Patent Publication Number: US-2023159640-A1

Title: Carrier-pd-l1 binding agent compositions for treating cancers

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/330,030 filed on Mar. 1, 2019, which is a U.S. National Stage Filing under 35 U.S.C. § 371 of International Patent Application Serial No. PCT/US2017/049746 filed Aug. 31, 2017 and entitled “CARRIER-PD-L1 BINDING AGENT COMPOSITIONS FOR TREATING CANCERS”, which claims priority to U.S. Provisional Patent Application No. 62/382,731 filed Sep. 1, 2016, all of which are hereby incorporated by reference in their entirety. 
    
    
     FIELD OF THE INVENTION 
     This application relates to novel compositions of binding agents and carrier proteins and methods of making and using the same, in particular, as a cancer therapeutic. 
     BACKGROUND 
     Chemotherapy remains a mainstay for systemic therapy for many types of cancer, including melanoma. Most chemotherapeutic agents are only slightly selective to tumor cells, and toxicity to healthy proliferating cells can be high (Allen TM. (2002)  Cancer  2:750-763), often requiring dose reduction and even discontinuation of treatment. In theory, one way to overcome chemotherapy toxicity issues as well as improve drug efficacy is to target the chemotherapy drug to the tumor using antibodies that are specific for proteins selectively expressed (or overexpressed) by tumors cells to attract targeted drugs to the tumor, thereby altering the biodistribution of the chemotherapy and resulting in more drug going to the tumor and less affecting healthy tissue. Despite 30 years of research, however, specific targeting rarely succeeds in the therapeutic context. 
     Conventional antibody dependent chemotherapy (ADC) is designed with a toxic agent linked to a targeting antibody via a synthetic protease-cleavable linker. The efficacy of such ADC therapy is dependent on the ability of the target cell to bind to the antibody, the linker to be cleaved, and the uptake of the toxic agent into the target cell. Schrama, D. et al. (2006)  Nature reviews. Drug discovery  5:147-159. 
     Antibody-targeted chemotherapy promised advantages over conventional therapy because it provides combinations of targeting ability, multiple cytotoxic agents, and improved therapeutic capacity with potentially less toxicity. Despite extensive research, clinically effective antibody-targeted chemotherapy remains elusive: major hurdles include the instability of the linkers between the antibody and chemotherapy drug, reduced tumor toxicity of the chemotherapeutic agent when bound to the antibody, and the inability of the conjugate to bind and enter tumor cells. In addition, these therapies did not allow for control over the size of the antibody-drug conjugates. 
     There remains a need in the art for antibody-based cancer therapeutics that retain cytotoxic effect for targeted drug delivery to provide reliable and improved anti-tumor efficacy over prior therapeutics. 
     The programmed cell death protein-1 (PD-1, also known as CD279, hereinafter “PD-1”) receptor is expressed on the surface of activated T cells, B cells, as well as myeloid cells. PD-1 ligands include programmed death ligand-1 (PD-L1, also known as B7-H1, CD274, hereinafter “PD-L1”) and programmed death ligand-2 (PD-L2, also known as B7-DC and CD273, hereinafter “PD-L2”), and are commonly expressed on the surface of dendritic cells or macrophages. PD-L1 is expressed on many tumors including cancers developing in various organs such as head and neck, lung, stomach, colon, pancreas, breast, kidney, bladder, ovary, cervix, as well as melanoma, glioblastoma, multiple myeloma, lymphoma, and various leukemias. PD-L1 is commonly over-expressed on the surface of tumor cells, for example, metastatic non-small cell lung carcinomas (NSLC). 
     When binding to the PD-1 receptors of activated T cells, the PD-L1 expressing tumor cells can exploit the inhibitory signaling of the PD-1 pathway, thereby limiting or even halting a host&#39;s own anti-tumor immune responses from T cells. On the flip side of this inhibitory signaling, the blocking or interference of the interaction of PD-1 to PD-L1/PD-L2 would disrupt the inhibition signaled by the pathway. As such, immunotherapies based on antibodies against PD-1, PD-L1 or PD-L2 aim to overcome such immune response resisting ability of tumors and to restore or re-stimulate a host&#39;s own immune mechanism against tumors. 
     Accordingly, there is a need for increasing the therapeutic effectiveness of an immunotherapy treatment of a patient suffering from a cancer which expresses PD-L1 or PD-L2. 
     SUMMARY 
     It has been unexpectedly and surprisingly found that the therapeutic effectiveness of an immunotherapy treatment of a patient suffering from a cancer which expresses PD-L1 or PD-L2 can be increased by the administration of (a) a therapeutically effective amount of nanoparticles or a nanoparticle composition as described herein, wherein the nanoparticles are capable of binding to PD-L1 or PD-L2, and (b) a PD-1 immunotherapy. 
     Both anti-PD-1 and anti-PD-L1 antibodies have been developed and approved for treating various cancers. Anti-PD-1 antibodies include, but are not intended to be limited to, Nivolumab (OPDIVO®), developed by Bristol-Myers Squibb U.S. and approved in the U.S. for treatment of metastatic melanoma and squamous NSCL cancer; Pembrolizumab (KEYTRUDA®), developed by Merck U.S. and approved for treatment of metastatic melanoma. Anti-PD-L1 antibodies include, but are not intended to be limited to, atezolizumab (TECENTRIQ®), developed by Roche, Switzerland (Genentech U.S.) and approved for treatment of the most common type of bladder cancer, i.e., urothelial carcinoma; BMS-936559/MDX-1105 (Bristol Myers Squibb), MeDI4736 (MedImmune/AstraZeneca), and MSB00100718C (EMD Serono). See, e.g., Philips and Atkins “Therapeutic uses of anti-PD-1 and anti-PD-Ll antibodies” International Immunology Vol. 27(1) pp. 39-46. 
     Atezolizumab is a humanized monoclonal antibody targeting the PD-1 pathway so as to block the immune checkpoint inhibition signaled thereby. The PD-1 pathway refers herein to the signaling of the inhibition of T cell immune responses upon the interaction of the PD-1 and PD-L1/PD-L2. Therapies using other anti-PD-L1 antibodies (e.g., avelumab, durvalumab, BMS 936559,) for treating various other types of cancers including, for example, non-squamous NSCLC, renal cell carcinoma and bladder cancer, are under investigation and development as well. 
     Like PD-L1, PD-L2 binds to PD-1. Human PD-L1 and PD-L2 are reported to share about 41 per cent of amino acide sequence identity with each other and have similar functionality. The binding of PD-L2 with PD-1 also inhibits T cell proliferation as well as cytokine production, demonstrating a similar inhibitory regulation of T cell immune responses. Therapies using anti-PD-L2 antibodies for treating various other types of cancers including, for example, non-squamous NSCLC, renal cell carcinoma and bladder cancer, are also under investigation and development. 
     According to the present invention, the nanoparticles comprise (a) carrier protein (b) a first binding agent, and (c) optionally a therapeutic agent, wherein the nanoparticles are capable of binding to PD-L1 or PD-L2. In a preferred embodiment, the nanoparticles are held together by non-covalent bonds between one or more of the components of the nanoparticles (carrier protein, binding agents, and/or therapeutic agent). 
     In one aspect, a method for treating a patient suffering from a cancer which expresses PD-L1 or PD-L2 is provided, where the method comprises administering to the patient (a) nanoparticles (or a nanoparticle composition comprising nanoparticles), wherein each of the nanoparticles comprise a carrier protein, first binding agents having an antigen binding portion, wherein said antigen is PD-L1 or PD-L2, and optionally at least one therapeutic agent, wherein the nanoparticles are capable of binding to PD-L1 or PD-L2, and (b) a PD-1 immunotherapy. In one embodiment, the PD-1 immunotherapy comprises a second binding agent capable of binding to PD-1. 
     In another aspect, the present invention relates to a method for increasing the therapeutic effectiveness of an immunotherapy treatment of a patient suffering from a cancer which expresses PD-L1 or PD-L2, the method comprising administering to the patient (a) a therapeutically effective amount of a nanoparticle composition as described herein, and (b) a PD-1 immunotherapy. In one embodiment, the PD-1 immunotherapy comprises administering a second binding agent capable of binding to PD-1. 
     In one aspect, the present invention relates to a method for treating a patient suffering from a cancer which expresses PD-L1 or PD-L2, where the method comprises administering to the patient (a) nanoparticles (or a nanoparticle composition comprising nanoparticles), wherein each of the nanoparticles comprise albumin, antibodies having an antigen-binding portion, wherein said antigen is PD-L1 or PD-L2, and paclitaxel; such that the nanoparticles are capable of binding to PD-L1 or PD-L2, and (b) a PD-1 immunotherapy. In one embodiment, the PD-1 immunotherapy comprises a second antibody capable of binding to PD-1 (an anti-PD-1 antibody). In one embodiment, the antibody is an anti-PD-L1 antibody. In one embodiment, the antibody is an anti-PD-L2 antibody. 
     In some embodiments, a CTLA-4 immunotherapy is administered to the patient in combination with the nanoparticles that are capable of binding PD-L1 or PD-L2. In one embodiment, the CTLA-4 immunotherapy is administered in addition to the PD-1 immunotherapy. In one embodiment, the CTLA-4 immunotherapy is administered instead of the PD-1 immunotherapy. In one embodiment, the CTLA-4 immunotherapy is an anti-CTLA-4 antibody. 
     In one aspect, each of the nanoparticles of the nanoparticle composition comprises between about 400 to about 1000 said first binding agents. 
     In some aspects, the first binding agents are aptamers. In some aspects, the second binding agent of the PD-1 immunotherapy is an aptamer. 
     In some aspects, the first binding agents are antibodies (e.g., anti-PD-L1 antibodies or anti-PD-L2 antibodies). In some aspects, the second binding agent of the PD-1 immunotherapy is an antibody (e.g., an anti-PD-1 antibody). In some aspects, the anti-PD-1 antibody comprises nivolumab, pembrolizumab, pidilizumab, PDR001, or biosimilars thereof. In some aspects, the anti-PD-L1 antibody is atezolizumab, avelumab, durvalumab, or BMS 936559 (MDX1105). In some aspects, the binding agent of the CTLA-4 immunotherapy is an anti-CTLA-4 antibody. In one embodiment, the anti-CTLA-4 antibody is ipilimumab. 
     In some aspects, the first binding agent and/or the second binding agent is a fusion protein. In one embodiment, the fusion protein is AMP-224 (PD-L2 IgG2a fusion protein; Amplimmune/GlaxoSmith Klein); AMP-514 (MEDI0680) (PD-L2 fusion protein; Amplimmune/GlaxoSmith Klein), or a biosimilar thereof. 
     In some aspects, the nanoparticles or nanoparticle composition is lyophilized. 
     In some aspects, the second binding agent of the PD-1 immunotherapy is a free binding agent, wherein the free binding agent is not complexed with or otherwise integrated onto and/or into a nanoparticle composition. 
     In some aspects, PD-1 immunotherapy is an immunotherapy nanoparticle composition comprising the second binding agent complexed with or integrated onto and/or into a nanoparticle composition, wherein the immunotherapy nanoparticle composition comprises a carrier protein and said second binding agent. 
     In some aspects, the second binding agent of the immunotherapy nanoparticle composition is an antibody. In some aspects, the second binding agent of the immunotherapy nanoparticle composition is an anti-PD-1 antibody. In some aspects, the antibody of the immunotherapy nanoparticle composition comprises atezolizumab, nivolumab, pembrolizumab, avelumab or durvalumab, pidilizumab, BMS 936559, PDR001, or a biosimilar thereof. 
     In some aspects, the second binding agent of the immunotherapy nanoparticle composition is a fusion protein. In one embodiment, the fusion protein is AMP-224 (PD-L2 IgG2a fusion protein; Amplimmune/GlaxoSmith Klein); AMP-514 (MEDI0680) (PD-L2 fusion protein; Amplimmune/GlaxoSmith Klein), or a biosimilar thereof. 
     In some aspects, the second binding agent of the immunotherapy nanoparticle composition is an aptamer. In some aspects, the second binding agent of the immunotherapy nanoparticle composition is a PD-1 aptamer. 
     In some aspects, the immunotherapy nanoparticle and/or nanoparticle composition is lyophilized. 
     In some aspects, the nanoparticle composition and the PD-1 immunotherapy are administered sequentially. In some aspects, the nanoparticle composition is administered prior to administration of the PD-1 immunotherapy. In some aspects, the PD-1 immunotherapy is administered prior to administration of the nanoparticle composition. In some aspects, the nanoparticle composition and the PD-1 immunotherapy are administered concurrently. 
     In some embodiments, the present invention relates to a method for increasing the therapeutic effectiveness of an immunotherapy treatment of a patient suffering from a cancer which expresses PD-L1 or PD-L2. In one embodiment, the method comprises administering to the patient a therapeutically effective amount of the nanoparticles or nanoparticle composition as described herein, and a PD-1 or CTLA-4 immunotherapy comprising a second binding agent. In one embodiment, the second binding agent is capable of binding to PD-1 or CTLA-4. In one embodiment, PD-1 or CTLA-4 immunotherapy comprises nanoparticles comprising a carrier protein (e.g., albumin) and the second binding agent, and optionally a therapeutic agent (e.g., paclitaxel). 
     In some embodiments, the present invention relates to a method for treating a patient suffering from a cancer which expresses PD-LI or PD-L2. In some embodiments, the method comprises administering to the patient a therapeutically effective amount of a nanoparticle composition as described herein, and administering top the patient an immunotherapy comprising a second binding agent, wherein the binding agents of the nanoparticle composition are capable of binding to PD-L1, PD-L2, or PD-1, and the second binding agent of the immunotherapy is capable of binding to PD-L1, PD-L2, or PD-1 . 
     Without being bound by theory, the binding agent is believed to be bound by the carrier protein through hydrophobic interactions, which, by their nature, are weak. Yet the activity of the individual components, as well as their relative relationship in the nanoparticle are preserved despite lyophilization and reconstitution of the composition. It is still further contemplated that binding to the carrier protein, e.g., complexation of the binding agent to the carrier protein, occurs through an albumin binding motif on the binding agent, and/or an antibody-binding motif on the carrier protein. Albumin-binding motifs and antibody-binding motifs are described in PCT Application No. PCT/US17/45643 , filed August 4, 2017, which is incorporated herein by reference in its entirety. In some embodiments, the binding agent is a non-therapeutic and non-endogenous human antibody, a fusion protein, or an aptamer. 
     Further challenges are imposed because the nanoparticles are used in therapy. 
     While rearrangement of the hydrophobic components in the nanoparticle may be mitigated through covalent bonds between the components, such covalent bonds pose challenges for the therapeutic use of nanoparticles in cancer treatment. The binding agent, carrier protein, and additional therapeutic agent typically act at different locations in a tumor and through different mechanisms. Non-covalent bonds permit the components of the nanoparticle to dissociate at the tumor. Thus, while a covalent bond may be advantageous for lyophilization, it may be disadvantageous for therapeutic use. 
     The size of nanoparticles, and the distribution of the size, is also important. Nanoparticles may behave differently according to their size. At large sizes, nanoparticles or the agglomeration of the particles may block blood vessels either of which can affect the performance and safety of the composition. 
     When administered intravenously, large particles (e.g. greater than 1μm) are typically disfavored because they can become lodged in the microvasculature of the lungs. At the same time, larger particles can accumulate in the tumor or specific organs. For example, TheraSphere® 20-60 micron glass particles that are injected into the hepatic artery feeding a tumor of the liver for the delivery of a radioactive element, also known as radioembolization, are in clinical use for liver cancer. 
     Therefore, for intravenous administration, particles under 1μm are used. Particles over 1μm are, more typically, administered directly into a tumor (“direct injection”) or into an artery feeding into the site of the tumor. 
     Finally, cryoprotectants and agents that assist in the lyophilization process must be safe and tolerated for therapeutic use. 
     Without wishing to be bound by theory, the binding agent is believed to be bound to the carrier protein through hydrophobic interactions which, by their nature, are weak. Yet, the activity of the individual components, and their relative relationship in the nanoparticle are still achieved despite lyophilization and reconstitution of the composition. 
     In one aspect, provided herein are nanoparticle compositions comprising nanoparticles wherein each of the nanoparticles comprises a carrier protein, binding agents, and optionally at least one therapeutic agent, wherein the binding agents are arranged outward from the surface of the nanoparticles and wherein the nanoparticles are capable of binding to PD-L1, PD-L2, or PD-1 in vivo. 
     In another aspect, provided herein are nanoparticle compositions comprising nanoparticles wherein each of the nanoparticles comprises a carrier protein that is not albumin, binding agents, and optionally at least one therapeutic agent, wherein the binding agents are arranged on an outside surface of the nanoparticles and wherein the nanoparticles are capable of binding to PD-L1, PD-L2, or PD-1 in vivo. In one embodiment, the nanoparticles comprise between about 100 to about 1000 binding agents, preferably about 400 to about 800 binding agents. When nanoparticles multimerize, the number of binding agents is increased proportionally. For example, if a 160 nm nanoparticle contains 400 binding agents, a 320 nm dimer contains about 800 binding agents. 
     In another aspect, provided herein are nanoparticle compositions comprising nanoparticles, wherein each of the nanoparticles comprises carrier protein binding agents, and optionally at least one therapeutic agent that is not paclitaxel, wherein the nanoparticles are capable of binding to PD-L1, PD-L2, or PD-1 in vivo. In one embodiment, the nanoparticles further comprise paclitaxel. In one embodiment, the binding agents are arranged on a surface of the nanoparticles such that a binding portion of the binding agent (e.g., variable region of an antibody) is directed outward from that surface. 
     In other embodiments, the nanoparticles multimerize, e.g. dimerize. Multimerization may be observed as multiples of the weight or size of the unit molecule, e.g. 160 nm particles multimerize to about 320 nm, 480 nm, 640 nm, etc. In some embodiments, less than 20% of the nanoparticles in a population are multimers. In some embodiments, more than 80% of the nanoparticles in a population are multimers. 
     In one embodiment, the weight ratio of carrier-bound drug to binding agent (e.g., albumin- bound paclitaxel and anti-PD-L1 or anti-PD-L2 antibody) is between about 5: 1 to about 1:1. In one embodiment, the weight ratio of carrier-bound drug to binding agent is about 10:4. In one embodiment, the binding agents are a substantially single layer on all or part of the surface of the nanoparticle. In one embodiment, less than 0.01% of nanoparticles in the composition have a size selected from greater than 200 nm, greater than 300 nm, greater than 400 nm, greater than 500 nm, greater than 600 nm, greater than 700 nm and greater than 800 nm. Larger sizes are believed to be the result of multimerization of several nanoparticles, each comprising a core and binding agent coating on all or part of the surface of each nanoparticle. 
     The invention further includes lyophilized compositions, and lyophilized compositions that do not materially differ from, or are the same as, the properties of freshly-prepared nanoparticles. In particular, the lypholized composition, upon resuspending in aqueous solution, is similar or identical to the fresh composition in terms of particle size, particle size distribution, toxicity for cancer cells, binding agent affinity, and binding agent specificity. Surprisingly, lyophilized nanoparticles after resuspension retain the properties of freshly-made nanoparticles, notwithstanding the presence of two different protein components in these particles. 
     In one aspect, this invention relates to lyophilized nanoparticles or a lyophilized nanoparticle composition comprising nanoparticles, wherein each of the nanoparticles comprises a carrier-bound drug core and an amount of binding agent that binds PD-L1, PD-L2 or PD-1. In one embodiment, the binding agent is arranged on a surface of the core such that a binding portion of the binding agent is directed outward from that surface, wherein the binding agents retain their association with the outside surface of the nanoparticle upon reconstitution with an aqueous solution. In one embodiment, the lyophilized composition is stable at room temperature for at least about 3 months, 4 months, 5 months, 6 months, 7 months, 8 months, 9 months, 10 months, 11 months, 12 months, or longer. In one embodiment, the lyophilized composition is stable at room temperature for at least 3 months. In one embodiment, the reconstituted nanoparticles retain the activity of the therapeutic agent and are capable of binding to the target in vivo. In another embodiment, the composition is stable at about 20° C. to about 25° C. for up to about 12 months or longer. 
     In one embodiment, the average reconstituted nanoparticle size is from about 90 nm to about 1 μm. In a preferred embodiment, the average reconstituted nanoparticle size is from about 100 nm to about 200 nm, and more preferably about 100 nm to about 160 nm. In one embodiment, in the average reconstituted nanoparticle size is from greater than 800 nm to about 3.5 μm, comprising multimers of smaller nanoparticles, e.g. multimers of 90-200 nm nanoparticles. In one embodiment, the weight ratio of core to binding agent is from greater than 1:1 to about 1:3. In one embodiment, in the average reconstituted nanoparticle size is about 90 nm to about 225 nm. 
     In one aspect, this disclosure relates to lyophilized nanoparticles or a lyophilized nanoparticle composition comprising nanoparticles, wherein each of the nanoparticles comprises: (a) an albumin-bound paclitaxel core and (b) a binding agent that binds PD-L1, PD-L2 or PD-larranged on a surface of the albumin-bound paclitaxel core such that the binding portion of the binding agent is directed outward from that surface, wherein the binding agents retain their association with the surface of the nanoparticle upon reconstitution with an aqueous solution, and said lyophilized composition is stable at about 20° C. to about 25° C. for at least 3 months and the reconstituted nanoparticles are capable of binding to PD-L1, PD-L2 or PD-lin vivo. 
     In one embodiment, the average reconstituted nanoparticle size is not substantially different from the particle size of the freshly prepared nanoparticles. In some embodiments, the average particle sizes are between 90 nm and 800 nm, including 90, 100, 110, 130, 150, 160, 200, 300, 400, 500, 600, 700 or 800nm. In other embodiments, the average particles are larger, e.g. from greater than 800 nm to about 3.5 μm. In some embodiments, the particles are multimers of nanoparticles. In some embodiments the nanoparticles have average particle sizes of about 90 nm to about 225 nm either freshly made or after lyophilization and resuspension in an aqueous solution suitable for inj ecti on. 
     In some embodiments, the weight ratio of albumin-bound paclitaxel to binding agents is between about 5:1 to about 1:1. In other embodiments, the weight ratio of albumin-bound paclitaxel to binding agent is about 10:4. In further embodiments, the weight ratio of albumin- bound paclitaxel to binding agent is from greater than 1:1 to about 1:3. 
     In some embodiments, the core is albumin-bound paclitaxel (e.g., ABRAXANE®), and the binding agents are selected from binding agents that selectively recognize PD-L1 or PD-L2. In some embodiments, the core is albumin-bound paclitaxel (e.g., ABRAXANE®), and the binding agents selectively recognize PD-1. In some embodiments, the core is albumin-bound paclitaxel (e.g., ABRAXANE®), and the binding agents selectively recognize CTLA-4. 
     In some embodiments, the at least one therapeutic agent is located inside the nanoparticle. In other embodiments, the at least one therapeutic agent is located on the outside surface of the nanoparticle. In yet other embodiments, the at least one therapeutic agent is located inside the nanoparticle and on the outside surface of the nanoparticle. 
     In some embodiments, the nanoparticle contains more than one type of therapeutic agent. For example, a taxane and a platinum drug, e.g. paclitaxel and cisplatin. 
     In some embodiments, the binding agents comprise atezolizumab, nivolumab, pembrolizumab, avelumab or durvalumab, pidilizumab, BMS 936559, or biosimilars thereof. In some embodiments, the binding agents are a substantially single layer of binding agents on all or part of the surface of the nanoparticle. 
     In further embodiments, the antibodies are less glycosylated than normally found in natural human antibodies. Such glycosylation can be influenced by e.g. the expression system, or the presence of glycosylation inhibitors during expression. In some embodiments, the glycosylation status of an antibody or other binding agent is altered through enzymatic or chemical action. 
     In some embodiments, the at least one therapeutic agent is selected from abiraterone, bendamustine, bortezomib, carboplatin, cabazitaxel, cisplatin, chlorambucil, dasatinib, docetaxel, doxorubicin, epirubicin, erlotinib, etoposide, everolimus, gefitinib, idarubicin, imatinib, hydroxyurea, imatinib, lapatinib, leuprorelin, melphalan, methotrexate, mitoxantrone, nedaplatin, nilotinib, oxaliplatin, paclitaxel, pazopanib, pemetrexed, picoplatin, romidepsin, satraplatin, sorafenib, vemurafenib, sunitinib, teniposide, triplatin, vinblastine, vinorelbine, vincristine, and cyclophosphamide. 
     In some embodiments, the binding agents, carrier protein and, when present, therapeutic agent, are bound through non-covalent bonds. 
     In some embodiments, the carrier protein is selected from gelatin, elastin, gliadin, legumin, zein, a soy protein, a milk protein, and a whey protein. In other embodiments, the carrier protein is albumin, for example, human serum albumin. In some embodiments, the carrier protein is a recombinant protein, e.g., recombinant human serum albumin. 
     In some embodiments, the nanoparticle composition is formulated for intravenous delivery. In other embodiments, the nanoparticle composition is formulated for direct injection or perfusion into a tumor. 
     In some embodiments, the second binding agent of the immunotherapy is formulated for intravenous delivery. In other embodiments, the second binding agent of the immunotherapy is formulated for direct injection or perfusion into a tumor. 
     In some embodiments, the average nanoparticle size in the nanoparticle composition is from greater than 800 nm to about 3.5 μm. 
     In some embodiments, the nanoparticles have a dissociation constant between about 1×10 −11 M and about 1×10 −9 M. 
     In another aspect, provided herein are methods of making nanoparticle compositions, wherein said methods comprise contacting the carrier protein and the optionally at least one therapeutic agent with the antibodies in a solution having a pH of between 5.0 and 7.5 and a temperature between about 5° C. and about 60° C., between about 23° C. and about 60° C., or between about 55° C. and about 60° C. under conditions and ratios of components that will allow for formation of the desired nanoparticles. In one embodiment, the nanoparticle is made at 55-60° C. and pH 7.0. In another aspect, provided herein are methods of making the nanoparticle compositions, wherein said method comprises (a) contacting the carrier protein and optionally the at least one therapeutic agent to form a core and (b) contacting the core with the antibodies in a solution having a pH of about 5.0 to about 7.5 at a temperature between about 5° C. and about 60° C., between about 23° C. and about 60° C., or between about 55° C. and about 60° C. under conditions and ratios of components that will allow for formation of the desired nanoparticles. 
     The amount of components (e.g., carrier protein, antibodies, therapeutic agents, combinations thereof) is controlled in order to provide for formation of the desired nanoparticles. A composition wherein the amount of components is too dilute will not form the nanoparticles as described herein. 
     In a preferred embodiment, weight ratio of carrier protein to binding agent is 10:4. In some embodiments, the amount of carrier protein is between about 1 mg/mL and about 100 mg/mL. In some embodiments, the amount of binding agent is between about 1 mg/mL and about 30 mg/mL. For example, in some embodiments, the ratio of carrier protein: binding agent: solution is approximately 9 mg of carrier protein (e.g., albumin) to 4 mg of binding agent in 1 mL of solution (e.g., saline). An amount of therapeutic agent (e.g., paclitaxel) can also be added to the carrier protein. 
     The nanoparticles as described herein are pre-formed, meaning that the carrier protein (e.g., albumin), therapeutic agent (e.g., paclitaxel) and binding agents (e.g., antibodies) are mixed in vitro under conditions that allow formation of the nanoparticles, prior to administration to the patient (and/or prior to lyophilization of the nanoparticles). In some embodiments, the pre-formed nanoparticles are diluted in an aqueous solution prior to administration to the patient. By way of non-limiting example, the pre-formed nanoparticles may be diluted for administration no more than 5, 10, 20, 30, 45 minutes, or 60 minutes, or 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, or 24 hours prior to administration to the patient. 
     In further embodiments, the nanoparticles are made as above, and then lyophilized. 
     In another aspect, provided herein are methods for treating a cancer cell, the method comprising contacting the cell with an effective amount of a nanoparticle composition and an immunotherapy disclosed herein to treat the cancer cell. 
     In another aspect, provided herein are methods for treating a tumor in a patient in need thereof, the method comprising contacting the tumor with an effective amount of a nanoparticle composition and an immunotherapy disclosed herein to treat the tumor. In some embodiments, the size of the tumor is reduced. 
     Generally, the immunotherapy (PD-1 immunotherapy and/or CTLA-4 immunotherapy) is administered in a manner consistent with standard clinical protocols, e g , consistent with an FDA—(or other regulatory body) approved label. 
     In some embodiments, the methods provided herein include the steps of: a) administering the nanoparticle composition and immunotherapy once a week for three weeks; b) ceasing administration of the nanoparticle composition and immunotherapy for one week; and c) repeating steps a) and b) as necessary to treat the cancer or tumor. 
     In related embodiments, the treatment comprises administration of the nanoparticle composition prior to administration of the immunotherapy. In one embodiment, the nanoparticle composition is administered between about 6 and 48, or 12 and 48 hours prior to administration of the immunotherapy. In another embodiment, the nanoparticle composition is administered between 6 and 12 hours prior to administration of the immunotherapy. In yet another embodiment, the nanoparticle composition is administered between 2 and 8 hours prior to administration of the immunotherapy. In still other embodiments, the nanoparticle composition is administered a week prior to administration of the immunotherapy. 
     In related embodiments, the treatment comprises administration of the immunotherapy prior to administration of the nanoparticle composition. In one embodiment, the immunotherapy is administered between about 6 and 48, or 12 and 48 hours prior to administration of the nanoparticle composition. In another embodiment, the immunotherapy is administered between 6 and 12 hours prior to administration of the nanoparticle composition. In yet another embodiment, the immunotherapy is administered between 2 and 8 hours prior to administration of the nanoparticle composition. In still other embodiments, the immunotherapy is administered a week prior to administration of the nanoparticle composition. 
     In some embodiments, the therapeutically effective amount of the nanoparticle composition comprises about 75 mg/m 2  to about 175 mg/m 2  of the carrier protein (i.e., milligrams carrier protein per m 2  of the patient). In other embodiments, the therapeutically effective amount comprises about 75 mg/m 2  to about 175 mg/m 2  of therapeutic agent (e.g., paclitaxel). In other embodiments, the therapeutically effective amount comprises about 30 mg/m 2  to about 70 mg/m 2  of the binding agent. In yet other embodiments, the therapeutically effective amount comprises about 30 mg/m 2  to about 70 mg/m 2  bevacizumab. 
     In one embodiment, the lyophilized composition comprises from about 75 mg/m 2  to about 175 mg/m 2  of the carrier protein which is preferably albumin; from about 30 mg/m 2  to about 70 mg/m 2  of the binding agent; and from about 75 mg/m 2  to about 175 mg/m 2  of paclitaxel. 
     In some embodiments, the present invention relates to a kit comprising: (a) an amount of the nanoparticle composition as described herein, (b) an amount of an immunotherapy agent capable of binding to PD-1, and optionally (c) instructions for use. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following figures are representative only of the invention and are not intended as a limitation. For the sake of consistency, nanoparticles using ABRAXANE® and rituximab employ the acronym “AR” and the number after AR such as AR160 is meant to confer the average particle size of these nanoparticles (in nanometers, based on Mastersizer 2000 analysis). Likewise, when the binding agent is atezolizumab, the acronym is “AA” and the number thereafter is the average particle size of the nanoparticles (in nanometers, based on Malvern Nanosight analysis). 
         FIGS.  1 A- 1 F  depict the results of an experiment in which CD20 positive Daudi lymphoma cells were labeled with fluorescent tagged anti-human CD20 ( FIG.  1 F ) or isotype matched control ( FIG.  1 A ), and analyzed by flow cytometry. In the other panels, the Daudi cells were pretreated with ABRAXANE® (ABX;  FIG.  1 B ), ABX/rituximab nanoparticles (AR160;  FIG.  1 C ), lyophilized and resuspended AR160 (AR160L;  FIG.  1 D ), or Rituxan ( FIG.  1 E ) prior to CD20 labeling. CD20 binding was specifically blocked by the AR160 nanoparticles and Rituxan, but not ABX alone, indicating that AR160 and AR160L binds CD20 on these cells and block binding of the fluorescent anti-CD20 antibody. 
         FIG.  2    is a histogram overlay of the scatterplots of  FIG.  1   . 
         FIGS.  3 A-B  depict particle size comparisons of ABX alone relative to ABX/rituximab nanoparticles (AR;  FIG.  3 A ) and ABX/trastuzumab nanoparticles (AT;  FIG.  3 B ), both freshly made and lyophilized/resuspended. 
         FIG.  4    compares the toxicity of ABX and AR particles in a Daudi cell proliferation assay. 
         FIGS.  5 A- 5 C  depict the results obtained in mice treated with either labeled ABRAXANE®, labeled ABRAXANE® coated with non-specific (bevacizumab) antibodies (AB IgG), or labeled ABRAXANE® coated with Rituximab (AR160).  FIG.  5 A  depicts the fluorescence accumulation in regions of interest (ROI) in each tumor (ROI 2, 3, and 4) and in background areas (ROI 1, 5, and 6). ROI 1, 5 and 6 serve as background references.  FIG.  5 B  is a bar graph of the average fluorescence per unit of tumor area of mice in all three treatment groups and shows gross tumor delivery.  FIG.  5 C  is a bar graph of the average fluorescence per unit of tumor area, normalized by background ROI, to give proportion of drug delivered to tumor versus body. The data demonstrate that administration of AR160 nanoparticles results in an increased fluorescence as compared to ABRAXANE® alone or ABRAXANE® coated with non-specific antibodies. 
         FIG.  6    depicts the survival of the mice treated with a single dose of saline, BEV24 (bevacizumab at 24 mg/kg), ABX30 (ABX at 30 mg/kg), AB160 (12mg/kg BEV and 30 mg/kg ABX) and AB225 (24 mg/kg BEV and 30 mg/kg ABX). At 30 days post-administration, the survival of mice treated with AB225 and with AB160 far exceeds the survival of mice treated with BEV alone or ABRAXANE® alone. 
         FIG.  7    shows the binding affinity between atezolizumab and ABX. The Kd was determined to be 1.462×10 −9 . Biolayer interferometry (BLItz) (Forte Bioscience) was performed using streptavidin probes. 
         FIG.  8 A  shows the particle size distribution for ABX alone (average size of 90 nm) and ABX-atezolizumab nanoparticles (AA; average size of 129 nm), as determined by Mastersizer NS300. 
         FIG.  8 B  is a photograph of the ABX-atezolizumab nanoparticles from  FIG.  8 A . 
         FIGS.  9 A- 9 E  show flow cytometry of ABX-atezolizumab nanoparticles (AA130) competing with labeled anti-PD-L1 antibody for binding to a PD-L1 positive human melanoma cell line, C8161. C8161 cells were pre-treated with isotype control antibody ( FIG.  9 A ), no treatment ( FIG.  9 B ), ABRAXANE® ( FIG.  9 C ), atezolizumab ( FIG.  9 D ), or AA130 ( FIG.  9 E ), then labeled with fluorescently-labeled anti-PD-L1 antibody. 
         FIG.  10    shows the dose-dependent toxicity of ABX (solid line) and AA130 (broken line) on C8161 cells. 
         FIGS.  11 A- 11 D  show the change in tumor volume over time in mice that were injected with 2×10 6  PD-L1 positive C8161 melanoma tumor cells, then treated by 100u1 IV tail vein injection with saline ( FIG.  11 A ), atezolizumab alone (18 mg/kg;  FIG.  11 B ), ABX alone (45 mg/kg;  FIG.  11 C ) and AA130 (18 mg/kg atezolizumab and 45 mg/kg ABX;  FIG.  11 D ) one time. Tumor growth was monitored 3 times per week. Tumor size was calculated with the equation: (length x width)/2. 
         FIG.  12    depicts the survival of the mice from the experiment shown in  FIGS.  11 A- 11 D . Kaplan Meier curves were generated using Graph Pad software. The median survival for each group was 14, 13, 16, and 21.5 days for saline, atezolizumab, Abraxane and AA130, respectively. Survival differences between AA130 and all other groups were significant, with p-values of 0.0008 for saline, 0.0015 for atezolizumab, and 0.0113 for ABX. 
     
    
    
     DETAILED DESCRIPTION 
     After reading this description it will become apparent to one skilled in the art how to implement the invention in various alternative embodiments and alternative applications. However, all the various embodiments of the present invention will not be described herein. It will be understood that the embodiments presented here are presented by way of an example only, and not limitation. 
     As such, this detailed description of various alternative embodiments should not be construed to limit the scope or breadth of the present invention as set forth below. 
     Before the present invention is disclosed and described, it is to be understood that the aspects described below are not limited to specific compositions, methods of preparing such compositions, or uses thereof as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting. 
     The detailed description of the invention is divided into various sections only for the reader&#39;s convenience and disclosure found in any section may be combined with that in another section. Titles or subtitles may be used in the specification for the convenience of a reader, which are not intended to influence the scope of the present invention. 
     Definitions 
     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. In this specification and in the claims that follow, reference will be made to a number of terms that shall be defined to have the following meanings: 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
     “Optional” or “optionally” means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where the event or circumstance occurs and instances where it does not. 
     The term “about” when used before a numerical designation, e.g., temperature, time, amount, concentration, and such other, including a range, indicates approximations which may vary by (+) or (−) 10%, 5%, 1%, or any subrange or subvalue there between. Preferably, the term “about” when used with regard to a dose amount means that the dose may vary by +/−10%. For example, “about 400 to about 800 binding agents” indicates that an outside surface of a nanoparticles contain an amount of binding agent between 360 and 880 particles. 
     “Comprising” or “comprises” is intended to mean that the compositions and methods include the recited elements, but not excluding others. “Consisting essentially of when used to define compositions and methods, shall mean excluding other elements of any essential significance to the combination for the stated purpose. Thus, a composition consisting essentially of the elements as defined herein would not exclude other materials or steps that do not materially affect the basic and novel characteristic(s) of the claimed invention. “Consisting of shall mean excluding more than trace elements of other ingredients and substantial method steps. Embodiments defined by each of these transition terms are within the scope of this invention. 
     The term “nanoparticle” or “nanoparticle complex” as used herein refers to particles having at least one dimension which is less than 5 microns. In preferred embodiments, such as for intravenous administration, the nanoparticle has at least one dimension which is less than 1 micron. For direct administration, the nanoparticle is larger. Even larger particles are expressly contemplated by the invention. 
     In a population of particles, the sizes of individual particles are distributed about a mean. Particle sizes for the population can therefore be represented by an average, and also by percentiles. D50 is the particle size below which 50% of the particles fall. 10% of particles are smaller than the D IO value and 90% of particles are smaller than D90. Where unclear, the “average” size is equivalent to D50. So, for example, AB160 and AR160 refer to nanoparticles having an average size of 160 nanometers. 
     The term “nanoparticle” may also encompass discrete multimers of smaller unit nanoparticles. For example, a 320 nm particle comprises a dimer of a unit 160 nm nanoparticle. For 160 nm nanoparticles, multimers would therefore be approximately 320 nm, 480 nm, 640 nm, 800 nm, 960 nm, 1120 nm, and so on. 
     The term “carrier protein” as used herein refers to proteins that function to transport binding agents and/or therapeutic agents. The binding agents of the present disclosure can reversibly bind to the carrier proteins. Examples of carrier proteins are discussed in more detail below. 
     The term “core” as used herein refers to central or inner portion of the nanoparticle which may be comprised of a carrier protein, a carrier protein and a therapeutic agent, or other agents or combination of agents. In some embodiments, a portion of the binding agent may be associated with (e.g., non-covalently bound to) the core. 
     The term “therapeutic agent” as used herein means an agent which is therapeutically useful, e.g., an agent for the treatment, remission or attenuation of a disease state, physiological condition, symptoms, or etiological factors, or for the evaluation or diagnosis thereof. A therapeutic agent may be a chemotherapeutic agent, for example, mitotic inhibitors, topoisomerase inhibitors, steroids, anti-tumor antibiotics, antimetabolites, alkylating agents, enzymes, proteasome inhibitors, or any combination thereof. 
     As used herein, the term, “binding agent”, “binding agent specific for,” or “binding agent that specifically binds” refers to an agent that binds to a target antigen and does not significantly bind to unrelated compounds. Examples of binding agents that can be effectively employed in the disclosed methods include, but are not limited to, lectins, proteins, and antibodies, such as monoclonal antibodies, e.g. humanized monoclonal antibodies, chimeric antibodies, or polyclonal antibodies, or antigen-binding fragments thereof, as well as aptamers, fusion proteins, and aptamers. In an embodiment the binding agent is an exogenous antibody. An exogenous antibody is an antibody not naturally produced in a particular mammal, e.g. in a human, by the mammalian immune system. 
     The term “antibody” or “antibodies” as used herein refers to immunoglobulin molecules and immunologically active portions of immunoglobulin molecules (i.e., molecules that contain an antigen binding site that immuno-specifically bind an antigen). The term also refers to antibodies comprised of two immunoglobulin heavy chains and two immunoglobulin light chains as well as a variety of forms including full length antibodies and portions thereof; including, for example, an immunoglobulin molecule, a monoclonal antibody, a chimeric antibody, a CDR- grafted antibody, a humanized antibody, a Fab, a Fab&#39;, a F(ab&#39;)2, a Fv, a disulfide linked Fv, a scFv, a single domain antibody (dAb), a diabody, a multispecific antibody, a dual specific antibody, an anti-idiotypic antibody, a bispecific antibody, a functionally active epitope-binding fragment thereof, bifunctional hybrid antibodies (e.g., Lanzavecchia et al.,  Eur. J lmmunol.  17,105 (1987)) and single chains (e.g., Huston et al.,  Proc. Natl. Acad Sci . US.A., 85, 5879-5883 (1988) and Bird et al.,  Science  242, 423-426 (1988), which are incorporated herein by reference). (See, generally, Hood et al.,  Immunology , Benjamin, N.Y., 2ND ed. (1984); Harlow and Lane,  Antibodies. A Laboratory Manual , Cold Spring Harbor Laboratory (1988); Hunkapiller and Hood,  Nature,  323, 15-16 (1986), which are incorporated herein by reference). The antibody may be of any type (e.g., IgG, IgA, IgM, IgE or IgD). Preferably, the antibody is IgG. An antibody may be non-human (e.g., from mouse, goat, or any other animal), fully human, humanized, or chimeric. Antibody or antibodies include any biosimilar(s) of the antibodies disclosed herein. Biosimilars, as used herein, refers to a biopharmaceutical which is deemed to be comparable in quality, safety, and efficacy to a reference product marketed by an innovator company (Section 351(i) of the Public Health Service Act (42 U.S.C. 262(i)). 
     The term “dissociation constant,” also referred to as “K d ,” refers to a quantity expressing the extent to which a particular substance separates into individual components (e.g., the protein carrier, antibody, and optional therapeutic agent). 
     The terms “lyophilized,” “lyophilization” and the like as used herein refer to a process by which the material (e.g., nanoparticles) to be dried is first frozen and then the ice or frozen solvent is removed by sublimation in a vacuum environment. An excipient is optionally included in pre-lyophilized formulations to enhance stability of the lyophilized product upon storage. In some embodiments, the nanoparticles can be formed from lyophilized components (carrier protein, antibody and optional therapeutic) prior to use as a therapeutic. In other embodiments, the carrier protein, binding agent, e.g., antibody, and optional therapeutic agent are first combined into nanoparticles and then lyophilized. The lyophilized sample may further contain additional excipients. 
     The term “bulking agents” comprise agents that provide the structure of the freeze-dried product. Common examples used for bulking agents include mannitol, glycine, lactose and sucrose. In addition to providing a pharmaceutically elegant cake, bulking agents may also impart useful qualities in regard to modifying the collapse temperature, providing freeze-thaw protection, and enhancing the protein stability over long-term storage. These agents can also serve as tonicity modifiers. In some embodiments, the lyophilized compositions described herein comprise bulking agents. In some embodiments, the lyophilized compositions described herein do not comprise bulking agents. 
     The term “buffer” encompasses those agents which maintain the solution pH in an acceptable range prior to lyophilization and may include succinate (sodium or potassium), histidine, phosphate (sodium or potassium), Tris(tris(hydroxymethyl)aminomethane), di ethanolamine, citrate (sodium) and the like. The buffer of this invention has a pH in the range from about 5.5 to about 6.5; and preferably has a pH of about 6.0. Examples of buffers that will control the pH in this range include succinate (such as sodium succinate), gluconate, histidine, citrate and other organic acid buffers. 
     The term “cryoprotectants” generally includes agents which provide stability to the protein against freezing-induced stresses, presumably by being preferentially excluded from the protein surface. They may also offer protection during primary and secondary drying, and long- term product storage. Examples are polymers such as dextran and polyethylene glycol; sugars such as sucrose, glucose, trehalose, and lactose; surfactants such as polysorbates; and amino acids such as glycine, arginine, and serine. 
     The term “lyoprotectant” includes agents that provide stability to the protein during the drying or ‘dehydration’ process (primary and secondary drying cycles), presumably by providing an amorphous glassy matrix and by binding with the protein through hydrogen bonding, replacing the water molecules that are removed during the drying process. This helps to maintain the protein conformation, minimize protein degradation during the lyophilization cycle and improve the long-term products. Examples include polyols or sugars such as sucrose and trehalose. 
     The term “pharmaceutical formulation” refers to preparations which are in such form as to permit the active ingredients to be effective, and which contains no additional components that are toxic to the subjects to which the formulation would be administered. 
     “Pharmaceutically acceptable” excipients (vehicles, additives) are those which can reasonably be administered to a subject mammal to provide an effective dose of the active ingredient employed. 
     “Reconstitution time” is the time that is required to rehydrate a lyophilized formulation into a solution. 
     A “stable” formulation is one in which the protein therein essentially retains its physical stability and/or chemical stability and/or biological activity upon storage. For example, various analytical techniques for measuring protein stability are available in the art and are reviewed in Peptide and Protein Drug Delivery, 247-301, Vincent Lee Ed., Marcel Dekker, Inc., New York, N.Y., Pubs. (1991) and Jones, A. Adv. Drug Delivery Rev. 10:29-90 (1993). Stability can be measured at a selected temperature for a selected time period. 
     The term “epitope” as used herein refers to the portion of an antigen which is recognized by a binding agent, e.g., an antibody. Epitopes include, but are not limited to, a short amino acid sequence or peptide (optionally glycosylated or otherwise modified) enabling a specific interaction with a protein (e.g., an antibody) or ligand. For example, an epitope may be a part of a molecule to which the antigen-binding site of a binding agent attaches. 
     The term “treating” or “treatment” covers the treatment of a disease or disorder (e.g., cancer), in a subject, such as a human, and includes: (i) inhibiting a disease or disorder, i.e., arresting its development; (ii) relieving a disease or disorder, i.e., causing regression of the disease or disorder; (iii) slowing progression of the disease or disorder; and/or (iv) inhibiting, relieving, or slowing progression of one or more symptoms of the disease or disorder. In some embodiments “treating” or “treatment” refers to the killing of cancer cells. 
     The term “kill” with respect to a cancer treatment is directed to include any type of manipulation that will lead to the death of that cancer cell or at least of portion of a population of cancer cells. 
     The term “aptamer” refers to a nucleic acid molecule that is capable of binding to a target molecule, such as a polypeptide. For example, an aptamer of the invention can specifically bind to PD-L1, PD-L2, PD-1, or CTLA-4. The generation of antibodies with a particular binding specificity and the therapeutic use of aptamers are well established in the art. See, e.g., U.S. Pat. Nos. 5,475,096, 5,270,163, 5,582,981, 5,840,867, 6,011,020, 6,051,698, 6,147,204, 6,180,348 and 6,699,843, and the therapeutic efficacy of Macugen® (Eyetech, New York) for treating age-related macular degeneration, each of which is incorporated herein by reference in its entirety. 
     The term “oligomer” or “oligomeric” or “oligomerized” as used herein refers to oligomers composed of two or more monomers. 
     Fusion proteins are bioengineered polypeptides that join one peptide (e.g., the crystallizable fragment (Fc) domain of an antibody) with another biologically active agent, e.g., a protein domain, peptide, or nucleic acid or peptide aptamer, to generate a molecule with desired structure—function properties and significant therapeutic potential. The gamma immunoglobulin (IgG) isotype is often used as the basis for generating Fc-fusion proteins because of favorable characteristics such as recruitment of effector function and increased plasma half-life. Given the range of aptamers, both peptide and nucleic acids, that can be used as fusion partners, fusion proteins have numerous biological and pharmaceutical applications. 
     The term “sequentially,” as used herein, refers to the administration of two or more treatments one after another in any order. In some embodiments, the treatments are administered within more than 48 hours of each other. In some embodiments, the treatments are administered within about 48 hours of each other, within about 36 hours of each other, within about 24 hours of each other, within about 12 hours of each other, within about 10 hours of each other, within about 8 hours of each other, within about 6 hours of each other, within about 4 hours of each other, within about two hours of each other, or within about 1 hour of each other. 
     The term “concurrently,” as used herein, refers two or more treatments administered at substantially about the same time in any order. 
     The term “PD-1,” as used herein, refers to programmed cell death protein-1, also known as CD279, which is expressed on the surface of activated T cells, B cells, as well as myeloid cells. 
     The term “PD-L1”, as used herein, refers to programmed death-ligand 1, also known as B7-H1 or CD274, is a PD-1 ligand which is commonly expressed on the surface of dendritic cells or macrophages. 
     The term “PD-L2,” as used herein, refers to programmed death ligand-2, also known as B7-DC or CD273, is a PD-1 ligand which is commonly expressed on the surface of dendritic cells or macrophages. 
     The terms “biosimilar” or “biosimilar,” also known as “follow-on biologic” or “subsequent entry biologic”, as used herein, refers to a biologic product which is substantially an identical copy of a product approved by a regulatory agency. 
     The terms “synergistic” or “synergistic effect” or “synergistically effective amount” “or “synergistic efficacy”, as used herein, refer to a greater-than-additive therapeutic effect which is produced by the administration of at least two agents, and which exceeds that which would otherwise result from administration of one of the agents without the administration of the other agent. For example, the therapeutic effect of the nanoparticle composition is increased when administered sequentially or concurrently with a binding agent to provide a synergistic effect, provided that the increase is greater than the additive effectiveness of the binding agent and the nanoparticle composition when administered alone. The term “synergistically therapeutic amount” typically refers to a less than standard therapeutic amount of one or both therapeutic agents, meaning that the amount required for the desired therapeutic effectiveness is lower than when the therapeutic agent is used alone. A synergistically therapeutic amount also includes when one therapeutic agent is given at a standard therapeutic dose and another therapeutic agent is administered in a less than standard therapeutic dose. 
     The term “therapeutically effective amount” or “therapeutic effectiveness,” as used herein, of a nanoparticle composition or binding agent refers to nanoparticle composition or binding agent levels in which the physiological effects of a disease or disorder are, at a minimum, ameliorated. A therapeutically effective amount can be given in one or more administrations using one or more tablets, capsules or other pharmaceutical units. The amount of a nanoparticle composition or binding agent which constitutes a therapeutically effective amount will vary depending on the nanoparticle composition or binding agent, the disorder and its severity, and the general health, age, sex, body weight and tolerance to drugs of the subject to be treated, but can be determined routinely by one of ordinary skill in the art. In some embodiments, the term “therapeutically effective amount” refers to a synergistically effective amount or synergistically therapeutic amount. 
     Additionally, some terms used in this specification are more specifically defined below. 
     Overview 
     The current invention is predicated, in part, on the surprising discovery that optionally lyophilized nanoparticles comprising a carrier protein, a binding agent, e.g., an antibody, an aptamer, or a fusion protein, having a PD-L1 or PD-L2 binding domain, and a therapeutic agent provide targeted therapy to a tumor while minimizing toxicity to the patient. The nanoparticles as described herein are thus a significant improvement versus conventional ADCs. 
     The invention is further predicated, in part, on the synergy of immune checkpoint inhibitor immunotherapy (e.g., PD-1 immunotherapy and/or CTLA-4 immunotherapy) with the nanoparticles. Without being bound by theory, it is contemplated that binding of PD-L1 or PD-L2 by the binding agents (e.g., antibodies) as described herein will deplete or diminish the amount of PD-L1 or PD-L2 available to bind PD-1 on T cells, thereby increasing the therapeutic effectiveness of PD-1-based immunotherapy. Administration of the nanoparticles, alone or in combination with PD-1 immunotherapy, may increase the number of T cells that are free from PD-1 pathway-mediated inhibition, and restore the patient&#39;s immune response against a PD-L1- or PD-L2-expressing cancer. 
     For conventional ADCs to be effective, it is critical that the linker be stable enough not to dissociate in the systemic circulation but allow for sufficient drug release at the tumor site. Alley, S.C., et al. (2008)  Bioconjug Chem  19:759-765. This has proven to be a major hurdle in developing effective drug conjugate (Julien, D.C., et al. (2011)  MAbs  3:467-478; Alley, S.C., et al. (2008)  Bioconjug Chem  19:759-765); therefore, an attractive feature of the nanoparticles described herein is that a biochemical linker is not required. 
     Another shortcoming of current ADCs is that higher drug penetration into the tumor has not been substantively proven in human tumors. Early testing of ADCs in mouse models suggested that tumor targeting with antibodies would result in a higher concentration of the active agent in the tumor (Deguchi, T. et al. (1986)  Cancer Res  46: 3751-3755); however, this has not correlated in the treatment of human disease, likely because human tumors are much more heterogeneous in permeability than mouse tumors. Jain, R. K. et al. (2010)  Nat Rev Clin Oncol  7:653-664. Also, the size of the nanoparticle is critical for extravasation from the vasculature into the tumor. In a mouse study using a human colon adenocarcinoma xenotransplant model, the vascular pores were permeable to liposomes up to 400 nm. Yuan, F., et al. (1995)  Cancer Res  55: 3752-3756. Another study of tumor pore size and permeability demonstrated that both characteristics were dependent on tumor location and growth status, with regressing tumors and cranial tumors permeable to particles less than 200 nm. Hobbs, S.K., et al. (1998)  Proc Natl Acad Sci  USA 95:4607-4612. The nano-immune conjugate (nanoparticles) described herein overcomes this issue by the fact that the large complex, which is less than 200 nm intact, is partially dissociated in systemic circulation into smaller functional units that are easily able to permeate tumor tissue. Furthermore, once the conjugate arrives to the tumor site, the smaller toxic payload can be released and only the toxic portion needs to be taken up by tumor cells, not the entire conjugate. 
     The advent of antibody- (i.e. AVASTINg) coated albumin nanoparticles containing a therapeutic agent (i.e., ABRAXANE®) has led to a new paradigm of directional delivery of two or more therapeutic agents to a predetermined site in vivo. See PCT Patent Publication Nos. WO 2012/154861 and WO 2014/055415, each of which is incorporated herein by reference in its entirety. 
     When compositions of albumin and a binding agent, e.g., antibody, are admixed together in an aqueous solution at specific concentrations and ratios, the binding agents useful in this invention spontaneously self-assemble into and onto the albumin to form nanoparticles having multiple copies of the binding agent (up to 500 or more). Without being limited to any theory, it is contemplated that binding agents (e.g., antibodies) non-covalently bind to the carrier protein (e.g., albumin) via one or more albumin-binding motifs of the binding agent, and one or more antibody-binding motifs on the carrier protein. Examples of such motifs can be found in PCT Application No. PCT/US17/45643, which is incorporated herein by reference in its entirety. 
     While protein compositions comprising a single source protein are commonly stored in lyophilized form where they exhibit significant shelf-life, such lyophilized compositions generally do not contain a self-assembled nanoparticle of two different proteins integrated together by hydrophobic-hydrophobic interactions. Moreover, the nanoparticle configuration wherein a majority of the binding portions of the binding agent are exposed on the surface of the nanoparticles lends itself to being susceptible to dislodgement or reconfiguration by conditions which otherwise would be considered benign. For example, during lyophilization, ionic charges on the proteins are dehydrated thereby exposing the underlying charges. Exposed charges allow for charge-charge interactions between the two proteins which can alter the binding affinity of each protein to the other. In addition, the concentration of the nanoparticles increases significantly as the solvent (e.g., water) is removed. Such increased concentrations of nanoparticles could lead to irreversible oligomerization. Oligomerization is a known property of proteins that reduces the biological properties of the oligomer as compared to the monomeric form and increases the size of the particle, sometimes beyond 1 micron. 
     On the other hand, a stable form of a nanoparticle composition is required for clinical and/or commercial use, where a shelf-life of at least 3 months is required and shelf-lives of greater than 6 months or 9 months are preferred. Such a stable composition must be readily available for intravenous injection, must retain its self-assembled form upon intravenous injection so as to direct the nanoparticle to the predetermined site in vivo, must have a maximum size of less than 1 micron so as to avoid any ischemic event when delivered into the blood stream, and finally must be compatible with the aqueous composition used for injection. 
     Compounds 
     As will be apparent to the skilled artisan upon reading this disclosure, the present disclosure relates to compositions of nanoparticles containing a carrier protein, binding agents, and optionally at least one therapeutic agent, wherein said compositions are optionally lyophilized. 
     In some embodiments, the carrier protein can be albumin, gelatin, elastin (including topoelastin) or elastin-derived polypeptides (e.g., a-elastin and elastin-like polypeptides (ELPs)), gliadin, legumin, zein, soy protein (e.g., soy protein isolate (SPI)), milk protein (e.g., 13-lactoglobulin (BLG) and casein), or whey protein (e.g., whey protein concentrates (WPC) and whey protein isolates (WPI)). In preferred embodiments, the carrier protein is albumin. In preferred embodiments, the albumin is egg white (ovalbumin), bovine serum albumin (BSA), or the like. In even more preferred embodiments, the carrier protein is human serum albumin (HSA). In some embodiments, the carrier protein is a recombinant protein, e.g. recombinant human serum albumin. In some embodiments, the carrier protein is a generally regarded as safe (GRAS) excipient approved by the United States Food and Drug Administration (FDA). 
     In some embodiments, the binding agents are antibodies. 
     In some embodiments, the anti-PD-1 antibody comprises nivolumab, pembrolizumab, pidilizumab, PDR001, or biosimilars thereof. In some aspects, the anti-PD-L1 antibody is atezolizumab, avelumab, durvalumab, or BMS 936559 (MDX1105). In some aspects, the binding agent of the CTLA-4 immunotherapy is an anti-CTLA-4 antibody. In one embodiment, the anti-CTLA-4 antibody is ipilimumab. 
     In some aspects, the first binding agent and/or the second binding agent is a fusion protein. In one embodiment, the fusion protein is AMP-224 (PD-L2 IgG2a fusion protein; Amplimmune/GlaxoSmith Klein); AMP-514 (MEDI0680) (PD-L2 fusion protein; Amplimmune/GlaxoSmith Klein), or a biosimilar thereof AMP-224 and AMP-514 target PD-1. 
     In some embodiments, the antibodies are a substantially single layer of antibodies on all or part of the surface of the nanoparticle. 
     Table 1 depicts a list of non-limiting list of antibodies. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Example Antibodies 
               
            
           
           
               
               
               
               
            
               
                   
                   
                   
                 Example of Possible 
               
               
                 Generic Name 
                 Brand Name 
                 Type 
                 Indication 
               
               
                   
               
               
                 Avelumab 
                 BAVENCIO ® 
                 anti-PD-L1; human 
                 Solid tumor, gastric cancer, 
               
               
                 (MSB0010718C) 
                   
                 IgG1 mAb 
                 Merkel cell carcinoma, 
               
               
                   
                   
                   
                 non-small cell lung cancer 
               
               
                 Durvalumab 
                 IMFINZI ™ 
                 anti-PD-L1; human 
                 NSCLC, head and neck, bladder, 
               
               
                 (MEDI4736) 
                   
                 IgG1 K  mAb 
                 gastric, pancreatic, HCC 
               
               
                   
                   
                   
                 and blood cancers 
               
               
                 Pidilizumab 
                   
                 anti-Delta-like 1 
                 Lymphoma, myeloma, diffuse 
               
               
                 (CT-011) 
                   
                 (secondary binding to 
                 intrinsic pontine glioma 
               
               
                   
                   
                 some forms of PD-1); 
               
               
                   
                   
                 humanized IgG1 mAb 
               
               
                 BMS 936559/ 
                   
                 anti-PD-L1 mAb 
                 melanoma, non-small cell 
               
               
                 MDX-1105 
                   
                   
                 lung cancer 
               
               
                 Nivolumab 
                 OPDIVO ® 
                 Anti-PD-1; human 
                 metastatic melanoma; 
               
               
                 (BMS-936558) 
                   
                 IgG4 mAb 
                 squamous non-small cell 
               
               
                   
                   
                   
                 lung cancer; renal cell 
               
               
                   
                   
                   
                 carcinoma 
               
               
                 atezolizumab 
                 TECENTRIQ ® 
                 anti-PD-L1 mAb 
                 bladder cancer, NSCLC, 
               
               
                 (RG7446; 
                   
                   
                 melanoma, breast, renal 
               
               
                 MPDL3280A) 
                   
                   
                 cell carcinoma, lymphoma 
               
               
                 Ipilimumab 
                 YERVOY ® 
                 Anti-CTLA-4; Human 
                 Melanoma 
               
               
                   
                   
                 IgG1 mAb 
               
               
                 Pembrolizumab 
                 KEYTRUDA ® 
                 Anti-PD-1; Human 
                 Melanoma 
               
               
                   
                   
                 IgG4 mAb 
               
               
                   
               
            
           
         
       
     
     In some embodiments, the at least one therapeutic agent is selected from abiraterone, bendamustine, bortezomib, carboplatin, cabazitaxel, cisplatin, chlorambucil, dasatinib, docetaxel, doxorubicin, epirubicin, erlotinib, etoposide, everolimus, gefitinib, idarubicin, imatinib, hydroxyurea, imatinib, lapatinib, leuprorelin, melphalan, methotrexate, mitoxantrone, nedaplatin, nilotinib, oxaliplatin, paclitaxel, pazopanib, pemetrexed, picoplatin, romidepsin, satraplatin, sorafenib, vemurafenib, sunitinib, teniposide, triplatin, vinblastine, vinorelbine, vincristine, and cyclophosphamide. Preferably, the therapeutic agent is paclitaxel. Additional therapeutic agents are known, for example those listed in PCT Publication No. WO2017/031368, which is incorporated herein by reference in its entirety. 
     It is to be understood that the therapeutic agent may be located inside the nanoparticle, on the outside surface of the nanoparticle, or both. The nanoparticle may contain more than one therapeutic agent, for example, two therapeutic agents, three therapeutic agents, four therapeutic agents, five therapeutic agents, or more. Furthermore, a nanoparticle may contain the same or different therapeutic agents inside and outside the nanoparticle. 
     In one aspect, the nanoparticle comprises at least 100 binding agents non-covalently bound to the surface of the nanoparticle. In one aspect, the nanoparticle comprises at least 200 binding agents non-covalently bound to the surface of the nanoparticle. In one aspect, the nanoparticle comprises at least 300 binding agents non-covalently bound to the surface of the nanoparticle. In one aspect, the nanoparticle comprises at least 400 binding agents non-covalently bound to the surface of the nanoparticle. In one aspect, the nanoparticle comprises at least 500 binding agents non-covalently bound to the surface of the nanoparticle. In one aspect, the nanoparticle comprises at least 600 binding agents non-covalently bound to the surface of the nanoparticle. 
     In one aspect, the nanoparticle comprises between about 100 and about 1000 binding agents non-covalently bound to the surface of the nanoparticle. In one aspect, the nanoparticle comprises between about 200 and about 1000 binding agents non-covalently bound to the surface of the nanoparticle. In one aspect, the nanoparticle comprises between about 300 and about 1000 binding agents non-covalently bound to the surface of the nanoparticle. In one aspect, the nanoparticle comprises between about 400 and about 1000 binding agents non-covalently bound to the surface of the nanoparticle. In one aspect, the nanoparticle comprises between about 500 and about 1000 binding agents non-covalently bound to the surface of the nanoparticle. In one aspect, the nanoparticle comprises between about 600 and about 1000 binding agents non-covalently bound to the surface of the nanoparticle. In one aspect, the nanoparticle comprises between about 200 and about 800 binding agents non-covalently bound to the surface of the nanoparticle. In one aspect, the nanoparticle comprises between about 300 and about 800 binding agents non-covalently bound to the surface of the nanoparticle. In preferred embodiments, the nanoparticle comprises between about 400 and about 800 binding agents non-covalently bound to the surface of the nanoparticle. Contemplated values include any value or subrange within any of the recited ranges, including endpoints. 
     In one aspect, the average particle size in the nanoparticle composition is less than about 1μm. In one aspect, the average particle size in the nanoparticle composition is between about 90 nm and about 1μm. In one aspect, the average particle size in the nanoparticle composition is between about 90 nm and about 900 nm. In one aspect, the average particle size in the nanoparticle composition is between about 90 nm and about 800 nm. In one aspect, the average particle size in the nanoparticle composition is between about 90 nm and about 700 nm. In one aspect, the average particle size in the nanoparticle composition is between about 90 nm and about 600 nm. In one aspect, the average particle size in the nanoparticle composition is between about 90 nm and about 500 nm. In one aspect, the average particle size in the nanoparticle composition is between about 90 nm and about 400 nm. In one aspect, the average particle size in the nanoparticle composition is between about 90 nm and about 300 nm. In one aspect, the average particle size in the nanoparticle composition is between about 90 nm and about 200 nm. In a preferred embodiment, the average particle size in the nanoparticle composition is between about 100 nm and about 180 nm. In an especially preferred embodiment, the mean particle size in the nanoparticle composition is about 130 nm or about 160 nm. Contemplated values include any value, subrange, or range within any of the recited ranges, including endpoints. In one embodiment, the nanoparticle size is determined using a Mastersizer 2000. In one embodiment, the nanoparticle size is determined using a Malvern Nanosight. 
     In one aspect, the nanoparticle composition is formulated for intravenous injection. In order to avoid an ischemic event, the nanoparticle composition formulated for intravenous injection should comprise nanoparticles with an average particle size of less than about 1 μm. 
     In one aspect, the average particle size in the nanoparticle composition is greater than about 1 μm. In one aspect, the average particle size in the nanoparticle composition is between about 1 μm and about 5 μm. In one aspect, the average particle size in the nanoparticle composition is between about 1 μm and about 4 μm. In one aspect, the average particle size in the nanoparticle composition is between about 1 μm and about 3 μm. In one aspect, the average particle size in the nanoparticle composition is between about 1 μm and about 2 μm. In one aspect, the average particle size in the nanoparticle composition is between about 1 μm and about 1.5 μm. Contemplated values include any value, subrange, or range within any of the recited ranges, including endpoints. 
     In one aspect, the nanoparticle composition is formulated for direct injection into a tumor. Direct injection includes injection into or proximal to a tumor site, perfusion into a tumor, and the like. When formulated for direct injection into a tumor, the nanoparticle may comprise any average particle size. Without being bound by theory, it is believed that larger particles (e.g., greater than 500 nm, greater than 1 μm, and the like) are more likely to be immobilized within the tumor, thereby providing a beneficial effect. Larger particles can accumulate in the tumor or specific organs. See, e.g., 20-60 micron glass particle that is used to inject into the hepatic artery feeding a tumor of the liver, called “TheraSphere®” (in clinical use for liver cancer). Therefore, for intravenous administration, particles under 1 μm are typically used. Particles over 1 μm are, more typically, administered directly into a tumor (“direct injection”) or into an artery feeding into the site of the tumor. 
     In one aspect, less than about 0.01% of the nanoparticles within the composition have a particle size greater than 200 nm, greater than 300 nm, greater than 400 nm, greater than 500 nm, greater than 600 nm, greater than 700 nm, or greater than 800 nm. In one aspect, less than about 0.001% of the nanoparticles within the composition have a particle size greater than 200 nm, greater than 300 nm, greater than 400 nm, greater than 500 nm, greater than 600 nm, greater than 700 nm, or greater than 800 nm. In a preferred embodiment, less than about 0.01% of the nanoparticles within the composition have a particle size greater than 800 nm. In a more preferred embodiment, less than about 0.001% of the nanoparticles within the composition have a particle size greater than 800 nm. 
     In a preferred aspect, the sizes and size ranges recited herein relate to particle sizes of the reconstituted lyophilized nanoparticle composition. That is, after the lyophilized nanoparticles are resuspended in an aqueous solution (e.g., water, other pharmaceutically acceptable excipient, buffer, etc.), the particle size or average particle size is within the range recited herein. 
     In one aspect, at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 99.9% of the nanoparticles are present in the reconstituted composition as single nanoparticles. That is, fewer than about 50%, 40%, 30%, etc. of the nanoparticles are dimerized or oligomerized. 
     In some embodiments, the nanoparticles in the composition have less than 20% by number dimerization, less than 10% by number dimerization and preferably less than 5% by number dimerization. 
     In some embodiments, the size of the nanoparticle can be controlled by the adjusting the amount (e.g., ratio) of carrier protein to binding agent. The size of the nanoparticles, and the size distribution, is also important. The nanoparticles of the invention may behave differently according to their size. At large sizes, an agglomeration may block blood vessels. Therefore, agglomeration of nanoparticles can affect the performance and safety of the composition. On the other hand, larger particles may be more therapeutic under certain conditions (e.g., when not administered intravenously). 
     In one aspect, the nanoparticle composition comprises at least one additional therapeutic agent. In one embodiment, the at least one additional therapeutic agent is non-covalently bound to the outside surface of the nanoparticle. In one embodiment, the at least one additional therapeutic agent is arranged on the outside surface of the nanoparticle. In one embodiment, the at least one additional therapeutic agent is selected from abiraterone, bendamustine, bortezomib, carboplatin, cabazitaxel, cisplatin, chlorambucil, dasatinib, docetaxel, doxorubicin, epirubicin, erlotinib, etoposide, everolimus, gemcitabine, gefitinib, idarubicin, imatinib, hydroxyurea, imatinib, lapatinib, leuprorelin, melphalan, methotrexate, mitoxantrone, nedaplatin, nilotinib, oxaliplatin, pazopanib, pemetrexed, picoplatin, romidepsin, satraplatin, sorafenib, vemurafenib, sunitinib, teniposide, triplatin, vinblastine, vinorelbine, vincristine, and cyclophosphamide. In one embodiment, the at least one additional therapeutic agent is an anti-cancer binding agent, e.g., an anti-cancer antibody. Additional anti-cancer antibodies are known, for example those listed in PCT Publication No. WO2017/031368, which is incorporated herein by reference in its entirety. 
     Methods of Making Nanoparticles 
     In some aspects, the current invention relates to methods of making nanoparticle compositions as described herein. 
     In one aspect, the nanoparticles of the nanoparticle composition are formed by contacting the carrier protein or carrier protein-therapeutic agent particle with the binding agent at a ratio of about 10:1 to about 10:30 carrier protein particle or carrier protein-therapeutic agent particle to binding agent. In one embodiment, the ratio is about 10:2 to about 10:25. In one embodiment, the ratio is about 10:2 to about 1:1. In a preferred embodiment, the ratio is about 10:2 to about 10:6. In an especially preferred embodiment, the ratio is about 10:4. Contemplated ratios include any value, subrange, or range within any of the recited ranges, including endpoints. 
     In one embodiment, the amount of solution or other liquid medium employed to form the nanoparticles is particularly important. No nanoparticles are formed in an overly dilute solution of the carrier protein (or carrier protein-therapeutic agent) and the antibodies. An overly concentrated solution will result in unstructured aggregates. In some embodiments, the amount of solution (e.g., sterile water, saline, phosphate buffered saline) employed is between about 0.5 mL of solution to about 20 mL of solution. In some embodiments, the amount of carrier protein is between about 1 mg/mL and about 100 mg/mL. In some embodiments, the amount of binding agent is between about 1 mg/mL and about 30 mg/mL. For example, in some embodiments, the ratio of carrier protein:binding agent:solution is approximately 9 mg of carrier protein (e.g., albumin) to 4 mg of binding agent, e.g., antibody (e.g., BEV) in 1 mL of solution (e.g., saline). An amount of therapeutic agent (e.g., taxol) can also be added to the carrier protein. For example, 1 mg of taxol can be added 9 mg of carrier protein (10 mg carrier protein-therapeutic) and 4 mg of binding agent, e.g., antibody, Fc fusion molecule, or aptamer, in 1 mL of solution. When using a typical i.v. bag, for example, with the solution of approximately 1 liter one would need to use 1000× the amount of carrier protein/carrier protein- therapeutic agent and antibodies compared to that used in 1 mL. Thus, one cannot form the present nanoparticles in a standard i.v. bag. Furthermore, when the components are added to a standard i.v. bag in the therapeutic amounts of the present invention, the components do not self-assemble to form nanoparticles. 
     In one embodiment, the carrier protein or carrier protein-therapeutic agent particle is contacted with the binding agent in a solution having a pH between about 4 and about 8. In one embodiment, the carrier protein or carrier protein-therapeutic agent particle is contacted with the binding agent in a solution having a pH of about 4. In one embodiment, the carrier protein or carrier protein-therapeutic agent particle is contacted with the binding agent in a solution having a pH of about 5. In one embodiment, the carrier protein or carrier protein-therapeutic agent particle is contacted with the binding agent in a solution having a pH of about 6. In one embodiment, the carrier protein or carrier protein-therapeutic agent particle is contacted with the binding agent in a solution having a pH of about 7. In one embodiment, the carrier protein or carrier protein-therapeutic agent particle is contacted with the binding agent in a solution having a pH of about 8. In a preferred embodiment, the carrier protein or carrier protein-therapeutic agent particle is contacted with the binding agent in a solution having a pH between about 5 and about 7. 
     In one embodiment, the carrier protein particle or carrier protein-therapeutic agent particle is incubated with the binding agent at a temperature of about 5° C. to about 60° C., or any range, subrange, or value within that range including endpoints. In a preferred embodiment, the carrier protein particle or carrier protein-therapeutic agent particle is incubated with the binding agent at a temperature of about 23° C. to about 60° C. 
     Without being bound by theory, it is believed that the stability of the nanoparticles within the nanoparticle composition is, at least in part, dependent upon the temperature and/or pH at which the nanoparticles are formed, as well as the concentration of the components (i.e., carrier protein, binding agent, and optionally therapeutic agent) in the solution. In one embodiment, the Kd of the nanoparticles is between about 1×10 −11  M and about 2×10 −5 M. In one embodiment, the K d  of the nanoparticles is between about 1×10 −11  M and about 2×10 −8  M. In one embodiment, the K d  of the nanoparticles is between about 1×10 −11 M and about 7×10 −9 M. In a preferred embodiment, the K d  of the nanoparticles is between about 1×10 −11 M and about 3×10 −8 M. Contemplated values include any value, subrange, or range within any of the recited ranges, including endpoints. 
     Lyophilization 
     Lyophilization, or freeze-drying, removes water from a composition. In the process, the material to be dried is first frozen and then the ice or frozen solvent is removed by sublimation in a vacuum environment. An excipient may be included in pre-lyophilized formulations to enhance stability during the freeze-drying process and/or to improve stability of the lyophilized product upon storage. Pikal, M. Biopharm. 3(9)26-30 (1990) and Arakawa et al., Pharm. Res. 8(3):285-291 (1991). 
     While proteins may be lyophilized, the process of lyophilization and reconstitution may affect the properties of the protein. Because proteins are larger and more complex than traditional organic and inorganic drugs (i.e. possessing multiple functional groups in addition to complex three-dimensional structures), the formulation of such proteins poses special problems. For a protein to remain biologically active, a formulation must preserve intact the conformational integrity of at least a core sequence of the protein&#39;s amino acids while at the same time protecting the protein&#39;s multiple functional groups from degradation. Degradation pathways for proteins can involve chemical instability (i.e. any process which involves modification of the protein by bond formation or cleavage resulting in a new chemical entity) or physical instability (i.e. changes in the higher order structure of the protein). Chemical instability can result from deamidation, racemization, hydrolysis, oxidation, beta elimination or disulfide exchange. Physical instability can result from denaturation, aggregation, precipitation or adsorption, for example. The three most common protein degradation pathways are protein aggregation, deamidation and oxidation. Cleland, et al., Critical Reviews in Therapeutic Drug Carrier Systems 10(4): 307-377 (1993). 
     The lyophilized compositions of this invention are prepared by standard lyophilization techniques with or without the presence of stabilizers, buffers, etc. Surprisingly, these conditions do not alter the relatively fragile structure of the nanoparticles. Moreover, at best, these nanoparticles retain their size distribution upon lyophilization and, more importantly, can be reconstituted for in vivo administration (e.g., intravenous delivery) in substantially the same form and ratios as if freshly made. 
     Formulations 
     In one aspect, the nanoparticle composition is formulated for systemic delivery, e.g., intravenous administration. 
     In one aspect, the nanoparticle composition is formulated for direct injection into a tumor. Direct injection includes injection into or proximal to a tumor site, perfusion into a tumor, and the like. Because the nanoparticle composition is not administered systemically, a nanoparticle composition is formulated for direct injection into a tumor may comprise any average particle size. Without being bound by theory, it is believed that larger particles (e.g., greater than 500 nm, greater than 1μm, and the like) are more likely to be immobilized within the tumor, thereby providing what is believed to be a better beneficial effect. 
     In another aspect, provided herein is a composition comprising nanoparticles as provided herein, and at least one pharmaceutically acceptable excipient. 
     In general, the compositions provided herein can be formulated for administration to a patient by any of the accepted modes of administration. Various formulations and drug delivery systems are available in the art. See, e.g., Gennaro, A.R., ed. (1995) Remington&#39;s Pharmaceutical Sciences, 18th ed., Mack Publishing Co. 
     In general, nanoparticles as provided herein will be administered as pharmaceutical compositions by any one of the following routes: oral, systemic (e.g., transdermal, intranasal or by suppository), or parenteral (e.g., intramuscular, intravenous or subcutaneous) administration. 
     The compositions are comprised of, in general, a nanoparticle of the present invention in combination with at least one pharmaceutically acceptable excipient. Acceptable excipients are non-toxic, aid administration, and do not adversely affect the therapeutic benefit of the claimed compounds. Such excipient may be any solid, liquid, semi-solid or, in the case of an aerosol composition, gaseous excipient that is generally available to one of skill in the art. 
     Solid pharmaceutical excipients include starch, cellulose, talc, glucose, lactose, sucrose, gelatin, malt, rice, flour, chalk, silica gel, magnesium stearate, sodium stearate, glycerol monostearate, sodium chloride, dried skim milk and the like. Liquid and semisolid excipients may be selected from glycerol, propylene glycol, water, ethanol and various oils, including those of petroleum, animal, vegetable or synthetic origin, e.g., peanut oil, soybean oil, mineral oil, sesame oil, etc. 
     Preferred liquid carriers, particularly for injectable solutions, include water, saline, aqueous dextrose, and glycols. Other suitable pharmaceutical excipients and their formulations are described in Remington&#39;s Pharmaceutical Sciences, edited by E. W. Martin (Mack Publishing Company, 18th ed., 1990). 
     The present compositions may, if desired, be presented in a pack or dispenser device containing one or more unit dosage forms containing the active ingredient. Such a pack or device may, for example, comprise metal or plastic foil, such as a blister pack, or glass, and rubber stoppers such as in vials. The pack or dispenser device may be accompanied by instructions for administration. Compositions comprising a nanoparticle of the invention formulated in a compatible pharmaceutical carrier may also be prepared, placed in an appropriate container, and labeled for treatment of an indicated condition. 
     Treatment Methods 
     The nanoparticle compositions as described herein are useful in treating cancer cells and/or tumors in a mammal having a cancer or tumor that expresses PD-LI and/or PD-L2. In a preferred embodiment, the mammal is a human (i.e., a human patient). Preferably, the lyophilized nanoparticle composition is reconstituted (suspended in an aqueous excipient) prior to administration. 
     In one aspect is provided a method for treating a cancer cell, the method comprising contacting the cell with an effective amount of nanoparticles and an immunotherapy (e.g., PD-1 or CTLA-4) as described herein to treat the cancer cell. Treatment of a cancer cell includes, without limitation, reduction in proliferation, killing the cell, preventing metastasis of the cell, and the like. 
     “Immune therapy”, “immune therapies”, “immunotherapy” or “immunotherapies,” as used herein, generally refer to treatments of a disease by inducing, enhancing, or suppressing an immune response. In some cases, immune therapies or immunotherapies can either elicit or activate or amplify immune responses (also known as “activation immunotherapies”), or reduce or suppress immune responses (also known as “suppression immunotherapies”). For example, cancer immune therapy or cancer immunotherapy attempts to stimulate or activate the immune responses against tumors or cancer cells. As would be understood by one skilled in the art, immune therapy or immunotherapy can utilize a variety of approaches or mechanisms including, but not limited to, antibodies, antigens, use and/or activation of immune responsive cells such as lymphocytes, macrophages, dendritic cells, other antigen presenting cells, natural killer cells (NK Cells; e.g., NK-92), T-cells (e.g., helper T-cells, cytotoxic T lymphocytes (CTL), etc.), therapies involving immune modulators (including, but not limited to: interleukins (e.g., IL-2, IL-7, IL-12, etc.), cytokines (e.g., interferons, G-CSF, imiquimod, etc.), chemokines (e.g., CCL3, CCL26, CXCL7, etc.), immunomodulatory imide drugs, etc.) and the like. Immune therapy or immunotherapy can be administered by the use of one type of antibody or multiple types of antibodies. Immune therapy or immunotherapy approaches can also be administered alone or in combination with other therapeutic agents or mechanisms, such as, for example, chemotherapy agents, and the like, in order to enhance immune responses against, for example, tumors. 
     In one aspect is provided a method for treating a tumor in a patient in need thereof, the method comprising administering to the patient a therapeutically effective amount of a nanoparticle composition and an immunotherapy as described herein to treat the tumor. In one embodiment, the size of the tumor is reduced. In one embodiment, the tumor size does not increase (i.e. progress) for at least a period of time during and/or after treatment. 
     In one embodiment, the nanoparticle composition is administered intravenously. In one embodiment, the nanoparticle composition is administered directly to the tumor. In one embodiment, the nanoparticle composition is administered by direct injection or perfusion into the tumor. 
     In one embodiment, the immunotherapy is administered intravenously. In one embodiment, the immunotherapy is administered directly to the tumor. In one embodiment, the immunotherapy is administered by direct injection or perfusion into the tumor. 
     In one aspect, a method for treating a patient suffering from a cancer which expresses PD-L1 or PD-L2 is provided, where the method comprises administering to the patient a nanoparticle composition comprising nanoparticles, wherein each of the nanoparticles comprise a carrier protein, binding agents having a PD-L 1 or PD-L2 binding portion, and optionally at least one therapeutic agent, wherein the nanoparticles are capable of binding to PD-L1 or PD-L2. In some embodiments, the method further comprises administering a PD-1 immunotherapy to the patient. In one embodiment, the PD-1 immunotherapy comprises administering a second binding agent capable of binding to PD-1. 
     In another aspect, the present invention relates to a method for increasing the therapeutic effectiveness of an immunotherapy treatment of a patient suffering from a cancer which expresses PD-L1 or PD-L2, the method comprising administering to the patient a therapeutically effective amount of the nanoparticle composition described herein. In some embodiments, the method further comprises administering a PD-1 immunotherapy to the patient. In one embodiment, the PD-1 immunotherapy comprises administering a second binding agent capable of binding to PD-1. 
     In one embodiment, the method comprises:
         a) administering the nanoparticle composition once a week for three weeks;   b) ceasing administration of the nanoparticle composition for one week; and   c) optionally repeating steps a) and b) as necessary to treat the tumor.       

     In one aspect, the PD-1 immunotherapy is administered concurrently with the nanoparticle composition. In one aspect, the PD-1 immunotherapy is administered before the nanoparticle composition. In one aspect, the PD-1 immunotherapy is administered subsequent to the nanoparticle composition. In one aspect, the PD-1 immunotherapy is administered according to the regulatory entity (e.g., FDA)-approved label. 
     In some aspects, each of the nanoparticles of the nanoparticle composition comprises between about 400 to about 800 said binding agents. 
     In some aspects, the first binding agents (binding agents in the nanoparticles) are aptamers. In some aspects, the second binding agent of the PD-1 immunotherapy is an aptamer. 
     In some aspects, the first binding agents(binding agents in the nanoparticles) are antibodies. In some aspects, the second binding agent of the PD-1 immunotherapy is an antibody. 
     In some aspects, the anti-PD-1 antibody comprises nivolumab, pembrolizumab, pidilizumab, PDR001, or biosimilars thereof In some aspects, the anti-PD-L1 antibody is atezolizumab, avelumab, durvalumab, or BMS 936559 (MDX1105), or biosimilar thereof. In some aspects, the binding agent of the CTLA-4 immunotherapy is an anti-CTLA-4 antibody. In one embodiment, the anti-CTLA-4 antibody is ipilimumab, or biosimilar thereof. 
     In some aspects, the first binding agent and/or the second binding agent is a fusion protein. In one embodiment, the fusion protein is AMP-224 (PD-L2 IgG2a fusion protein; Amplimmune/GlaxoSmith Klein); AMP-514 (MEDI0680) (PD-L2 fusion protein; Amplimmune/GlaxoSmith Klein), or a biosimilar thereof In some aspects, the nanoparticle composition is lyophilized. 
     In some aspects, the second binding agent of the PD-1 immunotherapy is a free binding agent, wherein the free binding agent is not complexed with or otherwise integrated onto and/or into a nanoparticle composition. 
     In some aspects, PD-1 immunotherapy is an immunotherapy nanoparticle composition comprising the second binding agent complexed with or integrated onto and/or into a nanoparticle composition, wherein the immunotherapy nanoparticle composition comprises a carrier protein and said second binding agent. In some aspects, the immunotherapy nanoparticle composition is lyophilized. 
     In some aspects, the second binding agent of the immunotherapy nanoparticle composition is an antibody. In some aspects, the second binding agent of the immunotherapy nanoparticle composition is an anti-PD-1 antibody. In some aspects, the anti-PD-1 antibody comprises nivolumab, pembrolizumab, pidilizumab, PDR001, or biosimilars thereof. 
     In some aspects, the second binding agent of the immunotherapy nanoparticle composition is an aptamer. In some aspects, the second binding agent of the immunotherapy nanoparticle composition is a PD-1 aptamer. 
     In some aspects, the second binding agent of the immunotherapy nanoparticle composition is a fusion protein. some aspects, the second binding agent of the immunotherapy nanoparticle composition is a PD-1-targeting fusion protein. In one embodiment, the fusion protein is AMP-224 (PD-L2 IgG2a fusion protein; Amplimmune/GlaxoSmith Klein); AMP-514 (MEDI0680) (PD-L2 fusion protein; Amplimmune/GlaxoSmith Klein), or a biosimilar thereof. 
     In some aspects, the nanoparticle composition and the PD-1 immunotherapy are administered sequentially. In some aspects, the nanoparticle composition is administered prior to administration of the PD-1 immunotherapy. In some aspects, the PD-1 immunotherapy is administered prior to administration of the nanoparticle composition. In some aspects, the nanoparticle composition and the PD-1 immunotherapy are administered concurrently. 
     In some embodiments, the present invention relates to a method for increasing the therapeutic effectiveness of an immunotherapy treatment of a patient suffering from a cancer which expresses PD-L1 or PD-L2. The method comprises administering to the patient a therapeutically effective amount of the nanoparticle composition as described herein, and a PD-1 immunotherapy comprising a second binding agent, wherein when the binding agents of the nanoparticle composition are capable of binding to PD-L 1 and/or PD-L2, the second binding agent of the immunotherapy is capable of binding to PD-1, and wherein when the binding agents of the nanoparticle composition are capable of binding to PD-1, the second binding agent of the immunotherapy is capable of binding to PD-L1 and/or PD-L2. 
     In some embodiments, the present invention relates to a method for treating a patient suffering from a cancer which expresses PD-LI or PD-L2. The method comprises administering to the patient a therapeutically effective amount of the nanoparticle composition as described herein, and an immunotherapy comprising a second binding agent, wherein the binding agents of the nanoparticle composition are capable of binding to PD-L1, PD-L2, or PD-1, and the second binding agent of the immunotherapy is capable of binding to PD-L1, PD-L2, or PD-1, respectively. 
     In one embodiment, a method for treating a patient suffering from a cancer which expresses PD-L1 or PD-L2 comprises administering to the patient a nanoparticle composition comprising nanoparticles and a PD-1 immunotherapy. Each of the nanoparticles of the nanoparticle composition comprises: (a) a carrier protein, (b) binding agents having a PD-L1 or PD-L2 binding portion and (c) optionally at least one therapeutic agent. Upon reconstitution with an aqueous solution, the binding agents of the nanoparticles are capable of binding to PD-L1 or PD-L2. 
     In one embodiment, a method for increasing the therapeutic effectiveness of an immunotherapy treatment of a patient suffering from a cancer which expresses PD-L1 or PD-L2 comprises administering to the patient (a) a therapeutically effective amount of the nanoparticle composition described herein and (b) a PD-1 immunotherapy. In some embodiments, the nanoparticle composition is lyophilized, and upon reconstitution with an aqueous solution, the binding agents of the nanoparticles are capable of binding to PD-L1 or PD-L2. 
     In some aspects, the amount of the nanoparticles and the amount of the second binding agents are determined in a relative ratio with each other. 
     In some aspects, a ratio of synergistically effective amounts of the nanoparticle composition and the second binding agent of the immunotherapy increases the therapeutic effectiveness of the immunotherapy such that the effectiveness of the immunotherapy is substantially greater than an administration thereof alone. In one aspect, the ratio of the amount of the nanoparticle composition to the second binding agent can range from about 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10 to about 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:15 or about 1:20. 
     In another aspect, the method for increasing the therapeutic efficacy of an immunotherapy reduces the therapeutically effective dose of the second binding agent required or preferred in the immunotherapy by administering the nanoparticles as described herein above to the patient. The ratio of the amount of the nanoparticle composition and the amount of the second binding agent is in a range of from about 1:1 to about 1:10 and/or wherein the synergistic therapeutic effectiveness of administration of such combination can achieve a synergistic therapeutic effectiveness that is at least about 5%, or about 10%, or about 15%, or about 20%, or about 25%, or about 30%, or about 35%, or about 40%, or about 45%, or about 50%, or about 55%, or about 60%, or about or about 65%, or about 70%, or about 80%, or about 90% or about 100% greater than the therapeutic effectiveness of mono-administration of the second binding agent. In another aspect, the synergistic therapeutic effectiveness of administration of such combination is at least about 25%, or about 30%, or about 35%, or about 40%, or about 45%, or about 50%, greater than the therapeutic effectiveness of mono-administrations of either the nanoparticle composition or the second binding agent. 
     In one embodiment, the second binding agent of the immunotherapy comprises about 60 mg/mL for intravenous delivery over a period of from about 30 minutes to about 60 minutes (e.g., atezolizumab). 
     In one embodiment, the second binding agent of the immunotherapy comprises about 1.0 mg/kg to about 3.0 mg/kg for intravenous delivery for a period of about 60 minutes (e.g., nivolumab). 
     In one embodiment, the second binding agent of the immunotherapy comprises about, 2 mg/kg for intravenous delivery for a period of about 30 minutes (e.g., pembrolizumab). 
     In some embodiments, the present invention relates to a method for increasing the therapeutic effectiveness of an immunotherapy treatment of a patient suffering from a cancer which expresses PD-L1 or PD-L2. The method comprises administering to the patient a therapeutically effective amount of the nanoparticle composition as described herein above, and an immunotherapy comprising a second binding agent, wherein when the binding agents of the nanoparticles are capable of binding to PD-L1 and/or PD-L2, the second binding agent of the immunotherapy is capable of binding to PD-1, and wherein when the binding agents of the nanoparticles are capable of binding to PD-1, the second binding agent of the immunotherapy is capable of binding to PD-L1 and/or PD-L2. 
     In some embodiments, the present invention relates to a method for treating a patient suffering from a cancer which expresses PD-L1 or PD-L2. The method comprises administering to the patient a therapeutically effective amount of the nanoparticle composition as described herein above, and an immunotherapy comprising a second binding agent, wherein the binding agents of the nanoparticles are capable of binding to PD-L1, PD-L2, PD-1, wherein the second binding agent of the immunotherapy is capable of binding to the same one of PD-L1, PD-L2, PD-1 as the binding agents of the nanoparticles 
     In some aspects, the amount of the nanoparticles is of an effective amount of the nanoparticle composition. In some aspect, the amount of the nanoparticles is of an amount less than the effective amount of the nanoparticle composition when administered to the patient alone. 
     In some aspects, the second binding agents are of an effective amount. In some aspects, the second binding agents are of an amount less than the effective amount when administered to the patient alone. 
     In one embodiment, the therapeutically effective amount of the nanoparticles described herein comprises about 1 mg/m 2  to about 200 mg/m 2  antibody, about 2 mg/m 2  to about 150 mg/m 2 , about 5 mg/m 2  to about 100 mg/m 2 , about 10 mg/m 2  to about 85 mg/m 2 , about 15 mg/m 2  to about 75 mg/m 2 , about 20 mg/m 2  to about 65 mg/m 2 , about 25 mg/m 2  to about 55 mg/m 2 , about 30 mg/m 2  to about 45 mg/m 2 , or about 35 mg/m 2  to about 40 mg/m 2  antibody. In other embodiments, the therapeutically effective amount comprises about 20 mg/m 2  to about 90 mg/m 2  antibody. In one embodiment, the therapeutically effective amount comprises 30 mg/m 2  to about 70 mg/m 2  antibody. In one embodiment, the therapeutically effective amount of the nanoparticles described herein comprises about 50 mg/m 2  to about 200 mg/m 2  carrier protein or carrier protein and therapeutic agent. In a preferred embodiment, the therapeutically effective amount comprises about 75 mg/m 2  to about 175 mg/m 2  carrier protein or carrier protein and therapeutic agent. Contemplated values include any value, subrange, or range within any of the recited ranges, including endpoints. 
     In one embodiment, the therapeutically effective amount of the nanoparticle composition comprises about 20 mg/m 2  to about 90 mg/m 2  binding agent, e.g., antibody, aptamer or Fc fusion. In a preferred embodiment, the therapeutically effective amount comprises 30 mg/m 2  to about 70 mg/m 2  binding agent, e.g., antibody, aptamer or Fc fusion. Contemplated values include any value, subrange, or range within any of the recited ranges, including endpoints. 
     Cancers or tumors that can be treated by the compositions and methods described herein include, but are not limited to: biliary tract cancer; brain cancer, including glioblastomas and medulloblastomas; breast cancer; cervical cancer; choriocarcinoma; colon cancer; endometrial cancer; esophageal cancer, gastric cancer; hematological neoplasms, including acute lymphocytic and myelogenous leukemia; multiple myeloma; AIDS associated leukemias and adult T-cell leukemia lymphoma; intraepithelial neoplasms, including Bowen&#39;s disease and Paget&#39;s disease; liver cancer (hepatocarcinoma); lung cancer; lymphomas, including Hodgkin&#39;s disease and lymphocytic lymphomas; neuroblastomas; oral cancer, including squamous cell carcinoma; ovarian cancer, including those arising from epithelial cells, stromal cells, germ cells and mesenchymal cells; pancreas cancer; prostate cancer; rectal cancer; sarcomas, including leiomyosarcoma, rhabdomyosarcoma, liposarcoma, fibrosarcoma and osteosarcoma; skin cancer, including melanoma, Kaposi&#39;s sarcoma, basocellular cancer and squamous cell cancer; testicular cancer, including germinal tumors (seminoma, non-seminoma[teratomas, choriocarcinomas]), stromal tumors and germ cell tumors; thyroid cancer, including thyroid adenocarcinoma and medullar carcinoma; and renal cancer including adenocarcinoma and Wilms tumor. In important embodiments, cancers or tumors include breast cancer, lymphoma, multiple myeloma, and melanoma. 
     In general, the compounds of this invention will be administered in a therapeutically effective amount by any of the accepted modes of administration for agents that serve similar utilities. The actual amount of the compound of this invention, i.e., the nanoparticles, will depend upon numerous factors such as the severity of the disease to be treated, the age and relative health of the subject, the potency of the compound used, the route and form of administration, and other factors well known to the skilled artisan. 
     An effective amount of such agents can readily be determined by routine experimentation, as can the most effective and convenient route of administration, and the most appropriate formulation. Various formulations and drug delivery systems are available in the art. See, e.g., Gennaro, A. R., ed. (1995)  Remington&#39;s Pharmaceutical Sciences,  18th ed., Mack Publishing Co. 
     An effective amount or a therapeutically effective amount or dose of an agent, e.g., a compound of the invention, refers to that amount of the agent or compound that results in amelioration of symptoms or a prolongation of survival in a subject. Toxicity and therapeutic efficacy of such molecules can be determined by standard pharmaceutical procedures in cell cultures or experimental animals, e.g., by determining the LD50 (the dose lethal to 50% of the population) and the ED50 (the dose therapeutically effective in 50% of the population). The dose ratio of toxic to therapeutic effects is the therapeutic index, which can be expressed as the ratio LD50/ED50. Agents that exhibit high therapeutic indices are preferred. 
     The effective amount or therapeutically effective amount is the amount of the compound or pharmaceutical composition that will elicit the biological or medical response of a tissue, system, animal or human that is being sought by the researcher, veterinarian, medical doctor or other clinician. Dosages may vary within this range depending upon the dosage form employed and/or the route of administration utilized. The exact formulation, route of administration, dosage, and dosage interval should be chosen according to methods known in the art, in view of the specifics of a subject&#39;s condition. 
     Dosage amount and interval may be adjusted individually to provide plasma levels of the active moiety that are sufficient to achieve the desired effects; i.e., the minimal effective concentration (MEC). The MEC will vary for each compound but can be estimated from, for example, in vitro data and animal experiments. Dosages necessary to achieve the MEC will depend on individual characteristics and route of administration. In cases of local administration or selective uptake, the effective local concentration of the drug may not be related to plasma concentration. 
     EXAMPLES 
     The present disclosure is illustrated using nanoparticles composed of albumin-bound paclitaxel (i.e., ABRAXANE®) or cisplatin as core, and antibodies that recognize PD-L1 (e.g., atezolizumab). One skilled in the art would understand that making and using the nanoparticles of the Examples are for the sole purpose of illustration, and that the present disclosure is not limited by this illustration. 
     Any abbreviation used herein, has normal scientific meaning. All temperatures are ° C. unless otherwise stated. Herein, the following terms have the following meanings unless otherwise defined: 
     
       
         
           
               
               
               
             
               
                   
                   
               
             
            
               
                   
                 ABX= 
                 ABRAXANE ® (albumin-bound paclitaxel) 
               
               
                   
                 ADC= 
                 antibody dependent chemotherapy 
               
               
                   
                 BEV= 
                 bevacizumab 
               
               
                   
                 BSA= 
                 bovine serum albumin 
               
               
                   
                 dH 2 O= 
                 distilled water 
               
               
                   
                 nM= 
                 nanomolar 
               
               
                   
                 EdU= 
                 5-ethyny1-2′-deoxyuridine 
               
               
                   
                 FITC= 
                 Fluorescein isothiocyanate 
               
               
                   
                 kD= 
                 kilo-dalton 
               
               
                   
                 Kd= 
                 dissociation constant 
               
               
                   
                 kg= 
                 kilogram 
               
               
                   
                 M= 
                 molar 
               
               
                   
                 mg= 
                 milligram 
               
               
                   
                 ml or mL= 
                 milliliter 
               
               
                   
                 m 2 = 
                 square meters 
               
               
                   
                 mm 3 = 
                 cubic millimeter 
               
               
                   
                 μg= 
                 microgram 
               
               
                   
                 μl= 
                 microliter 
               
               
                   
                 μm= 
                 micrometer/micron 
               
               
                   
                 PBS= 
                 Phosphate buffered saline 
               
               
                   
                 pK= 
                 pharmacokinetics 
               
               
                   
                 RT= 
                 room temperate 
               
               
                   
                 rpm= 
                 rotations per minute 
               
               
                   
                   
               
            
           
         
       
     
     Example 1 
     Antigen Binding of Lyophilized AR160 
     CD20 positive Daudi lymphoma cells were labeled with fluorescent tagged anti-human CD20 or isotype matched control in panel F and A, respectively, and analyzed by flow cytometry. In the other panels, the Daudi cells were pretreated with ABX, AR160, AR160L (AR160 lyophilized and resuspended into a solution suitable for injection), or Rituxan prior to CD20 labeling.  FIG.  1    demonstrates that CD20 binding was specifically blocked by the AR particles and Rituxan, but not ABX alone. These results suggest that the AR binds to its CD20 ligand on these cells blocking binding of the fluorescent anti-CD20. 
       FIG.  2    is a histogram overlay of the data presented in  FIG.  1   . 
       FIGS.  3 A and  3 B  depict the particle size comparisons of ABX alone relative to AR ( FIG.  3 A ) and AT ( FIG.  3 B ) freshly made and lyophilized. 
       FIG.  4    presents the results of a Daudi proliferation assay comparing the toxicity of ABX and the AR particles. The data demonstrates the lyophilized and non-lyophilized nanoparticles have essentially the same toxicity in the Daudi assay. 
     Example 2 
     Fluorescent Analysis of Tumor Accumulation of AlexaFluor 750 Labeled Nanoparticles 
     Mice received intravenous (IV) injections of equal amounts of either labeled ABRAXANE®, labeled ABRAXANE® coated with non-specific antibodies (AB IgG), or labeled ABRAXANE® coated with Rituximab (AR160). Regions of interest (ROI) 2, 3, and 4 ( FIG.  5 A ) track tumor accumulation based on a fluorescence threshold; ROI 1, 5, and 6 ( FIG.  5 A ) serve as background references. Fluorescence was determined in the ROIs 24 hours post injection.  FIG.  5 B  is a bar graph of the average fluorescence per unit of tumor area of mice in all three treatment groups were determined to provide the gross tumor delivery.  FIG.  5 C  is a bar graph of the average fluorescence per unit of tumor area normalized by background ROI to give proportion of drug delivered to tumor versus body. The data demonstrate that administration of AR160 nanoparticles results in an increased fluorescence as compared to ABRAXANE® alone or ABRAXANE® coated with non-specific antibodies. 
     Example 3 
     In Vivo Efficacy of ABX-Rituximab Nanoparticles having a Size of 225 nm 
     To make a nanoparticle having a size of 225 nm, the particles were prepared as described in PCT Pub. No. WO2017/031368 (incorporated herein by reference in its entirety), but the ratio of BEV to ABRAXANE® was 4:5, i.e., 4 parts BEV and 5 parts ABRAXANE. This ratio produced nanoparticles having a size of 225 nm (AB225). The effect of AB225 was assayed in animals as described in PCT Pub. No. WO2017/031368.  FIG.  6    depicts the survival of the mice treated with a single dose of saline, BEV, ABX, AB160 and AB225 and with AB160 with a BEV pretreatment. At 30 days post-administration the survival of mice treated with AB225, and with AB160 with or without pretreatment with BEV far exceeds the survival of mice treated with BEV alone of ABRAXANE® alone. 
     Example 4 
     Making Atezolizumab-ABRAXANE® Nanoparticles 
     Atezolizumab and ABRAXANE® (ABX) were co-incubated at room temperature for 30 minutes at a concentration of 4 mg/mL and 10mg/mL, respectively to form the nanoparticle, AA130. 
     To determine whether atezolizumab and ABX are capable of interacting to form nanoparticle complexes, Biolayer interferometry (BLItz) (Forte Bioscience) was performed using streptavidin probes. 100ug/ml of biotinylated atezolizumab in lx PBS was bound to the streptavidin probe. After washing unbound atezolizumab from the probe, the antibody-bound probe was exposed to ABX at concentrations of 100, 500, 1000 μg/mL in 1X PBS. An antibody probe exposed to PBS was used as background and background was subtracted. BLItz software was used to calculate dissociation constants ( FIG.  7   ). The Kd was determined to be 1.462×10 −9 . 
     Example 5 
     Size Determination of Atezolizumab-ABRAXANE® Nanoparticles 
     Mastersizer NS300 was employed to determine the particle size of atezolizumab bound ABX relative to ABX alone. Nanosight uses dynamic light scattering and Brownian motion to calculate particle size. 
     Atezolizumab and ABX were co-incubated to form the nanoparticle, AA130, as described above. ABX was diluted 1:200 and atezolizumab-bound ABX was diluted 1:800; three 30-second video clips were captured and analyzed to determine particle size ( FIG.  8 A ).  FIG.  8 B  is a still image from one of the video clips of AA130. The average particle size of the atezolizumab-ABX nanoparticles was determined to be about 129 nm; average size of ABX alone is about 90 nm. 
     Example 6 
     AA130 Binds PD-L1 
     Flow cytometry was performed to access binding of atezolizumab and atezolizumab bound Abraxane to the ligand, PD-L1. The PD-L1 positive melanoma cell line, C8161 was used for this experiment. AA130 was made as described above and an aliquot of the nanoparticles was spun at 6000 rpm for 10 minutes to remove any unbound atezolizumab. C8161 cells were stained with FITC labeled isotype control and anti-human PD-L1 as negative and positive controls, respectively. The C8161 cells were incubated for 30 minutes with ABX and atezolizumab alone and the AA130 nanoparticle. After the incubation the cells were labeled with FITC labeled anti-human PD-L1 for 30 minutes and washed with FACS buffer (lx PBS +0.5% BSA and 0.05% Na azide). After washing, the cells were analyzed by flow cytometer on the Guava 8HT and data analysis performed with Gauvasoft software (Millipore). 
     C8161 cells were pre-treated with isotype control antibody ( FIG.  9 A ), no treatment ( FIG.  9 B ), ABRAXANE® ( FIG.  9 C ), atezolizumab ( FIG.  9 D ), or AA130 ( FIG.  9 E ), then labeled with fluorescently-labeled anti-PD-L1 antibody. The atezolizumab in the context of the 130 nm particle retains its ability to bind its ligand, PD-L1. 
     Example 7 
     AA130 Cellular Toxicity 
     C8161 melanoma cells were exposed to ABX and AA130 at paclitaxel concentrations from 0 to 200 pg/mL overnight to determine cell toxicity. The cells were also incubated with EdU, a thymidine analog. The next day the cells were harvested, fixed with 2% paraformaldehyde and permeabolized with 1% saponin. After permeabolization the cells were incubated for 30 minutes with a FITC labeled anti-EdU antibody to determine the percentage of cells proliferating. After washing, the cells were analyzed by flow cytometer on the Guava 8HT and data analysis performed with Gauvasoft software (Millipore). The proliferation index was calculated by normalization to an untreated positive control. 
       FIG.  10    shows the dose-dependent toxicity of ABX (solid line) and AA130 (broken line) on C8161 cells. The AA130 has cellular toxicity similar to ABX alone. 
     Example 8 
     In Vivo Efficacy of AA130 Nanoparticles 
     Athymic nude mice (Harlan Sprague Dawley) were injected with 2×10 6  PD-L1 positive C8161 melanoma tumor cells. The tumors were allowed to grow until about 600 mm 3  and were treated by 100 1 1.1 IV tail vein injection with saline, atezolizumab alone (18 mg/kg), ABX alone (45 mg/kg) and AA130 (18 mg/kg atezolizumab and 45 mg/kg ABX) one time ( FIGS.  11 A- 11 D ). Tumor growth was monitored 3 times/week. Tumor size was calculated with the equation: (length×width 2 )/2. 
     Tumor growth curves ( FIG.  12   ) show slowed tumor growth in the mice treated with AA130 relative to saline and the individual drugs alone. Kaplan Meier curves were generated using Graph Pad software. The median survival for each group was 14, 13, 16, and 21.5 days for saline, atezolizumab, ABX and AA130, respectively. Survival differences between AA130 and all other groups were significant with p-values of 0.0008 for saline, 0.0015 for atezolizumab, and 0.0113 for Abraxane.