By Kevin E. Noonan —

Although Amgen's erythropoietin franchise has
weathered its most recent challenge by F. Hoffmann-La Roche's pegylated EPO analog,
Mircera® (see Amgen Inc. v. F. Hoffman-La Roche Ltd. (Fed. Cir. 2009)), the victory was not
absolute.  The status of three of
the patents-in-suit — U.S. Patent Nos. 5,547,933
(the '933 patent), 5,955,422
(the '422 patent, claim 1) and 5,756,349
(the '349 patent, claim 7) — were put in jeopardy by the Federal Circuit's
reversal of summary judgment and remand to the District Court on the question
of whether these patents are invalid for obviousness-type double
patenting.  If the District Court
were to make a determination that they are invalid, Amgen's EPO patent estate
will expire almost two years earlier than expected, with loss of at least a
portion of the company's significant revenues from its flagship product.  The likelihood of this outcome will
depend on the parties' reaction to the latest installment of Federal Circuit
jurisprudence on obviousness-type double patenting following its decision last
year in Pfizer, Inc. v. Teva Pharmaceuticals USA,
Inc.

The ultimate parent application, which matured into
U.S. Patent No. 4,703,008, was subject to a restriction requirement identifying
the following groups of claims:

I.  Claims
1–13, 16, 39–41, 47–54, and 59, drawn to polypeptide, classified in Class 260, subclass
112.
II.  Claims
14, 15, 17–36, 58, and 61–72, drawn to DNA, classified in Class 536, subclass
27.
III.  Claims
37–38, drawn to plasmid, classified in Class 435, subclass 317.
IV.  Claims
42–46, drawn to cells, classified in Class 435, subclass 240.
V.  Claims
55–57, drawn to pharmaceutical composition, classified in Class 435, subclass
177.
VI.  Claim
60, drawn to assay, classified in Class 435, subclass 6.

Pursuant to the restriction requirement, each of
these claim groupings defined an independently-patentable invention, and as
such would entitle Amgen to a separate patent unfettered by obviousness-type
double patenting.  It is
undisputed that Amgen prosecuted the claims of Group II in the '008
patent.  Thereafter, Amgen filed
two applications claiming priority to the '008 patent, the '178
application and the '179 application; these applications are
related to the patents-in-suit according to the following schematic diagram:

The Court characterized "in broad strokes"
the claims of the three patents under consideration:

[T]he '933 patent claims recombinant EPO, a
pharmaceutical composition comprising recombinant EPO, and methods of treating
kidney dialysis patients by administering pharmaceutical compositions
comprising recombinant EPO . . . .  The '422 patent claims a pharmaceutical
composition comprising recombinant EPO . . . .  The '349 patent claims the process
of producing recombinant EPO in vertebrate cells capable of producing EPO at a
specific rate.

At first blush, the claims of the '933 patent would appear
to correspond to Groups I and V from the '008 restriction requirement, and the
claims of the '422 patent correspond to Group V.  Two other patents-in-suit — U.S. Patent Nos. 5,441,868 (the '868 patent) and 5,618,698
(the '698 patent) — recite claims for methods of making EPO.

Roche's position, unpersuasive at the District Court, was that the claims of the '933, '422, and '394 patents were invalid for
obviousness-type double patenting over the claims of the '868 and '698 patents,
and in turn the claims of the '868 and '698 patents were invalid for
obviousness-type double patenting over the claims of the '008 patent.  This question depends on the meaning of
35 U.S.C. § 121, which sets forth a "safe harbor" provision protecting
claims subject to a restriction requirement (and thus determined by the Patent
Office to define separately-patentable inventions) from a determination of
obviousness-type double patenting:

A patent
issuing on an application with respect to which a requirement for restriction
under this section has been made, or on an application filed as a result of
such a requirement, shall not be used as a reference either in the Patent and
Trademark Office or in the courts against a divisional application or against
the original application or any patent issued on either of them, if the
divisional application is filed before the issuance of the patent on the other
application.

35 U.S.C.
§ 121, third sentence; see also Applied Materials, Inc. v. Advanced
Semiconductor Materials Am., Inc., 98 F.3d 1563 (Fed. Cir. 1996),
cited in the Court's opinion.  The District Court held that the '933, '422, and '349 patents were immunized from
obviousness-type double patenting, since they had issued from applications in
the chain back to the '178 and '179 applications, which were filed pursuant to
a Patent Office-imposed restriction requirement.  However, these applications when filed were not designated
as "divisional applications," the language of the statute, but rather
as "continuation applications," and Roche argued that this difference
precluded the '933, '422, and '349 patents from the § 121 safe harbor.

The Federal Circuit agreed, to the extent that
summary judgment and JMOL granted by the District Court was improper.  In its opinion, by Judge Schall and
joined by Judges Mayer and Clevenger, the CAFC granted no deference to the District Court's decision, first applying its own standard of review regarding
summary judgment, next using the 1st Circuit's standard of review
for JMOL, and last for the substantive question of obviousness-type double
patenting, which it interpreted as being analogous to claim construction, as a "matter
of what is claimed" and thus subject to the Federal Circuit's de novo review
precedent.  Using these standards,
the Federal Circuit held that the '933, '422, and '349 patents were not entitled to the
§ 121 safe harbor because the '178 and '179 applications were filed as
continuation applications and not divisional applications.  In interpreting the statute so
literally, the CAFC noted that, unlike the claims in the Pfizer case that arose from a continuation-in-part application,
each of the '933, '422, and '349 patents may have satisfied the substantive
requirements for divisional application status — being limited to the subject
matter disclosed in the prior parent application, reciting claims determined to
define a patentably-distinct invention, and being filed during the pendency of
the earlier-filed parent application.  Nonetheless, the Court held that "[t]his
distinction . . . does not justify departing from a strict application of the
plain language of §121, which affords its [safe harbor] benefits to 'divisional
applications.'"  In making
this decision, the CAFC distinguished both its Applied Materials and Symbol
Technologies, Inc. v. Opticon, Inc., 935 F.2d 1569 (Fed.
Cir. 1991) precedent, because in those cases the "continuation"
application was filed ultimately from a properly-designated divisional
application.

The CAFC reached a different conclusion with regard
to the '868 and '698 patents, because the parties litigated the
obviousness-type double patenting question on the merits before the District Court.  As characterized in the
Federal Circuit's opinion, the claims of the '008 patent recite a recombinant
cell that expresses human EPO, and the claims of the '868 and '698 patents
recite methods of producing recombinant EPO using such cells, either in vitro or in vivo.  The District Court distinguished the method claims of the '868 and '698 patents and the recombinant
cell (product or composition) claims of the '008 patent because:

none of the '008 claims require:  (1) that the
recited host cell actually express any EPO polypeptide; (2) that the recited
host cell actually express a glycosylated EPO polypeptide; (3) that the host
cell be capable of producing an isolatable amount of a glycosylated EPO
polypeptide; and (4) that any glycosylated EPO isolated from cells grown in
culture have the stated in vivo function.

The District Court relied on expert testimony for
the proposition that, even if in possession of the recombinant cell disclosed
in the '008 patent, at the priority date claims to methods for making EPO were
novel, useful, and non-obvious.  (The lower court also noted that the Patent Office had found these claims to
be patentably-distinct.)  The
Federal Circuit agreed with this distinction, that while the recombinant cells
claimed in the '008 patent might be "capable of producing"
recombinant EPO having in vivo biological function, the claim did not recite a
limitation that such cells actually produce functional EPO.  This requirement is affirmatively found
in the '868 and '698 patent claims, rendering them patentably distinct.

In making this determination, the Federal Circuit invoked a
number of recent, post-KSR decisions
on obviousness under 35 U.S.C. § 103, the standard used without using the '008
patent as prior art, including In re
Kubin, In re O'Farrell (where the
application, not the case, is recent), and Pharmastem
Therapeutics, Inc. v. Viacell Inc.  The CAFC opined that the skilled artisan would not have reasonably expected to
produce recombinant, glycosylated EPO having the properties — biological
activity, post-translational modifications and amount — required by the claims
of the '868 and '698 patents at the time of the invention.  In making this determination, the Federal Circuit
rejected Roche's argument that the capacity for making recombinant EPO was
inherent in the claimed cells (and did not address the issue of whether the
claims of the expired '008 patent would have satisfied the utility or
enablement requirements if the claimed cells did not inherently produce
functional recombinant EPO).  The CAFC applied the Supreme Court's KSR warning against hindsight in refusing to consider the actuality
that the cells claimed in the '008 patent produced biologically-active EPO in
determining whether the skilled worker would have had an expectation that they
would do so.

Finally, the Federal Circuit clarified the application of the
principles it enunciated in Takeda
Pharmaceutical Co. v.  Doll
regarding the availability of later-disclosed (or discovered) methods to
overcome obviousness-type double patenting invalidation of a process claim over
an earlier-issued product claim.  In Takeda,
the Federal Circuit held that art used by a patentee to support patentable
distinctiveness of process claims filed after grant of product claims was
limited to art-recognized processes known at the time the later (or "secondary"
in the Takeda court's parlance)
patent application was filed.  Roche argued that Amgen should not be permitted to introduce evidence
relating to processes for producing recombinant EPO after the 1984 filing date
of the '008 patent where Roche was precluded from asserting art available after
the 1984 priority date.

Here, the Federal Circuit held that Roche's
arguments "collide" with 35 U.S.C. § 120, wherein Amgen's later-filed
applications are entitled to the benefit of priority to the '008 patent.  The CAFC found that interpreting its Takeda precedent as Roche advocated
would "violate the plain language" of § 120, which entitles all of
Amgen's patents-in-suit to the priority benefit of the '008 patent and
accordingly prevents any of Amgen's patents-in-suit from being invalidated
based on art available after the November 30, 1984 priority date of the '008
patent.  The Court's opinion
acknowledged (and asserted that the Takeda court recognized) that this rule "could
'provide the patentee with the best of both worlds:  the applicant can use the
filing date as a shield, enjoying the earlier priority date in order to avoid
prior art, and rely on later-developed alternative processes as a sword
to defeat double patenting challenges.'"  Nonetheless, the Federal Circuit characterized this seeming
one-sidedness as being limited and hence not inequitable.  However, the CAFC noted that the
'349 patent could not benefit from the application of the principles in the
Takeda opinion, since it (unlike the '933 and '422 patents) recited claims to
methods and not products.  Thus:

Takeda will permit Amgen, if it
wishes to do so, to rely on alternative processes for making the products
claimed in the '933 and '422 patents up to their filing dates to prove that the
claims of those patents and the claims of the '868 and '698 patents are
patentably distinct.  If Amgen pursues
that course, Roche will be free to rely on subsequent developments in the art
up to the filing dates of the '933 and '422 patents to prove that any
alternative processes put forth by Amgen do not render the claims of the '933
and '422 patents and the claims of the '868 and '698 patents patentably
distinct.

Unless the parties settle, on remand it can be
expected that the District Court will be compelled to find the asserted claims
of the '933, '422, and '349 patents invalid for obviousness-type double patenting,
unless Amgen can establish patentable distinctiveness on the merits (i.e., outside the § 121 safe
harbor).  Until such time
(including any further appeals to the Federal Circuit or the Supreme Court),
the significant holding in this decision is that whether a claim is entitled to
the § 121 safe harbor depends, in the first instance, on whether the application
reciting that claim is designated as a "divisional" and not a "continuation"
application.  (Such claims must
also satisfy the requirements for divisional applications.)  The Federal Circuit's opinion is
stringent, harsh, and unyielding, and provides another "trap for the unwary"
for which patent law is infamous.  It also raises the specter of malpractice liability in designating
follow-on applications accurately, a practice tip that the
patent bar ignores at its peril.