[CANCER RESEARCH 58, 3320-3330, August I, 1998)
`
`In Vitro and in Vivo Targeting of lmmunoliposomal Doxorubicin to Human
`B-Cell Lymphoma1
`
`Daniel E. Lopes de Menezes, Linda M. Pilarski, and Theresa M. Allen2
`Department of Pharmacology, University of Alberta, Edmonton, Alberta, T6G 2H7 Canada {D. E .L d. M., T. M.A./, and Department of Oncology, Cross Cancer Institute,
`F.dmonton, Alberta, T6G IZ2 Canada {L M. P.J
`
`ABSTRACT
`
`The ability to selectively target liposomal anticancer drugs via speclftc
`ligands against antigens expressed ou malignant cells could Improve the
`therapeutic effectiveness of the llposomal preparations as well as reduce
`adverse side effects associated with chemotherapy. Long-circulating for(cid:173)
`mulations of Uposomes containing lipid derivatives of poly(etbyleneglycol)
`[sterically stabilbed Uposomes (SLs)] have been described previously, and
`new techniques have recendy been developed for coupling monoclonal
`antibodies (Abs) at the poly(ethyleneglycol) terminus of these Uposomes.
`Ab-targeted SLs [immunoUposomes (SILs)] containing entrapped anti(cid:173)
`cancer drugs are predicted to be useful in the treatment of hematological
`malignancies such as 8-cell lymphomas or multiple myeloma, in which the
`target cells are present in the vasculature.
`The specific binding, in vitro cytotoxidty, and in vivo antiueoplastic
`activity of doxorubidn (DXR) encapsulated in SILs coupled to monoclonal
`Ab anti-CD19 (SIL[anti-CD19]) were investigated against malignant 8
`cells expressing CD19 surface antigens. Binding experiments with SI(cid:173)
`L[anti-CD19] resulted in a 3-fold higher association of the SILs with a
`human c019+ B lymphoma cell line (Nanwwa) in comparison with
`nontargeted SLs. Using Dow cytometry, ftuorescendy labeled SIL[anti(cid:173)
`CD19] bound to B cells with no recognition of T cells in a mixture of B
`cells and T cells in culture. Nontargeted SLs demonstrated signlllcandy
`lower recognition of either 8 cells or T cells. Targeted DXR-SIL[anti(cid:173)
`CD19] displayed a higher cytotoxidty to B cells relative to DXR entrapped
`in nontargeted SLs.
`Therapeutic experiments in severe combined immunodeftdent mice
`implanted with Nanwwa cells by the Lv. or Lp. routes resulted in signif(cid:173)
`icandy increased effectiveness of DXR-SIL[anti-CD19] compared to
`similar amounts of free DXR, DXR-SL (no Ab), or isotype-matcbed
`nonspecific Abs attached to DXR-SL. Single doses (3 mg/kg) of DXR(cid:173)
`SIL[anti-CD19] administered i.v. resulted in a signUk:andy Improved
`therapeutic beneftt, including some long-term survivon. From our results,
`we infer that targeted anti-CD19 Uposomes containing the anticancer drug
`DXR may be selectively cytotoxic for B cells and may be useful in the
`selective elimination of drculating malignant 8 cells in vm>.
`
`largely incurable (1-4). Their immunological features and clinical
`prognosis are dependent on the malignant expansion of a clonal B-cell
`phenotype, and the diseased cells are confined mainly in the vascular
`compartment. Most patients initially respond to conventional chemo(cid:173)
`therapy and/or radiotherapy. but in nearly all cases, the disease recurs
`and becomes refractory to further treatment.
`Recent therapeutic approaches to cancer have focused on develop(cid:173)
`ing novel delivery systems to increase the therapeutic indices of
`anticancer agents by targeting drugs to diseased cells and away from
`normal tissues (5). One approach uses the expression of cell surface
`epitopes as unique targets for the selective delivery of Ab-based
`therapies (i.e., immunoconjugates, radiolabeled Abs, Ab-polymer
`conjugates, or immunoliposomes; Refs. 6-14). Liposome encapsula(cid:173)
`tion of anticancer drugs can alter their phannacokinetics and biodis(cid:173)
`tribution, resulting in increased efficacy and/or decreased toxicity
`(15-19). Long-circulating dose-independent liposome formulations
`containing engrafted PEG on their surface (SLs or Stealth liposomes)
`have been developed (20-24), and DXR-containing SL (Doxil) has
`been approved in a number of countries for treatment of Kaposi's
`sarcoma (25).
`With the recent development of methods for coupling specific
`ligands to the PEG terminus of SL (26-31), new opportunities exist
`for the use of liposomes as homing devices for selective targeting of
`anticancer drugs to diseased cells (13, 14, 32-36). Numerous studies
`have shown that SILs have significantly increased target cell binding
`in vitro (30-32, 34, 36) and result in improved therapeutic efficacy in
`vivo in the treatment of early (micrometastatic) solid tumors (14, 33).
`However. SILs seem to lose their advantage in treating more advanced
`solid tumors (14), likely because the binding site barrier restricts
`penetration of the SILs into the tumor interior (37, 38).
`Targeting of immunoliposomes within the vasculature, where the
`SILs should have unrestricted access to malignant cells, is a feasible
`strategy for the treatment of hematological diseases (e.g., B-cell or
`T-cell malignancies and MM). In particular, this strategy may allow
`selective eradication of the malignant 8-cell population from the
`blood of B-cell lymphoma or MM patients. Selective targeting of the
`malignant B cells may have the additional advantage of preventing
`nonspecific toxicity to T cells, preserving T-cell-mediated immune
`responses in patients. An additional advantage might come from the
`ability of the SILs to overcome MDR in B cells (39-41). Targeting an
`internalizing CDI 9 epitope may result in enhanced delivery of the
`liposome-drug package to the cell interior, bypassing the plasma
`membrane MOR pump mechanism.
`The CD19 receptors are exclusively expressed on most B-lineage
`malignancies and are absent on hematopoietic stem cells in the bone
`marrow (42, 43). This approach allows targeting to the malignant
`cells, leaving the progenitor population intact. The free anti-CD 19 Ab,
`by itself, has cytotoxic effects and is currently in preclinical and
`clinical trials for the therapy of B-cell leukemias and lymphomas,
`conjugated to toxins or as targeted radiotherapy (43-49).
`In this study, we selectively targeted CD19+ malignant B cells in
`vitro and in vivo with DXR-containing SIL coupled with mAb anti(cid:173)
`CDI 9 (DXR-SIL[anti-CD19]). A CD19+ human B-cell lymphoma
`(the Namalwa cell line) that grows readily in SCIO mice was chosen
`3320
`
`INTRODUCTION
`
`B-cell malignancies (B-cell leukemias/lymphomas and MM3) re(cid:173)
`main a major group of human hematological cancers and are still
`
`Received 9/16"1; accepled 6/2/98.
`The costs of publication of this article were defrayed in part by the payment of page
`charges. This article must therefore be hereby marked advertisement in accordance with
`18 U.S.C. Section 1734 solely to indicate this fact.
`1 Supported by The Medical Research Council of Canada, Canada (Ul-12411),
`SEQUUS Pharmaceuticals, Inc. (T. M. A.), and the National Cancer Institute of Canada
`with funds from the Canadian Cancer Society (L. M. P.).
`2 To whom requests for reprints should be addressed, at Department of Pharmacology,
`University of Alberta, Edmonton, Alberta, T6G 2H7 Canada. Phone: (403) 492-5710;
`Fax: (403) 492-8078; E-mail: terry.allen@ualberta.ca.
`3 The abbreviations used are: MM, multiple myeloma; PEG, poly(cthylencglycol); SL,
`sterically stabilized Jiposomc; SIL, sterically stabilized immunoliposomc; Ab, antibody;
`mAb, monoclonal Ab; DXR, doxorubicin; MDR, multidrug resistance; SCID, severe
`combined immunodeficient; HSPC, hydrogenated soy phosphatidylcholinc; DSPE, dis(cid:173)
`tearoylphosphatidylethanolaminc; PEG20IIO·DSPE, PEG (M, 2000) covalently linked to
`DSPE; HZ, hydrazide-derivatizcd; CHOL, cholesterol; NBD-PE, 12-(N-(nitrobcnz-2-oxa(cid:173)
`l,3-diazol-4-yl)amino]dodecanoylphosphatidylethanolaminc; M'IT, 3-(4,5-dimcthyltbia(cid:173)
`zol-2-yl)-2,5-diphenyltetrazolium bromide; FBS, fetal bovine scrum; [3H]CHE, cho(cid:173)
`lcsteryl-( l,2-[3H)(N)]-hexadecyl ether; Tl, tyraminylinulin; FACS, fluorescence-activated
`cell sorting; PhE, pbycoerythrin; PL, pbospbolipid; IF, immunofluorescence; MST, mean
`survival time; Kd, dissociation constant; MRT, mean residence time; t 112, blood half-life;
`AUC, area under the curve.
`
`Downloaded from
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`cancerres.aacrjournals.org
`
`on March 15, 2018. © 1998 American Association for Cancer Research.
`
`NOVARTIS EXHIBIT 2077
`Breckenridge v. Novartis, IPR 2017-01592
`Page 1 of 12
`
`

`

`IMMUNOLIPOSOMAL TARGETING TO B LYMPHOCYTES
`
`MATERIALS AND MEfflODS
`
`as a model system to examine liposome targeting. In these experi(cid:173)
`ments, we demonstrate increased targeting and specific cytotoxicity to
`Namalwa cells by DXR-SIL[anti-CDl9] relative to DXR-SL or free
`DXR. In addition, in vivo pharmacokinetics and survival experiments
`wen: performed in SCIO mice xenografts of the Namalwa cell line.
`Our results demonstrate that targeted immunoliposomal therapy com(cid:173)
`pared with either DXR-SL, free DXR, or free Ab can result in a
`significantly improved therapeutic benefit in mice implanted with the
`B-cell tumor.
`
`through a series of polycarbonate filters (Nuclepore Corp., Pleasanton, CA)
`with pore si7.es ranging from 0.4-0.08 µ.m. This extrusion procedure has been
`shown to produce primarily small unilamellar vesicles (54, 55). The mean
`diameter of liposomes was determined by dynamic light scattering using a
`Brookhaven Bl90 submicron particle si7.e analyzer (Brookhaven Instruments
`Corp., Holtsville, NY). The diameters of extruded liposomes were in the range
`of 110 :!: IO nm.
`For DXR-loaded liposomes, the drug was encapsulated by remote loading
`using an ammonium sulfate gradient (56). Briefly, liposomes were hydrated in
`155 mM ammonium sulfate (pH 5.5), and the external buffer was exchanged by
`eluting through a Sephadex 050 column equilibrated with 123 mM sodium
`citrate (pH 5.5). DXR was added to the liposomes at a PL:DXR ratio of I :0.2
`(w/w) and incubated for I hat 65"C. The liposome-encapsulated DXR was
`Materials. HSPC, PEG2000-DSPE, and HZ-PEG-DSPE were generous
`separated from the free DXR over a Sephadex 050 column eluted with 123 mM
`gifts from SEQUUS Pharmaceuticals, Inc. (Menlo Park, CA) and have been
`sodium citrate (pH 5.5). The concentration of the liposome-entrapped DXR
`described elsewhere (21, 29). CHOL and NBD-PE were purchased from was determined by spectrophotometry(,\ = 490 nm), and PL concentrations
`Avanti Polar Lipids (Alabaster, AL). N-Acetyl-methionine, Sephadex 050, were determined using the Bartlett colorimetric assay (57). The loading effi-
`ciency ofDXR was greater than 95%, and liposomes routinely contained DXR
`Sepharose CL-4B, sodium periodate, and MTI were purchased from Sigma
`Chemical Co. (St. Louis, MO). DXR (Adriamycin) was obtained from Adria
`at a concentration of 140-160 µ.g DXR/µ.mol PL (0.24-0.28 µ.mol DXR/
`Laboratories, Inc. (Mississauga, Ontario, Canada). RPMI 1640 and FBS was
`µ.mol PL).
`Sll.s were prepared by the hydrazide coupling method (31). Briefly, mAb
`purchased from Life Technologies, Inc. (Burlington, Ontario, Canada).
`[ 3H]CHE (l.48-2.22 TBq/mmol) was purchased from DuPont New England was oxidized with sodium periodate (10 mM in distilled water) for I hat 22"C.
`Nuclear (Mississauga, Ontario, Canada). Iodobeads were from Pierce Chem-
`The excess periodate was quenched with 50 mM N-acetyl-methionine, and
`ical Co. (Rockford, IL). Tl synthesis and preparation of 1251-TI have been
`oxidized mAb was incubated with HZ-PEG-liposomes overnight at 5"C at an
`described previously (50). All other chemicals were of analytical grade purity. Ab:PL molar ratio of I: I 000. Fmally, the immunoliposomes were separated
`Mice. Female CDl(ICR)BR outbred mice were obtained from Charles
`from the free mAb over a Sephadex CL-4B column equilibrated with 25 mM
`River Laboratories (St. Constant, Quebec, Canada) and kept in standard HEPES (pH 7.4). The efficiency of coupling was determined from the amount
`of 1251-labeled mAb bound to the surface of liposomes, expressed as µ.g
`housing.Female4-6-week-oldC.B.-17/lcr-Tac-SCIDmiceweighing 18-20g
`were purchased from Taconic Farms (German Town, NY). The SCIO mice mAb/µ.mol PL. All mAb coupling densities on liposomes (HSPC:CHOL:HZ-
`PEG2000-DSPE, 2:1:0.l molar ratio; 100 nm in diameter) were routinely in the
`were housed and maintained in sterile enclosures under specific virus and
`range of 40-60 µ.g anti-CD19/µ.mol PL (2.6-3.9 x 10-4 µmol mAb/µ.mol
`antigen-free conditions. SCIO mice were maintained on a specified diet with
`trimethoprim-sulfamethoxazole in their drinking water. Mice were used when
`PL).
`In Yllro Cell BlndlnlfUptake Experiments. Cell binding and uptake
`they were 7-10 weeks old. All experiments were approved by the Animal
`Welfare Committee of the University of Alberta (Edmonton, Alberta, Canada).
`experiments were performed with Namalwa cells and H9 cells. Cells were
`Cell Lines and Abs. Morine mAb anti-CD19 (from FMC-63 murine CD19
`plated at I X H>6 cells/100 µI RPMI 1640 supplemented with 10% FBS in
`hybridoma) and isotype-matched control lgG2a (IAGO.I I) were obtained from
`48-well tissue culture plates. Various formulations of [3H]CHE-labeled lipo-
`Dr. H. Zola (Children's Health Research Institute, Adelaide, Australia; Ref.
`somes, with or without coupled anti-CD19, were added to each well (50-1600
`51). The concentration of all mAbs was determined by spectrophotometry
`nmol/ml) and maintained at either 4"C or 37°C in a humidified atmosphere
`(,\ = 280 nm), and purity was assessed by SOS-PAGE. All mAb reactivities
`containing 5% CO2 in air in a total volume of 200 µI. In competition
`were checked before use by indirect IF using FITC-labeled goat antimouse Ab
`experiments, liposome binding was conducted in the presence of 6-200-fold
`and FACS (Becton Dickinson, San Jose, CA) against appropriate cell lines. To
`excess free Ab (6.4 X 10-4 µmol of free anti-CD19) that was added 15 min
`discriminate individual populations of Band T cells in FACS experiments, the
`before the addition of SIL[anti-CD19]. After a 1-h incubation, the cells were
`washed three times with cold PBS (pH 7.4), and the amount of [3H]CHE-
`following mAb-fluorescent conjugates were used: (a) FMC63-FITC (anti-
`CD19-FITC conjugate); (b) BlRDl (anti-CD20-PhE-conjugate; Coulter, Hi-
`liposomes associated with the cells was determined by scintillation counting
`aleah, FL); and (c) Leu-3-PhE (anti-CD4-PhE conjugate; Becton Dickinson)
`(Aqueous Counting Scintillant scintillation fluid) in a Beckmann LS-6800
`along with the appropriate FITC- or PhE-conjugated isotype-matched controls.
`counter. The amount of liposomes bound (in nmol PL) was calculated from the
`Anti-CD45-PhE was mAb 17010 from Dr. J. Wilkins (University of Manitoba,
`initial specific activity of [3H]CHE-liposomes.
`Winnipeg, Manitoba, Canada).
`In some experiments, immunoliposomes were labeled with a green fluores-
`For iodination of the mAb, 2 mg of mAb in 300 µI of 25 mM HEPES and
`cent lipid marker, NBD-PE (0.1 mo!% of PL), and liposome-cell recognition
`140 mM NaCl (pH 7.4) were treated with 185 MBq ofNa125I and 5 iodobeads was determined using FACS. Various formulations of NBD-PE-labeled lipo-
`somes were incubated with a mix of B and T lymphoma cells (l X 1()6
`in a 2-ml reaction vial at 22"C for I h. The resulting 1251-labeled mAb was
`cells/well) at a final PL concentration of 400 nmol/ml for l h at 37°C in a
`desalted over a Sephadex 025 column in the same HEPES buffer.
`humidified incubator containing 5% CO2• Cells were washed three times with
`The human B-cell lymphoma line Namalwa (A TCC CRL 1432) was ob-
`IF buffer (PBS containing 0.1 % FBS and 0.02% sodium azide) and fixed with
`tained from American Type Culture Collection (Rockville, MD). A human
`T-cell lymphoma line (H9; ATTC HTB 176) was a gift from Dr. L-J. Chang
`1% formaldehyde before analysis on the flow cytometer. Cell debris were
`excluded by appropriate gating on forward versus side angle scatter profiles.
`(Department of Medical Microbiology and Immunology, University of Al-
`Files were collected of 10,000-20,000 events and later analyzed using the
`berta, Edmonton, Alberta, Canada). All cell lines were grown as suspension
`cultures in RPMI 1640 supplemented with 10% heat-inactivated FBS and
`LYSIS II software program (Becton Dickinson). For two-color IF experiments
`maintained at 37°C in a humidified incubator (90% humidity) containing 5% with a mix of B and T lymphoma cells, cells were labeled with red-labeled
`anti-CD20-PhE (B-cell marker) or anti-CD4-PhE (T-cell marker) to identify
`CO2•
`Preparation of Liposomes. Llposomes were composed of either HSPC:
`the individual cell populations, in addition to the green-labeled liposomes.
`CHOL:PEG2000-DSPE at a 2:1:0.1 molar ratio of PLs or HSPC:CHOL:HZ-
`Appropriate fluorescent isotype control Abs were used to ascertain specific
`PEG2000-DSPE at a 2: l :0.1 molar ratio. For fluorescently labeled liposomes,
`labeling and identify appropriate cell types.
`In Vitro Cytotoxidty Experiments. A comparison of the in vitro cytotox-
`NBD-PE (l mo!% of PL) was incorporated into the lipid mixture. For 1251-
`icity of free drug and various liposomal formulations was performed on
`Tl-loaded liposomes, the aqueous-space label was added during liposome
`hydration. In some experiments, [3H]CHE was added as a nonmetabolized, CD 19+ Namalwa cells and on a CDI 9- T lymphoma cell line (H9) with an in
`vitro proliferation assay using MTI (58). Briefly, 5 x lo' cells were plated in
`nonexchangeable lipid tracer (52, 53). Briefly, dried lipid films were hydrated
`in 25 DlM HEPES and 140 mM NaCl buffer (pH 7.4) and sequentially extruded
`96-well plates and incubated with either free DXR or various formulations of
`(Lipex Biomembranes Extruder, Vancouver, British Columbia, Canada) DXR encapsulated in long-circulating liposomes with or without Ab. Groups
`3321
`
`
`
`cancerres.aacrjournals.org Downloaded from
`
`on March 15, 2018. © 1998 American Association for Cancer Research.
`
`NOVARTIS EXHIBIT 2077
`Breckenridge v. Novartis, IPR 2017-01592
`Page 2 of 12
`
`

`

`IMMUNOUPOSOMAL TARGETING TO B LYMPHOCYTES
`
`0
`
`8 -
`.! -; 6
`• 0 ... ::r 4
`a. • • 0 2
`E z
`
`8
`
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`
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`
`A
`
`SIL-[antl-CD11J
`
`SIL[antl-CD11J
`+free entl-CD11
`
`SL
`
`400
`
`800
`
`1200
`
`1800
`
`2000
`
`2400
`
`B
`
`1.ao
`
`II.II
`
`- - 1200
`
`81L-IHII-CD111
`
`IL
`
`IOOI ...
`
`1-
`
`SIL-[antl-CD19]
`SL
`
`400
`
`800
`
`1200
`
`1800
`
`2000
`
`2400
`
`C
`
`SL
`SIL-[antl-CD111J
`
`included free anti-CDl9, free isotype-matched Ig02a, free DXR (not
`liposome-entrapped), DXR-SL, and DXR-SL conjugated to anti-CD19 (DXR(cid:173)
`SIL[anti-CD19]). DXR-SL and DXR-SIL were used alone or in conjunction
`with free anti-CD19 (10 µ.g/H.f' cells). Additional experiment groups included
`nonspecific isotype-matched Ig02a mAb (DXR-NSIL[lg02a]) or empty (no
`DXR) SIL[anti-CD19]. Cells were incubated for l, 24, or 48 h at 37°C in an
`atmosphere of 95% humidity and 5% CO2• At the l and 24 h time points, the
`cells were washed twice before replacing with fresh media and incubated for
`an additional 47 and 24 h, respectively. All plates were incubated for a total of
`48 h. At the end of the incubation time, tetrazolium dye was added, and the
`plates were read on a Titertek Multiskan Plus (Flow Laboratories, Inc.,
`Mississauga, Ontario, Canada) at dual wavelengths of 570 and 650 nm.
`Pbannacokinetic and Biodistribution of Uposomes in CDl(ICR)BR
`(Outbred) nnru SCID Mice Implanted with CD19+ Namalwa Cells.
`Female CDl(ICR)BR (outbred) mice or SCIO mice bearing i.p. Namalwa cells
`in the weight range of 20-30 g were injected via the tail vein with a single
`bolus dose of 0.2 ml of liposomes (0.5 µ.mol PUmouse). Liposomes were
`composed of HSPC:CHOL:HZ-PEG2000-DSPE (2: l :0.1 molar ratio; 100 nm in
`diameter), with or without coupled anti-CD19 (or isotype-matched Ig02a), and
`contained approximately 2-4 x 1<>5 cpm of aqueous-space label 1251-TI (50,
`59). At selected time points (0.5, I, 2, 4, 6, 12, 24, or 48 h) postinjection, mice
`(three mice/group) were anesthetized with halothane and sacrificed by cervical
`dislocation. A blood sample (100 µ.I) was collected by heart puncture, and
`major organs (namely, the liver, spleen, lung, heart, and kidney) were excised.
`For tumor-bearing SCIO mice, in addition, the mesenteric lymph nodes were
`isolated. All organs were counted for the 1251 label in a Beckmann 8000 gamma
`counter. Blood correction factors were applied to all samples (60). Pharmaco(cid:173)
`kinetic parameters were calculated using polyexponential curve stripping and
`the least squares parameter estimation program PKAnalyst (Micromath, Salt
`Lake City, UT).
`In Vivo 11terapeutic Experiments. Namalwa cells were passaged i.p. in
`SCIO mice to develop a more virulent strain with reproducible tumor takes.
`The preadapted cell line was grown in tissue culture, and cells were harvested
`in sterile PBS. tell viability was assessed by dye exclusion using eosin
`staining before implantation. SCIO mice were injected with preadapted cells in
`0.2 ml of sterile PBS either i.p. (5 X-107 cells) or i.v. via the tail vein (5 X 1<>6
`cells). Mice injected i.p. developed ascitic tumors and had a MST of 23 days.
`Mice injected i.v. had a MST of approximately 20 days, and mice were
`sacrificed when they showed signs of hind leg paralysis. From some mice,
`blood samples were taken by tail vein bleeding, and the blood lymphocytes
`were separated using Ficoll-Paque gradients. Deceased animals were subjected
`to a gross histopathological examination to detect tumor dissemination. To
`detect tumor cells in the tissues, samples of liver, spleen, lung, heart, kidney,
`bone marrow, and solid tumors were dissociated with Pronase-collagenase
`treatment, followed by labeling with both anti-CD 19-ATC and anti-CD45-
`PhE, and analyzed by FACS.
`For therapeutic experiments, mice (five mice/group) implanted with cells
`i.v. (5 X 1<>6 or I X 1<>5 cells) or i.p. (5 X 1<>6 or 5 X 107 cells) were treated
`at either l or 24 h after implantation with single doses or three weekly doses
`of 3 mg/kg DXR (i.v. or i.p.) as either free DXR, DXR-SL (no Ab), DXR(cid:173)
`SIL[anti-CD19], or DXR-NSIL[lg02a]. Free mAb treatments (anti-CD19 or
`isotype-matched control Ig02a) were also investigated at doses of 10 µ.g/
`mouse. The contribution to the therapeutic results of the free mAb, anti-CDl 9,
`was investigated in conjunction with either free DXR, DXR-SL (no Ab), or
`DXR-SIL[anti-CD19]. Treatments were given as either a single dose or three
`weekly treatments at a dose of 3 mg/kg DXR. Mice were monitored routinely
`for weight loss, and survival times were noted.
`Statistical Analysis. All linear regression analyses were done using Quat(cid:173)
`tro Pro 4.0 (Borland, Inc., Scotts Valley, CA). Student's t test was used to
`measure statistical significance. Multiple comparisons of MSTs of various
`treatment groups were performed using ANOVA with INSTAT (GraphPAD
`software, version l.l la). Data were considered significant for Ps < 0.05.
`
`2400
`
`2000
`
`1800
`1200
`800
`PL (nmoles/mL)
`Fig. I. Binding/uptake of (3H]CHE-labeled liposomes by B cells and T cells as a
`function of liposome concentration. Liposomes were composed of HSPC:CHOL:
`PEG2e,oci-DSPE (2:1:0.1 molar ratio; 100 nm in diameter) ± mAb anti-CD19. SL or
`SIL[anti-CDl9) was incubated with 1 x 10" Namalwa cells at either 4°C or 37°C. In
`competition experimenls, the binding of SIL[anti-CDl9) was c:onduc:ted in the pmence of
`excess free anti-CD19. A, Namalwa cells. 37"C; B (including the inffn), Namalwa cells,
`4°C; C, H9 cells, 37°C. Data are expressed as nmol PL ± SD/10" cells (n = 3).
`
`the Namalwa cell line and a control CDI9- T-cell line (H9) (Fig. I,
`A-C). Binding was quantified from the specific activity of [3H]CHE
`counts associated with the cells. To discriminate the processes of cell
`binding and uptake, the experiments were conducted at 4 °C and 37°C.
`The association (binding and uptake) of Sll..[anti-CD19] or SL (no
`mAb) by I x 1()6 Namalwa cells after a 1-h incubation at 37°C is
`shown in Fig. IA. There was a 3-fold increase in association of
`Sll..[anti-CDI9] to Namalwa cells compared to that of Ab-free lipo(cid:173)
`somes (Fig. IA). Binding/uptake of the Sll..[anti-CDI9] increased
`In Vitro Recognition Experiments. To examine whether immu-
`linearly at low lipid concentrations (50-200 nmol PUml) and seemed
`to saturate at concentrations greater than 400 nmol PUml (Fig. IA).
`noliposomes (Sll..[anti-CDI9]) could specifically target CDI9+ B
`cells, in vitro binding studies were conducted at 4°C and 37°C with Association of Sll..[anti-CD19] with Namalwa cells could be compet-
`3322
`
`RESULTS
`
`
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`Downloaded from on March 15, 2018. © 1998 American Association for Cancer Research.cancerres.aacrjournals.org
`
`
`
`NOVARTIS EXHIBIT 2077
`Breckenridge v. Novartis, IPR 2017-01592
`Page 3 of 12
`
`

`

`IMMUNOLll'OSOMAL TARGETING TO B LYMPHOCYTES
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`itively inhibited by the addition of excess free anti-CD19, indicating
`that the association was mediated through the CD 19 surface epitope
`on B cells (Fig. IA). Nonspecific binding/uptake of SL (no Ab) was
`also observed but was significantly lower than specific binding (Fig.
`IA).
`From the binding data, the Kd and the maximum number of lipo(cid:173)
`somes bound/cell were determined. The number of liposomes/µ.mol
`PL was estimated to be 7.7 X 1012 liposomes/µ.mol PL (calculated
`from the literature values for bilayer thickness and the molecular areas
`of PL, CHOL, and PEG, with the assumptions that liposomes were
`spherical, 100 nm in diameter, monodisperse, and contained unila(cid:173)
`mellar bilayers; Refs. 61-65). This translates into approximately
`48,000 total binding sites for CD19+ Namalwa cells by SIL[anti-
`CDl 9] (versus 15,000 SL nonspecifically bound) at saturated concen-
`trations of PL. Therefore, there are 33,000 specific binding sites for
`SIL[anti-CD19] on Namalwa cells. The Kd for the SIL[anti-CD19]
`was 160 µ,M PL, which was 2.5-fold greater than than seen for the SL.
`The binding/uptake of SIL[anti-CD19] by the CD19- T-cell line
`H9 was significantly lower than that for the CDI 9+ B cells, and no
`significant differences were observed in comparison with control
`Ab-free liposomes (Fig. IC). Binding/uptake of SIL[anti-CD19] to
`Namalwa cells at 37°C was significantly higher than the binding at
`4°C (Fig. l, A versus B), suggesting a requirement for metabolic
`processes in the uptake of SIL[anti-CD19] by the target cell (66).
`Spedftc Recognition of Immunollposomes SD..[antl-CD19] to B
`Cells in a Mix ofB Cells and T Cells. Using flow cytometry (FACS)
`and green fluorescent NBD-liposomes, specific labeling to human
`B-cell lymphoma (the Namalwa cell line) was evaluated in a mix of
`CD19,20+ Namalwa and c04+c019- T-cell lines (Fig. 2). Fig. 2A
`shows cells stained with isotype-matched control Abs. In Fig. 28,
`after staining with fluorescent mAb anti-CD19-FITC (B cells) and
`anti-CD4-PhE (T cells), the mixture of cells could be resolved into
`two populations containing 44% of the CD19+ B cells and47% of the
`CD4 + T cells, respectively. Treatment with nontargeted SLs showed
`no appreciable association of the NBD green fluorescence to either the
`co20+ B cells (Fig. 2C) or the CD4 + T-cell population (Fig. 2D). On
`the other hand, SIL[anti-CD19] selectively bound B cells (Fig. 2E) in
`which 40% of the cells were dual-labeled with SIL[anti-CD19] (green
`fluorescence) and CD20-PhE (red fluorescence), as seen in the upper
`lations were significantly less cytotoxic than the free DXR in vitro
`right quadrant of Fig. 2E, with the rest of the cells almost exclusively
`(P < 0.001). With incubations of 24 and 48 h, the difference in
`unstained (presumably CD20- Tcells). To confmn the identity of this
`cytotoxicity between DXR-SL and DXR-SIL[anti-CD19] decreased
`unstained population (presumably T cells), cells were stained with
`4-fold (P < 0.01; Table 1). This likely results from the gradual release
`T-cell marker anti-CD4-PhE after treatment with SIL[anti-CD19]
`(Fig. 2F). In this case, the cell mixture was again separated into two
`of the encapsulated drug from the DXR-SL with uptake of the re(cid:173)
`leased drug with longer incubation times. When the cytotoxicities
`distinct populations (Fig. 2F). Cells (47%) were either exclusively
`CD4-PhE+ (Fig. 2F, lower right) with low NBD fluorescence (i.e., no were compared on the CD19- H9 T-cell line, no significant differ(cid:173)
`association of targeted liposomes with T cells) or c04- cells that
`ences were observed in the IC50 of DXR-SIL[anti-CD19] compared
`were labeled (33%) SIL[anti-CD19] (Fig. 2F, upper left; i.e., CD4- B with nontargeted DXR-SL both at 1 and 24 h (P > 0.05), suggesting
`cells). Only a small proportion of cells (12% or less) seemed dual-
`the requirement of CD19 receptors in mediating cytotoxicity of tar(cid:173)
`labeled with both NBD and CD4-PhE seen in the upper right quad-
`geted DXR-SIL[anti-CD19]. Free DXR demonstrated a 3-fold greater
`cytotoxicity to B cells (Namalwa), compared to the T-cell line (H9;
`rant). In comparison, neither SL (Fig. 2, C and D) nor NSIL[lgG2a]
`P < 0.05; Table 1). However, the cytotoxic effects of the liposomal
`(data not shown) bound any of the cells.
`In Vitro Cytotoxicity of SD..[anti-CD19]. The cytotoxicity of
`formulations to T cells versus B cells were reversed. The liposomal(cid:173)
`DXR-SIL[anti-CDl 9], DXR-SL, free DXR, free mAb, and drug-free DXR formulations were 1.5-2-fold less cytotoxic to B cells in com(cid:173)
`parison to T cells (P < 0.01) at 1- and 24-h incubations (Table 1).
`controls were compared as a function of time. As seen in Table 1, the
`IC50 decreased as the exposure of cells to drug increased from 1 h to Because cytotoxicity is mediated by DXR released from liposomes,
`this suggests that the T-cell preparations may increase leakage of the
`48 h. After a 1-h incubation, targeted DXR-SIL[anti-CD19] was
`6-fold more cytotoxic than nontargeted liposomes (P < 0.001) or
`drug from DXR-SL.
`isotype-matched liposomes DXR-NSIL[lg02a] (P < 0.001) for the
`Additional control experiments were performed to rule out the
`Namalwa cell line. This suggests that binding and/or internalization of possibility that the cytotoxic effect may arise from either the lipid,
`the targeted liposomes are contributing to the increased cytotoxicity. mAb, or a combination of both. Free mAb (anti-CD19) molecules
`Whereas DXR-SIL[anti-CD19] displayed a cytotoxicity approaching were, on a molar basis, equivalent in cytotoxicity to free DXR
`that of the free DXR (P > 0.05), both nontargeted liposomal formu- molecules (P > 0.05; Table 1). The isotype-matched control IgG2a
`3323
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`104
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`antl-C04-PhE
`antl-C020-PhE
`Fig. 2. Two-color flow cytometry for selective recognition of fluorescent NBD-labeled
`liposomcs by c019+ B lymphoma cells (Namalwa). NBD-labeled (0.1 mol'I> of PL)
`liposomcs were composed ofHSPC:CHOL:PEG21lOO·DSPE (2:1:0.1 molar ratio; 100 nm
`in diameter) :!: mAb anti-CD19. A mixture of CDl9,20+ B cells and CD4•,c019- T
`cells was incubated with either Sll.[anti-CD19] or SL and stained with either anti-CD20-
`PhE (BIRD!, B-ccll marker) or anti-CD4-PbE (T-ccll marker). A, cells stained with the
`appropriate fluoraccnt isotypc-marched CODbOI Abs; B, mAbs anti-CD 19-FITC and
`anti-CD4-PbE; C, SL and anti-CD20-PbE; D, SL and anti-CD4-PbE; E, Sll.[anti-CDl9]
`and anti-CD20-PbE; F, Sll..[anti-CDl9) and anti-CD4-PbE.
`
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`on March 15, 2018. © 1998 American Association for Cancer Research.
`
`NOVARTIS EXHIBIT 2077
`Breckenridge v. Novartis, IPR 2017-01592
`Page 4 of 12
`
`

`

`IMMUNOUPOSOMAL TAROETINO TO B L YMPHOCYTI!S
`
`Table I Cytoto:xicity data (ICsoJfor free anti-CD/9, isotype-matched control mAb, S/Ls,free DXR. and DXR-liposomalfonnMlations (with or without anti-CD/9) deterntiMd on
`CD/9+ B cells (Namalwa) and CD/9- T lymphoma (H9) cells by the MTT assay
`Five x I fr cells were plated in 96-well plates and incubated with either free DXR or various formulations of DXR encapsulated in long-cin:ulating liposomes with or without Ab.
`Groups included free anti-CD19, isotype-matched control mAb Ig02a, free DXR,