
art references that used 30 to 60 minute infusions and a 500 mL volume and (3)
Defendants only hypothesize that the Preiss studies used volumes and
concentrations similar to those in the claimed administrations, such
speculations about Preiss's infusion rate and volume, however, are only based
on "conclusory and unsupported expert testimony" and they do not
support a finding of obviousness by clear and convincing evidence.
With respect to secondary consideration, Plaintiffs offered
at trial evidence of four secondary considerations that bear on the administration
claims: skepticism, long-felt need, commercial success, and industry praise.
Court, however, did not find this evidence to be probative indicia of
nonobviousness.
Indefiniteness:
Defendants argued that the asserted formulation claims are
invalid because they each require "a stabilizing amount of
antioxidant"-a requirement Defendants contend is indefinite. Specifically,
Defendants argued that the term is indefinite because "[t]he specification
does not explain how to determine whether stability has been 'increased' or
'enhanced.’ Court, however, disagreed
& said that the patents provide a POSA with a method for measuring
stability: using HPLC to compare the amount of overall bendamustine degradation
with and without the antioxidant. Example 3 demonstrates that a POSA would
compare the amount of bendamustine remaining in the same formulation, stored
under the same conditions, with and without the antioxidant. In addition to
providing exemplary test methods, the specification also lists "suitable
antioxidant amounts" and "antioxidants," and provides examples
of "stabilizing" amounts. Court, thus found that the term
"stabilizing amount of antioxidant" is not indefinite and court
construed it as: any amount of an antioxidant that decreases the amount of
bendamustine degradation after any time period and at any temperature.
Enablement:
Defendants asserted that the asserted formulation claims are
invalid for lack of enablement because the formulation patents disclosed
neither the use of sodium hydroxide (NaOH) or of "other undisclosed
variables." Specifically, Defendants argued that the asserted formulation
claims are not enabled because the claims do not contain NaOH and "a pH
adjuster like NaOH is necessary to obtain the PG ester levels claimed in the
[a]sserted [f]ormulation claims. Court said that evidence that some claimed
formulations did not result in the PG ester limitations, does not establish
that the claims are not enabled. Defendants have not presented any evidence to
show that a POSA would have had to undertake undue experimentation to alter the
formulation to obtain the PG ester limitations. That some formulations with the
claimed ingredients do not satisfy the PG ester limitations does not support
non-enablement unless the number of such formulations is significant enough to
have required a POSA to experiment unduly. [Atlas
Powder, 750 F.2d at 1576-77….Even if some of the claimed combinations were
inoperative, the claims are not necessarily invalid ....)]. Accordingly,
Defendants failed to establish by clear and convincing evidence that the
asserted claims are invalid for lack of enablement.
Lack of written description:
Apotex argued that claim 9 of the #797 patent is invalid for
lack of written description. It asserted that "the absence of any mention
of a pH adjuster like NaOH in the [#]797 patent demonstrates that the inventors
did not have possession of it at that time, as confirmed by their later filing
of another patent application that discloses and claims it." Court said
that "written description is about whether the skilled reader of the
patent disclosure can recognize that what was claimed corresponds to what was
described .... ["Alcon Research Ltd.
v. Barr Labs., Inc., 745 F.3d 1180, 1191 (Fed. Cir. 2014)]. And Apotex
never citeed the intrinsic record to show that the asserted formulation patents
claim something that they do not describe in their written descriptions.
Instead, Apotex improperly cited extrinsic evidence-the later-filed Eagle
patent application. Apotex has thus failed to establish that claim 9 is invalid
for lack of written description.
Infringement:
Defendants stipulated to infringement of the asserted claims
with two exceptions. Apotex, Fresenius Kabi, and Mylan argued that (1) they do
not infringe the asserted formulation claims because their ANDA products do not
contain "a stabilizing amount of an antioxidant" as the asserted
formulation claims require, and (2) they do not directly infringe or induce
infringement of claim 9 of the #797 patent, which requires that the
"bendamustine-containing composition ha[ve] less than or equal to 0.43 %
total PG esters at about 3 months of storage at a temperature of about
25°C," because their proposed labeling does not direct physicians to store
their ANDA products for about 3 months at about 25°C.
With respect to first point, court said that it has construed
the term as any amount of an antioxidant that decreases the amount
of bendamustine degradation after any time period and at any temperature. Defendants'
ANDA products each contain 5 mg/mL of the antioxidant monothioglycerol and the
formulation patents' written description shows that 5 mg/mL of monothioglycerol
is a stabilizing amount. The written description identifies "5 mg/mL to
about 20 mg/mL" as a "preferable" stabilizing amount of
antioxidant. Moreover, Example 3 demonstrates that adding "5 mg/m[L] of lipoic
acid ... as a stabilizing antioxidant" to 20 mg/mL of bendamustine in PEG
decreased the amount of bendamustine degradation after 15 days at 25°C and 40°C
as compared to the same formulation without an antioxidant. Moreover, Fresenius
Kabi and Mylan represented to the FDA that 5 mg/mL monothioglycerol was
sufficient to ensure that the amount of bendamustine in their ANDA products did
not fall below specification limits.
With respect to second point, Defendants stipulated that their ANDA
Products have "less than or equal to 0.43% total PG esters at about 3
months of storage at a temperature of about 25° C," but contend that they
do not directly infringe or induce infringement of claim 9 because their proposed
labeling does not recommend storing their ANDA Products for "about 3 months"
at "a temperature of about 25° C." Court, however, said that even
though Defendants' labeling does not mention storage, Defendants' ANDA products
directly and indirectly infringe claim 9 because the PG ester limitation does
not require the user to store the products for three months at 25°C. Claim 9's
PG ester limitation describes a characteristic of the claimed formula; it is
not a method step and thus, does not require action to infringe. The claim does
not recite testing for the PG ester limitation; it just describes a composition
that would have less than 0.43% PG esters if one were to test for them after
storing the composition for three months at 25°C. Therefore, Defendants
infringe and induce infringement of each of the asserted claims.