09.04.19 | IP Alert | Federal Circuit’s Decision in Eli Lilly v. Hospira May Signal Possible Pro-Patentee Swing

Federal Circuit’s Decision in Eli Lilly v. Hospira May

Signal Possible Pro-Patentee Swing

By Sarah A. Kagan, Ph.D.

Two opinions and three judges do not necessarily
make a trend, nonetheless, one could suspect that the prosecution history
estoppel pendulum is beginning to swing in a more liberal direction for
patentees.

Three days after the U.S. Court of Appeals for the
Federal Circuit handed down its decision in Ajinomoto
v. ITC,
(2018-1590, 2018-1629) (August 6, 2019), it released an opinion in Eli Lilly and Co. v. Hospira, Inc.,
(2018-2126, 2018-2127) (August 9, 2019). 
In both cases, the court held that an amendment made by an applicant
during examination bore no more than a tangential relation to the equivalent at
issue. Therefore, the amendment in each case — which excluded the equivalent
from the literal scope of the claim — did not bar the court from applying the
doctrine of equivalents and finding infringement.

Under Festo,[1]
prosecution history estoppel limits infringement under the doctrine of
equivalents when a patent applicant narrows the scope of its claims for a
reason substantially related to patentability. 
A presumption arises that the application has surrendered all
equivalents within the territory between the original and the amended
claim.  A patentee can successfully rebut
the presumption if the rationale for its amendment bore no more than a
tangential relation to the equivalent in question.[2] 

The Eli
Lilly
case arose out of the filings of New Drug Applications (NDA) by
parties Hospira and Dr. Reddy’s Laboratories. 
Eli Lilly sued the two NDA filers, alleging that their filings
constituted acts of infringement of its U.S. Patent 7,772,209 (the ’209 patent)
under 35 U.S.C. § 271 (e)(2).  Eli Lilly’s
patent protects use of the drug Alimta® (pemetrexed disodium) when administered
after administration of folic acid and a methylmalonic acid-lowering agent. The
pre-treatments reduce the severe hematological and immunological side effects
of pemetrexed, an antifolate, taken alone.

During examination of the application which
resulted in the ‘209 patent, Eli Lilly amended generic claim term “antifolate”
to “pemetrexed disodium,” arguing that this amendment overcame a prior art reference
that did not disclose “pemetrexed disodium.” 
The two NDA filers sought approval to market a different salt of
pemetrexed, a ditromethamine salt. 

The Federal Circuit reversed the U.S. District
Court of the Southern District of Indiana’s finding that administration of
pemetrexed ditromethamine literally meets the claim recitation of
administration of pemetrexed disodium. The district court had relied on the
ionization of the ditromethamine salt in sodium chloride solution to yield the
same ionic species as pemetrexed disodium in solution. The appellate court
found that despite ionization in solution, administration of a solution of
pemetrexed ditromethamine does not meet the claim limitation of administration
of pemetrexed disodium.  Therefore, the
court held that the filing of the NDAs did not constitute literal infringement.

Having found no literal infringement, the Federal
Circuit then reviewed the district court’s finding of infringement under the
doctrine of equivalents.  The Federal
Circuit affirmed the district court’s holding that the reason for Eli Lilly’s
amendment of “antifolate” to “pemetrexed disodium” was to distinguish pemetrexed
from antifolates generally, and the recitation of a salt type was merely
tangential to that purpose.  The object of
the amendment was to avoid the cited prior art disclosure of antifolates, the
court stated, and the particular recited salt is only tenuously related to that
object.

The Federal Circuit addressed its prior, seemingly
harsh, statements about application of the tangential exception, such as, that applicant’s
remorse at ceding too much territory does not trigger application of the exception.
While it acknowledged such tough statements as generally true, the existence of
the U.S. Supreme Court-mandated tangential exception requires looking into the
purpose of the amendment in the context of the prosecution history.  The Federal Circuit found analogies to other
cases to be unhelpful.  Rather, it
directly applied the framework from the Supreme Court to the specific record in
this case.  The Federal Circuit also
cited Supreme Court statements that the doctrine of prosecution history
estoppel is an equitable in nature and must be flexibly applied.  The doctrine, according to the Federal
Circuit’s own precedent, is “resistant to rigid legal formulae” and “there is
no hard-and-fast test” for determining a tangential relation. 

The Eli
Lilly
panel included Judges Alan Lourie, Kimberly Moore, and Richard
Taranto.  The Ajinomoto panel included Judges Timothy Dyk, Kimberly Moore, and
Richard Taranto. In Ajinomoto, Judge
Dyk dissented from the portion of the majority opinion pertaining to the tangential
relation exception to the doctrine of equivalents.  Therefore, all told, only three judges out of
the full court’s 18 judges were involved in this possible pro-patentee swing. 

Two opinions by four Federal Circuit judges within three days does not necessarily make a trend.  Nonetheless, we should be alert to the possibility that a warm breeze may be melting some of the ice surrounding prosecution history estoppel.


Click here
to view the Federal Circuit’s decision in Eli
Lilly and Co. v. Hospira, Inc.,
and here
for its opinion in Ajinomoto Co., Inc. v.
International Trade Commission.

To read an August 26 Banner Witcoff alert
analyzing the court’s decision in Ajinomoto
v. ITC
, click here.


[1]
Festo Corp. v. Shoketsu Kinzoku Kogyo
Kabushiki Co.,
344 F.3d 1359, 1366-67 (Fed. Cir. 2003) (en banc).

[2]
Festo Corp. v. Shoketsu Kinzoku Kogyo
Kabushiki Co.
, 535 U.S. 722, 740 (2002).