Pfizer Inc. v. Sanofi Vaccines Us Inc., Sk Bioscience Co., Ltd.

N OTE: This disposition is nonprecedential.
United States Court of Appeals
for the Federal Circuit
______________________
PFIZER INC.,
Appellant
v.
SANOFI VACCINES US INC., SK BIOSCIENCE CO.,
LTD.,
Appellees
______________________
2024-2199, 2024-2201, 2024-2202
______________________
Appeals from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in Nos. IPR2017-
02131, IPR2017-02132, IPR2018-00187.
______________________
Decided: July 31, 2026
______________________
J OHN P AUL SCHEIBELER , White & Case LLP, New York,
NY, argued for appellant. Also represented by D IMITRIOS
T. D RIVAS , AMIT T HAKORE; CATALIN SEBASTIAN Z ONTE, Los
Angeles, CA.
SIEGMUND Y. G UTMAN, Mintz, Levin, Cohn, Ferris,
Glovsky and Popeo, PC, Los Angeles, CA, argued for appel-
lees. Also represented by ERIN J ANELLE SHORT ; P ETER
CUOMO, Boston, MA.
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PFIZER INC. v. SANOFI VACCINES US INC. 2
______________________
Before L OURIE, P ROST , and STARK, Circuit Judges.
L OURIE, Circuit Judge.
This case comes back to us after we previously re-
manded it for the Patent Trial and Appeal Board (“the
Board”) to consider, in its inter partes review (“IPR”) pro-
ceeding, the patentability of proposed substitute claims 48
and 49 of Pfizer Inc.’s (“Pfizer’s”) U.S. Patent 9,492,559
(“the ’559 patent”). On remand, the Board determined in a
final written decision that those proposed substitute claims
would have been obvious over certain prior art publications
and therefore denied Pfizer’s motion to amend its claims.
Sanofi Pasteur Inc. v. Pfizer Inc., Nos. IPR2018-00187,
IPR2017-02131, IPR2017-02132, 2024 WL 2927019
(P.T.A.B. June 10, 2024) (“Decision”), J.A. 71–105.1 For the
following reasons, we affirm.
BACKGROUND
The ’559 patent is directed to compositions for use in
pneumococcal vaccines; specifically, “immunogenic compo-
sitions comprising conjugated Streptococcus pneumoniae
[(“S. pneumoniae”)] capsular saccharide antigens (gly-
coconjugates).” ’559 patent, Abstract. S. pneumoniae (also
known as pneumococcus) is “[t]he etiological agent of pneu-
mococcal disease,” and “is a Gram-positive encapsulated
coccus, surrounded by a polysaccharide capsule.” Id. col. 1
ll. 49–52. The polysaccharide capsule can be made of vari-
1 The Board issued three substantively identical de-
cisions for three IPRs: IPR2017-02131 (J.A. 1–35),
IPR2017-02132 (J.A. 36–70), and IPR2018-00187 (J.A.
71–105). We cite the IPR2018-00187 decision, and filings
relevant to that proceeding, throughout this opinion, but
our determinations are applicable to all three IPRs.
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PFIZER INC. v. SANOFI VACCINES US INC. 3
ous compositions, which results in at least ninety-one dif-
ferent serotypes, or variations, of S. pneumoniae, some of
which can cause diseases such as pneumonia, febrile bac-
terium, and meningitis. Id. col. 1 ll. 27–30, 52–53.
The claims of the ’559 patent recite various serotypes
of S. pneumoniae, with each separate serotype designated
by a numeric or alphanumeric identifier. For example,
claim 1 recites serotype 22F, dependent claim 3 further re-
cites serotypes 15B and 33F, and dependent claim 4 further
recites serotypes 12F, 10A, 11A, and 8. Id. col. 141
ll. 27–33, col. 141 ll. 38–46.
Sanofi Vaccines US Inc.2 and SK Bioscience Co., Ltd.3
(collectively, “Sanofi”) petitioned for IPR, challenging all
claims of the ’559 patent. J.A. 14477–571. The Board in-
stituted IPR proceedings, and Pfizer moved to substitute
proposed claims 46, 48, and 49 for claims 1, 3, and 4. Those
proposed substitute claims recite:
46. An immunogenic composition comprising:
a Streptococcus pneumoniae serotype 22F glycocon-
jugate, wherein the 22F glycoconjugate has a mo-
lecular weight of between 1000 kDa and 12,500
kDa and comprises an isolated capsular polysac-
charide from S. pneumoniae serotype 22F and a
CRM197 carrier protein, and wherein a ratio (w/w)
of the polysaccharide to the carrier protein is be-
tween 0.4 and 2;
2 During the course of litigation, Sanofi changed its
full name from “Sanofi Pasteur Inc.” to “Sanofi Vaccines US
Inc.” See ECF Docket No. 48.
3 During the course of litigation, the appeal and re-
lated interests transferred from SK Chemicals Co., Ltd. to
its subsidiary, SK Bioscience Co., Ltd. See ECF Docket No.
30.
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PFIZER INC. v. SANOFI VACCINES US INC. 4
glycoconjugates from S. pneumoniae serotypes 1, 3,
4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F all
individually conjugated to CRM197;
an aluminum salt adjuvant; and
wherein the composition exhibits more than a 2-log
increase above baseline in serum IgG levels in New
Zealand White Rabbits across all serotypes in the
composition following administration of two equal
doses of the composition in the form of an initial
dose and a booster dose.
48. The immunogenic composition of claim 1 46,
wherein the composition further comprises a S.
pneumoniae serotype 15B glycoconjugate and a S.
pneumoniae serotype 33F glycoconjugate, wherein
said serotypes 15B and 33F are all individually
conjugated to CRM197.
49. The immunogenic composition of claim 3 48,
wherein the composition further comprises a S.
pneumoniae serotype 12F glycoconjugate, a S.
pneumoniae serotype 10A glycoconjugate, a S.
pneumoniae serotype 11A glycoconjugate and a S.
pneumoniae serotype 8 glycoconjugate, wherein
said serotypes 12F, 10A, 11A and 8 are all individ-
ually conjugated to CRM197.
J.A. 11072–73 (proposed additions underlined and pro-
posed deletions struck through). In relevant part, the pro-
posed substitute claims included additional serotypes and
the limitation that “the composition exhibits more than a
2-log increase above baseline in serum IgG levels in New
Zealand White Rabbits across all serotypes in the composi-
tion following administration of two equal doses of the com-
position.” Id. at 11072 (emphasis added). The claimed “2-
log increase” corresponds to a more than 100-fold increase
above baseline serum IgG levels.
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PFIZER INC. v. SANOFI VACCINES US INC. 5
The Board denied Pfizer’s motion to amend, determin-
ing that the proposed claims would have been obvious over
a combination of U.S. Patent Application Publication
2012/0237542 (“Hausdorff”), U.S. Patent Application Pub-
lication 2011/0195086 (“Merck-086”), and PCT Patent Ap-
plication Publication 2007/071711 (“GSK-711”). See J.A.
22286–303.
Pfizer appealed to this court, and we affirmed as to pro-
posed claim 46 and remanded as to proposed claims 48 and
49. Pfizer Inc. v. Sanofi Pasteur Inc., 94 F.4th 1341,
1351–53 (Fed. Cir. 2024). We determined that substantial
evidence supported the Board’s conclusion that proposed
substitute claim 46 would have been obvious, but that the
Board’s decision was “silent as to why proposed substitute
claims 48 and 49 would have been obvious over the refer-
ences,” offering no analysis and only “a conclusory state-
ment” for those claims. Id. Specifically, we concluded that
the Board’s determination as to the 2-log increase for the
serotypes recited in proposed substitute claims 48 and 49
was not supported by substantial evidence, and it therefore
abused its discretion in denying Pfizer’s motion to amend.
Id. at 1353. We therefore remanded “for the Board to fur-
ther consider Pfizer’s motion[].” Id.
On remand, the Board concluded that proposed substi-
tute claims 48 and 49 would also have been obvious, and in
doing so concluded that a skilled artisan would have had a
reasonable expectation of success in achieving a 2-log in-
crease above serum IgG levels for the serotypes recited in
those claims. Decision, 2024 WL 2927019, at *8, *10–14.
The Board therefore denied Pfizer’s motion to amend. Id.
at *14.
Pfizer timely appealed. We have jurisdiction under
28 U.S.C. § 1295(a)(4)(A).
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PFIZER INC. v. SANOFI VACCINES US INC. 6
D ISCUSSION
“We review the Board’s decision to deny a motion to
amend under the APA and must set aside the Board’s ac-
tion if it is ‘arbitrary, capricious, an abuse of discretion, or
otherwise not in accordance with law.’” Pfizer, 94 F.4th at
1350 (quoting 5 U.S.C. § 706(2)(A)). “Obviousness is a
question of law that we review de novo, but the Board’s un-
derlying findings of fact are reviewed for substantial evi-
dence.” Liqwd, Inc. v. L’Oreal USA, Inc., 941 F.3d 1133,
1136 (Fed. Cir. 2019). “Whether or not a person of ordinary
skill would have had the requisite motivation to combine
references, and whether or not she would have had a rea-
sonable expectation of success in doing so, are questions of
fact we review for substantial evidence.” Pfizer, 94 F.4th
at 1347. Substantial evidence is “such relevant evidence
as a reasonable mind might accept as adequate to support
a conclusion.” Consol. Edison Co. of N.Y. v. Nat’l Lab. Rels.
Bd., 305 U.S. 197, 229 (1938).
Pfizer argues that the Board’s determination that pro-
posed substitute claims 48 and 49 would have been obvious
lacks substantial evidence, and the Board therefore abused
its discretion in denying Pfizer’s motion to amend. See
Open. Br. 30–32. Specifically, Pfizer argues that there was
no substantial evidence supporting the Board’s conclusion
that a skilled artisan would have had a reasonable expec-
tation of success in achieving “more than a 2-log increase
above baseline in serum IgG levels in New Zealand White
Rabbits across” serotypes 15B and 33F in claim 48 and
serotypes 12F, 10A, 11A and 8 in claim 49. We disagree.
For that limitation, the Board pointed to Hausdorff’s
Table 3, which showed a more than 2-log increase above
baseline serum IgG levels for thirteen of the fourteen sero-
types required by proposed substitute claim 46. Decision,
2024 WL 2927019, at *11 (citing J.A. 4034). To the Board,
this indicated that “there would have been a reasonable ex-
pectation of success in the inclusion of serotypes 22F, 33F,
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PFIZER INC. v. SANOFI VACCINES US INC. 7
8, 10A, 11A, 12F, and 15B in Hausdorff’s pneumococcal
vaccine while retaining the 2-log increased immune re-
sponse of the thirteen serotypes and also retaining a 2-log
increase in the immune response to the added serotypes.”
Id. (emphasis added). Indeed, Sanofi’s expert testified that
“[t]here was a clear motivation to further increase the IgG
levels above the baseline for all serotypes as serum IgG lev-
els are one of the indicators of immunogenicity of vaccine.”
J.A. 20182.
The Board additionally pointed to expert testimony
from another Sanofi expert in a related IPR proceeding,
also concerning the ’559 patent. Decision, 2024 WL
2927019, at *11. The expert acknowledged that “[w]ith
conjugates on CRM197 it has been possible to induce good
immunity to new serotypes without negatively affecting
the components already in the vaccine.” J.A. 5272 (empha-
sis omitted) (quoting J.A. 5246).
The Board’s conclusion that a skilled artisan would
have had a reasonable expectation of success in achieving
the 2-log increase for all serotypes in proposed substitute
claims 48 and 49 is therefore supported by substantial evi-
dence consisting of: (1) Hausdorff’s Table 3 showing a 2-log
increase for all serotypes included in a vaccine, (2) expert
testimony that a skilled artisan would want to increase
baseline IgG levels to improve immunogenicity, and (3) ex-
pert testimony that adding additional serotypes is possible
without negatively affecting other components in the vac-
cine (that is, without negatively affecting the immunogen-
icity of other components).
While it is true that the prior art references contain no
immunogenicity data for serotypes 15B, 33F, 12F, 10A,
11A, and 8, these are all known serotypes, and “a finding
of obviousness does not require a guarantee of success.”
Pfizer, 94 F.4th at 1352. Indeed, “an expectation of success
need only be reasonable, not absolute.” Id. (emphasis in
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PFIZER INC. v. SANOFI VACCINES US INC. 8
original). As explained above, substantial evidence sup-
ports the Board’s conclusion that there was a reasonable
expectation of success in achieving a 2-log increase above
baseline serum IgG levels for the additional serotypes
listed in proposed substitute claims 48 and 49.
In sum, proposed substitute claims 48 and 49 are com-
position claims that recite known serotypes. They include
a limitation that all those known serotypes exhibit a 2-log
increase above baseline serum IgG levels. Although the
prior art references do not show every serotype recited in
claims 48 and 49 achieving the 2-log increase, the Board
relied on substantial evidence showing that a skilled arti-
san would have had a reasonable expectation of success in
achieving the 2-log increase for all the claimed serotypes.
The Board therefore did not abuse its discretion in denying
Pfizer’s motion to amend.
CONCLUSION
We have considered Pfizer’s remaining arguments but
find them unpersuasive. For the foregoing reasons, we af-
firm.
AFFIRMED
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