Patent Publication Number: US-2015064189-A1

Title: Method of Treating Cancer with DLL4 Antagonist and Chemotherapeutic Agent

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 13/948,919, filed Jul. 23, 2013, which is a divisional of U.S. application Ser. No. 12/823,680, filed June 25, 2010, now U.S. Pat. No. 8,518,887, which claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application Nos. 61/220,465, filed Jun. 25, 2009, and 61/301,881, filed Feb. 5, 2010, each of which are herein specifically incorporated by reference in their entirety. 
    
    
     SEQUENCE LISTING 
     This application includes an electronic sequence listing in a file named “450476-Sequence.txt”, created on August 12, 2014 and containing 48,259 bytes. The contents of the text file are herein incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to methods of treating cancers or tumors with a delta-like ligand 4 (Dll4) antagonist, in particular, human antibodies or fragments thereof that specifically bind human Dll4, in combination with one or more chemotherapeutic agents, and pharmaceutical compositions comprising a Dll4 antagonist and a chemotherapeutic agent. 
     2. Description of Related Art 
     Dll4 is a member of the Delta family of Notch ligands which exhibits highly selective expression by vascular endothelium (Shutter et al., 2000,  Genes Develop.  14:1313-1318). Dll4 is a ligand for Notch receptors, including Notch 1 and Notch 4. Dll4 antagonists are useful for inhibiting tumor growth in various cancers. The nucleic acid and amino acid sequences for human Dll4 (hDll4) are shown in SEQ ID NOS:1 and 2, respectively. Antibodies specific for human Dll4 and cancer/tumor treatment using Dll4 antibodies are disclosed in international patent application publications WO 2007/143689, WO 2008/042236, and WO 2007/070671. 
     Chemotherapeutic agents are widely used for the treatment of cancer both alone and in combination with surgery and/or radiation therapy. Combination therapies using a Dll4 antagonist and chemotherapeutic agents are disclosed in US patent application publications US 2008/0014196 and US 2008/0107648. 
     BRIEF SUMMARY OF THE INVENTION 
     In a first aspect, the invention features a method of treating cancer in a subject in need thereof, comprising administering to the subject a Dll4 antagonist in combination with a chemotherapeutic agent, wherein the cancer is treated. The subject to be treated by the method of the invention may include any mammalian species, but preferably humans suffering from cancer. 
     The combination therapies of the present invention are particularly useful in Dll4-associated or Dll4-mediated condition or disease, which is affected directly or indirectly by modulation of Dll4 activity. More specifically, since Dll4 is now shown to be involved in blood vessel growth and development, inhibiting or reducing Dll4-mediated blood vessel growth or development or maturation using Dll4 antagonists, is an effective treatment for cancer/tumor that requires sufficient blood supply for its growth and survival. Furthermore, combining Dll4 antagonists with chemotherapeutic agents, including growth inhibitory agents and other cytotoxic agents, synergistically enhances their anti-cancer/anti-tumor effects. Cancers/tumors treatable by the methods of the present invention include, but not by way of limitation, various solid malignancies, including ovarian cancer, uterus cancer, breast cancer, lung cancer, liver cancer, colorectal cancer, bladder cancer, renal cancer, prostate cancer, pancreatic cancer, stomach cancer, bone cancer, skin cancer, including melanoma, malignant soft tissue sarcoma, including, but not limited to, Ewing&#39;s sarcoma, rhabdomyosarcoma, leiomyosarcoma, adipocytic sarcoma, synovial sarcoma, malignant fibrous histiocytoma, epithelioid hemangioendothelioma, angiosarcoma, fibrosarcoma, and unclassified sarcomas, leukemia, including myeloma, and the like. 
     In one embodiment, the Dll4 antagonist is a Dll4 antibody or fragment thereof (“Dll4 Ab”) that specifically binds Dll4 with high affinity and blocks the binding of Dll4 to the Notch receptors and/or neutralizes Dll4 activities. The antibody may be polyclonal, monoclonal, chimeric, humanized, or a wholly human antibody. Preferably the antibody is a fully human monoclonal antibody or monoclonal antibody fragment. The antibody fragment may be a single chain antibody, an Fab, or an (Fab) 2 . 
     In another embodiment, the Dll4 Ab binds an epitope within the N-terminal domain (S27-R172), or the DSL domain (V173-C217), or the N-terminal-DSL domain (S27-C21 7), of Dll4 (SEQ ID NO:2). The Dll4 Ab to be used in the methods of the invention is capable of binding human Dll4 with high affinity and its dissociation constant (K D ) is about 500 pM or less, including about 300 pM or less, and including about 200 pM or less, as measured by surface plasmon resonance. For example, the Dll4 Ab has a heavy chain variable region (HCVR) comprising three heavy chain CDRs (H-CDRs) and a light chain variable region (LCVR) comprising three light chain CDRs (L-CDRs), wherein the three heavy chain CDRs comprise CDR1, CDR2 and CDR3 of the amino acid sequence of SEQ ID NO:20 and the three light chain CDRs comprise CDR1, CDR2 and CDR3 of the amino acid sequence of SEQ ID NO:28. In another embodiment, the heavy chain CDR1, CDR2 and CDR3 of the Dll4 Ab comprise the amino acid sequences of SEQ ID NOS: 22, 24 and 26, respectively. In another embodiment, the light chain CDR1, CDR2 and CDR3 of Dll4 Ab comprise the amino acid sequences of SEQ ID NOS:30, 32 and 34, respectively. In yet another embodiment, the Dll4 Ab comprises heavy chain CDR1, CDR2 and CDR3 sequences comprising SEQ ID NO:22, 24 and 26, respectively, and light chain CDR1, CDR2 and CDR3 sequences comprising SEQ ID NO:30, 32 and 34, respectively. In yet another embodiment, the Dll4 Ab comprises a HCVR comprising the amino acid sequence of SEQ ID NO:20 or 116, or a LCVR comprising the amino acid sequence of SEQ ID NO:28 or 118. In yet another embodiment, the Dll4 Ab comprises a HCVR/LCVR combination of SEQ ID NO:20/28 (REGN281) or 116/118 (REGN421). 
     In another embodiment, the Dll4 Ab comprises a heavy chain CDR1/CDR2/CDR3 combination and a light chain CDR1/CDR2/CDR3 combination selected from: SEQ ID NO:6/8/10 and SEQ ID NO:14/16/18, respectively; SEQ ID NO:38/40/42 and SEQ ID NO:46/48/50, respectively; SEQ ID NO:54/56/58 and SEQ ID NO:62/64/66, respectively; SEQ ID NO:70/72/74 and SEQ ID NO:78/80/82, respectively; SEQ ID NO:86/88/90 and SEQ ID NO:94/96/98, respectively; and SEQ ID NO:102/104/106 and SEQ ID NO:110/112/114, respectively. In another embodiment, the Dll4 Ab comprises a HCVR comprising the amino acid sequence of SEQ ID NO:4, 36, 52, 68, 84, or 100, or a LCVR comprising the amino acid sequence of SEQ ID NO:12, 44, 60, 76, 92, or 108. In yet another embodiment, the Dll4 Ab comprises a HCVR/LCVR combination selected from: SEQ ID NO:4/12 (REGN279); SEQ ID NO:36/44 (REGN290); SEQ ID NO:52/60 (REGN306); SEQ ID NO:68/76 (REGN309); SEQ ID NO:84/92 (REGN310); and SEQ ID NO:100/108 (REGN289). 
     The nucleotide sequences encoding the amino acid sequences of SEQ ID NOS:4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116 and 118, are shown as SEQ ID NOS:3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99, 101, 103, 105, 107, 109, 111, 113, 115 and 117, respectively. 
     In one embodiment, the chemotherapeutic agent is an anti-mitotic agent, such as docetaxel, paclitaxel, and the like; a platinum-based chemotherapeutic compound, such as cisplatin, carboplatin, iproplatin, oxaliplatin, and the like; or other conventional cytotoxic agent, such as 5-fluorouracil (5-FU), capecitabine, irinotecan, leucovorin, gemcitabine; inhibitors of receptor tyrosine kinases and/or angiogenesis, such as ErbB inhibitors, RTK class III inhibitors, VEGFR inhibitors, and the like, and the Dll4 antagonist is a Dll4 antibody or fragment thereof as described above. 
     In a second aspect, the invention features a method of decreasing, reducing, or halting tumor growth in a subject in need thereof, comprising administering to the subject a Dll4 antagonist in combination with a chemotherapeutic agent, wherein tumor growth is decreased, reduced, or halted. 
     In a third aspect, the invention features a method of reducing the amount of a chemotherapeutic agent or a Dll4 antagonist necessary to achieve a desired therapeutic effect, compared to the administration of each agent alone, comprising administering the chemotherapeutic agent with a Dll4 antagonist. In one embodiment, the amount of a chemotherapeutic agent to achieve a desired therapeutic effect, such as, for example, halting or reducing tumor growth, is at least 10% less, at least 20% less, at least 30% less, at least 40% less, or at least 50% less, in the presence of co-administered Dll4 antagonist, or vice versa. In general, it is desirable that the amount of a chemotherapeutic agent or the Dll4 antagonist can be reduced by about 30% to about 50%. Thus, the methods of the invention are particularly beneficial for cancer patients who have low tolerance to the side effects caused by high dosages required for the treatment by either agent alone, by being able to reduce effective dosages. 
     In a fourth aspect, the invention features a pharmaceutical composition comprising a Dll4 antagonist, a chemotherapeutic agent, and a pharmaceutically acceptable carrier. In one embodiment, the Dll4 antagonist is a Dll4 Ab or fragment thereof that specifically binds to Dll4 with high affinity and neutralizes Dll4 activities, and the chemotherapeutic agent is any of those described herein. 
     In a fifth aspect, the invention features a kit comprising a container comprising the pharmaceutical composition of the present invention, and a package insert with an instruction for use. In one embodiment, a kit may comprise a container comprising therein an antibody or antigen-binding fragment thereof that specifically binds hDll4, one or more additional containers comprising therein at least one chemotherapeutic agent selected from any of those described herein, and a package insert with an instruction for use. 
     Other objects and advantages will become apparent from a review of the ensuing detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  shows the effects of Dll4 Ab in combination with cisplatin on the growth of human VMCub1 tumors (bladder carcinoma) implanted in Severe Combined Immunodeficiency (SCID) mice expressing humanized Dll4 protein (humanized Dll4 SCID mice) (Example 1). Human Fc control (♦ with solid line); REGN421 (Dll4 Ab) 2 mg/kg/injection (♦ with dashed line); cisplatin 0.5 mg/kg/injection (□); cisplatin 2 mg/kg/injection (▪); REGN421 2 mg/kg/injection+cisplatin 0.5 mg/kg/injection (◯); and REGN421 2 mg/kg/injection+cisplatin 2 mg/kg/injection (). 
         FIG. 2  shows the effects of Dll4 Ab in combination with cisplatin on the growth of human A549 tumors (non-small cell lung cancer) implanted in humanized Dll4 SCID mice (Example 2). Human Fc control (); REGN421 6 mg/kg total dose (◯); cisplatin 5 mg/kg total dose (Δ); cisplatin 9 mg/kg total dose (▴); REGN421 6 mg/kg+cisplatin 5 mg/kg total doses (⋄); and REGN421 6 mg/kg+cisplatin 9 mg/kg total doses (♦). 
         FIG. 3  shows the effects of Dll4 Ab in combination with 5-FU on the growth of human HCT116 (colorectal carcinoma) implanted in humanized Dll4 SCID mice (Example 5). Human Fc control (); REGN421 6 mg/kg total dose (◯); 5-FU 45 mg/kg total dose (Δ); 5-FU 75 mg/kg total dose (▴); REGN421 6 mg/kg+5-FU 45 mg/kg total doses (⋄); and REGN421 6 mg/kg+5-FU 75 mg/kg total doses (♦). 
         FIG. 4  shows the effects of Dll4 Ab in combination with Irinotecan on the growth of human HCT116 tumors implanted in humanized Dll4 SCID mice (Example 6). Human Fc control (); REGN421 6 mg/kg total dose (◯); irinotecan 22.5 mg/kg total dose (Δ); irinotecan 75 mg/kg total dose (▴); REGN421 6 mg/kg+irinotecan 22.5 mg/kg total doses (⋄); and REGN421 6 mg/kg+irinotecan 75 mg/kg total doses (♦). 
         FIG. 5  shows the average (4 mice/group) fold changes of Hey1 gene expression in Colo205 human colorectal tumor cells implanted in humanized Dll4 SCID mice, with a single dose of REGN421 at 0.5, 5 or 15 mg/kg, compared to the hFc at 15 mg/kg, measured at 5, 10, 24 and 72 hours and 7 days post-dose. 
     
    
    
     DETAILED DESCRIPTION 
     Before the present methods are described, it is to be understood that this invention is not limited to particular methods, and experimental conditions described, as such methods and conditions may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims. 
     As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. Thus for example, a reference to “a method” includes one or more methods, and/or steps of the type described herein and/or which will become apparent to those persons skilled in the art upon reading this disclosure. 
     Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are now described. All publications mentioned herein are incorporated herein by reference in their entirety. 
     Definitions 
     “Delta-like ligand 4”, “Dll4”, “hDll4” are used interchangeably to refer to the protein encoded by the nucleic acid sequence of SEQ ID NO:1 and the protein having the amino acid sequence of SEQ ID NO:2. 
     Dll4 antagonists include antibodies to Dll4 and fragments thereof capable of blocking the binding of Dll4 to a Notch receptor (such as Notch1 and Notch4), fusion proteins comprising the extracellular domain of Dll4 fused to a multimerizing component, or fragments thereof (see for example, US patent application publication nos. 2006/0134121 and 2008/0107648), and peptides and peptibodies (see for example, US patent application publication no. 2003/0229023). 
     Unless specifically indicated otherwise, the term “antibody,” as used herein, shall be understood to encompass antibody molecules comprising two immunoglobulin heavy chains and two immunoglobulin light chains (i.e., “full antibody molecules”) as well as antigen-binding fragments thereof. The terms “antigen-binding portion” of an antibody, “antigen-binding fragment” of an antibody, and the like, as used herein, include any naturally occurring, enzymatically obtainable, synthetic, or genetically engineered polypeptide or glycoprotein that specifically binds an antigen to form a complex. Antigen-binding fragments of an antibody may be derived, e.g., from full antibody molecules using any suitable standard techniques such as proteolytic digestion or recombinant genetic engineering techniques involving the manipulation and expression of DNA encoding antibody variable and optionally constant domains. Such DNA is known and/or is readily available from, e.g., commercial sources, DNA libraries (including, e.g., phage-antibody libraries), or can be synthesized. The DNA may be sequenced and manipulated chemically or by using molecular biology techniques, for example, to arrange one or more variable and/or constant domains into a suitable configuration, or to introduce codons, create cysteine residues, modify, add or delete amino acids, etc. 
     Non-limiting examples of antigen-binding fragments include: (i) Fab fragments; (ii) F(ab′) 2  fragments; (iii) Fd fragments; (iv) Fv fragments; (v) single-chain Fv (scFv) molecules; (vi) dAb fragments; and (vii) minimal recognition units consisting of the amino acid residues that mimic the hypervariable region of an antibody (e.g., an isolated complementarity determining region (CDR)). Other engineered molecules, such as diabodies, triabodies, tetrabodies and minibodies, are also encompassed within the expression “antigen-binding fragment,” as used herein. 
     An antigen-binding fragment of an antibody will typically comprise at least one variable domain. The variable domain may be of any size or amino acid composition and will generally comprise at least one CDR which is adjacent to or in frame with one or more framework sequences. In antigen-binding fragments having a V H  domain associated with a V L  domain, the V H  and V L  domains may be situated relative to one another in any suitable arrangement. For example, the variable region may be dimeric and contain V H -V H , V H -V L  or V L -V L  dimers. Alternatively, the antigen-binding fragment of an antibody may contain a monomeric V H  or V L  domain. 
     In certain embodiments, an antigen-binding fragment of an antibody may contain at least one variable domain covalently linked to at least one constant domain. Non-limiting, exemplary configurations of variable and constant domains that may be found within an antigen-binding fragment of an antibody of the present invention include: (i) V H -C H 1; (ii) V H -C H 2; (iii) V H -C H 3; (iv) V H -C H 1-C H 2; (v) V H -C H 1-C H 2-C H 3; (vi) V H -C H 2-C H 3; (vii) V H -C L ; (viii) V L -CH1; (ix) V L -C H 2; (x) V L -C H 3; (xi) V L -C H 1-C H 2; (xii) V L -C H 1-C H 2-C H 3; (xiii) V L -C H 2-C H 3; and (xiv) V L -C L . In any configuration of variable and constant domains, including any of the exemplary configurations listed above, the variable and constant domains may be either directly linked to one another or may be linked by a full or partial hinge or linker region. A hinge region may consist of at least 2 (e.g., 5, 10, 15, 20, 40, 60 or more) amino acids which result in a flexible or semi-flexible linkage between adjacent variable and/or constant domains in a single polypeptide molecule. Moreover, an antigen-binding fragment of an antibody of the present invention may comprise a homo-dimer or hetero-dimer (or other multimer) of any of the variable and constant domain configurations listed above in non-covalent association with one another and/or with one or more monomeric V H  or V L  domain (e.g., by disulfide bond(s)). 
     As with full antibody molecules, antigen-binding fragments may be monospecific or multispecific (e.g., bispecific). A multispecific antigen-binding fragment of an antibody will typically comprise at least two different variable domains, wherein each variable domain is capable of specifically binding to a separate antigen or to a different epitope on the same antigen. Any multispecific antibody format, including the exemplary bispecific antibody formats disclosed herein, may be adapted for use in the context of an antigen-binding fragment of an antibody of the present invention using routine techniques available in the art. 
     The term “human antibody”, as used herein, is intended to include antibodies having variable and constant regions derived from human germline immunoglobulin sequences. The human mAbs of the invention may include amino acid residues not encoded by human germline immunoglobulin sequences (e.g., mutations introduced by random or site-specific mutagenesis in vitro or by somatic mutation in vivo), for example in the CDRs and in particular CDR3. However, the term “human antibody”, as used herein, is not intended to include mAbs in which CDR sequences derived from the germline of another mammalian species (e.g., mouse), have been grafted onto human FR sequences. 
     The fully-human anti-Dll4 antibodies disclosed herein may comprise one or more amino acid substitutions, insertions and/or deletions in the framework and/or CDR regions of the heavy and light chain variable domains as compared to the corresponding germline sequences. Such mutations can be readily ascertained by comparing the amino acid sequences disclosed herein to germline sequences available from, for example, public antibody sequence databases. The present invention includes antibodies, and antigen-binding fragments thereof, which are derived from any of the amino acid sequences disclosed herein, wherein one or more amino acids within one or more framework and/or CDR regions are back-mutated to the corresponding germline residue(s) or to a conservative amino acid substitution (natural or non-natural) of the corresponding germline residue(s) (such sequence changes are referred to herein as “germline back-mutations”). A person of ordinary skill in the art, starting with the heavy and light chain variable region sequences disclosed herein, can easily produce numerous antibodies and antigen-binding fragments which comprise one or more individual germline back-mutations or combinations thereof. In certain embodiments, all of the framework and/or CDR residues within the V H  and/or V L  domains are mutated back to the germline sequence. In other embodiments, only certain residues are mutated back to the germline sequence, e.g., only the mutated residues found within the first 8 amino acids of FR1 or within the last 8 amino acids of FR4, or only the mutated residues found within CDR1, CDR2 or CDR3. Furthermore, the antibodies of the present invention may contain any combination of two or more germline back-mutations within the framework and/or CDR regions, i.e., wherein certain individual residues are mutated back to the germline sequence while certain other residues that differ from the germline sequence are maintained. Once obtained, antibodies and antigen-binding fragments that contain one or more germline back-mutations can be easily tested for one or more desired property such as, improved binding specificity, increased binding affinity, improved or enhanced antagonistic or agonistic biological properties (as the case may be), reduced immunogenicity, etc. Antibodies and antigen-binding fragments obtained in this general manner are encompassed within the present invention. 
     The present invention also includes anti-Dll4 antibodies comprising variants of any of the HCVR, LCVR, and/or CDR amino acid sequences disclosed herein having one or more conservative substitutions. For example, the present invention includes anti-Dll4 antibodies having HCVR, LCVR, and/or CDR amino acid sequences with, e.g., 10 or fewer, 8 or fewer, 6 or fewer, 4 or fewer, 2 or 1, conservative amino acid substitution(s) relative to any of the HCVR, LCVR, and/or CDR amino acid sequences disclosed herein. In one embodiment, a HCVR comprises the amino acid sequence of SEQ ID NO:116 with 10 or fewer conservative amino acid substitutions therein. In another embodiment, a HCVR comprises the amino acid sequence of SEQ ID NO:116 with 8 or fewer conservative amino acid substitutions therein. In another embodiment, a HCVR comprises the amino acid sequence of SEQ ID NO:116 with 6 or fewer conservative amino acid substitutions therein. In another embodiment, a HCVR comprises the amino acid sequence of SEQ ID NO:116 with 4 or fewer conservative amino acid substitutions therein. In yet another embodiment, a HCVR comprises the amino acid sequence of SEQ ID NO:116 with 2 or 1 conservative amino acid substitution(s) therein. In one embodiment, a LCVR comprises the amino acid sequence of SEQ ID NO:118 with 10 or fewer conservative amino acid substitutions therein. In another embodiment, a LCVR comprises the amino acid sequence of SEQ ID NO:118 with 8 or fewer conservative amino acid substitutions therein. In another embodiment, a LCVR comprises the amino acid sequence of SEQ ID NO:118 with 6 or fewer conservative amino acid substitutions therein. In another embodiment, a LCVR comprises the amino acid sequence of SEQ ID NO:118 with 4 or fewer conservative amino acid substitutions therein. In yet another embodiment, a LCVR comprises the amino acid sequence of SEQ ID NO:118 with 2 or 1 conservative amino acid substitution(s) therein. 
     A “neutralizing” or “blocking” antibody, is intended to refer to an antibody whose binding to Dll4 results in inhibition of the biological activity of Dll4. This inhibition of the biological activity of Dll4 can be assessed by measuring one or more indicators of Dll4 biological activity. These indicators of Dll4 biological activity can be assessed by one or more of several standard in vitro or in vivo assays known in the art. For instance, the ability of an antibody to neutralize Dll4 activity is assessed by inhibition of Dll4 binding to a Notch receptor. 
     The term “specifically binds,” or the like, means that an antibody or antigen-binding fragment thereof forms a complex with an antigen that is relatively stable under physiologic conditions. Specific binding can be characterized by an equilibrium dissociation constant of at least about 1×10 −6  M or less (e.g., a smaller K D  denotes a tighter binding). Methods for determining whether two molecules specifically bind are well known in the art and include, for example, equilibrium dialysis, surface plasmon resonance, and the like. An isolated antibody that specifically binds hDll4 may, however, exhibit cross-reactivity to other antigens such as Dll4 molecules from other species. Moreover, multi-specific antibodies (e.g., bispecifics) that bind to hDll4 and one or more additional antigens are nonetheless considered antibodies that “specifically bind” hDll14, as used herein. 
     The term “K D ”, as used herein, is intended to refer to the dissociation constant of a particular antibody-antigen interaction. 
     The term “high affinity” antibody refers to those antibodies that bind Dll4 with a K D  of less than about 500 pM, less than about 400 pM, less than about 300 pM, or less than about 200 pM, as measured by surface plasmon resonance, e.g., BIACORE™ or solution-affinity ELISA, using, for example, monomeric Dll4; or a K D  of less than about 100 pM, less than about 50 pM, or less than about 20 pM, as measured by surface plasmon resonance, using, dimeric Dll4. 
     The term “surface plasmon resonance”, as used herein, refers to an optical phenomenon that allows for the analysis of real-time biospecific interactions by detection of alterations in protein concentrations within a biosensor matrix, for example using the BIACORE™ system (Pharmacia Biosensor AB, Uppsala, Sweden and Piscataway, N.J.). 
     The term “epitope” is a region of an antigen that is bound by an antibody. Epitopes may be defined as structural or functional. Functional epitopes are generally a subset of the structural epitopes and have those residues that directly contribute to the affinity of the interaction. Epitopes may also be conformational, that is, composed of non-linear amino acids. In certain embodiments, epitopes may include determinants that are chemically active surface groupings of molecules such as amino acids, sugar side chains, phosphoryl groups, or sulfonyl groups, and, in certain embodiments, may have specific three-dimensional structural characteristics, and/or specific charge characteristics. 
     Chemotherapeutic agents are chemical compounds useful in the treatment of cancer and include growth inhibitory agents or other cytotoxic agents. Examples of chemotherapeutic agents that can be used in the present methods include alkylating agents such as thiotepa and cyclosphosphamide (CYTOXAN®); alkyl sulfonates such as busulfan, improsulfan and piposulfan; aziridines such as benzodopa, carboquone, meturedopa, and uredopa; ethylenimines and methylamelamines including altretamine, triethylenemelamine, trietylenephosphoramide, triethylenethiophosphaoramide and trimethylolomelamine; nitrogen mustards such as chlorambucil, chlornaphazine, cholophosphamide, estramustine, ifosfamide, mechlorethamine, mechlorethamine oxide hydrochloride, melphalan, novembichin, phenesterine, prednimustine, trofosfamide, uracil mustard; nitrosureas such as carmustine, chlorozotocin, fotemustine, lomustine, nimustine, ranimustine; antibiotics such as aclacinomysins, actinomycin, authramycin, azaserine, bleomycins, cactinomycin, calicheamicin, carabicin, carminomycin, carzinophilin, chromomycins, dactinomycin, daunorubicin, detorubicin, 6-diazo-5-oxo-L-norleucine, doxorubicin, epirubicin, esorubicin, idarubicin, marcellomycin, mitomycins, mycophenolic acid, nogalamycin, olivomycins, peplomycin, potfiromycin, puromycin, quelamycin, rodorubicin, streptonigrin, streptozocin, tubercidin, ubenimex, zinostatin, zorubicin; anti-metabolites such as methotrexate and 5-FU; folic acid analogues such as denopterin, methotrexate, pteropterin, trimetrexate; purine analogues such as fludarabine, 6-mercaptopurine, thiamiprine, thioguanine; pyrimidine analogues such as ancitabine, azacitidine, 6-azauridine, carmofur, cytarabine, dideoxyuridine, doxifluridine, enocitabine, floxuridine; androgens such as calusterone, dromostanolone propionate, epitiostanol, mepitiostane, testolactone; anti-adrenals such as aminoglutethimide, mitotane, trilostane; folic acid replenisher such as frolinic acid; aceglatone; aldophosphamide glycoside; aminolevulinic acid; amsacrine; bestrabucil; bisantrene; edatraxate; defofamine; demecolcine; diaziquone; elfornithine; elliptinium acetate; etoglucid; gallium nitrate; hydroxyurea; lentinan; lonidamine; mitoguazone; mitoxantrone; mopidamol; nitracrine; pentostatin; phenamet; pirarubicin; podophyllinic acid; 2-ethylhydrazide; procarbazine; PSK®; razoxane; sizofiran; spirogermanium; tenuazonic acid; triaziquone; 2,2′,2″-trichlorotriethylamine; urethan; vindesine; dacarbazine; mannomustine; mitobronitol; mitolactol; pipobroman; gacytosine; arabinoside (“Ara-C”); cyclophosphamide; thiotepa; members of taxoid or taxane family, such as paclitaxel (TAXOL®, Bristol-Myers Squibb Oncology, Princeton, N.J.), docetaxel (TAXOTERE®; Aventis Antony, France) and analogues thereof; chlorambucil; gemcitabine; 6-thioguanine; mercaptopurine; methotrexate; platinum analogues such as cisplatin and carboplatin; vinblastine; platinum; etoposide (VP-16); ifosfamide; mitomycin C; mitoxantrone; vincristine; vinorelbine; navelbine; novantrone; teniposide; daunomycin; aminopterin; xeloda; ibandronate; CPT-11; topoisomerase inhibitor RFS 2000; difluoromethylornithine (DMFO); retinoic acid; esperamicins; capecitabine; inhibitors of receptor tyrosine kinases and/or angiogenesis, including sorafenib (NEXAVAR® by Bayer Pharmaceuticals Corp.), sunitinib (SUTENT® by Pfizer), pazopanib (VOTRIENT™ by GlaxoSmithKline), toceranib (PALLADIA™ by Pfizer), vandetanib (ZACTIMA™ by AstraZeneca), cediranib (RECENTIN® by AstraZeneca), regorafenib (BAY 73-4506 by Bayer), axitinib (AG013736 by Pfizer), lestaurtinib (CEP-701 by Cephalon), erlotinib (TARCEVA® by Genentech), gefitinib (IRESSA™ by AstraZeneca), BIBW 2992 (TOVOK™ by Boehringer Ingelheim), lapatinib (TYKERB® by GlaxoSmithKline), neratinib (HKI-272 by Wyeth/Pfizer), and the like, and pharmaceutically acceptable salts, acids or derivatives of any of the above. Also included in this definition are anti-hormonal agents that act to regulate or inhibit hormone action on tumors such as anti-estrogens including for example tamoxifen, raloxifene, aromatase inhibiting 4(5)-imidazoles, 4-hydroxytamoxifen, trioxifene, keoxifene, LY 117018, onapristone, and toremifene (FARESTON®); and anti-androgens such as flutamide, nilutamide, bicalutamide, leuprolide, and goserelin; and pharmaceutically acceptable salts, acids or derivatives of any of the above. Other conventional cytotoxic chemical compounds as those disclosed in Wiemann et al., 1985, in  Medical Oncology  (Calabresi et al., eds.), Chapter 10, McMillan Publishing, are also applicable to the methods of the present invention. 
     The term “growth inhibitory agents” refers to a compound or composition which inhibits growth of a cell, especially a cancer cell either in vitro or in vivo. Examples of growth inhibitory agents include agents that block cell cycle progression (at a place other than S phase), such as agents that induce G1 arrest and M-phase arrest. Classical M-phase blockers include the vincas (vincristine and vinblastine), taxane family members, including, but not limited to, paclitaxel (TAXOL®), docetaxel (TAXOTERE®), and analogues thereof (e.g., XRP9881 and XRP6258; see Ojima et al.,  Curr Opin Investig Drugs  4:737, 2003), and topoisomerase inhibitors, such as irinotecan, topotecan, camptothecin, lamellarin D, doxorubicin, epirubicin, daunorubicin, etoposide, and bleomycin. Those agents that arrest G1 also spill over into S-phase arrest, for example, DNA alkylating agents, such as tamoxifen, prednisone, dacarbazine, mechlorethamine, cisplatin, methotrexate, 5-FU, and ara-C. 
     General Description 
     The present invention is based on the findings that co-administration of a Dll4 antagonist, for example, a Dll4 antibody or fragment thereof that specifically binds Dll4 and blocks Dll4 activities, with a chemotherapeutic agent, for example, cisplatin or docetaxel, results in greater inhibition of tumor growth than either single agent. For a description of fully human Dll4 Ab, including recombinant human Dll4 Ab, see international patent application publication no. WO 2008/076379. 
     Methods of Preparing Dll4 Ab 
     Methods for preparing antibodies are known to the art. See, for example, Kohler &amp; Milstein (1975) Nature 256:495-497; Harlow &amp; Lane (1988) Antibodies: a Laboratory Manual, Cold Spring Harbor Lab., Cold Spring Harbor, N.Y.). Antibodies that are isolated from organisms other than humans, such as mice, rats, rabbits, cows, can be made more human-like through chimerization or humanization. 
     “Humanized” or chimeric forms of non-human (e.g., murine) antibodies are immunoglobulins, immunoglobulin chains or fragments thereof (such as Fv, Fab, Fab′, F(ab′) 2  or other antigen-binding subsequences of antibodies) that contain minimal sequences required for antigen binding derived from non-human immunoglobulin. They have the same or similar binding specificity and affinity as a mouse or other nonhuman antibody that provides the starting material for construction of a chimeric or humanized antibody. Chimeric antibodies are antibodies whose light and heavy chain genes have been constructed, typically by genetic engineering, from immunoglobulin gene segments belonging to different species. For example, the variable (V) segments of the genes from a mouse monoclonal antibody may be joined to human constant (C) segments, such as IgG1 and IgG4. A typical chimeric antibody is thus a hybrid protein consisting of the V or antigen-binding domain from a mouse antibody and the C or effector domain from a human antibody. Humanized antibodies have variable region framework residues substantially from a human antibody (termed an acceptor antibody) and complementarity determining regions (CDR regions) substantially from a mouse antibody, (referred to as the donor immunoglobulin). See, Queen et al.,  Proc. Natl. Acad Sci. USA  86:10029-10033 (1989) and international patent application publication no. WO 90/07861 and U.S. Pat. Nos. 5,693,762, 5,693,761, 5,585,089, 5,530,101 and 5,225,539. The constant region(s), if present, are also substantially or entirely from a human immunoglobulin. The human variable domains are usually chosen from human antibodies whose framework sequences exhibit a high degree of sequence identity with the murine variable region domains from which the CDRs were derived. The heavy and light chain variable region framework residues can be derived from the same or different human antibody sequences. The human antibody sequences can be the sequences of naturally occurring human antibodies or can be consensus sequences of several human antibodies. See international patent application publication no. WO 92/22653. Certain amino acids from the human variable region framework residues are selected for substitution based on their possible influence on CDR conformation and/or binding to antigen. Investigation of such possible influences may be performed by modeling, examination of the characteristics of the amino acids at particular locations, or empirical observation of the effects of substitution or mutagenesis of particular amino acids. For example, when an amino acid differs between a murine variable region framework residue and a selected human variable region framework residue, the human framework amino acid should usually be substituted by the equivalent framework amino acid from the mouse antibody when it is reasonably expected that the amino acid: (1) noncovalently binds antigen directly; (2) is adjacent to a CDR region; (3) otherwise interacts with a CDR region (e.g., is within about 6 A of a CDR region), or (4) participates in the V L -V H  interface. Other candidates for substitution are acceptor human framework amino acids that are unusual for a human immunoglobulin at that position. These amino acids can be substituted with amino acids from the equivalent position of the mouse donor antibody or from the equivalent positions of more typical human immunoglobulins. Other candidates for substitution are acceptor human framework amino acids that are unusual for a human immunoglobulin at that position. The variable region frameworks of humanized immunoglobulins usually show at least 85% sequence identity to a human variable region framework sequence or consensus of such sequences. 
     Methods for generating human antibodies include, for example, VELOCIMMUNE™ (Regeneron Pharmaceuticals), XENOMOUSE™ technology (Abgenix), the “minilocus” approach, and phage display. The VELOCIMMUNE™ technology (U.S. Pat. No. 6, 596,541) encompasses a method of generating a high specificity fully human antibody to a select antigen. This technology involves generation of a transgenic mouse having a genome comprising human heavy and light chain variable regions operably linked to endogenous mouse constant region loci such that the mouse produces an antibody comprising a human variable region and a mouse constant region in response to antigenic stimulation. The DNA encoding the variable regions of the heavy and light chains of the antibody are isolated and operably linked to DNA encoding the human heavy and light chain constant regions. The DNA is then expressed in a cell capable of expressing the fully human antibody. In one embodiment, the cell is a CHO cell. 
     The XENOMOUSE™ technology (Green et al., 1994,  Nature Genetics  7:13-21) generates a mouse having both human variable and constant regions from both the heavy chain and kappa light chain loci. In an alternative approach, others have utilized a ‘minilocus” approach in which an exogenous Ig locus is mimicked through inclusion of individual genes from the Ig locus (see, for example, U.S. Pat. No. 5,545,807). The DNA encoding the variable regions can be isolated with or without being operably linked to the DNA encoding the human heavy and light chain constant region. 
     Alternatively, phage display or related display technologies can be used to identify antibodies, antibody fragments, such as variable domains, and heteromeric Fab fragments that specifically bind to Dll4. (see, for example, US patent application publication no. 2003/0229023). 
     Screening and selection of preferred immunoglobulins (antibodies) can be conducted by a variety of methods known to the art. Initial screening for the presence of monoclonal antibodies specific to Dll4 may be conducted through the use of ELISA-based methods or phage display, for example. A secondary screen is preferably conducted to identify and select a desired monoclonal antibody. Secondary screening may be conducted with any suitable method known to the art. One preferred method, termed “Biosensor Modification-Assisted Profiling” (“BiaMAP”) is described in U.S. patent application publication no. 2004/101920. BiaMAP allows rapid identification of hybridoma clones producing monoclonal antibodies with desired characteristics. More specifically, monoclonal antibodies are sorted into distinct epitope-related groups based on evaluation of antibody:antigen interactions. Alternatively, ELISA-based, bead-based, or BIACORE®-based competition assays can be used to identify binding pairs that bind different epitopes of Dll4 and thus are likely to cooperate to bind the ligand with high affinity. 
     Methods of Administration 
     The present invention provides methods of treatment comprising administering to a subject an effective amount of a pharmaceutical composition comprising a Dll4 antagonist, such as a Dll4 Ab, and a chemotherapeutic agent, such as anti-mitotic agents, for example, docetaxel, paclitaxel, and the like (taxanes); platinum-based chemotherapeutic compounds, such as cisplatin, carboplatin, iproplatin, oxaliplatin, and the like; pyrimidine analogue, such as 5-Fu, capecitabine (XELODA®, Roche), and the like; topoisomerase inhibitors, such as irinotecan, topotecan, camptothecin, lamellarin D, and the like; and/or adjuvants, such as leucovorin (folinic acid), and the like (for details, see the definition section above). 
     The Dll4 antagonist and the chemotherapeutic agent can be co-administered together or separately. Where separate dosage formulations are used, the Dll4 antagonist and the chemotherapeutic agent can be administered concurrently, or separately at staggered times, i.e., sequentially. 
     Various delivery systems are known and can be used to administer the pharmaceutical composition of the invention, e.g., encapsulation in liposomes, microparticles, microcapsules, recombinant cells capable of expressing the mutant viruses, receptor mediated endocytosis (see, e.g., Wu and Wu, 1987,  J. Biol. Chem.  262:4429 4432). Methods of introduction include but are not limited to intradermal, intramuscular, intraperitoneal, intravenous, subcutaneous, intranasal, intraocular, epidural, and oral routes. The composition may be administered by any route, for example by infusion or bolus injection, by absorption through epithelial or mucocutaneous linings (e.g., oral mucosa, rectal and intestinal mucosa, etc.) and may be administered together with other biologically active agents. Administration can be systemic or local. Administration can be acute or chronic (e.g., daily, weekly, monthly, etc.) or in combination with other agents. Pulmonary administration can also be employed, for example, by use of an inhaler or nebulizer, and formulation with an aerosolizing agent. 
     With respect to subcutaneous delivery, a pen delivery device readily has applications in delivering a pharmaceutical composition of the present invention. Such a pen delivery device can be reusable or disposable. A reusable pen delivery device generally utilizes a replaceable cartridge that contains a pharmaceutical composition. Once all of the pharmaceutical composition within the cartridge has been administered and the cartridge is empty, the empty cartridge can readily be discarded and replaced with a new cartridge that contains the pharmaceutical composition. The pen delivery device can then be reused. In a disposable pen delivery device, there is no replaceable cartridge. Rather, the disposable pen delivery device comes prefilled with the pharmaceutical composition held in a reservoir within the device. Once the reservoir is emptied of the pharmaceutical composition, the entire device is discarded. 
     Numerous reusable pen delivery devices have applications in the subcutaneous delivery of a pharmaceutical composition of the present invention. Examples include, but certainly are not limited to AUTOPEN™ (Owen Mumford, Inc., Woodstock, UK), DISETRONIC™ pen (Disetronic Medical Systems, Burghdorf, Switzerland), HUMALOG MIX 75/25™ pen, HUMALOG™ pen, HUMALIN 70/30™ pen (Eli Lilly and Co., Indianapolis, Ind.), NOVOPEN™ I, II and III (Novo Nordisk, Copenhagen, Denmark), NOVOPEN JUNIOR™ (Novo Nordisk, Copenhagen, Denmark), BD™ pen (Becton Dickinson, Franklin Lakes, N.J.), OPTIPEN™, OPTIPEN PRO™, OPTIPEN STARLET™, and OPTICLIK™ (sanofi-aventis, Frankfurt, Germany), to name only a few. Examples of disposable pen delivery devices having applications in subcutaneous delivery of a pharmaceutical composition of the present invention include, but certainly are not limited to the SOLOSTAR™ pen (sanofi-aventis), the FLEXPEN™ (Novo Nordisk), and the KWIKPEN™ (Eli Lilly). 
     In another embodiment, the active agent can be delivered in a vesicle, or a liposome (see Langer (1990)  Science  249:1527-1533). In yet another embodiment, the active agent can be delivered in a controlled release system. In one embodiment, a pump may be used (see Langer (1990) supra). In another embodiment, polymeric materials can be used (see Howard et al. (1989)  J. Neurosurg.  71:105). In another embodiment where the active agent of the invention is a nucleic acid encoding a protein, the nucleic acid can be administered in vivo to promote expression of its encoded protein, by constructing it as part of an appropriate nucleic acid expression vector and administering it so that it becomes intracellular, e.g., by use of a retroviral vector (see, for example, U.S. Pat. No. 4,980,286), or by direct injection, or by use of microparticle bombardment (e.g., a gene gun; Biolistic, Dupont), or coating with lipids or cell-surface receptors or transfecting agents, or by administering it in linkage to a homeobox-like peptide which is known to enter the nucleus (see e.g., Joliot et al., 1991,  Proc. Natl. Acad. Sci. USA  88:1864-1868), etc. Alternatively, a nucleic acid can be introduced intracellularly and incorporated within host cell DNA for expression, by homologous recombination. 
     In a specific embodiment, it may be desirable to administer the pharmaceutical compositions of the invention locally to the area in need of treatment; this may be achieved, for example, and not by way of limitation, by local infusion during surgery, topical application, e.g., by injection, by means of a catheter, or by means of an implant, said implant being of a porous, non-porous, or gelatinous material, including membranes, such as sialastic membranes, fibers, or commercial skin substitutes. 
     The amount of the active agent of the invention which will be effective in the treatment of cancer/tumor can be determined by standard clinical techniques based on the present description. In addition, in vitro assays may optionally be employed to help identify optimal dosage ranges. The precise dose to be employed in the formulation will also depend on the route of administration, and the seriousness of the condition, and should be decided according to the judgment of the practitioner and each subject&#39;s circumstances. However, suitable dosage ranges for intravenous administration are generally about 0.2 to 30 mg of active compound per kilogram body weight. Suitable dosage ranges for intranasal administration are generally about 0.01 pg/kg body weight to 1 mg/kg body weight. Effective doses may be extrapolated from dose-response curves derived from in vitro or animal model test systems. 
     For systemic administration, a therapeutically effective dose can be estimated initially from in vitro assays. For example, a dose can be formulated in animal models to achieve a circulating concentration range that includes the 10 50  as determined in cell culture. Such information can be used to more accurately determine useful doses in humans. Initial dosages can also be estimated from in vivo data, e.g., animal models, using techniques that are well known in the art. One having ordinary skill in the art could readily optimize administration to humans based on animal data. 
     The dose may vary depending upon the age and the size (e.g., body weight or body surface area) of a subject to be administered, target disease, conditions, route of administration, and the like. For systemic administration of Dll4 antagonists, in particular, for Dll4 antibodies, typical dosage ranges for intravenous administration are at a daily dose of about 0.01 to about 100 mg/kg of body weight, about 0.1 to about 50 mg/kg, or about 0.2 to about 10 mg/kg. For subcutaneous administration, the antibodies can be administered at about 10 mg to about 500 mg, about 20 mg to about 400 mg, about 30 mg to about 300 mg, or about 50 mg to about 200 mg, at the antibody concentration of, at least, about 25 mg/ml, about 50 mg/ml, about 75 mg/ml, about 100 mg/ml, about 125 mg/ml, about 150 mg/ml, about 175 mg/ml, about 200 mg/ml, or about 250 mg/ml, at least, 1 to 5 times per day, 1 to 5 times per week, or 1 to 5 times per month. Alternatively, the antibodies can be initially administered via intravenous injection, followed by sequential subcutaneous administration. 
     In general, chemotherapeutic agents are used intravenously or orally at a dose range of between 50 mg/m 2  and 5000 mg/m 2  per week, but the dosage ranges vary depending on various factors, including the subject being treated, the subject&#39;s weight and age, the severity of the affliction, the manner of administration, the type of chemotherapeutic agent being used, the judgment of the prescribing physician, and the like. The therapy may be repeated intermittently while symptoms are detectable or even when they are not detectable. The duration of the treatment may also vary depending on the severity of the conditions treated as well as tolerance levels of subjects for possible adverse effects, if any, and may last as long as necessary or so long as the benefit outweighs any adverse effect. 
     The dosage of each agent may be further adjusted in the combination therapy, where the amount of each agent necessary to achieve a desired therapeutic effect is reduced (i.e., exhibiting a synergistic effect), compared to the administration of either agent alone (see Examples 1 and 2, infra). 
     Chemotherapeutic agents that can be used in the combination therapies of the invention also include those which are employed in well-known chemotherapeutic regimens. For example, FOLFOX is a chemotherapeutic regimen for treating colorectal cancer (CRC) and is a combination of 5-FU, folinic acid and oxaliplatin. FOLFIRI is another chemotherapeutic regimen for CRC and is a combination of 5-FU, folinic acid and irinotecan. XELOX is a second-line chemotherapeutic regimen for CRC and is a combination of capecitabine and oxaliplatin. 
     Further, the therapy with the combination of a chemotherapeutic agent and a Dll4 antagonist may be provided alone or in combination with additional drugs, such as other anti-angiogenic agents, e.g., VEGF antagonists, including anti-VEGF antibodies (e.g., AVASTIN® by Genentech), VEGF-binding fusion proteins (e.g., aflibercept by Regeneron Pharmaceuticals), and the like, and other therapeutic agents, such as analgesics, anti-inflammatory agents, including non-steroidal anti-inflammatory drugs (NSAIDS), such as Cox-2 inhibitors, and the like, so as to ameliorate and/or reduce the symptoms accompanying the underlying cancer/tumor. 
     Metronomic Chemotherapies 
     Metronomic chemotherapy is emerging as an improved way of administering chemotherapy. Traditional chemotherapy has been administered in single doses or short courses of therapy as the highest dose possible without causing life-threatening levels of toxicity, e.g., at the maximum tolerated dose (MTD). MTD therapy requires prolonged breaks of 2-3 weeks between successive cycles of therapy. Despite the number of such chemotherapeutics and large number of clinical trials undertaken to test them, progress has been modest in terms of curing or significantly prolonging the lives of patients with cancer (Kerbel et al., 2004,  Nature Reviews Cancer  4:423-436). 
     Metronomic chemotherapy refers to the frequent, even daily, administration of chemotherapeutics at doses significantly below the MTD, with no prolonged drug-free breaks. In addition to reduced acute toxicity, the efficacy of metronomic chemotherapy may increase when administered in combination with specific anti-angiogenic drugs, such as inhibitors of VEGF (Kerbel et al., 2004, supra). 
     Accordingly, the present invention features a metronomic chemotherapy for treating cancer in a subject in need thereof, comprising administering to the subject a Dll4 antagonist in combination with a chemotherapeutic agent, wherein the cancer is treated. In a specific embodiment, the Dll4 antagonist and a chemotherapeutic agent may be administered together or sequentially for a relatively short period of time, for example, 1-12 weeks, followed by metronomic administration of the chemotherapeutic agent over a prolonged period of time, for example, 6-24 months. 
     Pharmaceutical Compositions 
     The present invention provides pharmaceutical compositions comprising a Dll4 antagonist, a chemotherapeutic agent, and a pharmaceutically acceptable carrier. The term “pharmaceutically acceptable” means approved by a regulatory agency of the Federal or a state government or listed in the U.S. Pharmacopeia or other generally recognized pharmacopeia for use in animals, and more particularly, in humans. The term “carrier” refers to a diluent, adjuvant, excipient, or vehicle with which the therapeutic is administered. Such pharmaceutical carriers can be sterile liquids, such as water and oils, including those of petroleum, animal, vegetable or synthetic origin, such as peanut oil, soybean oil, mineral oil, sesame oil and the like. Suitable pharmaceutical excipients include starch, glucose, lactose, sucrose, gelatin, malt, rice, flour, chalk, silica gel, sodium stearate, glycerol monostearate, talc, sodium chloride, dried skim milk, glycerol, propylene, glycol, water, ethanol and the like. The composition, if desired, can also contain minor amounts of wetting or emulsifying agents, or pH buffering agents. These compositions can take the form of solutions, suspensions, emulsion, tablets, pills, capsules, powders, sustained-release formulations and the like. The composition can be formulated as a suppository, with traditional binders and carriers such as triglycerides. Oral formulation can include standard carriers such as pharmaceutical grades of mannitol, lactose, starch, magnesium stearate, sodium saccharine, cellulose, magnesium carbonate, etc. Examples of suitable pharmaceutical carriers are described in “Remington&#39;s Pharmaceutical Sciences” by E. W. Martin. 
     In a preferred embodiment, the composition is formulated in accordance with routine procedures as a pharmaceutical composition adapted for intravenous administration to human beings. Where necessary, the composition may also include a solubilizing agent and a local anesthetic such as lidocaine to ease pain at the site of the injection. Where the composition is to be administered by infusion, it can be dispensed with an infusion bottle containing sterile pharmaceutical grade water or saline. Where the composition is administered by injection, an ampoule of sterile water for injection or saline can be provided so that the ingredients may be mixed prior to administration. 
     The active agents of the invention can be formulated as neutral or salt forms. Pharmaceutically acceptable salts include those formed with free amino groups such as those derived from hydrochloric, phosphoric, acetic, oxalic, tartaric acids, etc., and those formed with free carboxyl groups such as those derived from sodium, potassium, ammonium, calcium, ferric hydroxides, isopropylamine, triethylamine, 2-ethylamino ethanol, histidine, procaine, etc. 
     A composition useful in practicing the methods of the invention may be a liquid comprising an agent of the invention in solution, in suspension, or both. The term “solution/suspension” refers to a liquid composition where a first portion of the active agent is present in solution and a second portion of the active agent is present in particulate form, in suspension in a liquid matrix. The liquid composition may be aqueous and also includes a gel and an ointment forms. 
     An aqueous suspension or solution/suspension useful for practicing the methods of the invention may contain one or more polymers as suspending agents. Useful polymers include water-soluble polymers such as cross-linked carboxyl-containing polymers. An aqueous suspension or solution/suspension of the present invention is preferably viscous or muco-adhesive, or even more preferably, both viscous and mucoadhesive. 
     Kits 
     The invention further provides an article of manufacturing or kit, comprising a packaging material, container and a pharmaceutical agent contained within the container, wherein the pharmaceutical agent comprises at least one Dll4 antagonist, such as Dll4 antibody, and at least one chemotherapeutic agent, and wherein the packaging material comprises a label or package insert which indicates that the Dll4 antagonist and chemotherapeutic agent can be used for treating cancer or reducing or halting tumor growth. In one embodiment, the Dll4 antagonist and the chemotherapeutic agent may be contained in separate containers; thus, the invention provides a kit comprising a container comprising therein an antibody or antigen-binding fragment thereof that specifically binds hDll4, and one or more additional containers comprising therein at least one chemotherapeutic agent. 
     EXAMPLES 
     The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how to make and use the methods and compositions of the invention, and are not intended to limit the scope of what the inventors regard as their invention. Efforts have been made to ensure accuracy with respect to numbers used (e.g., amounts, temperature, etc.), but some experimental errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in degrees Centigrade, and pressure is at or near atmospheric. (Figure error bars=mean±SEM). 
     Example 1 
     Effect of Anti-hDll4 Antibody in Combination with Cisplatin 
     The effect of anti-Dll4 antibody (REGN421) in combination with cisplatin (platinol, cis-diamminedichloroplatinum) on tumor growth was evaluated on tumors implanted in Severe Combined Immunodeficiency (SCID) mice expressing a humanized Dll4 protein (humanized Dll4 SCID mice). The humanized Dll4 SCID mouse was made by replacing the entire extracellular domain of the mouse Dll4 gene with the corresponding extracellular region of the human Dll4 gene (7 kb) in embryonic stem (ES) cells. Homozygous hDll4 mice were generated and bred into SCID background. 
     Each mouse was implanted subcutaneously (sc) with 1×10 6  human VM-Cub1 tumor cells (bladder carcinoma cells) plus MATRIGEL™ (BD Biosciences, #354234). After the tumors were established in the mice (tumor size of 150-200 mm 3 , approximately 14 days after implantation), tumors were measured, randomized and treated with hFc, REGN421, cisplatin, or combination of REGN421 and cisplatin. A total of 45 mice were divided into nine groups (n=5 per cohort). The first group was treated subcutaneously (sc) with hFc at 2 mg/kg; the second and third groups were treated sc with REGN421 at 0.5 and 2 mg/kg, respectively; the fourth and fifth groups were treated intraperitoneally (ip) with cisplatin at 0.5 and 2 mg/kg, respectively; the sixth group was treated sc with REGN421 at 0.5 mg/kg and ip with cisplatin at 0.5 mg/kg; the seventh group was treated sc with REGN421 at 0.5 mg/kg and ip with cisplatin at 2 mg/kg; the eighth group was treated sc with REGN421 at 2 mg/kg and ip with cisplatin at 0.5 mg/kg; and the ninth group was treated sc with REGN421 at 2 mg/kg and ip with cisplatin at 2 mg/kg. REGN421 was administered every 3-4 days starting on day 14 and mice received three doses total. Cisplatin was administered every 24 hours starting on day 14; mice received four doses total. 
     To assess the effects of REGN421 and cisplatin as single agents or in combination treatments, the changes in tumor size were recorded. Tumor growth was measured three days before the initial REGN421 treatment, on the day of each REGN421 treatment (days 14, 17 and 21) and thereafter every 3-4 days until tumors reached ˜600 mm 3  in size. In vivo tumor size was calculated using the formula (length×width 2 )/2 ( FIG. 1  and Table 1). 
     
       
         
           
               
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 TREATMENT 
                 TGI 
                 TGD 
                 Euthanized 
               
               
                   
                 (mg/kg/dose) 
                 (%) 
                 (days) 
                 (day) 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 hFc 
                 — 
                 — 
                 32 
               
               
                   
                 REGN421 (0.5) 
                 −13.7 
                 0 
                 32 
               
               
                   
                 REGN421 (2) 
                 83.1 
                 12 
                 44 
               
               
                   
                 Cisplatin (0.5) 
                 60.7 
                 13 
                 45 
               
               
                   
                 Cisplatin (2) 
                 53.8 
                 9 
                 41 
               
               
                   
                 REGN421 (0.5) + 
                 4.4 
                 2 
                 34 
               
               
                   
                 cisplatin (0.5) 
               
               
                   
                 REGN421 (0.5) + 
                 −0.8 
                 0 
                 28 
               
               
                   
                 cisplatin (2) 
               
               
                   
                 REGN421 (2) + 
                 104.8 
                 49 
                 &gt;81 
               
               
                   
                 cisplatin (0.5) 
               
               
                   
                 REGN421 (2) + 
                 57.9 
                 7 
                 39 
               
               
                   
                 cisplatin (2) 
               
               
                   
                   
               
            
           
         
       
     
     Tumor Growth Inhibition, TGI, was determined by calculating the difference in tumor size for treated (T) versus vehicle control (C) tumor at the day the control cohort was euthanized (i.e., at day 32); TGI=[1−(T final −T initial )/(C final −C initial )]×100. 
     Tumor growth delay, TGD, was assessed as the difference in days between treated (T) versus control (C) tumors when each cohort reached a specified tumor size. The predetermined tumor size for this experiment was 600 mm 3 . 
     The results show that treatment with REGN421 alone caused a 54% reduction in tumor growth. Treatment with cisplatin alone resulted in reduced tumor growth (61% reduction for the dose of 0.5 mg/kg/injection; and 54% reduction for the dose of 2 mg/kg/injection). The combination treatments produced higher reductions in tumor growth than either single agent treatment (104% reduction for 0.5 mg/kg/injection cisplatin plus 2 mg/kg/injection REGN421; and 58% reduction for 2 mg/kg/injection cisplatin plus 2 mg/kg/injection REGN421). 
     These results showed that the treatment of tumors with a combination of Dll4 blocker together with cisplatin, at 2 mg/kg/injection of Dll4 blocker and 0.5 mg/kg/injection cisplatin, can result in greater inhibition of tumor growth than either single agent. 
     Example 2 
     Effect of Anti-hDll4 Antibody in Combination with Cisplatin 
     The effect of REGN421 in combination with cisplatin on tumor growth was evaluated on tumors implanted in humanized Dll4 SCID mice, as described above. Each mouse was implanted subcutaneously (sc) with 5×10 6  human A549 tumor cells (non-small cell lung cancer or “NSCLC”). After the tumors were established in the mice (tumor size of 100-150 mm 3 , approximately 29 days after implantation), tumors were measured, randomized and treated with hFc, REGN421, cisplatin or combination of REGN421 and cisplatin. A total of 36 mice were divided into 6 groups (n=6 per cohort). The first group was treated sc with hFc at 2 mg/kg; the second group was treated sc with REGN421 at 2 mg/kg; the third and fourth groups were treated ip with cisplatin at 2.5 and 4.5 mg/kg, respectively; the fifth group was treated sc with REGN421 at 2 mg/kg and ip with cisplatin at 2.5 mg/kg; and the sixth group was treated sc with REGN421 at 2 mg/kg and ip with cisplatin at 4.5 mg/kg. REGN421 was administered every 3-4 days starting on day 29 and mice received three doses total. Cisplatin was administered every 24 hours starting on day 29 and mice received two doses total. 
     To assess the effects of REGN421 and cisplatin as single agents or in combination we measured tumor size (volume), beginning three days before the initial REGN421 treatment, on the day of each agent treatment (days 29, 30, 33, 36) and thereafter every 3-4 days until tumors reached ˜600 mm 3  in size. In vivo tumor size was calculated using the formula (length×width 2 )/2. The effects on tumor growth are indicated in  FIG. 2  and Table 2. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 TREATMENT 
                 TGI (%) at 
                 TGD 
               
               
                   
                 (mg/kg total dose) 
                 Day 57 
                 (days) 
               
               
                   
                   
               
             
            
               
                   
                 hFc 
                 — 
                 — 
               
               
                   
                 REGN421 2 mg/kg (6) 
                 54 
                 8 
               
               
                   
                 Cisplatin 2.5 mg/kg (5) 
                 35 
                 4 
               
               
                   
                 Cisplatin 4.5 mg/kg (9) 
                 22 
                 11 
               
               
                   
                 REGN421 2 mg/kg (6) + 
                 69 
                 21 
               
               
                   
                 Cisplatin 2.5 mg/kg (5) 
               
               
                   
                 REGN421 2 mg/kg (6) + 
                 80 
                 26 
               
               
                   
                 Cisplatin 4.5 mg/kg (9) 
               
               
                   
                   
               
            
           
         
       
     
     The results show that treatment with REGN421 alone caused a 54% reduction in tumor growth. Treatment with cisplatin alone resulted in reduced tumor growth (35% reduction for the dose of 2.5 mg/kg/injection; and 22% reduction for the dose of 4.5 mg/kg/injection). The combination treatments produced higher reductions in tumor growth than either single agent treatment (69% reduction for 2.5 mg/kg/injection of cisplatin plus 2 mg/kg/injection of REGN421; and 80% reduction for 4.5 mg/kg/injection of cisplatin plus 2 mg/kg/injection of REGN421). The combination treatments delayed tumor growth significantly (21 days for 2.5 mg/kg/injection of cisplatin plus 2 mg/kg/injection of REGN421; and 26 days for 4.5 mg/kg/injection of cisplatin plus 2 mg/kg/injection of REGN421), compared to control and either single agent (p&lt;0.01). 
     These results show that treatment of tumors with a combination of Dll4 blocker together with cisplatin, at 2 mg/kg/injection of Dll4 blocker and 2.5-4.5 mg/kg/injection of cisplatin, can result in greater inhibition of tumor growth than either single agent. 
     Example 3 
     Effect of Anti-hDll4 Antibody in Combination with Docetaxel 
     The effect of anti-Dll4 antibody in combination with docetaxel (TAXOTERE®) on tumor growth was evaluated on tumors implanted in Severe Combined Immunodeficiency (SCID) mice. Each mouse was implanted subcutaneously (sc) with 1×10 6  rat C6 tumor cells (glioblastoma cells). After the tumors were established (tumor size of ˜100-150 mm 3 , approximately 13 days after implantation), the mice were treated with hFc, docetaxel, Dll4 antibody, or a combination of docetaxel plus Dll4 antibody. Since these mice expressed mouse Dll4, the Dll4 Ab used in this experiment was prepared in-house, based on the published sequence (WO 2007/143689), and designated as REGN 577. REGN 577 binds to human and mouse Dll4, but does not detectably binds human Dill and JAG1. A total of 30 tumor-bearing male mice were randomized into six groups (N=5). The first group was treated subcutaneously with hFc (at 25 mg/kg) and intravenously (iv) with vehicle; the second group was treated with REGN577 sc at 5 mg/kg; the third group was treated with docetaxel iv at 4.5 mg/kg; the fourth group was treated with docetaxel iv at 6 mg/kg; the fifth group was treated with docetaxel iv at 4.5 mg/kg plus REGN577 sc at 5 mg/kg; the sixth group was treated with docetaxel iv at 6 mg/kg plus REGN577 sc at 5 mg/kg. Docetaxel and/or Dll4 antibody were administered on the same day. Animals were treated 2 times per week and received a total of 3 doses. Starting from the day of initial treatment, body weight and tumors were measured twice a week until the mice were euthanized when tumors reached ˜600 mm 3  in size. Tumor size was calculated using the formula, (length×width 2 )/2. 
     The control tumors reached the size of ˜600 mm 3  and were harvested on day 25. At Day 25, the results show that treatment with Dll4 antibody alone caused a modest reduction in tumor growth (by approximately 44%). Treatment with docetaxel alone resulted in reduced tumor growth (62% reduction for the dose of 4.5 mg/kg; and 70% reduction for the dose of 6 mg/kg). The combination treatments produced larger reductions in tumor growth (75% reduction for 4.5 mg/kg docetaxel plus Dll4 Ab; and 81% reduction for 6 mg/kg docetaxel plus Dll4 Ab) than control and either single agent treatment. TGI and TGD were determined (Table 3). 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                 TREATMENT 
                 TGI(%) at 
                 TGD 
               
               
                   
                 (mg/kg total dose) 
                 Day 25 
                 (days) 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 REGN577 5 mg/kg (15) 
                 44 
                 3 
               
               
                   
                 Docetaxel 4.5 mg/kg (13.5) 
                 62 
                 6 
               
               
                   
                 Docetaxel 6 mg/kg (18) 
                 70 
                 7 
               
               
                   
                 REGN577 5 mg/kg (15) + 
                 75 
                 10 
               
               
                   
                 Docetaxel 4.5 mg/kg (13.5) 
               
               
                   
                 REGN577 5 mg/kg (15) + 
                 81 
                 13 
               
               
                   
                 Docetaxel 6 mg/kg (18) 
               
               
                   
                   
               
            
           
         
       
     
     These results show that treatment of tumors with a combination of Dll4 blocker together with various doses of docetaxel, can delay tumor growth almost twice as long and result in greater tumor growth inhibition than either single agent. 
     Example 4 
     Effect of Anti-hDll4 Antibody in Combination with Docetaxel 
     The effect of anti-Dll4 antibody in combination with docetaxel (TAXOTERE®, sanofi-aventis) on tumor growth was evaluated on tumors implanted in Severe Combined Immunodeficiency (SCID) mice. Each mouse was implanted ‘pseudo-orthotopically’ (subcutaneously into mammary gland #3) with 5×10 6  human MDA-MB-231 breast tumor cells with MATRIGEL™ (BD Biosciences lot #84540). After the tumors were established in the mice (tumor size of ˜150-200 mm 3 , approximately 45 days after implantation), mice were treated with hFc, docetaxel, Dll4 antibody, or a combination of docetaxel plus Dll4 antibody. A total of 25 tumor-bearing male mice were randomized into five groups (N=5 mice per group). The first group was treated subcutaneously with hFc (at 25 mg/kg) and intravenously (iv) with vehicle; the second group was treated with Dll4 antibody REGN577 sc at 5 mg/kg; the third group was treated with docetaxel iv at 4.5 mg/kg; the fourth group was treated with docetaxel iv at 6 mg/kg; the fifth group was treated with docetaxel iv at 6 mg/kg plus REGN577 sc at 5 mg/kg. Docetaxel and/or Dll4 antibody were administered on the same day. Animals were treated 2 times per week and received a total of 3 doses. Starting from the day of initial treatment, body weight and tumors were measured twice a week until the mice are euthanized. Mice were euthanized when tumors reached ˜600 mm 3  in size. Tumor size was calculated using the formula (length×width 2 )/2. 
     The control tumors reached ˜600 mm 3  and were harvested on day 63. At Day 63, the results show that treatment with docetaxel alone produced modest reduction of tumor growth (37% reduction for the dose of 4.5 mg/kg; and 52% reduction for the dose of 6 mg/kg). Treatment with Dll4 antibody alone caused a significant reduction in tumor growth (approximately 85% reduction); meanwhile the combination treatment resulted in tumor regression (105% reduction for 6 mg/kg docetaxel plus Dll4 Ab). TGI and TGD were determined (Table 4). 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 4 
               
               
                   
                   
               
               
                   
                 TREATMENT 
                 TGI(%) at 
                 TGD 
               
               
                   
                 (mg/kg total dose) 
                 Day 25 
                 (days) 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 REGN577 5 mg/kg (15) 
                 85 
                 21 
               
               
                   
                 Docetaxel 4.5 mg/kg (13.5) 
                 37 
                 4 
               
               
                   
                 Docetaxel 6 mg/kg (18) 
                 52 
                 4 
               
               
                   
                 REGN577 5 mg/kg (15) + 
                 105 
                 28 
               
               
                   
                 Docetaxel 6 mg/kg (18) 
               
               
                   
                   
               
            
           
         
       
     
     Docetaxel treatment alone resulted in minimal delay in tumor growth (4 days for the dose of 4.5 mg/kg; and 4 days for the dose of 6 mg/kg). Tumors treated with Dll4 antibody alone delayed tumor growth by 21 days. The combination treatments delayed tumor growth further, compared to control and either single agent treatment (28 days for 6 mg/kg docetaxel plus Dll4 Ab; p&lt;0.5). 
     These results show that MDA-MB-231 tumors are modestly responsive to docetaxel treatment alone but are very sensitive to treatment with anti-Dll4 antibody. Combination of Dll4 blocker together with docetaxel can further delay tumor growth and slightly improve tumor growth inhibition (tumor regression) compared to either single agent. 
     Example 5 
     Effect of Anti-hDll4 Antibody in Combination with 5-FU 
     The effect of anti-Dll4 Ab (REGN421) in combination with 5-FU on tumor growth was evaluated on tumors implanted in humanized Dll4 SCID mice. Each mouse was implanted subcutaneously (sc) with 5×10 6  human HCT116 tumor cells (CRC). After the tumors were established in the mice (tumor size of ˜150 mm 3 , 22 days after implantation), tumors were measured and randomized. The mice were then treated with hFc, REGN421, 5-FU or combination of REGN421 and 5-FU. A total of 30 mice were divided into 6 groups (n=5 per cohort). The first group was treated sc with hFc at 2 mg/kg; the second group was treated sc with REGN421 at 2 mg/kg; the third and fourth groups were treated ip with 5-FU at 15 and 25 mg/kg, respectively; the fifth group was treated sc with REGN421 at 2 mg/kg and ip with 5-FU at 15 mg/kg; and the sixth group was treated sc with REGN421 at 2 mg/kg and ip with 5-FU at 25 mg/kg. REGN421 was administered every 3-4 days starting on day 22 and mice received three doses total. 5-FU was administered every 3-4 days starting on day 22 and mice received three doses total. 
     To assess the effects of REGN421 and 5-FU as single agents or in combination, the changes in tumor size (volume) were measured, beginning three days before the initial REGN421 treatment, and then on the day of each agent treatment (days 22, 26, 29) and thereafter every 3-4 days until tumors reach ˜600 mm 3  in size. In vivo tumor size is calculated using the formula (length×width 2 )/2 ( FIG. 3  and Table 5). 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 5 
               
               
                   
                   
               
               
                   
                 TREATMENT 
                 TGI(%) at 
                 TGD 
               
               
                   
                 (mg/kg total dose) 
                 Day 39 
                 (days) 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 REGN421 2 mg/kg (6) 
                 36.3 
                 6 
               
               
                   
                 5-FU 15 mg/kg (45) 
                 5.6 
                 4 
               
               
                   
                 5-FU 25 mg/kg (75) 
                 0 
                 2 
               
               
                   
                 REGN421 2 mg/kg (6) + 
                 66.8 
                 7 
               
               
                   
                 5-FU 15 mg/kg 15 mg/kg (45) 
               
               
                   
                 REGN421 2 mg/kg (6) + 
                 63.3 
                 7 
               
               
                   
                 5-FU 25 mg/kg (75) 
               
               
                   
                   
               
            
           
         
       
     
     5-FU treatment alone resulted in minimal delay in tumor growth (4 days for the total dose of 45 mg/kg; and 2 days for the total dose of 75 mg/kg). Tumors treated with Dll4 antibody alone delayed tumor growth by 6 days. The combination treatments delayed tumor growth further, compared to control (p&lt;0.043). 
     Example 6 
     Effect of Anti-hDll4 Antibody in Combination with Irinotecan 
     The effect of anti-Dll4 Ab (REGN421) in combination with irinotecan (irinotecan hydrochloride) on tumor growth was evaluated on tumors implanted in humanized Dll4 SCID mice. 
     Each mouse was implanted subcutaneously (sc) with 5×10 6  human HCT116 tumor cells. After the tumors were established in the mice (tumor size of ˜150 mm 3 , 15 days after implantation), tumors were measured and randomized. The mice were then treated with hFc, REGN421, irinotecan or combination of REGN421 and irinotecan. A total of 30 mice were divided into 6 groups (n=5 per cohort). The first group was treated sc with hFc at 2 mg/kg; the second group was treated sc with REGN421 at 2 mg/kg; the third and fourth groups were treated ip with irinotecan at 7.5 and 25 mg/kg, respectively; the fifth group was treated sc with REGN421 at 2 mg/kg and ip with irinotecan at 7.5 mg/kg; and the sixth group was treated sc with REGN421 at 2 mg/kg and ip with irinotecan at 25 mg/kg. REGN421 was administered every 3-4 days starting on day 15 and mice received three doses total. Irinotecan was administered every 3-4 days starting on day 15 and mice received three doses total. 
     To assess the effects of REGN421 and irinotecan as single agents or in combination treatments, the changes in tumor size (volume) are measured, starting three days before the initial REGN421 treatment, and then on the day of each agent treatment (days 15, 19, 22) and thereafter every 3-4 days until tumors reach ˜600 mm 3  in size. In vivo tumor size is calculated using the formula (length×width 2 )/2. Results are shown in  FIG. 4  and Table 6. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 6 
               
               
                   
                   
               
               
                   
                 TREATMENT 
                 TGI(%) at 
                 TGD 
               
               
                   
                 (mg/kg total dose) 
                 Day 39 
                 (days) 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 REGN421 2 mg/kg (6) 
                 81.3 
                 9 
               
               
                   
                 Irinotecan 7.5 mg/kg (22.5) 
                 71.2 
                 8 
               
               
                   
                 Irinotecan 25 mg/kg (75) 
                 100.5 
                 16 
               
               
                   
                 REGN421 2 mg/kg (6) + 
                 91.5 
                 10 
               
               
                   
                 Irinotecan 7.5 mg/kg (22.5) 
               
               
                   
                 REGN421 2 mg/kg (6) + 
                 119.6 
                 19 
               
               
                   
                 Irinotecan 25 mg/kg (75) 
               
               
                   
                   
               
            
           
         
       
     
     Irinotecan treatment alone resulted in delay in tumor growth (8 days for the total dose of 22.5 mg/kg; and 16 days for the total dose of 75 mg/kg). Tumors treated with Dll4 antibody alone delayed tumor growth by 9 days. The combination treatments significantly improved anti-tumor efficacy and delayed tumor growth further, compared to either single agent treatment (19 days for 75 mg/kg irinotecan plus Dll4 Ab; p&lt;0.0001). 
     Example 7 
     Effect of Anti-hDll4 Antibody on Hey1 Gene Expression in Colo205 Tumor 
     The effect of anti-hDll4 antibody on differential gene expression in tumors was studied in humanized Dll4 SCID mice implanted with human Colo205 colorectal tumor cells. Briefly, Male and female humanized Dll4 SCID mice were subcutaneously implanted with 2×10 6  Colo205 cells per mouse. When the tumors reached ˜150 mm 3 , mice (4 animals per group) were treated with a single dose of REGN421 at 0.5, 5 or 15 mg/kg, or of hFc control at 15 mg/kg. The tumors were excised at 5 hrs, 10 hrs, 24 hrs, 72 hrs and 7 days after the treatment and stored in RNA later stabilization reagent (Qiagen). Tumor RNA was purified using the RNEASY® Midi Kit (Qiagen). Tissue was homogenized in lysis buffer containing β-mercaptoethanol in a mixer mill, loaded onto the columns and unbound contaminants washed through. DNase I digestion was performed on the column and RNA was eluted in RNase-free water. Cyanine 3 (Cy3)-CTP was incorporated into amplified cRNA from 500 ng of total RNA using the QUICK AMP™ RNA Amplification Kit (Agilent Technologies). Cy3-labeled cRNA from each sample was then hybridized to a custom array covering both the mouse and human transcriptome. The hybridization and wash of the arrays were performed according to the manufacture&#39;s protocol and arrays were scanned on an Agilent Microarray scanner. The data were extracted from scanned array images using the Agilent Feature Extraction Software 9.5. 
     To identify genes differentially expressed between control and treatment groups, per-chip median centering is applied to the complete genomic profile of each sample. Gene expression values are then compared between two groups using a random variance model t-test (Simon, R. A. et al., 2007, “Analysis of Gene Expression Data Using BRB-Array Tools”,  Cancer Inform  3:11-7). Those genes with a mean difference greater than 1.5-fold and p-value&lt;0.05 between the two groups are selected and ranked descending fold change. A global test is also performed in which the individual sample labels are permuted up to 1000 times and the gene selection process is repeated. This determines if the number of genes identified as differentially expressed between the two groups is more than would be expected by chance alone. 
     Hey1 is a member of Hey family that has been identified as immediate downstream targets of Notch activation and it has been shown that inhibition of Dll4-Notch pathway signaling in tumors in vivo in mice studies results in the reduction of Hey-1 RNA levels (Noguera-Troise, I et al., 2006,  Nature  444(7122):1032-7). As shown in  FIG. 5 , analysis of Hey1 mRNA levels in the current study using microarray revealed that Hey1 mRNA levels were decreased in the REGN421-treated mice compared to control hFc-treated mice starting at 10 hours post-treatment, but were most significantly decreased at 72 hours and 7 days post-treatment. No significant decrease was observed at 0.5 mg/kg, i.e., the lowest dose of REGN421. These results indicated that REGN421 effectively blocked the Notch signal pathway and that Hey1 could be a useful pharmacodynamic marker for inhibition of Notch signaling by a Dll4 antibody. 
     Example 8 
     Preliminary Pharmacokinetic Study in Phase I 
     REGN421 is currently being studied in a first-in-human trial. The primary objective of the study is to determine the recommended dose of REGN421 for future efficacy trials. The secondary objectives are to characterize the drug safety profile, its pharmacokinetics, immunogenicity, and pharmacodynamics, as well as preliminary evidence of efficacy. In this study, anti-hDll4 antibody REGN 421 is administered intravenously every 3 weeks to patients whose cancer has progressed on conventional therapy. The study design follows standard methodology for dose escalation and definition of dose-limiting toxicity. To date, 7 patients have been treated at 0.25 mg/kg/dose every three weeks, and 6 patients have been treated at 0.50 mg/kg/dose every three weeks. For the pharmacokinetic study, blood samples were taken at pre-dose, 0 hour, and post-dose 1, 2, 4 and 8 hours on Day 1, followed by Days 2, 3, 4, 8 and 15 of Cycle 1; and pre-dose, 0 hour on Day 1 of Cycles 2, and post-treatment follow-up on Days 15, 30 and 60. Plasma/serum levels of REGN421 in the samples are measured by ELISA with an upper limit of quantification of 2.5 μg/mL and a lower limit of quantification of 0.039 μg/mL in the undiluted serum sample. The study is ongoing with the intent to administer higher doses, defined in the protocol as 1, 2, 4, and 7 mg/kg/dose. 
     The currently available data showing plasma pharmacokinetic parameters following single 30-min. IV infusion of REGN421 at 0.25 mg/kg (7 patients) and 0.5 mg/kg (2 patients), are shown in Table 7. C max : Maximum serum concentration of the drug; T last : Time to the last quantifiable concentration of the drug; C last : Last quantifiable concentration of the drug; AUC last : Area under curve up to the last concentration of the drug; AUC: Total area under the curve (i.e., drug exposure); t 1/2Z : Terminal half life; V ss : Volume of distribution at steady state; CL: Drug clearance rate. Values are: mean, (CV %), and [range] (a: median [range]). 
     
       
         
           
               
               
               
               
               
               
               
               
               
             
               
                 TABLE 7 
               
               
                   
               
               
                 Dose 
                 C max   
                 T last   a   
                 C last   
                 AUC last   
                 AUC 
                 T 1/2Z   
                 V ss   
                 CL 
               
               
                 (mg/kg) 
                 (μg/mL) 
                 (h) 
                 (μg/mL) 
                 (μg*h/mL) 
                 (μg*h/mL) 
                 (h) 
                 (L) 
                 (L/h) 
               
               
                   
               
             
            
               
                 0.25 
                 6.27 
                 170 
                 0.51 
                 452 
                 489 
                 47.1 
                 2.85 
                 0.0473 
               
               
                 (n = 7) 
                 (30.5) 
                 [72-240] 
                 (57.7) 
                 (56.7) 
                 (55.9) 
                 (33.5) 
                 (27.3) 
                 (39.5) 
               
               
                 0.5  
                 9.88 
                 203 
                 2.24 
                 759 
                 963 
                 92.3 
                 3.64 
                 0.0355 
               
               
                 (n = 2) 
                 [9.25-10.5] 
                 [73-333] 
                 [0.976-3.51] 
                 [479-1040] 
                 [684-1240] 
                 [40.6-144] 
                 [2.65-4.63] 
                 [0.0273-0.0436] 
               
               
                   
               
            
           
         
       
     
     As shown in Table 7, peak serum concentrations of REGN421 were average values of 6.27 μg/mL at the 0.25 mg/kg dose level, and 9.88 μg/mL at the 0.50 mg/kg dose level. These values are in the range of REGN421 concentrations associated with anti-tumor activity in animal xenograft models. 
     The pharmacodynamic effect of REGN421 on the Dll4-notch signaling pathway has been analyzed using microarray technology on the patient serum samples collected prior to as well as 24 hours following REGN421 administration. The results are shown in Table 8. 
     
       
         
           
               
               
               
             
               
                 TABLE 8 
               
               
                   
               
               
                   
                 Dose 
                 Hey-1 transcript Post-treatment 
               
               
                 Patient 
                 (mg/kg) 
                 vs. Pre-treatment ratio 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 1 
                 0.25 
                 0.52 
               
               
                 2 
                 0.25 
                 0.85 
               
               
                 3 
                 0.25 
                 0.77 
               
               
                 4 
                 0.25 
                 0.51 
               
               
                 5 
                 0.25 
                 0.61 
               
               
                 6 
                 0.25 
                 0.55 
               
               
                 7 
                 0.25 
                 0.75 
               
               
                 8 
                 0.5 
                 0.68 
               
               
                 9 
                 0.5 
                 0.82 
               
               
                   
               
            
           
         
       
     
     As shown in Table 8, the expression of the Hey-1 gene upon REGN421 administration was reduced compared to pre-treatment samples, in all samples. As observed in the xenograft tumor model in humanized Dll4 SCID mice (see Example 7 above), the findings suggest that REGN421 is indeed inhibiting the biological activity of Dll4 in humans. 
     Example 9 
     Dll4 Ab in Combination with Gemcitabine to Phase I Patients 
     The study will be conducted in adult patients with advanced or metastatic cancer that is refractory to standard therapy or have no approved treatment options. Patients who are diagnosed The study will be conducted in adult patients with advanced or metastatic cancer that is refractory to standard therapy or have no approved treatment options. Patients who are diagnosed to have advanced solid malignancies according to pathological, physical and radiological examination, with an ECOG (Eastern Cooperative Oncology Group) performance status score of 0-2 (0-5 scale) and adequate renal, hepatic and hematological laboratory parameters are eligible for participation in the study. Patients are allowed to receive concurrent supportive care, such as blood transfusions and analgesics, during the study. Patients may have received prior chemotherapy or biologic therapy for metastatic disease. Patients are assigned in sequential dosing cohorts in a 3+3 design. Three patients will be enrolled at one dose level and, if no dose limiting toxicities (DLT) occur, dose escalation to the next dose level will transpire. If 1 of the first 3 patients experiences a DLT, then 3 additional patients may be enrolled at that dose level. If 2 of the first 3 patients experience a DLT, then that dose level will be considered to have excessive toxicity, and 3 additional patients will be enrolled at the previous dose level. Patients will receive Day 1: anti-Dll4 antibody (e.g., REGN421 or REGN281) at 0.25 to 10 mg/kg IV over 30 minutes plus gemcitabine 1250 mg/m 2  IV infusion over 30 minutes and Day 8: gemcitabine 1250 mg/m 2  IV infusion over 30 minutes. The combination regimen is repeated every 3 weeks until cancer progression or intolerable toxicity develops. 
     The primary end point is to assess the safety, tolerability, and dose-limiting toxicities of the anti-Dll4 antibody in combination with gemcitabine and to identify the maximum tolerated dose (MTD) of the anti-Dll4 antibody in combination with gemcitabine in patients with advanced solid malignancies. The secondary end points include a description of antitumor activity according to RECIST criteria (by Eisenhauer et al., 2009,  Eur J Cancer  4 5:228-247), assessment of the pharmacokinetic (PK) profile of the anti-Dll4 antibody when given in combination with gemcitabine and determination of immunogenicity to the anti-Dll4 antibody. Disease remission is evaluated using physical examination, radiological methods (X-Ray, Computed Tomography, or Magnetic Resonance Imaging). Adverse events are assessed using the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE v 4.0, available under Cancer Therapy Evaluation Program or CTEP at the National Cancer Institute web site). Serum samples are taken from the patients to measure the concentrations of the anti-Dll4 antibody as well as the presence of possible antibodies against the anti-Dll4 antibody. 
     Example 10 
     Administration of Dll4 Ab and FOLFOX to CRC Patients 
     Briefly, adult patients who are diagnosed to have locally advanced or metastatic colorectal cancer according to pathological, physical and radiological examination, with an ECOG (Eastern Cooperative Oncology Group) performance status score of 0-2 (0-5 scale) and adequate renal, hepatic and hematological laboratory parameters are eligible for participation in the study. Patients are allowed to receive concurrent supportive care, such as blood transfusions and analgesics, during the study. Patients may not have received prior chemotherapy (or anti-angiogenic, or anti EGFR therapy) for metastatic disease; prior such therapy for the adjuvant treatment of their disease is allowed, and must have been completed at least 12 months prior to enrollment on this study. The patients are randomly assigned in a 1:1 ratio to receive intravenous FOLFOX chemotherapy (Day 1: Oxaliplatin 85 mg/m 2  IV infusion and leucovorin (folinic acid) 200 mg/m 2  IV infusion, followed by 5-FU 400 mg/m 2  IV bolus given over 2-4 minutes, followed by 5-FU 600 mg/m 2  IV as a 22-hour continuous infusion. Day 2: Leucovorin 200 mg/m 2  IV infusion, followed by 5-FU 400 mg/m 2  IV bolus given over 2-4 minutes, followed by 5-FU 600 mg/m 2  IV infusion as a 22-hour continuous infusion) with bevacizumab (AVASTIN®: Humanized monoclonal Ab against vascular endothelial growth factor (VEGF), Genentech) (Day 1: 10 mg/kg IV) every 2 weeks, or an anti-Dll4 antibody (REGN421) at 0.25 to 10 mg/kg IV on day 1, in combination with the previously mentioned treatment. The treatment is repeated every 2 weeks until cancer progression or intolerable toxicity develops. 
     The primary end point is the proportion of patients who have achieved at least a partial remission (a 30% or more decrease in the sum of diameters of identified cancer lesions, according to RECIST criteria (by Eisenhauer et al., 2009, supra) and the secondary end points include time to tumor progression, and overall survival. Disease remission is evaluated using physical examination, radiological methods (X-Ray, Computed Tomography, or Magnetic Resonance Imaging), and the Carcino-Embryonic Antigen (CEA) level measured in serum. Other clinical parameters, such as adverse events are also assessed, using the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE v 4.0, supra). The patients&#39; serum samples are taken to measure the serum concentrations of the anti Dll4 antibody as well as the presence of possible antibodies against the anti-Dll4 antibody.  
     Example 11 
     Phase II of Dll4 Ab in Combination with Docetaxel 
     The study will be conducted in adult patients with advanced inoperable or metastatic breast cancer. They may have failed prior adjuvant therapy. Patients who are diagnosed to have breast cancer according to pathological, physical and radiological examination, with an ECOG (Eastern Cooperative Oncology Group) performance status score of 0-2 (in 0-5 scale) and adequate renal, hepatic and hematological laboratory parameters are eligible for participation in the study. Patients are allowed to receive concurrent supportive care, such as blood transfusions and analgesics, during the study. Patients may not have received prior chemotherapy or biologic therapy for metastatic disease. A sequential cohort of up to 100 patients will be treated after successfully passing screening procedures to determine patient eligibility. Patients will receive Day 1: anti-Dll4 antibody (REGN421) at 0.25 to 10 mg/kg IV over 30 minutes plus docetaxel 75 mg/m 2  IV infusion over 30 minutes. The combination regimen is repeated every 3 weeks until cancer progression or intolerable toxicity develops. 
     The primary end point is to assess the efficacy of the treatment based on tumor response rate according to RECIST criteria (by Eisenhauer et al., 2009,  Eur J Cancer  4 5:228-247), and time to disease progression. Secondary endpoints will include a description of the safety and of the pharmacokinetic (PK) profile of the anti-Dll4 antibody when given in combination with docetaxel as well as determination of immunogenicity to the anti-Dll4 antibody. Disease remission is evaluated using physical examination, radiological methods (X-Ray, Computed Tomography, or Magnetic Resonance Imaging). Adverse events are assessed using the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE v 4.0, available under Cancer Therapy Evaluation Program or CTEP at the National Cancer Institute web site). Serum samples are taken from the patients to measure the concentrations of the anti-Dll4 antibody as well as the presence of possible antibodies against the anti-Dll4 antibody. 
     Example 12 
     A Phase II Study of Dll4 Ab with Cisplatin/Gemcitabine 
     The study will be conducted in adult patients with advanced inoperable or metastatic bladder cancer. Patients who are diagnosed to have invasive bladder cancer according to pathological, physical and radiological examination, with an ECOG (Eastern Cooperative Oncology Group) performance status score of 0-2 (in 0-5 scale) and adequate renal, hepatic and hematological laboratory parameters are eligible for participation in the study. Patients are allowed to receive concurrent supportive care, such as blood transfusions and analgesics, during the study. Patients may not have received prior chemotherapy or biologic therapy for metastatic disease. A sequential cohort of up to 100 patients will be treated after successfully passing screening procedures to determine patient eligibility. Patients will receive anti-Dll4 antibody (REGN421) at 0.25 to 10 mg/kg IV over 30 minutes on day 1 plus gemcitabine 1,000 mg/m 2  over 30 to 60 minutes on days 1, 8, and 15, plus cisplatin 70 mg/m 2  on day 2. The combination regimen is repeated every 4 weeks until cancer progression or intolerable toxicity develops. 
     The primary end point is to assess the efficacy of the treatment based on tumor response rate according to RECIST criteria (by Eisenhauer et al., 2009,  Eur J Cancer  4 5:228-247), and time to disease progression. Secondary endpoints will include safety profile and a description of the pharmacokinetic (PK) profile of the anti-Dll4 antibody when given in combination with docetaxel and determination of immunogenicity to the anti-Dll4 antibody. Disease remission is evaluated using physical examination, radiological methods (X-Ray, Computed Tomography, or Magnetic Resonance Imaging). Adverse events are assessed using the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE v 4.0, available under Cancer Therapy Evaluation Program or CTEP at the National Cancer Institute web site). Serum samples are taken from the patients to measure the concentrations of the anti-Dll4 antibody as well as the presence of possible antibodies against the anti-Dll4 antibody.