Case: 21-1939 Document: 44 Page: 1 Filed: 03/25/2022
NOTE: This disposition is nonprecedential.
United States Court of Appeals
for the Federal Circuit
______________________
IMMUNOGEN, INC.,
Plaintiff-Appellant
v.
ANDREW HIRSHFELD, PERFORMING THE
FUNCTIONS AND DUTIES OF THE UNDER
SECRETARY OF COMMERCE FOR
INTELLECTUAL PROPERTY AND DIRECTOR OF
THE UNITED STATES PATENT AND TRADEMARK
OFFICE,
Defendant-Appellee
______________________
2021-1939
______________________
Appeal from the United States District Court for the
Eastern District of Virginia in No. 1:20-cv-00274-TSE-IDD,
Judge T. S. Ellis, III.
______________________
Decided: March 25, 2022
______________________
MICHAEL E. JOFFRE, Sterne Kessler Goldstein & Fox,
PLLC, Washington, DC, argued for plaintiff-appellant.
Also represented by PAULINE PELLETIER, ERIC STEFFE.
DANIEL KAZHDAN, Office of the Solicitor, United States
Case: 21-1939 Document: 44 Page: 2 Filed: 03/25/2022
2 IMMUNOGEN, INC. v. HIRSHFELD
Patent and Trademark Office, Alexandria, VA, argued for
defendant-appellee. Also represented by MARY L. KELLY,
THOMAS W. KRAUSE, FARHEENA YASMEEN RASHEED;
MATTHEW JAMES MEZGER, RAJ PAREKH, Office of the United
States Attorney for the Eastern District of Virginia, United
States Department of Justice, Alexandria, VA.
______________________
Before NEWMAN, CLEVENGER, and STOLL, Circuit Judges.
CLEVENGER, Circuit Judge.
This case involves a civil action to obtain a patent un-
der
35 U.S.C. § 145. Appellee ImmunoGen, Inc.’s (“Immu-
noGen”) U.S. Application No. 14/509,809 (“the ’809
Application”) describes methods of administering the im-
munoconjugate mirvetuximab for the treatment of cancer.
After the Patent Trial and Appeal Board (“Board”) of the
United States Patent and Trademark Office (“USPTO”) af-
firmed the examiner’s rejection of the pending claims for
obviousness and obviousness-type double patenting, Im-
munoGen filed its § 145 suit in the Eastern District of Vir-
ginia.
The district court determined on summary judgment
that the claims of the ’809 Application are “fatally indefi-
nite and fatally obvious” as a matter of law. ImmunoGen,
Inc. v. Iancu,
523 F. Supp. 3d 773, 799 (E.D. Va. 2021). Im-
munoGen appeals from the summary judgment. We have
jurisdiction under
28 U.S.C. § 1295(a)(1).
In its analysis, the district court resolved numerous
factual disputes against non-movant ImmunoGen, an error
that is fatal to its ultimate ruling. We therefore vacate the
grant of summary judgment and remand for proceedings
consistent with this opinion.
THE ’809 APPLICATION
Immunoconjugates, such as mirvetuximab, are com-
posed of an antibody coupled to a drug via a chemical
Case: 21-1939 Document: 44 Page: 3 Filed: 03/25/2022
IMMUNOGEN, INC. v. HIRSHFELD 3
linker. The antibody portion allows the immunoconjugate
to bind to a cell of interest, thereby permitting selective
targeting of cancer cells for treatment. Mirvetuximab spe-
cifically targets Folate Receptor 1 (“FOLR1”), which is
overexpressed in ovarian and peritoneal cancer cells.
Although mirvetuximab showed promise as a cancer
treatment, Phase 1 clinical trials revealed it can have se-
vere ocular side effects when administered at a dose of
7 mg per kg of the patient’s total body weight (“TBW”). Im-
munoGen determined that a dose of 6 mg per kg of the pa-
tient’s adjusted ideal body weight (“AIBW”) successfully
maintains exposure of the drug at the therapeutically ef-
fective level while keeping it below the ocular toxicity
threshold. It is undisputed that AIBW dosing had not pre-
viously been used for mirvetuximab, let alone any other im-
munoconjugate. 1
ImmunoGen filed the ’809 Application to claim this
AIBW dosing method. Claim 1 is representative:
1. A method for treating a human patient having
an FOLR1-expressing ovarian cancer or cancer of
the peritoneum comprising administering to the
patient an immunoconjugate which binds to
FOLR1 polypeptide,
wherein the immunoconjugate comprises an anti-
body or antigen-binding fragment thereof that com-
prises the variable light chain (VL)
complementarity determining region (CDR)-1, VL
CDR-2, VL CDR-3, variable heavy chain (VH)
CDR-1, VH CDR-2, and VH CDR-3 of SEQ ID NOs:
1 See, e.g., J.A. 9916–17, 9919 (Resps. to Request for
Admission (“RFA”) Nos. 3 & 8–9); J.A. 10445 (Shah Dep.
Tr. at 41:1–12); J.A.10655 (Tolcher Dep. Tr. at 55:4–19);
J.A. 9992, 10043 (Figg Dep. Tr. at 36:7–21, 87:5–9).
Case: 21-1939 Document: 44 Page: 4 Filed: 03/25/2022
4 IMMUNOGEN, INC. v. HIRSHFELD
6-9, 11, and 12,[2] respectively, and a maytansinoid,
and
wherein the immunoconjugate is administered at a
dose of 6 milligrams (mg) per kilogram (kg) of ad-
justed ideal body weight (AIBW) of the patient.
The ’809 Application defines AIBW as “a size descriptor
that accounts for sex, total body weight, and height.” ’809
Application at [0071]. It defines ideal body weight (“IBW”),
which is used to calculate AIBW, as “a size descriptor that
is unrelated to total body weight,” as it is “an estimate of
weight corrected for sex and height, and optionally frame
size.”
Id. at [0069]. The application further discloses that
IBW and AIBW “are discussed in more detail in Green and
Duffull, British Journal of Clinical Pharmacology 58: 119-
133 (2004)” (“Green”), which it incorporates by reference.
Id. at [0072]. Green discloses several methods for calculat-
ing IBW and lists correction factors, each specific to a dif-
ferent drug, that can be used to adjust IBW to AIBW.
The AIBW and IBW definitions each includes a for-
mula, introduced by the phrase “for example,” for calculat-
ing the respective values. These “example” formulas are
reproduced in Example 4, which relates to dosing
IMGN853, i.e., mirvetuximab. As described in both the def-
initions and Example 4, AIBW is calculated as the patient’s
IBW plus 0.4 times their total (actual) body weight in kg
minus their IBW.
Id. at [0069], [0200]. For males, IBW is
calculated as 0.9 times their height in centimeters minus
88; for females, IBW is calculated as 0.9 times their height
in centimeters minus 92.
Id. at [0071], [0200]. The equa-
tions are reproduced below:
2 The claimed “SEQ ID Nos” and other recited fea-
tures identify the immunoconjugate as IMGN853, which is
also known as mirvetuximab.
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IMMUNOGEN, INC. v. HIRSHFELD 5
AIBW = IBW + 0.4(Actual weight in kg – IBW)
IBW (male) = 0.9H – 88
IBW (female) = 0.9H – 92
The ’809 Application does not identify any other formu-
las for calculating AIBW or IBW. The “0.4” value in the
AIBW formula is a specific correction factor for mirvetuxi-
mab, and is the only one presented in the ’809 Application.
DISCUSSION
Summary judgment is appropriate when, drawing all
justifiable inferences in favor of the non-moving party,
there exists no genuine issue of material fact and the mov-
ing party is entitled to judgment as a matter of law. See
Fed. R. Civ. P. 56(c); Anderson v. Liberty Lobby, Inc.,
477
U.S. 242, 247–48 (1986). We review a district court’s sum-
mary judgment determination under the law of the re-
gional circuit, see Syngenta Crop Prot., LLC v. Willowood,
LLC,
944 F.3d 1344, 1355 (Fed. Cir. 2019), which, here, is
the Fourth Circuit. “The Fourth Circuit reviews the grant
of a motion for summary judgment de novo, viewing all ev-
idence in the light most favorable to the non-moving party.”
Id. (citing cases).
Indefiniteness and obviousness are both issues of law
that may rely on underlying factual findings, such as the
knowledge, level, or understanding of those skilled in the
art. See BASF Corp. v. Johnson Matthey Inc.,
875 F.3d
1360, 1365 (Fed. Cir. 2017) (indefiniteness); Teva Pharms.
USA, Inc. v. Sandoz, Inc.,
789 F.3d 1335, 1342 (Fed. Cir.
2015) (same); Acorda Therapeutics, Inc. v. Roxane Lab’ys,
Inc.,
903 F.3d 1310, 1328 (Fed. Cir. 2018) (obviousness).
Obviousness may also rely on factual findings regarding
motivation to combine, reasonable expectation of success,
and secondary considerations of nonobviousness. Acorda,
903 F.3d at 1328.
Case: 21-1939 Document: 44 Page: 6 Filed: 03/25/2022
6 IMMUNOGEN, INC. v. HIRSHFELD
I
Although neither the examiner nor the Board rejected
the claims of the ’809 Application for indefiniteness, the
USPTO (as permitted by statute) argued in the § 145 action
that the term “AIBW” is indefinite. The district court
agreed, concluding that the ’809 Application fails to define
IBW or AIBW in such a way that a skilled artisan would be
informed, with reasonable certainty, as to the scope of the
invention. 3 ImmunoGen, 523 F. Supp. 3d at 787, 799.
For support, the district court relies mainly on the def-
initions section of the ’809 Application. In the district
court’s view, the “for example” language preceding the
AIBW formula “makes clear that there are multiple ways
to calculate AIBW,” thereby “leav[ing] a skilled artisan to
wonder or to guess whether the formula provided is the
only one covered by the ’809 Application.” Id. at 787. This
supposed uncertainty is compounded by the “for example”
accompanying the IBW formula; the disclosure that IBW
corrects “for sex and height, and optionally frame size”;
and the incorporation of Green. Id. Although Example 4 of
the ’809 Application discloses dosing mirvetuximab using
the same IBW and AIBW formulas provided in the defini-
tions section, the district court declined to read Example 4
as “limit[ing] the scope of the claims.” Id. at 788. The dis-
trict court likewise declined to consider expert testimony
as to whether a skilled artisan reviewing the ’809 Applica-
tion would understand which AIBW formula to use,
3 As dictated by the Supreme Court, “a patent is in-
valid for indefiniteness if its claims, read in light of the
specification delineating the patent, and the prosecution
history, fail to inform, with reasonable certainty, those
skilled in the art about the scope of the invention.” Nauti-
lus, Inc. v. Biosig Instruments, Inc.,
572 U.S. 898, 901
(2014). The district court applied this standard in its anal-
ysis. See, e.g., ImmunoGen, 523 F. Supp. 3d at 786, 787.
Case: 21-1939 Document: 44 Page: 7 Filed: 03/25/2022
IMMUNOGEN, INC. v. HIRSHFELD 7
characterizing the experts’ disagreement as nothing more
than an “attempt[] to create a factual dispute” in a situa-
tion where “[t]he undisputed, intrinsic evidence demon-
strates that the term AIBW . . . is indefinite.” Id.
Our review of the evidence, however, reveals that the
underlying material factual findings are far from undis-
puted. For example, the district court found that the ’809
Application “provides no limiting or defining guidance [to a
skilled artisan] on the calculation of AIBW.” ImmunoGen,
523 F. Supp. 3d at 787. Similarly, the district court found
that the ’809 Application discloses multiple formulas for
calculating AIBW. Id. at 787–88. While the district court is
correct that the definition section incorporates Green in its
entirety and identifies the recited AIBW and IBW formulas
as “example[s],” ImmunoGen identified other intrinsic evi-
dence a skilled artisan would consider in determining the
scope of the claims, including that: (1) the claims and spec-
ification are drawn to a specific dosing regimen for a spe-
cific immunoconjugate, which is significant in light of
expert testimony that the correction factor used to calcu-
late AIBW is drug-specific; 4 (2) Example 4 describes dosing
mirvetuximab in accordance with the claimed method and
uses the same AIBW and IBW formulas disclosed in the
definitions section; 5 and (3) during the prosecution of the
4 See, e.g., J.A. 9985–86, 10059 (Figg Dep. Tr. at
29:17–30:4, 103:2–6); J.A. 10225–26 (Figg Opening Rpt.,
¶ 146); J.A. 10368–69, 10370 (Shah Reply Rpt., ¶¶ 11–12,
15).
5 The district court incorrectly concluded that Exam-
ple 4 plays no role in the indefiniteness inquiry. See, e.g.,
Interval Licensing LLC v. AOL, Inc.,
766 F.3d 1364, 1373
(Fed. Cir. 2014) (“We recognize that a patent which defines
a claim phrase through examples may satisfy the definite-
ness requirement.”); Enzo Biochem, Inc. v. Applera Corp.,
599 F.3d 1325, 1336 (Fed. Cir. 2010) (holding that the
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8 IMMUNOGEN, INC. v. HIRSHFELD
’809 Application, the USPTO never disputed the definite-
ness, or gave any indication it failed to understand the
meaning, of the now-allegedly indefinite term. 6 Immuno-
Gen also presented extrinsic evidence regarding the
knowledge of a skilled artisan. For instance, both parties’
experts testified that AIBW dosing involves drug-specific
formulas and correction factors. 7 This is confirmed by
Green, which is incorporated into the ’809 Application and
identifies drug-specific correction factors for use in calcu-
lating AIBW. 8 When we view this evidence in the light
most favorable to ImmunoGen—as we must in our re-
view—we conclude that there are still disputed questions
of material fact and summary judgment is therefore inap-
propriate.
II
The district court also held that the pending claims
would have been obvious, concluding that the prior art
taught every element of the pending claims, ImmunoGen,
523 F. Supp. 3d at 792–93; that a skilled artisan would
have been motivated to use AIBW dosing to address the
ocular toxicity problems associated with mirvetuximab
with a reasonable expectation of success, id. at 793–95; and
phrase “not interfering substantially” is sufficiently defi-
nite because a skilled artisan could use “the examples in
the specification to determine whether interference with
hybridization is substantial”).
6 See, e.g., J.A. 11007 (Shah Opening Rpt., ¶¶ 197–
200); J.A. 10369–70 (Shah Reply Rpt., ¶¶ 13–14); see also
J.A. 10899–900.
7 See, e.g., J.A. 9985–86, 10059 (Figg Dep. Tr. at
29:17–30:4, 103:2–6); J.A. 10225–26 (Figg Opening Rpt.,
¶¶ 144, 146); J.A. 10368–69 (Shah Reply Rpt., ¶¶ 11–12).
8 J.A. 4445; see also J.A. 10225–26 (Figg Opening
Rpt., ¶ 146).
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IMMUNOGEN, INC. v. HIRSHFELD 9
that ImmunoGen’s secondary considerations were unper-
suasive, id. at 795–798.
In reaching this conclusion, the district court improp-
erly resolved a number of factual findings against Immu-
noGen. For example, the district court found that “ocular
toxicity was a known negative effect of [immunoconjugates]
like IMGN853.” Id. at 793. But the expert testimony on
which the district court relies does not directly support that
statement. See id. at 793, n.40. Further, ImmunoGen pre-
sented evidence that (1) ocular toxicity is not well-under-
stood; 9 (2) immunoconjugates have unique
pharmacokinetic characteristics, making it difficult to gen-
eralize pharmacological effects; 10 (3) it was not known that
mirvetuximab would cause ocular toxicity; 11 and (4) pub-
lished results for Phase 1 testing of mirvetuximab reported
no study drug-related serious adverse events or dose-limit-
ing toxicity. 12 As another example, the district court con-
cluded, based on statements made in International
Published Application Nos. WO 2011/106528 (“Ab ’528”)
and WO 2012/135675 (“Carrigan ’675”), that “dosing of
IMGN853 could ‘easily’ be determined.” ImmunoGen, 523
F. Supp. 3d at 795 (quoting Carrigan ’675); see also id. at
781 (quoting Ab ’528). ImmunoGen’s experts, however, tes-
tified that the contested statements relate to dosing in the
context of treating patients, not in the context of determin-
ing a safe and effective dose in drug development, and that
9 See, e.g., J.A. 10095–96 (Figg Dep. Tr. at 139:7–
140:5); J.A. 11028 (Shah Opening Rpt., ¶ 235); J.A. 9595,
9597 (Tolcher Opening Rpt., ¶¶ 34, 39).
10 See, e.g., J.A. 9595 (Tolcher Opening Rpt., ¶ 34);
J.A. 10980–81 (Shah Opening Rpt., ¶ 50).
11 See, e.g., J.A. 9995, 10021, 10024 (Figg Dep. Tr. at
39:6–14, 65:16–20, 68:13–22); J.A. 9941–45 (Resps. to RFA
Nos. 64–74).
12 See, e.g., J.A. 9541.
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10 IMMUNOGEN, INC. v. HIRSHFELD
determining a safe and effective dose for immunoconju-
gates is difficult. 13 Similarly, the district court found that
switching “from 6 mg/kg of [TBW] dosing to 6 mg/kg AIBW
dosing does not significantly change the dose for patients
who are not significantly overweight or underweight,” id.
at 792–93, even though the ’809 Application and other evi-
dence show that this switch to AIBW dosing reduced ad-
verse ocular events in Phase 1 clinical trials. 14
For each of these examples, the district court erred in
concluding that there is no disputed question of material
fact. This error repeats across its other factual findings, in-
cluding those relating to motivation to combine, reasonable
expectation of success, and secondary considerations.
CONCLUSION
For the reasons stated above, we hold that the district
court erred in granting summary judgment. We therefore
vacate the district court’s determination that the pending
claims of the ’809 Application are indefinite and would
have been obvious, and remand for proceedings consistent
with this opinion.
VACATED AND REMANDED
COSTS
No costs.
13See, e.g., J.A. 9612 (Tolcher Opening Rpt., ¶ 106);
J.A. 10521–25 (Shah Dep. Tr. at 117:15–121:19); J.A.
10980–81 (Shah Opening Rpt., ¶ 50); J.A. 9595 (Tolcher
Opening Rpt., ¶ 34).
14 See, e.g., ’809 Application, Example 4; J.A. 11030–
31 (Shah Opening Rpt., ¶ 239).
