By Kevin Noonan —

The peripatetic case of Amgen Inc. v. Hoechst Marion Roussel, Inc. has once again been
reviewed by the Federal Circuit (decided August 3,
2006).  Once again the CAFC
has failed to lay the several issues in the case to rest.  While affirming infringement and validity of
two of the patents in suit, the Federal Circuit has remanded the matter once again to the District Court in view of its de novo claim construction, and perhaps
predictably disagreed with the lower court and reversed a determination of
infringement under the doctrine of equivalents.

The case has two interesting aspects.  First, citing the rubrics of Phillips the Federal Circuit came to its own determination of the meaning of the term
"therapeutically effective amount" with regard to a claim for recombinant
erythropoietin (EPO).  EPO is a
naturally-occurring hormone that stimulates the body to produce red blood
cells, and its absence (or insufficiency) causes anemia.  The standard clinical measure of anemia is
the hematocrit, or the percent of whole blood comprised of red blood cells.  In
construing the term "therapeutically-effective amount," the District Court had required that EPO falling within the scope of the claim containing
the term increase hematocrit and have any other biological properties of
naturally-occurring EPO.

The Federal Circuit disagreed, and in doing so provided a
nice illustration that Phillips has not changed the Court’s capacity for
arriving at its own idiosyncratic construction.  The CAFC determined that the lower court had improperly focused on
hematocrit, which is one of EPO’s biological properties recited in the
specification, to the exclusion of several others, including increasing
stimulation of reticulocyte response, development of ferrokinetic effects,
erythrocyte mass changes, and stimulation of hemoglobin.  The Federal Circuit noted in particular that the
specification recited that the therapeutic properties of recombinant EPO
"included" all of these, and that the specification further stated
that recombinant EPO was therapeutically useful even if it lacked some but not
all of these properties.

Of course, the CAFC seems to have not considered the
fact that all of the recited properties are related to the clinical measurement
of hematocrit, since they are all part of the biological developmental pathway
leading to an increase in the number of red blood cells in blood.  Thus, by cherry-picking the language of the
specification, the Court was able to arrive at a facially-reasonable claim
construction that seems to run contra to clinical reality.  This portion of the matter has been remanded,
for further consideration in view of the CAFC’s claim construction, on the
issue of invalidity over prior art references to EPO preparations that did not
increase hematocrit but may have had one of the other recited biological
properties.

The second issue is the doctrine of equivalents.  The "predicted" recombinant EPO
protein contains 166 amino acids, but as produced naturally (and using HMR’s
recombinant process) EPO has only 165 amino acids.  The issue before the Federal Circuit was whether Amgen
was entitled to assert claims to HMR’s recombinant EPO as an equivalent.  The District Court twice found in the
affirmative, and the Federal Circuit remanded in its first review so the lower
court could consider the issue in view of Festo Corp. v. Shoketsu Kinzoku Kogyo
Kabushiki Co., 535 U.S. 722, 740-41 (2002).  The District Court
having arrived at the same conclusion, infringement under the doctrine of
equivalents, the Federal Circuit reversed, finding estoppel arising during
prosecution.  Specifically, the CAFC
held that preliminary amendments
resulting in claim language reciting the 166 amino acid species were not made
for reasons tangentially related to the asserted equivalent, as found below,
but raised prosecution history estoppel that precluded asserting the claim
against HMR’s 165-amino acid species.  The Federal Circuit’s holding was based in part on Amgen’s cancellation of claim
limitations related to "fragments" of the 166-amino acid species, and
in part because it found erroneous the District Court’s determination that the
amendments were made to limit the species to human EPO (the CAFC noted that if
Amgen had intended to so limit the claims the mere addition of the word
"human" would have been sufficient).  Finally, the Federal Circuit rejected the notion that amendments made to avoid a
double-patenting rejection were "tangential to patentability."

For those keeping score, the Federal Circuit in its two decisions
has affirmed the District Court’s judgment that two of Amgen’s patents are not
invalid and are infringed, also affirmed that another Amgen patent is invalid,
reversed a finding of infringement under the doctrine of equivalents (but
affirmed that this patent is also not invalid), and for one patent remanded the
issue of invalidity to the District Court while affirming that if valid this
patent is also infringed.  As noted in
Judge Michel’s dissent (over the claim construction issue), the District Court
is now in position to decide whether to grant an injunction, keeping HMR’s competing
EPO product off the market until at least the expiration of two of Amgen’s
patents.  For the parties, that may be
(or have to be) enough.

Amgen Inc. v. Hoechst Marion Roussel, Inc. (Fed. Cir. 2006)
Panel: Chief Judge Michel, Senior Circuit Judge Clevenger, and Circuit Judge Schall
Opinion by Circuit Judge Schall; dissenting-in-part opinion by Chief Judge Michel

This article was originally published on Patently-O on August 13, 2006.