Depomed, Inc. v. Lupin Pharmaceuticals, Inc. et al

Filing 107

ORDER by Judge Hamilton Construing Claims; Order denying 95 Motion to Strike (pjhlc1, COURT STAFF) (Filed on 5/17/2011)

1
2
3
4
UNITED STATES DISTRICT COURT
5
NORTHERN DISTRICT OF CALIFORNIA
6
7
8
9

DEPOMED, INC.,

11
For the Northern District of California

United States District Court

10

12

Plaintiff,
v.

No. C 09-5587 PJH
ORDER CONSTRUING CLAIMS

LUPIN PHARMACEUTICALS, INC.,
et al.,

13
14

Defendants.
_______________________________/

15

Plaintiff Depomed, Inc. (“Depomed”) asserts three patents against defendants Lupin

16

Pharmaceuticals, Inc. and Lupin Limited (collectively, “Lupin”). The patents at issue involve

17

or relate to orally-administered drug formulations.

18

Depomed, which is based in California, is a specialty pharmaceutical company,

19

which was founded in 1995 to design, develop, and market pharmaceutical products

20

utilizing optimized drug delivery technologies. Depomed focused its early research efforts

21

on the development of a gastric-retentive drug delivery system designed as a

22

conventionally-sized pill, which swells over time in the stomach, thus providing continuous

23

and controlled drug to the patient’s upper gastrointestinal (“GI”) tract.1

24

U.S. Patent Nos. 6,340,475 (“the ‘475 patent”) and 6,635,280 (“the ‘280 patent”),

25

both entitled “Extending the Duration of Drug Release Within the Stomach During the Fed

26

Mode,” were issued to Depomed as assignee of the inventors on January 22, 2002, and

27

October 21, 2003, respectively. The invention of the ‘475 and ‘280 patents relates

28
1

The upper GI tract includes the stomach, the duodenum, and the upper small intestine.

1
2

generally to oral formulations for drugs, also known as “drug dosage forms.”
Oral drug dosage forms typically contain one or more “excipients” in addition to a

3

biologically active ingredient (“the drug”). Excipients are biologically inactive components

4

that provide desirable characteristics to the dosage form. Some excipients, such as

5

binders, disintegrants and lubricants, do not contribute to the control of release of the drug

6

from the dosage form. Others, termed “release controlling excipients,” contribute to or

7

actually control the release of the drug from the dosage form.

8

Dosage forms are directed to a variety of routes of administration including, for

9

example, intravenous or intramuscular injections, tablets or capsules for oral administration,
patches that adhere to the skin for administration of drugs across the skin, and

11
For the Northern District of California

United States District Court

10

suppositories. The invention of the ‘475 and ‘280 patents relates to an oral drug dosage

12

form (a dosage form that is swallowed or ingested – typically, one or more tablets), which

13

benefits from a prolonged period of controlled release in the upper GI tract, and from an

14

enhanced opportunity of absorption in the upper GI tract rather than in the lower portions of

15

the GI tract.

16

The ‘475 and ‘280 patents arise out of a common application filed in June 1997. The

17

‘280 patent is a continuation of the ‘475 patent, which itself is a continuation-in-part of an

18

application now abandoned. Thus, the ‘475 and ‘280 patents provide substantively

19

identical disclosures, the specifications differing only by cross-references made to related

20

applications.2

21

The primary objectives of the invention of the ‘475 and ‘280 patents are to control

22

the duration of drug release and to determine the location of delivery in the patient’s body

23

(where the active ingredient is released from the dosage form). “Controlled release”

24

dosage forms, such as those described in the ‘475 and ‘280 patents, are different from

25

“immediate release” dosage forms. With respect to immediate release dosage forms, the

26

patents explain that “drugs that are administered in the form of conventional tablets or

27
28

2

Thus, in citing to the specification of the ‘475 patent in this order, the court for the
most part also intends citations to the specification of the ‘280 patent.
2

1

capsules become available to body fluids at a rate that is initially very high, followed by a

2

rapid decline.” ‘475 Patent, Col. 1:30-33. The problem with conventional immediate

3

release dosage forms is that they can result in a transient overdose, followed by a long

4

period of underdosing to the patient. Id., Col. 1:33-35.

5

A variety of controlled release dosage forms have been developed since the

6

1970’s. The controlled release oral dosage form described in Claim 1 of the ‘475 and ‘280

7

patents, comprises a drug dispersed within a polymeric matrix. Id., Col. 17:48-50. A

8

polymer is a very large molecule made up of many repeating subunits. The polymeric

9

matrix described in the patents-in-suit has a special property of being able to absorb or
imbibe water, thereby causing the dosage form to increase in size and, in turn, retard the

11
For the Northern District of California

United States District Court

10

rate of release of drug from the swollen dosage form. Id., Col. 17:51-55.

12

U.S. Patent No. 6,448,962 (“the ‘962 patent”), entitled Tablet Shapes To Enhance

13

Gastric Retention of Swellable Controlled-Release Oral Dosage Forms,” was issued to

14

Depomed as assignee of the inventors on December 3, 2002, and arises out of an

15

application filed in June 2000. The invention of the ‘962 patent discloses an improvement

16

over the ‘475 and ‘280 patents, by extending gastric retention of a dosage form by using

17

particular shapes, sizes, and swelling properties. The particular shape of these dosage

18

forms and the minimum dimensions of the dosage form increase gastric retention over the

19

dosage forms of the ‘475 and ‘280 patents.

20

Lupin Pharmaceuticals, Inc. is located in Maryland, and is a wholly-owned subsidiary

21

of Lupin Limited, an Indian company. Lupin is in the business of making and selling

22

generic pharmaceutical products.

23

Depomed commercialized Glumetza® – a once-daily treatment for adults diagnosed

24

with type-2 diabetes. Glumetza® contains the drug metformin HCL, formulated in extended

25

controlled-release 500 mg. and 1000 mg. tablets. In 2009, Lupin submitted Abbreviated

26

New Drug Application (“ANDA”) No. 91-664 to the FDA pursuant to 21 U.S.C. § 355(j),

27

seeking approval to market generic Glumetza® metformin HCL extended-release tablets in

28

the 500mg and 1000mg dosage strengths.
3

1

In November 2009, Lupin sent Depomed written notification that Lupin had filed the

2

Lupin ANDA, and also asserting that the ‘475, ‘280, and ‘962 patents are invalid or will not

3

be infringed by the commercial manufacture, use, or sale of the Lupin products. Following

4

this notification, Depomed filed the present lawsuit.
The parties now seek an order construing nine disputed terms, and Depomed also

5
6

seeks an order striking certain statements from Lupin’s responsive claim construction brief,

7

and certain portions of one of Lupin’s declarations. The court heard argument on January

8

26, 2011, and now rules as follows, and for the reasons stated at the hearing.
DISCUSSION

9

11
For the Northern District of California

United States District Court

10

A.

Legal Standard
Patent infringement analysis involves a two-step process. The court must first

12

determine as a matter of law the correct scope and meaning of disputed claim terms, and

13

must then compare the properly construed claims to the accused device to see whether the

14

device contains all the limitations (literally or by equivalents) in the claims at issue.

15

Markman v. Westview Instruments, Inc., 517 U.S. 370, 384 (1996).

16

“[T]he claims of a patent define the invention to which the patentee is entitled the

17

right to exclude.” Phillips v. AWH Corp., 415 F.3d 1303, 1312 (Fed. Cir. 2005) (citation and

18

quotation omitted). The court must determine the meaning of disputed claim terms from

19

the perspective of one of ordinary skill in the pertinent art at the time the patent was filed.

20

Chamberlain Group, Inc. v. Lear Corp., 516 F.3d 1331, 1335 (Fed. Cir. 2008).

21

A patentee is presumed to have intended the ordinary meaning of a claim term in the

22

absence of an express intent to the contrary. See York Prods., Inc. v. Central Tractor Farm

23

& Family Ctr., 99 F.3d 1568, 1572 (Fed. Cir. 1996). The ordinary and customary meaning

24

of a claim term is “the meaning that the term would have to a person of ordinary skill in the

25

art in question at the time of the invention.” Phillips, 415 F.3d at 1313.

26

The person of ordinary skill in the art is “deemed to read the claim term not only in

27

the context of the particular claim . . . but in the context of the entire patent, including the

28

specification.” Id. Indeed, a patent's specification “is always highly relevant to the claim
4

1

construction analysis” and claims “must be read in view of the specification, of which they

2

are a part.” Id. at 1312-15 (citations and quotations omitted). Because the specification

3

must contain a description of the invention that is clear and complete enough to enable

4

those of ordinary skill in the art to make and use it, the specification is therefore “always

5

highly relevant” to the court's claim construction analysis. Vitronics Corp. v. Conceptronic,

6

Inc., 90 F.3d 1576, 1582 (Fed. Cir. 1996).

7

In some cases, the specification may reveal that the patentee has given a special

inventor's lexicography controls.” Phillips, 415 F.3d at 1316. The specification also may

10

reveal the patentee's intentional disclaimer or disavowal of claim scope. “In that instance,

11
For the Northern District of California

definition to a claim term that differs from its ordinary meaning; in such cases, “the

9

United States District Court

8

as well, the inventor has dictated the correct claim scope, and the inventor's intention, as

12

expressed in the specification, is regarded as dispositive.” Id. Although the court must

13

read the claim in view of the specification, the claims are not limited to preferred

14

embodiments or illustrative examples appearing in the specification. Kraft Foods, Inc. v.

15

International Trading Co., 203 F.3d 1362, 1366 (Fed. Cir. 2000).

16

The words in the claim may also be interpreted in light of the prosecution history, if in

17

evidence. Teleflex, Inc. v. Ficosa North Am. Corp., 299 F. 3d 1313, 1324-25 (Fed. Cir.

18

2002) (citations omitted). The prosecution history “can often inform the meaning of the

19

claim language by demonstrating how the inventor understood the invention and whether

20

the inventor limited the invention in the course of prosecution, making the claim scope

21

narrower than it would otherwise be.” Phillips, 415 F.3d at 1317. These components of the

22

intrinsic record are the primary resources in properly construing claim terms.

23

Finally, after reviewing the intrinsic evidence, if the court is unable to resolve a

24

disputed claim term, it may consider extrinsic evidence, such as expert testimony, inventor

25

testimony, and technical treatises and articles. Vitronics, 90 F.3d at 1584. However, while

26

courts have discretion to consider extrinsic evidence, such evidence is “less significant than

27

the intrinsic record in determining the legally operative meaning of claim language.”

28

Phillips, 415 F.3d at 1317–18 (internal quotations omitted).
5

1
2

B.

The Disputed Terms
The parties seek an order construing nine disputed terms. Five of the terms appear

3

in Claim 1 of the ‘475 patent, and similar disputed terms appear in Claim 1 of the ‘280

4

patent (for which the specification is the same as for the ‘475 patent). The remaining two

5

terms appear in Claim 1 of the ‘962 patent.

6

Claim 1 of the ‘475 patent recites (with disputed terms set forth in boldface font):

7

A controlled-release oral drug dosage form for releasing a drug whose
solubility in water is greater than one part by weight of said drug in ten parts
by weight of water, said dosage form comprising a solid polymeric matrix with
said drug dispersed therein at a weight ratio of drug to polymer of from about
15:85 to about 80:20, said polymeric matrix being one that swells upon
imbibition of water thereby attaining a size large enough to promote
retention in the stomach during said fed mode, that releases said drug
into gastric fluid by the dissolution and diffusion of said drug out of said
matrix by said gastric fluid, that upon immersion in gastric fluid retains at least
about 40% of said drug one hour after such immersion and releases
substantially all of said drug within about eight hours after such
immersion, and that remains substantially intact until all of said drug is
released.

8
9

11
For the Northern District of California

United States District Court

10

12
13
14

‘475 Patent, Col. 17:45-59.

15

Claim 1 of the ‘280 patent recites (with disputed terms set forth in boldface font):

16

A controlled-release oral drug dosage form for releasing a drug whose
solubility in water is greater than one part by weight of said drug in ten parts
by weight of water, said dosage form comprising one or more polymers
forming a solid polymeric matrix with said drug incorporated therein at a
weight ratio of drug to polymer of from 15:85 to 80:20, said dosage form
being one that when swollen in a dimensionally unrestricted manner as
a result of imbibition of water is of a size exceeding the pyloric diameter
in the fed mode to promote retention in the stomach during the fed
mode that releases said drug into gastric fluid by the dissolution and
diffusion of said drug out of said matrix by said gastric fluid, that upon
immersion in gastric fluid retains at least about 40% of said drug one hour
after such immersion and releases substantially all of said drug after such
immersion, and that remains substantially intact until substantially all of
said drug is released.

17
18
19
20
21
22
23

‘280 Patent, Col. 17:45-61.
24
Finally, two disputed terms appear in Claim 1 of the ‘962 patent. Claim 1 of the ‘962
25
patent recites (with disputed terms set forth in boldface font):
26
27
28

A controlled-release oral drug dosage form for releasing a drug into at least a
portion of a region defined by the stomach and the upper gastrointestinal
tract, said dosage form consisting essentially of a solid monolithic matrix
with said drug contained therein, said matrix being non-circular in shape and
6

having first and second orthogonal axes of unequal length, said matrix being
one that swells in an unrestricted manner along both such axes upon
imbibition of water, the longer such axis having a maximum length of 3.0 cm
when said matrix is unswollen, and the shorter such axis achieving a
minimum length of 1.2 cm within one hour of immersion of said dosage form
in water and wherein said matrix has a shape which when projected onto a
plane, is either an oval or a parallelogram.

1
2
3
4
5

‘962 Patent, Col. 11:14-25.

6

C.

7

The Parties’ Proposed Constructions and Arguments
(1)

said polymeric matrix being one that swells upon imbibition of water

8

thereby attaining a size large enough to promote retention in the stomach during

9

said fed mode (‘475 patent)
(2)

said dosage form being one that when swollen in a dimensionally

11
For the Northern District of California

United States District Court

10

unrestricted manner as a result of imbibition of water is of a size exceeding the

12

pyloric diameter in the fed mode to promote retention in the stomach during the fed

13

mode (‘280 patent)

14
15
16

The parties agree that these two terms should be given the same construction.
Depomed proposes the following construction:

17

The polymeric matrix of the drug dosage form increases in size such that
when the dosage form is introduced into the stomach in the fed mode, the
dosage form remains in the stomach for several hours.

18

In the joint claim construction statement, Lupin proposed the following construction:

19

Unrestricted swelling to a size at least 20% greater than that of the starting
tablet due to the ingress of water, resulting in a swollen polymeric matrix that
is larger than the diameter of the pylorus in the fed mode.

20
21

However, in its responsive claim construction brief, Lupin now proposes the following

22

alternative construction:

24

An unrestricted swelling to a size greater than that of the starting tablet due to
the ingress of water, resulting in a swollen solid polymeric matrix that is larger
than the diameter of the pylorus in the fed mode.

25

In this revised construction, Lupin has removed the size limitation “at least 20%,”

23

26

and has also added the word “solid” to the phrase “swollen polymeric matrix.” Lupin says it

27

eliminated the phrase “at least 20%” in response to Depomed’s argument in the opening

28

brief that Lupin’s proposed construction is faulty because it requires numerical precision,
7

1
2

and that it added “solid” because it seemed necessary to properly construe the term.
Both Claim 1 of the ‘475 patent and Claim 1 of the ‘280 patent recite a “controlled-

3

release oral dosage form.” The oral dosage form in Claim 1 of the ‘475 patent comprises “a

4

solid polymeric matrix” with the drug “dispersed therein,” and in Claim 1 of the ‘280 patent,

5

it comprises “one or more polymers forming a solid polymeric matrix” with the drug

6

“dispersed therein.” The dosage form “swells upon imbibition of water” (‘475 patent) or is

7

“swollen in a dimensionally unrestricted manner as a result of imbibition of water” (‘280

8

patent).

9

The specification explains that “[t]he water-swellable polymer forming the matrix in
accordance with this invention is any polymer that is non-toxic, that swells in a

11
For the Northern District of California

United States District Court

10

dimensionally unrestricted manner upon imbibition of water, and that provides for sustained

12

release of an incorporated drug.”3 ‘475 patent, Col. 7:54-58. As set forth in the parties’

13

briefs, the dispute concerning the construction of these two terms involves whether the

14

polymeric matrix swells in an “unrestricted” manner, and whether the polymeric matrix

15

remains “solid” when it swells. Depomed also asserts that Lupin’s alteration of its original

16

proposed construction was improper.

17

According to the Abstract for the ‘475 and ‘280 patents, in the disclosed invention,

18

“[d]rugs are formulated as unit oral dosage forms by incorporating them into polymeric

19

matrices comprised of hydrophilic polymers that swell upon imbibition of water to a size that

20

is large enough to promote a retention of the dosage form in the stomach during the fed

21

mode.” The matrix “is a relatively high molecular weight polymer that swells upon

22

ingestion, preferably to a size that is at least about twice its unswelled volume, and that

23

promotes gastric retention during the fed mode.” ‘475 patent, Col. 5:66-6:3.

24

The swelling of the polymeric matrix achieves two objectives for the administration of

25
26
27
28

3

At the hearing, in response to questions by the court, counsel for Depomed defined
“polymeric matrix” as used in the context of “dosage form” in the patents-in-suit as “the
amalgamation of the individual polymers that are used.” That is, “the polymer matrix is the
meshing together of all the polymers to form a matrix.” Hearing Transcript, January 26, 2011
(“Tr.”) at 8-9; see also Tr. at 78-81.
8

1

highly soluble drugs – “(i) the tablet swells to a size large enough to cause it to be retained

2

in the stomach during the fed mode, and (ii) it retards the rate of diffusion of the highly

3

soluble drug long enough to provide multi-hour, controlled delivery of the drug into the

4

stomach.” Id. at Col. 6:19-24. The drug-containing polymeric matrix “swell[s] in size in the

5

gastric cavity due to ingress of water in order to achieve a size that will be retained in the

6

stomach when introduced during the fed mode.” Id. at Col. 9:1-5.

7

Both parties agree that because of the ingestion of water, the polymeric matrix

of time. Depomed argues, however, that Lupin is impermissibly reading limitations into the

10

claim phrases. Depomed asserts that there is no basis in the claims or the specification for

11
For the Northern District of California

increases to a size that causes the dosage form to remain in the stomach for some period

9

United States District Court

8

construing these terms as including “unrestricted” swelling of the dosage form, or as

12

including the limitation that the resulting “swollen” polymeric matrix will be “solid.”

13

In response, Lupin argues that the limitation “unrestricted swelling” is already part of

14

the claim language, referring to Claim 1 of the ‘280 patent, which describes the dosage

15

form as “one that when swollen in a dimensionally unrestricted manner as a result of

16

imbibition of water . . . “ ‘280 patent, Col. 17:51-53. Lupin also points to the specification,

17

which explains that “[t]he water-swellable polymer forming the matrix in accordance with

18

this invention is any polymer that is non-toxic, that swells in a dimensionally unrestricted

19

manner upon imbibition of water, and that provides for sustained release of an incorporated

20

drug.” ‘475 Patent, Col. 7:54-58.

21

Lupin argues that unrestricted swelling is essential for the claimed formulation to

22

avoid passing through the pylorus during the fed mode, citing the following portion of the

23

‘962 specification:

24
25
26

When dosage forms such as [cylindrical tablets elongated in shape to
facilitate swallowing] swell due to imbibition of water, one dimension may
achieve a length great enough to exceed the pyloric opening while the others
may be significantly smaller . . . Accordingly, for a certain percentage of the
administered units of these swelling forms, prolonged retention in the
stomach is not achieved and the beneficial effect of the swelling is lost.

27
‘962 Patent, Col. 3:8-17.
28
9

1

As the court noted at the hearing, the claim language requires that the dosage form

2

swells or increases in size, and does not place any restriction on that swelling. However,

3

Claim 1 of the ‘280 patent (the claim where the word “unrestricted” appears) refers to the

4

dosage form being swollen in a “dimensionally unrestricted” manner. It is not the swelling

5

itself that is unrestricted, but the swelling of the dimensions of the dosage form – that is,

6

length, the width, or other dimension of the dosage form – based on the swelling

7

characteristics of the selected polymer.

8
9

As Depomed asserts, the specification does not qualify the rate of swelling for the
polymeric matrix, as Lupin’s construction does, but simply addresses the dimensional
swelling characteristics of a selected polymer. Since there are no restrictions placed on the

11
For the Northern District of California

United States District Court

10

size by either the claim language or the specification, the addition of the limitation

12

“unrestricted” to the construction of these two terms is unnecessary.

13

Moreover, the patent specification describes the swelling in a broadly functional

14

manner not tied to “unrestricted” swelling. See ‘475 Patent, Col. 6:19-24; id., Col. 9:1-7. It

15

is improper to read “unrestricted” into Claim 1 of the ‘475 patent because of the broad,

16

functional description of swelling in the specification. See Prima Tek II, L.L.C. v. Polypap

17

S.A.R.L., 318 F.3d 1143, 1151 (Fed. Cir. 2005) (“varied use of a disputed term in the

18

written description demonstrates the breadth of the term rather than providing a limited

19

definition”).

20

Because Claim 1 of ‘280 patent contains the express language “when swollen in a

21

dimensionally unrestricted manner,” the dosage form in Claim 1 of the ‘280 patent must be

22

in a state where it has swollen in all dimensions. Lupin’s proposed construction appears to

23

be an attempt to alter this limitation on the swollen state to a restriction on the swelling

24

process itself.

25

Similarly, there is no need to include the limitation “greater than that of the starting

26

tablet.” It is inherent in the meaning of “swell” that the dosage form will increase in size. All

27

that is necessary is that the polymeric matrix that comprises the dosage form must swell to

28

a size large enough so that the dosage form is retained in the stomach for some period of
10

1

time. The specification states only that the matrix is a polymer that “swells upon ingestion,

2

preferably to a size that is at least about twice its unswelled volume . . . .“ ‘475 patent, Col.

3

5:66-6:2 (emphasis added).

that is, a size that promotes retention – rather than in terms of absolute size. See id., Col.

6

5:66-6:3 (the matrix “swells upon ingestion, preferably to a size that . . . promotes gastric

7

retention during the fed mode”); id. at Col. 6:19-24 (“the tablet swells to a size large enough

8

to cause it to be retained in the stomach during the fed mode” and “it retards the rate of

9

diffusion of the highly soluble drug long enough to provide multi-hour, controlled delivery of

10

the drug into the stomach”); id. at Col. 9:1-7 (“the drug-containing matrices . . . swell in size

11
For the Northern District of California

Indeed, the specification describes the size of the dosage form in functional terms –

5

United States District Court

4

in the gastric cavity due to ingress of water in order to achieve a size that will be retained in

12

the stomach when introduced during the fed mode”).

13

With regard to its proposal that the result of the swelling is a “swollen solid polymeric

14

matrix,” Lupin relies on the statement in the specification that the claimed formulation

15

“remains undissolved in (i.e., is not eroded by) the gastric fluid for a period of time sufficient

16

to permit the majority of the drug to be released by the solution diffusion process during the

17

fed mode.” Id., Col. 6:10-15. In other words, Lupin argues, the polymeric matrix remains

18

solid when swollen to a size large enough to block the pylorus, thus enabling the release of

19

the drug to be “controlled diffusion . . . rather than erosion, dissolving, or chemical

20

decomposition.” Id., Col. 6:15-18. However, Lupin does not explain why it has added

21

“solid” to this proposed construction, when the construction it originally proposed in the joint

22

claims construction statement did not include the word “solid.”

23
24
25
26
27
28

Moreover, the addition of the term “solid” is contrary to the specification, which reads
as follows:
Upon swelling, the matrix may also convert over a prolonged period of time
from a glassy polymer to a polymer that is rubbery in consistency, or from a
crystalline polymer to a rubbery one. The penetrating fluid then causes
release of the drug in a gradual and prolonged manner by the process of
solution diffusion, i.e., dissolution of the drug in the penetrating fluid and
diffusion of the dissolved drug back out of the matrix. The matrix itself is solid
prior to administration and, once administered, remains undissolved in (i.e., is
11

3

not eroded by) the gastric fluid for a period of time sufficient to permit the
majority of the drug to be released by the solution diffusion process during the
fed mode. The rate-limiting factor in the release of the drug is therefore
controlled diffusion of the drug from the matrix rather than erosion, dissolving
or chemical decomposition of the matrix.

4

Id., Col. 6:3-17. While the polymeric matrix is clearly “solid” at the time the dosage form is

5

ingested, and remains “undissolved” for a period of time thereafter, as it imbibes water and

6

swells, the polymer will become rubber, spongy, or gel-like (that is, less than “solid”).

1
2

7

Accordingly, “said polymeric matrix being one that swells upon imbibition of

during said fed mode” and “said dosage form being one that when swollen in a

10

dimensionally unrestricted manner as a result of imbibition of water is of a size

11
For the Northern District of California

water thereby attaining a size large enough to promote retention in the stomach

9

United States District Court

8

exceeding the pyloric diameter in the fed mode to promote retention in the stomach

12

during the fed mode“ mean “[t]he dosage form, which comprises a polymeric matrix,

13

increases in size due to the ingress of water, such that when the dosage form is

14

introduced into the stomach in the fed mode, the dosage form remains in the

15

stomach for several hours.”

16

(3)

17

Depomed proposes the following construction for this term:

18

Both the fluid in the stomach and simulated or artificial fluids recognized by
those skilled in the art as a suitable model for the fluid of the human stomach.

gastric fluid (‘475 and ‘280 patents)

19
Lupin proposes the following construction:
20
21

Fluid that maintains the essential characteristics of gastric fluid (such as low
pH or enzymes) and is recognized by a person of ordinary skill in the art as a
suitable model for the fluid of the human stomach.

22
At the hearing, the court noted that the two proposed constructions are the same,
23
except that Lupin’s proposed construction includes examples of “essential characteristics of
24
gastric fluid,” and stated that it would accept Depomed’s proposed construction.
25
Accordingly, “gastric fluid” means “[b]oth the fluid in the stomach and simulated
26
or artificial fluids recognized by those skilled in the art as a suitable model for the
27
fluid of the human stomach.”
28
12

1

(4)

2

Depomed proposes the following construction for this term:

3

Rapid dissolution of the drug by the gastric fluid, followed by slow diffusion of
the drug out of the matrix, such that the drug is released at a rate primarily
controlled by the rate of diffusion.

4
5
6

dissolution and diffusion (‘475 and ‘280 patents)

Lupin proposes the following construction:
Dissolution of the drug by the gastric fluid, followed by diffusion of the drug
out of the monolithic matrix.

7
The dispute between the parties involves whether the construction must specify the
8
primary release mechanism, whether it is necessary or appropriate to specify “rapid”
9
dissolution and “slow” diffusion, and whether the patent discloses a “monolithic matrix.”
The patent specification states that controlled release of water-soluble drugs can be
11
For the Northern District of California

United States District Court

10
achieved using a polymeric matrix that swells to create a diffusion barrier so that water12
soluble drugs are released primarily by diffusion: “[D]rugs that are highly soluble in water
13
can be administered orally in a manner that will prolong their delivery time to spread their
14
release rate more evenly throughout the duration of the fed mode and beyond or not as
15
desired.” ‘475 Patent, Col. 5:31-36.
16
Depomed argues that a person of ordinary skill in the art would understand that
17
release mechanisms for dosage forms are characterized by their dominant release
18
mechanism, because all dosage forms have multiple mechanisms occurring at the same
19
time. Here, Depomed asserts, a person of ordinary skill would understand “dissolution and
20
diffusion” in the context of water soluble drugs, as recited in Claim 1 and the specification,
21
to mean that the primary release mechanism of the dosage form was “diffusion.”
22
Lupin argues that Depomed’s proposed construction is improper, because if the
23
dominant mechanism is “primarily diffusion,” it would permit erosion of the dosage form.
24
However, it is not true that the patent does not contemplate the possibility of some erosion.
25
The specification refers to a formulation that “has an erosion rate that is substantially
26
slower than its swelling rate, and that releases the drug primarily by diffusion.” Id., Col.
27
28
13

1
2

5:57-62.4
Lupin also contends that there is no support for a construction specifying that the

3

release of the drug is “rapid” and that the dissolution is “slow;” and that because the term

4

“rapid” is not defined in the patent, its meaning is unknown. Lupin claims that a person of

5

skill in the art would know that the specific dissolution rate is a kinetic property of a drug,

6

which can be manipulated by different factors, including temperature, pH, volume, and

7

salinity.

achieved by using a formulation in which the drug is dispersed in a polymeric matrix that is

10

water-swellable rather than merely hydrophilic, that has an erosion rate that is substantially

11
For the Northern District of California

The specification explains that each of the enumerated beneficial effects “is

9

United States District Court

8

slower than its swelling rate, and that releases the drug primarily by diffusion.” Id., Col.

12

5:57-62. In other words, while there may be some erosion, the rate of erosion is

13

substantially slower than the rate of swelling.

14

Further, “[t]he rate limiting factor in the release of the drug is therefore controlled

15

diffusion of the drug from the matrix rather than erosion, dissolving, or chemical

16

decomposition of the matrix.” Id., Col. 6:14-17 (emphasis added). Thus, the primary

17

release mechanism of the dosage form is “diffusion.” See also id., Col. 6:6-14 (the drug is

18

released “by the process of solution diffusion, i.e., dissolution of the drug in the penetrating

19

fluid and diffusion of the dissolved drug back out of the matrix,” while “[t]he matrix itself is

20

solid prior to administration, and . . . remains undissolved in (i.e., is not eroded by) the

21

gastric fluid for a period of time sufficient to permit the majority of the drug to be released

22

by the solution diffusion process”).

23

As for Lupin’s inclusion of the term “monolithic matrix” in its proposed construction,

24

Depomed asserts that this term appears nowhere in the language of the ‘475 or the ‘280

25

patents, but only in the ‘962 patent, and that Lupin appears to be improperly attempting to

26
27
28

4

At the hearing, counsel for Lupin indicated that Lupin was not disputing that the
release is controlled by diffusion, and further agreed that deleting the word “primarily” from
Depomed’s proposed construction would resolve the objection that Depomed’s construction
would improperly allow for the drug to be released by erosion (rather than diffusion).
14

1

read a limitation from the ‘962 patent into the ‘475 and ‘280 limitation on “diffusion and

2

dissolution.”

3

Lupin disagrees with this assessment, arguing that the polymer formulation

4

disclosed in the ‘475 patent specification is a monolithic matrix, which it defines as a solid,

5

single unit tablet.

6

Claim 1 of the ‘475 patent claims “[a] controlled-release oral drug dosage form . . . ,

7

said dosage form comprising a solid polymeric matrix . . . . “ Claim 1 of the ‘280 patent

8

claims “[a] controlled-release drug dosage form . . . , said dosage form comprising one or

9

more polymers forming a solid polymeric matrix . . . .” Neither patent claims a dosage form
comprising a “monolithic matrix.” Nor does the specification provide any support for

11
For the Northern District of California

United States District Court

10

including “monolithic matrix” as part of the construction of “dissolution and diffusion.”

12

“Dissolution and diffusion” means “rapid dissolution of the drug, followed by

13

slow diffusion of the drug out of the matrix, such that the drug is released at a rate

14

controlled by the rate of diffusion.”

15
16

(5)

releases substantially all of said drug within about eight hours after

such immersion (‘475 patent)

17

Depomed proposes the following construction of this term:

18

At least 80% of the drug has been released after eight hours of immersion in
gastric fluid.

19
Lupin argues that the term “substantially” is ambiguous and does not describe the claimed
20
subject matter in such a way that one in the field of the invention would understand the
21
scope of the invention. However, Lupin also proffers the following construction in the event
22
that the court finds the term capable of construction:
23
24

At least 80% of the drug is released from the polymer matrix by solution
diffusion within about 8 hours.

25

The parties agree that “substantially all” means “at least 80 per cent.” As indicated

26

at the hearing, since the parties agree to the meaning of “substantially all,” there is no

27

dispute. The addition of “solution diffusion” is improper, because the issue of dissolution

28

and diffusion is addressed in the distinct claim term “dissolution and diffusion,” and
15

1

because “solution diffusion” appears to constitute an attempt to read an additional limitation

2

into the claim. The court adopts Depomed’s proposed construction.

3
4

“Substantially all of said drug” means “[a]t least 80% of the drug has been
released after eight hours of immersion in gastric fluid.”

5

(6)

(until) substantially all of said drug is released (‘280 patent)

6

Depomed proposes the following construction for this term:

7

At least 80% of the drug has been released after eight hours of immersion in
gastric fluid.

8
As above, Lupin argues that the term “substantially” is insolubly ambiguous, and
9
therefore indefinite, and does not describe the claimed subject matter in such a way that
one in the field of the invention would understand the scope of the invention. However,
11
For the Northern District of California

United States District Court

10
Lupin also proffers the following construction in the event that the court finds the term
12
capable of construction:
13
14

At least 80% of the drug is released from the polymer matrix by solution
diffusion within about 8 hours.

15

The parties’ arguments with regard to this term are the same as for term (5),

16
17
18

discussed above, and the court’s ruling is the same.
“(Until) substantially all of said drug is released” means “[a]t least 80% of the
drug has been released after eight hours of immersion in gastric fluid.”

19

(7)

20

Depomed proposes the following construction of this term:

21

Until the plateau of the dissolution profile characterizing drug release from the
swollen dosage form is reached.

until all of said drug is released (’475 patent)

22
Lupin proposes the following construction, which it asserts is based on the plain and
23
ordinary meaning:
24
25

Until 100% of the drug is dissolved and released from the polymer matrix by
solution diffusion.

26

As explained by the parties, the dispute regarding the construction of this term

27

involves whether “all of said drug” must be construed so as to distinguish it from

28

“substantially all of said drug” (terms (5) and (6), above); and whether “all of said drug”
16

1
2

means 100%, or something less than 100%.
The court agrees that “until all of said drug is released” as used in Claim 1 of the

3

‘475 patent must be construed in such a way that distinguishes it from “until substantially all

4

of said drug is released,” as used in Claim 1 of the ‘475 patent (and in Claim 1 of the ‘280

5

patent), which the court has found means simply that “at least 80% of the drug is released

6

after eight hours of immersion in gastric fluid. The question, however, is whether the

7

appropriate construction of “all of said drug is released” is “100% of said drug is released.”

8

The ‘475 patent describes the invention as a “dosage form” that swells upon

9

imbibition of water to provide gastric retention and allowing the extended release of the
drug within the gastric cavity over a prolonged dosing period. ‘475 Patent, at Abstract; see

11
For the Northern District of California

United States District Court

10

also id., Col. 5:57-6:17. In addition, the invention provides enhanced absorption of soluble

12

drugs that are absorbed mostly within the stomach or high in the GI tract, such as

13

metformin hydrochloride. Id., Col. 6:38-41.

14

The patent shows, as preferred embodiments, release profiles for metformin dosage

15

forms in Figs. 1, 4, 5, 7 and 9. Id., Figs. 1, 4, 5, 7, 9. These release profiles show a

16

release plateau for metformin from the dosage forms of the invention that typically does not

17

reach 100%. Id.; see also Declaration of Harold B. Hopfenberg, Ph.D., at ¶ 74-77. Thus,

18

Depomed asserts, the specification of the ‘475 patent teaches that the dosage form

19

remains intact until the drug release from the dosage form reaches the plateau of its

20

release profile.

21

Depomed contends that the intrinsic evidence supporting its proposed construction

22

is buttressed by extrinsic evidence contained in the FDA Guidance documents attached to

23

the Declaration of Depomed’s counsel William G. Gaede. The FDA recommends a

24

minimum of three time points for a dissolution study: “early, middle and late,” the last of

25

which “should be the time point where at least 80% of drug has dissolved,” or, “[i]f the

26

maximum amount dissolved is less than 80%, the last time point should be the time when

27

the plateau of the dissolution profile has been reached.” Gaede Decl., Exh. 3 at 17. The

28

FDA guidance entitled SUPAC-MR: Modified Release Solid Oral Dosage Forms
17

1

(September 1997) states the end point of a dissolution assay as “either 80% of the drug

2

from the drug product is released or an asymptote is reached.” Gaede Decl., Ex. 4.

3

Depomed contends that according to these guidelines, a person of ordinary skill in

4

the art would conclude that all drug has been released when the plateau of the release

5

curve is reached, even if the plateau corresponds to a release of less than 80% of the drug

6

loading, within the context of the dosing or bioequivalence schedule being conducted. See

7

Hopfenberg Decl., ¶¶ 77-80.

8
9

Depomed asserts that Lupin’s proposed construction would exclude from the claim
the metformin dosage forms disclosed in the ‘475 Patent that do not reach 100% drug
release, and thus would improperly read out the disclosed embodiments. “A claim

11
For the Northern District of California

United States District Court

10

construction that excludes a preferred embodiment ‘is rarely, if ever, correct and would

12

require highly persuasive evidentiary support.’” Adams Respiratory Therapeutics, Inc. v.

13

Perrigo Co., 616 F.3d 1283, 1290 (Fed. Cir. 2010) (quoting Vitronics, 90 F.3d at 1583).

14

Depomed contends that Lupin’s construction would also ignore the understanding of a

15

person of skill in the art as reflected in the FDA Guidance documents.

16

Lupin, on the other hand, argues that the specification supports a construction of

17

“all” as meaning “100%.” Lupin notes that the specification teaches that “because these

18

polymers dissolve very slowly in gastric fluid, the matrix maintains its physical integrity over

19

at least a substantial period of time, in many cases 90% and preferably over 100% of the

20

dosing period,” ‘475 Patent, Col. 9:13-21; and that “[i]n all cases, . . . the drug will be

21

substantially all released from the matrix within about ten hours, and preferably within about

22

eight hours, after ingestion, and the polymeric matrix will remain substantially intact until all

23

of the drug is released, id., Col. 9:32-36

24

However, Lupin does not dispute that its proposed construction would exclude the

25

specification’s metformin examples and the dissolution profiles depicted in Figures 1, 4, 5,

26

7 and 9 that show a release plateau of less than 100%.

27

Based on the patent specification, the court finds that “all of said drug is released”

28

means “100% or something less than 100% of said drug is released.” In most situations,
18

1

an analysis of the intrinsic evidence alone will resolve any ambiguity in a disputed claim

2

term. In such circumstances, it is improper to rely on extrinsic evidence. Vitronics, 90 Fed.

3

3d at 1583 (and cases cited therein). Here, however, the court finds that the testimony of

4

Depomed’s expert Dr. Hopfenberg, and the relevant evidence from the FDA guidance

5

documents, supports a construction of 100% or something less than 100%.

6
7

“Until all of said drug is released” means “until the plateau of the dissolution
profile characterizing drug release from the swollen dosage form is reached.”

8

(8)

9

Depomed proposes the following construction for this term:

11
For the Northern District of California

United States District Court

10

12

solid monolithic matrix (‘962 patent)

A single entire matrix.5
Lupin proposes the following construction:
A polymeric matrix that is compressed as a single-unit tablet, and not as two
or more layers

13
Lupin objects to Depomed’s proposed construction for several reasons. The dispute
14
between the parties centers on whether the “monolithic matrix” is a tablet; whether coatings
15
are allowed under the claim; and whether the “monolithic matrix” must be compressed.
16
Claim 1 of the ‘962 patent recites “[a] controlled-release oral drug dosage form . . .
17
consisting essentially of a solid monolithic matrix with said drug contained therein.”
18
“Consisting essentially of” is a transition phrase commonly used to signal a partially open
19
claim in a patent. Typically, this transition phrase precedes a list of ingredients in a
20
composition claim or a series of steps in a process claim.
21
22
23

By using the term “consisting essentially of,” the drafter signals that the
invention necessarily includes the listed ingredients and is open to unlisted
ingredients that do not materially affect the basic and novel properties of the
invention. A “consisting essentially of” claim occupies a middle ground
between closed claims that are written in a “consisting of” format and fully

24
25
26
27
28

5

Depomed originally proposed the following construction: “A single entire matrix, not
just the upper or lower half of it.” At the hearing, however, counsel for Depomed agreed with
the court that the addition of “not just the upper or lower half of it” was unnecessary. Counsel
stated that he would be “happy with ‘the entire matrix,’” so long as the “dosage form” which
“consist[s] essentially of a solid monolithic matrix,” is not interpreted as “comprising” a solid
monolithic matrix, or “a single tablet.”
19

1
2
3

open claims that are drafted in a “comprising” format.
PPG Industries v. Guardian Industries Corp., 156 F.3d 1351, 1254 (Fed. Cir. 1998).
The specification explains that “[t]he dosage form is a swellable body, preferably a

4

polymeric matrix in which a drug is dispersed.” ‘962 Patent, Col. 3:52-53. The specification

5

refers generally to “dosage forms” as “tablets,” although it also states that “some other

6

forms are contemplated as well.” Id., Col. 4:6-11.

7

In certain embodiments of the invention, “the dosage form is a multilayered tablet in

Alternatively, the dosage form may be “a tablet with a core surrounded by a shell, and the

10

core swells while the shell remains relatively dimensionally stable, or vice versa.” Id., Col.

11
For the Northern District of California

which one or more of the layers swells while the others do not.” Id., Col. 3:62-64.

9

United States District Court

8

3:64-67.

12

Thus, while the dosage form is referred to in the patent as a tablet, see, e.g., id., Col.

13

3:22-41, the tablet/dosage form claimed in Claim 1 “consist[s] essentially of a solid

14

monolithic matrix” in which the drug is contained. To construe “solid monolithic matrix” as

15

“a tablet,” or to construe said “tablet” as “not hav[ing] two or more layers,” as in Lupin’s

16

proposed construction, is to confuse the “oral dosage form” element of Claim 1 with the

17

“solid monolithic matrix” element, which is the element being construed. Moreover, as

18

noted above, in certain embodiments of the invention, “the dosage form is a multilayered

19

tablet.”

20

Further, the specification plainly contemplates that coatings are allowed under the

21

claim. “[T]he dosage form may contain an additional amount of the drug in a quickly

22

dissolving coating on the outer surface of the dosage form,” which coating “is referred to as

23

a ‘loading dose,’” the purpose of which is “to provide immediate release into the patient’s

24

bloodstream upon ingestion of the dosage without first requiring the drug to diffuse through

25

the polymeric matrix. . . . A film coating may also be included on the outer surface of the

26

dosage for reasons other than a loading dose.” Id., Col. 8:3-19. Lupin’s proposed

27

construction would exclude these preferred coatings embodiments of the invention that are

28

disclosed in the specification.
20

1

Lupin asserts, however, that the prosecution history of the ‘962 patent shows that

2

Depomed surrendered all coatings on the monolithic matrix, as it disclaimed any

3

construction of a “solid monolithic matrix” that would include anything other than a tablet

4

“cast as a single piece” – i.e., compressed as a single-unit tablet, and not as two or more

5

layers.

6

Specifically, Lupin argues that Depomed distinguished its invention from U.S. Patent

a secondary matrix. According to Lupin, Depomed argued that its claimed tablet was –

9

unlike the tablet taught by Wong – “necessarily comprised of a single monolithic matrix;”

10

and also emphasized that Wong incorporated a “rigid, constraining secondary matrix into

11
For the Northern District of California

No, 6,120,803 (Wong, et al.), which disclosed a dosage form that was partially coated with

8

United States District Court

7

the structure of the tablet,” whereas Depomed’s claimed invention “rel[ied] solely on the

12

unrestricted swelling of a monolithic polymer matrix to maintain the tablet in the stomach for

13

prolonged periods of time.” Lupin asserts that the fact that Depomed disclosed coatings in

14

the specification, but argued during the prosecution of the ‘962 patent that Wong was

15

distinguishable because it was coated with a “secondary matrix,” means that coatings are

16

dedicated to the public.

17

Lupin argues further that because the patent teaches “multilayered tablets,” ‘962

18

Patent, Col. 3:63, and because Depomed chose to draft its claims to a “solid monolithic

19

matrix” instead, the public can infer that Depomed knew about multilayered tablets at the

20

time it drafted its claims, but did not intend to claim multilayered tablets, and that those

21

forms were also dedicated to the public.

22

Lupin also contends that Depomed specified during prosecution what “monolithic”

23

means by citing a dictionary definition in which “monolithic” is defined as “cast in a single

24

piece,” adding that in the context of the applicants’ “this means the entire matrix, not just

25

the upper or lower half of it,” and that “Wong does not teach or suggest a monolithic matrix

26

that swells in an unrestricted manner along both orthogonal axes.”

27
28

It is true that claim amendments made during prosecution can narrow the meaning
of a claim term if there is a clear and unequivocal surrender of subject matter. Phillips, 415
21

1

F.3d at 1317; see also Omega Eng’g, Inc. v. Raytek Corp., 334 F.3d 1314, 1324 (Fed. Cir.

2

2003). Here, however, the prosecution history does not include a clear and unequivocal

3

surrender of coatings that may be around the matrix, as the prosecution history addresses

4

only the matrix itself.

on the inability of the Wong matrix to swell in an unrestricted manner along both orthogonal

7

axes of the dosage form. See April 25, 2002 Correction and Request for Reconsideration.

8

The Wong unswollen and swollen dosage form was depicted in the Wong patent prior art.

9

The figures in the Wong Patent show a pill form with a band around the center. Because of

10

the banding, the matrix in Wong was unable to swell in a dimensionally unrestricted fashion

11
For the Northern District of California

During prosecution, Depomed distinguished the claimed invention from Wong based

6

United States District Court

5

as claimed in the dosage form of the ‘962 Patent, which was the basis upon which

12

Depomed overcame the Wong reference during prosecution, as it represented that its

13

invention swelled in all dimensions.

14

Disclaimers require a clear and unmistakable disavowal of subject matter to which

15

the patentee would otherwise have an exclusive right by virtue of the claim language.

16

Vita-Mix Corp. v. Basic Holding, Inc., 581 F.3d 1317, 1324 (Fed. Cir. 2009). In this case,

17

Depomed disclaimed only the use of bands that restricted the swelling of the monolithic

18

matrix in one section. There is no evidence that Depomed totally disclaimed the use of

19

coatings during prosecution.

20

Finally, the patent does not require that the monolithic matrix be “compressed.” The

21

specification broadly teaches that “[t]ablets in accordance with this invention can be

22

prepared by conventional techniques, including common tabletting methods.” The

23

specification provides examples of such methods, which include “[d]irect compression,”

24

“[i]njection or compression molding,” “[g]ranulation . . . followed by compression,” and

25

“[e]xtrusion of a paste into a mold or to an extrudate to be cut into lengths.” 962 Patent,

26

Col. 6:39-67. The inclusion of the last example demonstrates that the inventor

27

contemplated manufacture of the monolithic matrix by means other than compression.

28

Accordingly, “solid monolithic matrix” means “single entire matrix.”
22

1

(9)

an oval (‘962 patent)

2

The parties proposed competing constructions in the joint claim construction

3

statement. In its responsive claim construction brief, however, Lupin asserts that both

4

proposed constructions are legally equivalent, and states that it no longer opposes

5

Depomed’s proposed construction.

6
7

In view of the fact that the construction is no longer disputed, the court adopts
Depomed’s proposed construction.

8
9

wherein the geometric form bounded by the closed curve has first and second
orthogonal axes of unequal length.”
remains substantially intact (‘475 patent)

11
For the Northern District of California

United States District Court

10

“An oval” means “[a]ny curve that is closed and concave towards the center

(10)

12

This term was listed in the claims construction statement as having the following

13

agreed construction:
A polymeric matrix in which the polymer portion substantially retains its size
and shape without deterioration due to becoming solubilized in the gastric
fluid or due to breakage into fragments or small particles.

14
15
16

In its responsive claim construction brief, Lupin argues that the term is “insolubly

17

ambiguous” and therefore indefinite because “substantially” is too imprecise. Lupin also

18

assert, however, that if the court is inclined to construe the term, the court should use the

19

agreed-upon construction, above, which appears in the claims construction statement.
The court agrees. The court finds that “remains substantially intact” has the

20
21

meaning agreed by the parties in the joint claim construction statement: “A polymeric

22

matrix in which the polymer portion substantially retains its size and shape without

23

deterioration due to becoming solubilized in the gastric fluid or due to breakage into

24

fragments or small particles.”

25

D.

26

Depomed’s Motion to Strike
Depomed seeks an order striking Lupin’s newly-proposed claim construction for

27

terms (1) and (2). Depomed argues that Lupin’s proposed construction differs from that in

28

the claim construction statement in that it omits the phrase “at least 20%” and adds “solid”
23

1

to the phrase “swollen polymeric matrix.” Depomed also seeks an order striking what it

2

claims is newly-offered evidence to support Lupin’s proposed constructions.

3

As the court indicated at the hearing, neither side’s position in this dispute is

4

particularly meritorious. Lupin’s problem is that the Local Rules are clear that the joint

5

claim construction statement is a final binding document. Depomed’s problem is that it

6

appears to view this motion as providing an opportunity to go through every line of Lupin’s

7

opposition brief – in other words, to permit another bite at framing the arguments in reply to

8

Lupin’s opposition. The court has considered the motion, to the extent discussed at the

9

hearing, and has determined that it should be DENIED.

11
For the Northern District of California

United States District Court

10
IT IS SO ORDERED.

12

Dated: May 17, 2011
______________________________
PHYLLIS J. HAMILTON
United States District Judge

13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
24