Treatment with protein kinase C (PKC) inhibitors and cytotoxic agents

Abstract

The present disclosure provides a PKC inhibitor and a cytotoxic agent for use in therapy, wherein the PKC inhibitor reaches a peak concentration before the cytotoxic agent reaches a peak concentration in a subject. The PKC inhibitor and the cytotoxic agent may be used to treat cancer or an autoimmune disease.

Description

[Technical field]

[0001] The present invention relates to the use of protein kinase C (PKC) inhibitors in combination with cytotoxic agents for the treatment of diseases such as cancer and autoimmune diseases. [Background technology]

[0002] Over the past decade, next-generation sequencing technologies have provided the opportunity to comprehensively describe the spectrum of genomic abnormalities found in a variety of different B-cell malignancies (Non-Patent Documents 2, 17-19). Ultimately, this has led to an increased understanding of the underlying genetic mutations that contribute to uncontrolled proliferation and extended cell survival, and to the development of targeted therapies. At the same time, increasing experimental evidence indicates that tumor cells do not survive autonomously, but require signals from the microenvironment to fully unfold the pathogenicity caused by genetic mutations. Indeed, the composition of the microenvironment has prognostic value in the treatment of patients with follicular lymphoma (Non-Patent Document 3) and diffuse large B-cell lymphoma (Non-Patent Document 13), highlighting the importance of tumor cell-microenvironment interactions for treatment outcome. These observations have prompted the development of targeted therapies that inhibit tumor-host interactions.

[0003] The introduction of inhibitors targeting kinases downstream of the B cell receptor (BCR) for the treatment of chronic lymphocytic leukemia (CLL) is a recent example of the success of such therapies. This class of drugs, which also affects the blockade of BCR signaling and integrin-mediated adhesion to stromal cells, induces a significant redistribution of malignant B cells from the spleen and lymph nodes to the peripheral blood (Non-Patent Documents 4 and 8). Outside of a protective niche, malignant B cells stop proliferating and die. Other approaches targeting malignant B cell-host cell interactions focus on T cell interactions treatable with PD-1 / PD-L1 inhibitors (Non-Patent Document 21) or lenalidomide (Non-Patent Document 11), and have demonstrated clinical responses in a subset of patients.

[0004] The genomic instability and rapid evolution of tumor cells limits the long-term success of targeted and non-targeted therapies, leading to the selection of drug-resistant clones that overcome the treatment pressure. The selection of BTK mutations in patients treated with ibrutinib, especially in cells with dysfunctional p53, illustrates this problem (Non-Patent Document 1). Therefore, it is desirable to develop therapies that truly target the functions of cells in the microenvironment that support tumor cells. Since there is no evidence yet that these cells evolve by clonal evolution, such therapies may be more effective for a longer period before malignant B cells adapt. Survival signals from mesenchymal stromal cells (MSCs) to malignant B cells depend on the function of protein kinase C-β (PKC-β) in the microenvironment, mediating NF-κB activation and stromal cell remodeling. Surprisingly, Prkcb-deficient (KO) mice were completely resistant to adoptively transferred tumor cells from diseased TCL1-transgenic (tg) mice, whereas Prkcb wild-type (WT) recipient mice developed lymphoproliferative disease within weeks, indicating that the tumor microenvironment is essential for disease progression (Non-Patent Document 14).

[0005] Autoimmune diseases are characterized by the presence of autoreactive immune cells that lead to tissue damage (Non-Patent Document 22). B cells have been identified as the driver of many autoimmune diseases (Non-Patent Document 16). The functions of B cells in autoimmune diseases include various cellular functions such as secretion of established autoantibodies, autoantigen presentation and subsequent interaction with T cells, secretion of inflammatory cytokines, and generation of ectopic germinal centers. Through these mechanisms, B cells are involved in autoimmune diseases that were traditionally considered to be antibody-mediated and those that are generally classified as T cell-mediated (Non-Patent Document 7). Depletion of B cells has been shown to be beneficial in various autoimmune diseases (Non-Patent Document 9). The immunosuppressive quality of chemotherapeutic agents means that they are useful in the treatment of autoimmune diseases, such as cyclophosphamide (an alkylating agent) in the treatment of multiple sclerosis (Non-Patent Documents 15 and 6), rituximab (an anti-CD20 antibody) in the treatment of systemic lupus erythematosus, Sjogren's syndrome and Grave's disease (Non-Patent Documents 10 and 5), and methotrexate (antimetabolite) in the treatment of rheumatoid arthritis (Non-Patent Document 20). [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Ahn et al.(2017)Blood 129,1469-1479 [Non-Patent Document 2] Chapuy et al. (2018) Nat. Med. 24, 679-690. [Non-Patent Document 3] Dave et al. (2004) N. Engl. J. Med. 351, 2159-2169. [Non-Patent Document 4] de Rooij et al.(2012)Blood 119,2590-2594. [Non-Patent Document 5] El Fassi et al.(2007)J.Clin.Endocrinol.Metab.92,1769-1772. [Non-Patent Document 6] Gladstone et al. (2006) Arch Neurol. 63, 1388-1393. [Non-Patent Document 7] Hampe,(2012)Scientifica 2012,215308. [Non-Patent Document 8] Herman et al. (2015) Clin. Cancer Res. 21, 4642-4651. [Non-Patent Document 9] Hofmann et al., (2018) Front Immunol.9,835.

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[0007] There is a need for improved therapeutic approaches that disrupt the interactions between host and disease cells, such as autoreactive immune cells and cancer cells. [Means for solving the problem]

[0008] The inventors recognize that pretreatment with a PKC inhibitor for a specific time frame prior to treatment with a cytotoxic agent may enhance the efficacy of the treatment, which may be useful, for example, to enhance cell death induced by the cytotoxic agent, reduce side effects, and improve the outcome of the treatment.

[0009] In a first aspect of the invention, there is provided a protein kinase C (PKC) inhibitor and a cytotoxic agent for use in therapy, wherein the PKC inhibitor reaches a peak concentration in a subject before the cytotoxic agent reaches a peak concentration. Advantageously, the PKC inhibitor sensitizes the subject to cytotoxic agents.

[0010] In a second aspect, a method is provided for increasing the sensitivity of a subject to a cytotoxic agent, comprising administering to the subject a PKC inhibitor and a cytotoxic agent, wherein the PKC inhibitor reaches a peak concentration in the subject before the cytotoxic agent reaches a peak concentration. Specifically, the present inventors have found that a combination of a PKC inhibitor and a cytotoxic agent can be used to treat cancer or autoimmune diseases.

[0011] In a third aspect, there is provided a PKC inhibitor and a cytotoxic agent for use in treating cancer or an autoimmune disease, wherein the PKC inhibitor reaches a peak concentration in a subject before the cytotoxic agent reaches a peak concentration.

[0012] In a fourth aspect, a method is provided that includes administering a PKC inhibitor and a cytotoxic agent to a subject, wherein the PKC inhibitor reaches a peak concentration in the subject before the cytotoxic agent reaches a peak concentration. The peak concentration of a PKC inhibitor can be understood to be the maximum concentration reached after the PKC inhibitor is administered to a subject. Similarly, the peak concentration of a cytotoxic agent can be understood to be the maximum concentration reached after the cytotoxic agent is administered to a subject. The peak concentration can be understood to be the maximum concentration of the PKC inhibitor or cytotoxic agent in the blood, cerebrospinal fluid, target organ, or tumor. In an embodiment, the peak concentration can be understood to be the maximum concentration of the PKC inhibitor or cytotoxic agent in the blood.

[0013] The PKC inhibitor may be a PKC-β inhibitor. Suitable PKC inhibitors are known in the art and include enzastaurin, sotrastaurin, midostaurin (PKC412), MS-553, Gouml6983, staurosporine, GF109203X (bisindolylmaleimide I), Go6976, ZIP, LY333531 hydrochloride (ruboxistaurin), Ro31-8220 mesylate, Ro32-0432 hydrochloride, rottlerin, baicalein, quercetin, luteolin, bisindolylmaleimide II, calphostin C, chelerythrine chloride, L-threo dihydrosphingosine (safingol), melittin, and the like. In one embodiment, the PKC inhibitor is enzastaurin (3-(1-methylindol-3-yl)-4-[1-[1-(pyridin-2-ylmethyl)piperidin-4-yl]indol-3-yl]pyrrole-2,5-dione; CAS 170364-57-5), sotrastaurin (5-hydroxy-4-(1H-indol-3-yl)-3-[2-(4-methylpiperazin-1-yl)quinazolin-4-yl]-2H-pyrrol-2-one; CAS 4 25637-18-9), midostaurin (N-((5R,7R,8R,9S)-8-methoxy-9-methyl-16-oxo-6,7,8,9,15,16-hexahydro-5H,14H-17-oxa-4b,9a,15-triaza-5,9-methanodibenzo[b,h]cyclonona[jkl]cyclopenta[e]-as-indacen-7-yl)-N-methylbenzamide; CAS 120685-11-2), MS-553. In a preferred embodiment, the PKC inhibitor is enzastaurin.

[0014] Cytotoxic agents are agents that are toxic to mammalian cells and induce cell death. Cytotoxic agents can directly target cell viability. For example, cytotoxic agents can target anti-apoptotic pathways or be mitotic inhibitors, nucleoside analogs, or DNA intercalating agents (e.g., anthracyclines). Suitable cytotoxic agents include alkylating agents such as bendamustine and chlorambucil; antimetabolites including purine analogues such as fludarabine, and cladribine, pyrimidine analogues such as cytarabine; anti-microtubule agents such as vincristine; folate antagonists such as methotrexate; topoisomerase inhibitors; DNA intercalating agents (including anthracyclines such as doxorubicin and daunorubicin); apoptosis inducers (including BCL-2 inhibitors such as venetoclax (ABT-199), AZD5991, AMG176, A-1210477, navitoclax); BTK inhibitors such as ibrutinib; P3K inhibitors such as idealisib; steroids such as prednisolone and dexamethasone; and cytotoxic antibodies, particularly antibodies directed against B cells such as rituximab. In certain preferred embodiments, the cytotoxic agent can be selected from fludarabine, cladribine, cytarabine, chlorambucil, venetoclax, navitoclax, AZD5991, AMG176, A-1210477, bendamustine, cyclophosphamide, prednisolone, methotrexate, vincristine, doxorubicin, daunorubicin, and rituximab.

[0015] The cytotoxic agent may be a mitotic inhibitor, a nucleoside analog, an anthracycline, a DNA intercalating agent, an alkylating agent, an antimetabolite, an antimicrotubule agent, an antifolate, a topoisomerase inhibitor, an apoptosis inducer, a BCL-2 inhibitor, a BTK inhibitor, a P3K inhibitor, a glucocorticoid, or a cytotoxic antibody. The cytotoxic agent may be a chemotherapeutic agent or an immunosuppressant.

[0016] cytotoxicity Agent are fludarabine, venetoclax, methotraxate, vincristine, dexamethasone, anthracyclines, bendamustine, idealisib, ibrutinib, methotrexate, cyclophosphamide, Monoclonal antibodies targeting steroids or B cells or a pharmaceutically acceptable salt or solvate thereof. The anthracycline may be doxorubicin, daunorubicin, epirubicin, or idarubicin, or a pharmaceutically acceptable salt or solvate thereof. The steroid may be prednisolone, or a pharmaceutically acceptable salt or solvate thereof. The monoclonal antibody targeting B cells may be rituximab, or a pharmaceutically acceptable salt or solvate thereof. In some embodiments, the cytotoxic agent is fludarabine. In some embodiments, the cytotoxic agent is venetoclax. In some embodiments, the cytotoxic agent is bendamustine.

[0017] In one embodiment, the PKC inhibitor and the cytotoxic agent are used to treat cancer. The cancer may include B-cell malignancies or may be a myeloid cancer. The cancer is selected from the group consisting of lymphoma, leukemia, breast cancer, cholangiocarcinoma, bladder cancer, gastric cancer, lung cancer, prostate cancer, colon cancer, and colorectal cancer. The cancer may be a B-cell lymphoma. The cancer is selected from the group consisting of chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL), acute lymphoblastic leukemia (B-ALL), and acute myeloid leukemia (AML), follicular lymphoma, diffuse large B-cell lymphoma, and Burkitt's lymphoma. In one embodiment, the cancer is chronic lymphocytic leukemia (CLL). In another embodiment, the cancer is acute myeloid leukemia (AML). The cancer may be a drug-resistant cancer.

[0018] In one embodiment, the PKC inhibitor and the cytotoxic agent are used to treat an autoimmune disease. The autoimmune disease is selected from the group consisting of rheumatoid arthritis, systemic lupus erythematosus, inflammatory bowel disease, multiple sclerosis, type 1 diabetes, celiac disease, Grave's disease, psoriasis, and vasculitis. In one embodiment, the autoimmune disease is systemic lupus erythematosus (SLE). In another embodiment, the autoimmune disease is rheumatoid arthritis (RA).

[0019] The PKC inhibitor can reach a peak concentration in the subject at least 30 minutes before the cytotoxic agent reaches a peak concentration, at least 1 hour before the cytotoxic agent reaches a peak concentration, at least 2 hours before the cytotoxic agent reaches a peak concentration, or at least 3 hours before the cytotoxic agent reaches a peak concentration. The PKC inhibitor can reach a peak concentration in the subject less than 12 hours before the cytotoxic agent reaches a peak concentration, less than 8 hours before the cytotoxic agent reaches a peak concentration, less than 6 hours before the cytotoxic agent reaches a peak concentration, or less than 5 hours before the cytotoxic agent reaches a peak concentration. The PKC inhibitor can reach a peak concentration in the subject 30 minutes to 12 hours before the cytotoxic agent reaches a peak concentration, 1 hour to 8 hours before the cytotoxic agent reaches a peak concentration, 2 hours to 6 hours before the cytotoxic agent reaches a peak concentration, or 3 hours to 5 hours before the cytotoxic agent reaches a peak concentration. Alternatively, the PKC inhibitor may reach a peak concentration in the subject 30 minutes to 12 hours before the cytotoxic agent reaches a peak concentration, 45 minutes to 6 hours before the cytotoxic agent reaches a peak concentration, 1 hour to 5 hours before the cytotoxic agent reaches a peak concentration, or 1 hour to 4 hours before the cytotoxic agent reaches a peak concentration.

[0020] The medicament comprising the PKC inhibitor and / or cytotoxic substance described herein may be used in many ways. The composition comprising the PKC inhibitor and / or cytotoxic substance of the present invention may be administered by inhalation (e.g., intranasally). The composition may also be formulated for topical application. For example, it may be applied to the skin as a cream or ointment.

[0021] The PKC inhibitors and / or cytotoxic agents and compositions according to the invention can be administered by injection into the bloodstream or directly into the bloodstream at the site in need of treatment, e.g., at or adjacent to a cancerous tumor. Injection can be intravenous (bolus or infusion), subcutaneous (bolus or infusion), intradermal (bolus or infusion), or intramuscular (bolus or infusion).

[0022] The PKC inhibitor and / or cytotoxic agent can be administered orally. Thus, the PKC inhibitor and / or cytotoxic agent may be contained within a composition that can be taken orally in the form of, for example, a tablet, capsule, or liquid.

[0023] It will be understood that the amount of PKC inhibitor and / or cytotoxic agent required will be determined by its biological activity and bioavailability, which will depend on the method of administration, the physicochemical properties of the PKC inhibitor and / or cytotoxic agent, and whether it is used as a monotherapy or a combination therapy. The frequency of administration will also be influenced by the half-life of the PKC inhibitor and / or cytotoxic agent in the treated subject. The optimal dose to be administered may be determined by one skilled in the art and will vary depending on the particular PKC inhibitor and / or cytotoxic agent being used, the strength of the pharmaceutical composition, the method of administration, and the progression of the disease. Additional factors that depend on the particular subject being treated may require the dosage to be adjusted, including the subject's age, weight, sex, diet, and time of administration.

[0024] The inhibitor is administered before, during, or after the onset of the disease being treated. A single daily dose may be administered. Alternatively, the PKC inhibitor and / or cytotoxic agent may be administered more than once per day, most preferably twice per day. Generally, a daily dose of the PKC inhibitor and / or cytotoxic agent according to the present invention may be used between 0.01 μg / kg and 500 mg / kg of body weight. More preferably, the daily dose is between 0.01 mg / kg and 400 mg / kg of body weight, more preferably between 0.1 mg / kg and 200 mg / kg of body weight, and most preferably between about 1 mg / kg and 100 mg / kg of body weight.

[0025] A patient undergoing treatment would receive one dose upon awakening, followed by a second dose in the evening if two doses are administered, or at 3 or 4 hour intervals thereafter. Alternatively, a sustained release device could be used to provide the patient with an optimal dose of the inhibitor according to the invention without the need for repeated administration. Known procedures (e.g., in vivo experiments, clinical trials, etc.) as conventionally employed in the pharmaceutical industry can be used to formulate specific formulations containing PKC inhibitors and / or cytotoxic agents according to the present invention and precise treatment regimens (e.g., daily dose and frequency of administration of inhibitors, etc.) The present inventors are the first to report pharmaceutical compositions based on the use of PKC inhibitors and cytotoxic agents.

[0026] Thus, in a fifth aspect, there is provided a pharmaceutical composition comprising a PKC inhibitor and a cytotoxic agent, or a pharma- ceutically acceptable salt or solvate thereof, and a pharma- ceutically acceptable vehicle. Preferably, the composition is configured such that, after administration, the PKC inhibitor reaches a peak concentration in the subject before the cytotoxic agent reaches a peak concentration. This can be achieved using a delayed release formulation. Alternatively, depending on the PKC inhibitor and the cytotoxic agent, such a formulation may not be necessary. For example, PKC inhibitors tend to reach a peak concentration about 3 hours after administration. Conversely, BCL-2 inhibitors tend to reach a peak concentration about 8 hours after administration. Thus, when a composition including a PKC inhibitor and a BCL-2 inhibitor is administered to a patient, the PKC inhibitor will reach a peak concentration in the subject about 5 hours before the BCL-2 inhibitor reaches a peak concentration.

[0027] The present invention also provides, in a sixth aspect, a method for producing a composition according to the fifth aspect, the method comprising contacting a therapeutically effective amount of a PKC inhibitor, or a pharma- ceutically acceptable salt or solvate thereof, a cytotoxic agent, or a pharma- ceutically acceptable salt or solvate thereof, and a pharma- ceutically acceptable vehicle.

[0028] A "subject" may be a vertebrate, a mammal, or a livestock animal. Thus, the PCK inhibitors and cytotoxic agents may be used to treat any mammal, such as livestock (e.g., horses), pets, or for other veterinary purposes. However, most preferably, the subject is a human.

[0029] A "therapeutically effective amount" of a PCK inhibitor and a cytotoxic agent is the amount of drug required to treat cancer or an autoimmune disease when administered to a subject. For example, the therapeutically effective amounts of the PCK inhibitor and cytotoxic agent used are about 0.01 mg to about 800 mg, preferably about 0.01 mg to about 500 mg. The amounts of the PCK inhibitor and cytotoxic agent are about 0.1 mg to about 250 mg, preferably about 0.1 mg to about 20 mg.

[0030] A "pharmaceutically acceptable vehicle" disclosed herein refers to a compound or combination of compounds known to those of ordinary skill in the art to be useful in formulating a pharmaceutical composition. In one embodiment, the pharma- ceutically acceptable vehicle may be a solid, and the composition may be in the form of a powder or tablet. A solid pharma- ceutically acceptable vehicle may include one or more substances that may also act as flavorings, lubricants, solubilizers, suspending agents, dyes, fillers, lubricants, compression aids, inert binders, sweeteners, preservatives, dyes, coating agents, or tablet disintegrating agents. The vehicle may also be an encapsulating material. In the case of powders, the vehicle is a finely divided solid that is mixed with the finely divided active agent (i.e., inhibitor) in the present invention. In the case of tablets, the inhibitor may be mixed with a vehicle having the necessary compression properties in suitable proportions and compressed into the desired shape and size. Powders and tablets preferably contain up to 99% of the inhibitor. Suitable solid vehicles include, for example, calcium phosphate, magnesium stearate, talc, sugar, lactose, dextrin, starch, gelatin, cellulose, polyvinylpyrrolidine, low melting waxes, and ion exchange resins. In other embodiments, the pharmaceutical vehicle may be a gel, the composition may be in the form of a cream, or the like.

[0031] However, the pharmaceutical vehicle may be liquid and the pharmaceutical composition is in the form of a solution. Liquid vehicles are used in the preparation of solutions, suspensions, emulsions, syrups, elixirs and pressurized compositions. The inhibitors according to the invention may be dissolved or suspended in a pharma- ceutically acceptable liquid vehicle, such as water, an organic solvent, a mixture of both, or a pharma- ceutically acceptable oil or fat. The liquid vehicle may contain other suitable pharmaceutical excipients, such as solubilizers, emulsifiers, buffers, preservatives, sweeteners, flavorings, suspending agents, thickeners, colorants, viscosity modifiers, stabilizers or osmolality modifiers. Suitable examples of liquid vehicles for oral and parenteral administration include water (partially containing the above-mentioned excipients, e.g., cellulose derivatives, preferably sodium carboxymethylcellulose solutions), alcohols (including monohydric and polyhydric alcohols, e.g., glycols) and their derivatives, and oils (e.g., fractionated coconut oil and arachis oil). For parenteral administration, the vehicle may also be an oily ester, such as ethyl oleate or isopropyl myristate. Sterile liquid vehicles are useful in sterile liquid form compositions for parenteral administration. Liquid vehicles for pressurized compositions can be halogenated hydrocarbons or other pharma- ceutically acceptable propellants. Liquid pharmaceutical compositions that are sterile solutions or suspensions can be utilized by, for example, intramuscular, intrathecal, epidural, intraperitoneal, intravenous, and particularly subcutaneous injection. The inhibitors can be prepared as sterile solid compositions that can be dissolved or suspended at the time of administration using sterile water, saline, or other appropriate sterile injectable medium.

[0032] The PCK inhibitors and / or cytotoxic agents of the present invention may be administered in the form of a sterile solution or suspension containing other solutes or suspending agents (e.g., sufficient saline or glucose to make the solution isotonic), bile salts, acacia, gelatin, sorbitan monooleate, polysorbate 80 (oleic acid esters of sorbitol and its anhydrides copolymerized with ethylene oxide), and the like. The PCK inhibitors and / or cytotoxic agents used according to the present invention may also be administered orally in the form of liquid or solid compositions. Compositions suitable for oral administration include solid forms such as tablets, capsules, granules, pills, powders, and the like, and liquid forms such as solutions, syrups, elixirs, suspensions, and the like. Forms useful for parenteral administration include sterile solutions, emulsions, suspensions, and the like.

[0033] A seventh aspect provides a method of increasing a subject's sensitivity to a cytotoxic agent comprising administering to the subject a PKC inhibitor in combination with a cytotoxic agent, wherein the PKC inhibitor is administered to the subject 2-6 hours prior to administration of the cytotoxic agent. PKC inhibitors may sensitize diseased cells, such as cancer cells, including autoreactive immune cells and malignant B cells, of a subject to cytotoxic agents. An eighth aspect of the invention provides a method of treating cancer in a subject comprising administering to the subject a PKC inhibitor in combination with a cytotoxic agent, wherein the PKC inhibitor is administered to the subject 2 to 6 hours prior to administration of the cytotoxic agent. A ninth aspect of the present invention provides a method of treating an autoimmune disease in a subject comprising administering to the subject a PKC inhibitor in combination with a cytotoxic agent, wherein the PKC inhibitor is administered to the subject 2 to 6 hours prior to administration of the cytotoxic agent. A tenth aspect of the invention provides a PKC inhibitor for use in a method according to any of the seventh, eighth or ninth aspects. An eleventh aspect of the invention provides the use of a PKC inhibitor in the manufacture of a medicament for use in a method according to any of the seventh, eighth or ninth aspects. A twelfth aspect of the invention provides a cytotoxic agent for use in a method according to any of the seventh, eighth or ninth aspects. A thirteenth aspect of the invention provides the use of a cytotoxic agent in the manufacture of a medicament for use in a method according to any of the seventh, eighth or ninth aspects. A fourteenth aspect of the invention provides a combination of a PKC inhibitor and a cytotoxic agent for use in a method according to any of the seventh, eighth or ninth aspects. A fifteenth aspect of the invention provides the combination of a PKC inhibitor and a cytotoxic agent in the manufacture of a medicament for use in a method according to any of the seventh, eighth or ninth aspects. Preferred PKC inhibitors for use in the first to ninth aspects include enzastaurin, sotrastaurin and midostaurin, preferably enzastaurin. Cytotoxic agents for use in the first to ninth aspects preferably include fludarabine, methotraxate, vincristine, doxorubicin and other anthracyclines, steroids such as bendamustine, cyclophosphamide, prednisolone, and monoclonal antibodies targeting B cells, such as rituximab. Cancers treated in the second and fourth to ninth aspects may include B-cell malignancies and myeloid cancers. Autoimmune diseases treated in the third to ninth aspects may include systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA).

[0034] In another aspect, the invention relates to the discovery that administration of a PKC inhibitor within a specific time frame prior to administration of a cytotoxic agent significantly enhances chemosensitization and increases the efficacy of the cytotoxic agent. This effect is not observed when the PKC inhibitor is administered outside of the time frame. PKC inhibitors can sensitize diseased cells, e.g., tumor cells, to cytotoxic agents and enhance cell death compared to treatment with the cytotoxic agent alone. PKC inhibitors can, in some embodiments, antagonize environmentally mediated resistance to cytotoxic agents. These findings can be useful, for example, in improving patient outcomes by increasing the efficacy of cancer treatments and autoimmune disease treatments, reducing side effects, and / or reducing the effective dose of cytotoxic agents.

[0035] The PKC inhibitor can be administered to the subject 2-6 hours, e.g., 2-5 hours, 2-4 hours, 2-3 hours, 3-6 hours, 3-5 hours, 3-4 hours, 4-6 hours, 4-5 hours, or 5-6 hours, prior to administration of the cytotoxic agent. In a preferred embodiment, the PKC inhibitor can be administered to the subject 3-6 hours prior to administration of the cytotoxic agent. Administration of the PKC inhibitor within this time frame has been shown to increase the efficacy and / or cytotoxic effect of the cytotoxic agent, whereas administration outside this particular time frame has no such effect. In certain embodiments, the optimal time for administration of the PKC inhibitor to a subject within a time frame of 2 to 6 hours prior to administration of a cytotoxic agent may vary depending on the particular dose and the particular PKC inhibitor and cytotoxic agent used. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] Protein kinase C (PKC); (EC 2.7.11.13) is a family of enzymes in the serine / threonine protein kinases that transmit signals and regulate other proteins through phosphorylation. The family consists of several isozymes, including PKC-α, PKC-β, PKC-γ, PKC-η, PKC-ε, PKC-δ, PKC-θ, PKC-ι, PKC-ζ, PRK1, and PRK2. PKC isozymes play a key role in controlling signaling pathways related to proliferation, migration, invasion, tumorigenesis, and metastasis. Recently, the transmission of anti-apoptotic signals by PKC-β has been linked to environmentally mediated drug resistance. PKC inhibitors may be selective for one or more PKC isotypes, preferably PKC-β. PKC inhibitors suitable for use as described herein preferably inhibit PKC-β (ie, the PKC inhibitor is a PKC-β inhibitor). PKC inhibitors are drugs that inhibit the activity of PKC or reduce / inhibit the expression of PKC. Suitable agents for inhibiting the activity of PKC or reducing / inhibiting the expression of PKC include antibodies and other immunoglobulin molecules, aptamers, suppressor nucleic acids, small chemical molecules, e.g., non-polymeric organic compounds with a molecular weight of 900 daltons or less. Suitable PKC inhibitors are known in the art and include enzastaurin, sotrastaurin, midostaurin (PKC412), MS-553, Gouml 6983, staurosporine, GF109203X (bisindolylmaleimide I), Go6976, ZIP, LY333531 hydrochloride (ruboxistaurin), Ro31-8220 mesylate, Ro32-0432 hydrochloride, rottlerin, baicalein, quercetin, luteolin, bisindolylmaleimide II, calphostin C, chelerythrine chloride, L-threo dihydrosphingosine (safingol), melittin, and the like. In one embodiment, the PKC inhibitor is enzastaurin (3-(1-methylindol-3-yl)-4-[1-[1-(pyridin-2-ylmethyl)piperidin-4-yl]indol-3-yl]pyrrole-2,5-dione; CAS 170364-57-5), sotrastaurin (5-hydroxy-4-(1H-indol-3-yl)-3-[2-(4-methylpiperazin-1-yl)quinazolin-4-yl]-2H-pyrrol-2-one; CAS 4 25637-18-9), midostaurin (N-((5R,7R,8R,9S)-8-methoxy-9-methyl-16-oxo-6,7,8,9,15,16-hexahydro-5H,14H-17-oxa-4b,9a,15-triaza-5,9-methanodibenzo[b,h]cyclonona[jkl]cyclopenta[e]-as-indacen-7-yl)-N-methylbenzamide; CAS 120685-11-2), MS-553. In a preferred embodiment, the PKC inhibitor is enzastaurin. The PKC inhibitor is administered to a subject in combination with a cytotoxic agent in the methods described herein.

[0037] Cytotoxic agents are agents that are toxic to mammalian cells and induce cell death. Cytotoxic agents can directly target cell viability. For example, cytotoxic agents can target anti-apoptotic pathways or be mitotic inhibitors, nucleoside analogs, or DNA intercalating agents (e.g., anthracyclines). Suitable cytotoxic agents include alkylating agents such as bendamustine and chlorambucil; antimetabolites including purine analogues such as fludarabine, and cladribine, pyrimidine analogues such as cytarabine; anti-microtubule agents such as vincristine; folate antagonists such as methotrexate; topoisomerase inhibitors; DNA intercalating agents (including anthracyclines such as doxorubicin and daunorubicin); apoptosis inducers (including BCL-2 inhibitors such as venetoclax (ABT-199), AZD5991, AMG176, A-1210477, navitoclax); BTK inhibitors such as ibrutinib; P3K inhibitors such as idealisib; steroids such as prednisolone and dexamethasone; and cytotoxic antibodies, particularly antibodies directed against B cells such as rituximab. In certain preferred embodiments, the cytotoxic agent can be selected from fludarabine, cladribine, cytarabine, chlorambucil, venetoclax, navitoclax, AZD5991, AMG176, A-1210477, bendamustine, cyclophosphamide, prednisolone, methotrexate, vincristine, doxorubicin, daunorubicin, and rituximab.

[0038] While it is possible for the cytotoxic agent or PKC inhibitor to be administered alone to an individual, preferably, the cytotoxic agent or PKC inhibitor is present in a pharmaceutical composition or formulation. In addition to the active compound, a pharmaceutical composition may contain one or more pharma- ceutically acceptable carriers, adjuvants, excipients, diluents, fillers, buffers, stabilizers, preservatives, lubricants, or other materials known to those skilled in the art. Such materials should be non-toxic and should not interfere with the efficacy of the active compound. The exact nature of the carrier or other materials will depend on the route of administration, be it by bolus, infusion, injection, or other suitable route, as described below. Suitable materials will have suitable isotonicity and stability, and will be sterile and pyrogen-free. Examples include sterile saline (e.g., 0.9% NaCl), water, dextrose, glycerol, ethanol, or the like, or combinations thereof. The composition may further contain auxiliary substances, such as wetting agents, emulsifying agents, pH buffering agents, and the like. Suitable carriers, excipients, etc. can be found in standard pharmaceutical textbooks, such as Remington's Pharmaceutical Sciences, 18th Edition, Mack Publishing Company, Easton, Pa., 1990.

[0039] As used herein, the term "pharmacologically acceptable" refers to compounds, materials, compositions, and / or dosage forms that are suitable for use in contact with the tissues of a subject (e.g., a human) without undue toxicity, irritation, allergic response, or other problem or complication, within the scope of sound medical judgment, commensurate with a reasonable benefit / risk ratio. Each carrier, excipient, etc. must also be "acceptable" in the sense of being compatible with the other ingredients of the formulation.

[0040] The formulations can be conveniently presented in unit dosage form and can be prepared by any method known in the art of pharmacy. Such methods include bringing the active compound into association with a carrier which constitutes one or more accessory ingredients. In general, the formulations are prepared by uniformly and intimately bringing the active compound into association with a liquid carrier or a finely divided solid carrier or both, and then, if necessary, shaping the product. Formulations include liquids, solutions, suspensions, emulsions, elixirs, syrups, tablets, troches, granules, powders, capsules, cachets, pills, ampoules, suppositories, pessaries, ointments, gels, pastes, creams, sprays, mist, foams, lotions, oils, boluses, electaries, or aerosol forms.

[0041] The active compound or pharmaceutical composition comprising the active compound may be administered to a subject by any convenient route of administration, whether systemic / peripheral or at the desired site of action, including, but not limited to, oral (e.g., by ingestion) and parenteral, e.g., by injection, such as subcutaneous, intradermal, intramuscular, intravenous, intraarterial, intracardiac, intrathecal, intraspinal, subcapsular, intraorbital, intraperitoneal, intratracheal, subcutaneous, intraarticular, subarachnoid, and intrasternal; by implantation of a subcutaneous or intramuscular depot, etc. Usually, administration is by the oral route, but other convenient routes such as intraperitoneal, subcutaneous, transdermal, intravenous, intranasal, intramuscular, etc. are not excluded. Pharmaceutical compositions containing the active compound can be formulated in dosage unit formulations appropriate for the intended route of administration. Formulations suitable for oral administration (e.g., by ingestion) can be presented as discrete units, such as capsules, cachets, or tablets containing a predetermined amount of the active compound; as a powder or granules; as a solution or suspension in an aqueous or non-aqueous liquid; or as an oil-in-water liquid emulsion or a water-in-oil liquid emulsion; as a bolus; as an electrolyte; or as a paste.

[0042] Tablets can be manufactured by conventional means such as compression or molding, optionally with the addition of one or more accessory ingredients. Compressed tablets can be prepared by mixing the active compound in a free-flowing form such as powder or granules with one or more binders (e.g., povidone, gelatin, acacia, sorbitol, tragacanth, hydroxypropylmethylcellulose); fillers or diluents (e.g., lactose, microcrystalline cellulose, calcium hydrogen phosphate); lubricants (e.g., magnesium stearate, talc, silica, etc.); disintegrants (e.g., sodium starch glycolate, cross-linked povidone, cross-linked sodium carboxymethylcellulose, etc.); surfactants, dispersants, wetting agents (e.g., sodium lauryl sulfate, etc.); preservatives (e.g., methyl p-hydroxybenzoate, propyl p-hydroxybenzoate, ascorbic acid, etc.) in a suitable machine. Molded tablets can be manufactured by molding a mixture of the powdered compound moistened with an inert liquid diluent in a suitable machine. The tablets may optionally be coated or scored and formulated to provide slow or controlled release of the active compound therein, for example with hydroxypropyl methylcellulose, to provide a desired release profile. Tablets may optionally be enteric coated, to provide release in parts of the gut other than the stomach. Suitable formulations for parenteral administration (including, for example, cutaneous, subcutaneous, intramuscular, intravenous, and intradermal injections) include aqueous and non-aqueous isotonic, pyrogen-free sterile injection solutions that may contain antioxidants, buffers, preservatives, stabilizers, bacteriostats, and solutes that render the formulation isotonic with the blood of the intended recipient; aqueous and non-aqueous sterile suspensions that may also contain suspending agents and thickening agents, as well as liposomes or other particulate systems designed to target the compound to blood components or one or more organs. Examples of isotonic vehicles suitable for use in such formulations include sodium chloride injection, Ringer's solution, or lactated Ringer's solution. Typically, the concentration of the active compound in the solution is from about 1 ng / ml to about 10 g / ml, for example, from about 10 ng / ml to about 1 g / ml. The formulations may be presented in unit-dose or multi-dose sealed containers, such as ampoules or vials, and may be stored in a lyophilized (lyophilized) state, which may be supplemented with a sterile liquid carrier, such as water for injection, immediately prior to use. Extemporaneous injection solutions and suspensions can be prepared from sterile powders, granules, or tablets. Formulations may be in the form of liposomes or other microparticulate systems which are designed to target the active compound to blood components or one or more organs.

[0043] An individual or subject suitable for the treatments described herein may be in a disease state, for example, one or more of the individual's cells may be diseased cells. In some embodiments, an individual may have cancer. For example, one or more cells of an individual may be cancer cells. Cancer includes any unwanted cell proliferation (or any disease manifested by unwanted cell proliferation), neoplasm or tumor, or an increased risk or predisposition to unwanted cell proliferation, neoplasm or tumor. Cancer may be benign or malignant, primary or secondary (metastatic). Cancer suitable for treatment as described herein may be any type of solid or non-solid cancer or malignant lymphoma, in particular leukemia, sarcoma, skin cancer, bladder cancer, blood cancer, breast cancer, uterine cancer, ovarian cancer, prostate cancer, lung cancer, colon cancer, cervical cancer, liver cancer, head and neck cancer, esophageal cancer, pancreatic cancer, renal cancer, gastric cancer and brain cancer. Cancer may be familial or sporadic. In a preferred embodiment, the cancer is a hematological cancer. Hematological cancer may include B-cell malignancies, i.e. cancers affecting B-cells. For example, the cancer cells may be malignant B-cells. B-cell malignancies include lymphomas, such as non-Hodgkin's lymphoma (NHL), Hodgkin's lymphoma (HL), Burkitt's lymphoma, diffuse large B-cell lymphoma, mantle cell lymphoma (MCL), follicular lymphoma, and leukemias, such as chronic lymphocytic leukemia (CLL), acute lymphoblastic leukemia (B-ALL), and acute myeloid leukemia (AML). In a preferred embodiment, the cancer is chronic lymphocytic leukemia (CLL). In another preferred embodiment, the cancer is acute myeloid leukemia (AML).

[0044] In some embodiments, the cancer may be resistant to a cytotoxic agent in the absence of a PKC inhibitor and / or may be resistant to a PKC inhibitor in the absence of a cytotoxic agent. For example, the cancer may exhibit environmentally mediated resistance to a cytotoxic agent. A PKC inhibitor administered in a defined time frame as described herein may antagonize environmentally mediated resistance and sensitize tumor cells to the cytotoxic agent, leading to enhanced cytotoxicity and efficacy.

[0045] In certain embodiments, the individual may have minimal residual disease (MRD) after initial cancer treatment.

[0046] In other embodiments, the individual may have an autoimmune disease, for example, one or more cells of the individual may be an autoreactive immune cell. An autoimmune disease is a disease in which a subject's immune system produces antibodies that attack the subject's normal body tissues. The autoimmune disease may be an autoimmune disease of the nervous system, the gastrointestinal tract, the blood and blood vessels, the skin, the endocrine system, and / or the musculoskeletal system. Autoimmune diseases suitable for treatment as described herein include rheumatoid arthritis, systemic lupus erythematosus, inflammatory bowel disease, multiple sclerosis, type 1 diabetes, celiac disease, Grave's disease, and psoriasis. In a preferred embodiment, the autoimmune disease is systemic lupus erythematosus (SLE). In another preferred embodiment, the autoimmune disease is rheumatoid arthritis (RA). PKC inhibitors administered in the time frames described herein may antagonize environmentally mediated resistance and sensitize autoreactive immune cells to cytotoxic agents, leading to enhanced cytotoxicity and efficacy.

[0047] An individual suitable for such treatment may be a mammal, such as a rodent (e.g., guinea pig, hamster, rat, mouse), murine (e.g., mouse), canine (e.g., dog), feline (e.g., cat), equine (e.g., horse), primate, ape (e.g., monkey and ape), monkey (e.g., marmoset, baboon), ape (e.g., gorilla, chimpanzee, orangutan, gibbon), human, etc. In certain preferred embodiments, the individual is a human. In other preferred embodiments, non-human mammals can be used, particularly mammals that have traditionally been used as models to demonstrate therapeutic efficacy in humans (e.g., murine, primate, porcine, canine, or leporid). An individual with a disease, such as cancer or an autoimmune disease, may exhibit at least one identifiable sign, symptom, or laboratory finding sufficient to diagnose the disease according to clinical criteria known in the art, examples of which may be found in medical textbooks such as Harrison's Principles of Internal Medicine, 15th Edition, edited by Fauci AS et al., McGraw-Hill, New York, 2001. In some cases, diagnosing a disease, such as cancer or an autoimmune disease, in an individual may include identifying a particular cell type (e.g., cancer cells) in a fluid or tissue sample taken from the individual. In some embodiments, an individual may have previously been identified or diagnosed with a disease, such as cancer or an autoimmune disease, and the methods of the invention may include identifying or diagnosing the disease in the individual, for example, by determining the presence of an identifiable sign, symptom, or laboratory finding indicative of the disease in the individual.

[0048] Treatment is any procedure or treatment, whether in a human or (e.g., in veterinary uses) animal, in which some desired therapeutic effect is achieved, such as inhibiting or slowing the progression of a disease condition, slowing the rate of progression, halting the rate of progression, ameliorating a disease condition, curing or remission (whether partially or totally) a disease condition, preventing, slowing, alleviating or halting one or more symptoms or signs of a disease condition, or prolonging the survival of the patient or subjects beyond that expected if treatment is not administered. The treatment of cancer includes suppression of cancer growth, including complete remission of cancer, and / or suppression of cancer metastasis. Cancer growth generally refers to any of a number of indicators that indicate a change within the cancer to a more developed form. Thus, indicators that measure inhibition of cancer growth include a decrease in cancer cell viability, a decrease in tumor volume or morphology (e.g., as determined using computed tomography (CT), ultrasound, or other imaging), a slowing of tumor growth, a disruption of tumor vasculature, an improvement in delayed-type hypersensitivity skin test performance, an increase in the activity of cytolytic immune cells, a decrease in tumor-specific antigen levels, and the like.

[0049] The PKC inhibitors and cytotoxic agents can be administered in therapeutically effective amounts as described herein. As used herein, the term "therapeutically effective amount" refers to an amount of an active compound, or a combination, material, composition or dosage form containing an active compound, effective to produce some desired therapeutic effect commensurate with a reasonable benefit / risk ratio. Appropriate doses of PKC inhibitors and cytotoxic agents may vary from individual to individual. Determining optimal doses generally requires balancing the level of therapeutic benefit against any risk or adverse side effects of administration. The selected dose level will depend on a variety of factors, including but not limited to the route of administration, the time of administration, the rate of excretion of the active compound, other drugs, compounds, and / or co-administered materials, and the individual's age, sex, weight, condition, general health, and previous medical history. The amount and route of administration of the active compound are ultimately at the discretion of the physician, but will generally be a dose that achieves therapeutic plasma concentrations of the active compound without causing substantial adverse or deleterious side effects. In general, a suitable dose of the active compound is in the range of about 100 μg to about 400 mg per kg of subject body weight per day, preferably 200 μg to about 200 mg per kg of subject body weight per day. When the active compound is a salt, ester, prodrug, etc., the dosage is calculated based on the parent compound, so the mass actually used increases proportionately.

[0050] Methods of determining the most effective means and dosages of administration are known in the art and will vary with the formulation used for therapy, the purpose of the therapy, the cell being treated, and the subject being treated. Single or multiple administrations may be administered with dosage levels and pattern selected by a physician. In certain embodiments, administration of a PKC inhibitor enhances the cytotoxic effect of a cytotoxic agent. A cytotoxic effect is "potentiated" if administration of a PKC inhibitor followed by administration of the cytotoxic agent results in a greater therapeutic effect (i.e., greater cell death) than administration of the cytotoxic agent alone. In certain embodiments, administration of a PKC inhibitor may potentiate immunosuppression by a cytotoxic agent. Immunosuppression is "potentiated" if administration of a PKC inhibitor followed by administration of a cytotoxic agent results in a greater therapeutic effect (e.g., increased death of autoreactive T cells or B cells) than administration of the cytotoxic agent alone.

[0051] Other aspects and embodiments of the present invention are provided with the above aspects and embodiments replaced with the term "comprising" and with the above aspects and embodiments replaced with the term "consisting essentially of". It should be understood that the present application discloses all combinations of any of the above aspects and embodiments with each other unless otherwise specified in the context.Similarly, the present application discloses all combinations of preferred features and / or any features alone or with any of the other aspects unless otherwise specified in the context. Modifications of the above embodiments, further embodiments and modifications thereof will be apparent to those skilled in the art from this disclosure and, accordingly, are within the scope of the present invention. All documents and sequence database entries mentioned herein are hereby incorporated by reference in their entirety for all purposes. As used herein, "and / or" means that each of the two specified features or components is specifically disclosed without regard to the presence or absence of the other. For example, "A and / or B" means that (i) A, (ii) B, and (iii) A and B are each specifically disclosed as if each were individually defined. Every feature described in this specification (including the accompanying claims, abstract and drawings), and / or every step of any method or process so disclosed may be combined with any of the above aspects in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. For a better understanding of the present invention and to show how embodiments thereof may be carried into effect, reference is herein made, by way of example, to the accompanying drawings in which: FIG. [Brief description of the drawings]

[0052] [Figure 1] FIG. 1 shows the effect of enzastaurin administered 1 hour at the indicated times prior to fludarabine administration on the efficacy of the cytotoxic agent fludarabine; FIG. 1A shows the administration method for each experimental condition; FIG. 1B shows the percentage of surviving cancer cells after treatment. [Diagram 2] Figure 2 shows the effect of enzastaurin administered 1 hour at the indicated times prior to venetoclax administration on the efficacy of the cytotoxic agent venetoclax; Figure 2A shows the dosing regimen for each experimental condition; Figure 2B shows the percentage of viable cancer cells following treatment. [Diagram 3] Figure 3 shows the effect of enzastaurin administered at the indicated times, including 24 hours of venetoclax treatment, on the efficacy of the cytotoxic agent venetoclax; Figure 3A shows the dosing regimen for each experimental condition; Figure 3B shows the percentage of surviving cancer cells following treatment. [Figure 4] IC50 graphs of human CLL cells after 72 h of monoculture, PKC-βWT coculture or PKC-βKO coculture in the presence of venetoclax, bendamustine, fludarabine, ibrutinib or idealisib administered 24 h after CLL inoculation, respectively (5 per culture condition). CLL viability was normalized to the respective DMSO control. Statistical significance of PKC-βWT vs. PKC-βKO is shown using paired two-tailed Student's t-test. [Diagram 5] Shown is the synergy calculated using Compusyn Software (CRUK) within the Bliss model for venetoclax in combination with enzastaurin, sotrastaurin, or midostaurin (n=6). Heatmap reflects the assessment scores listed for each compound combination, with error (±) shown below. Values ​​are applied on a 50 to -50 scale, with 50 representing maximal synergy and -50 representing maximal antagonism. Non-significant values ​​are colored as no synergy or antagonism by default. [Figure 6]We show that expression of PKC-β in mesenchymal stromal cells (MSCs) is essential for normal B1 cell development. Figure 6A shows an experimental schematic to evaluate the functional outcome of adoptive transfer of CD45+ selected PKC-βWT bone marrow cells (BM) or KO BM into lethally irradiated (10 Gy) PKC-βWT or KO recipients, respectively. Figure 6B shows the evaluation of chimerism in CD45 isotype-mismatched mice. The percentage of each donor CD45 isotype is shown ± SEM. Donor BM genotypes are indicated in italics; WT:WT (n=3), KO:WT (n=4), WT:KO (n=4). Tissue abbreviations: PB, peripheral blood; PC, peritoneal cavity; SPC, spleen cells. FIG. 6C shows non-irradiated WT control (n=3), WT:KO (n=7), and four individuals each of WT:WT, KO:WT, and KO:KO assessed for peritoneal CD19+CD5+IgM+ cells with donor cell labels in italics. [Figure 7] Figure 1 shows the effect of enzastaurin administered 1 hour prior to bendamustine at the indicated times on the efficacy of the cytotoxic agent bendamustine.The figure shows the percentage of viable cancer cells following administration. [Figure 8] 1 shows the effect of enzastaurin administered at the indicated times prior to bendamustine on the efficacy of the cytotoxic agent bendamustine.The figure shows the percentage of viable cancer cells following administration. [Figure 9] 1 shows the effect of midostaurin administered at the indicated times prior to bendamustine on the efficacy of the cytotoxic agent bendamustine.The figure shows the percentage of viable cancer cells following treatment. [Figure 10] Figure 10 shows the effect of ruboxistaurin administered 1 hour prior to venetoclax at the indicated times on the observed efficacy of the cytotoxic agent venetoclax; Figure 10A shows the dosing regimen for each experimental condition; Figure 10B shows the percentage of viable cancer cells following treatment. Example 1

[0053] Example 1 - Pretreatment with enzastaurin enhances the efficacy of fludarabine and venetoclax 1 hour exposure to Enzastaurin Approximately 20,000 wild-type bone marrow-derived stromal cells were seeded in tissue culture wells and then co-cultured with approximately 200,000 CLL patient cells. For the next 24 hours, co-cultures were treated with 5 μM enzastaurin for 1 hour at the indicated time points before treatment with fludarabine or venetoclax (Figures 1A and 2A). Equivalent exposure to PKC-β inhibitors was maintained by removal of the enzastaurin-treated co-cultures and subsequent washout. Co-cultures were centrifuged at 500 g for 5 minutes before removal of the enzastaurin-containing medium. After washout with cell culture medium, they were centrifuged again at 500 g for 5 minutes and the washed-out medium was replaced with fresh medium. Each co-culture was then treated with fludarabine (2.5 μM) or venetoclax (2.5 nM) for 24 hours. Cell viability was then assessed by staining on a flow cytometer using Annexin V-FITC and DAPI, or 4',6-diamidino-2-phenylindole (Figures 1B and 2B). Continuous exposure to enzastaurin Approximately 20,000 wild-type bone marrow-derived stromal cells were seeded in tissue culture wells and then co-cultured with approximately 200,000 CLL patient cells. After 24 h, co-culture with 5 μM enzastaurin was performed at the indicated time points prior to treatment with venetoclax (Figure 3A). Co-culture with venetoclax (2.5 nM) was then performed for 24 h. Cell viability was then assessed using Annexin V-FITC and DAPI staining on a flow cytometer (Figure 3B).

[0054] result Pretreatment with comparable enzastaurin exposure demonstrated enhanced efficacy of both cytotoxic agents at 2-6 hours prior to dosing, with the greatest effect observed at 3-6 hours (Figures 1B and 2B). Additionally, continuous exposure to enzastaurin from 1, 2, 3, 4, 6, and 12 hours prior to 24 hours of venetoclax treatment and continued enzastaurin treatment demonstrated reduced chemosensitization to venetoclax with enzastaurin pretreatment at 3-6 hours prior to venetoclax treatment compared to reduced chemosensitization to venetoclax with enzastaurin pretreatment around the 3-6 hour pretreatment window (Figure 3B). Example 2

[0055] Inhibition of interstitial PKC-β ameliorates environmentally mediated drug resistance Approximately 20,000 PKC-βWT or PKC-βKO bone marrow-derived stromal cells were seeded into tissue culture wells. Approximately 200,000 CLL patient cells were then seeded for monoculture or coculture with PKC-βWT or PKC-βKO cells. They were then cultured for 24 hours and exposed to increasing doses of venetoclax (a BCL2 inhibitor), bendamustine (an alkylating agent), fludarabine (a purine analogue), ibrutinib or idealisib (a B-cell receptor-induced kinase inhibitor). Culture viability was then assessed using flow cytometry analysis.

[0056] result Co-culture with PKC-βWT cells significantly enhanced the resistance of CLL cells to cytotoxic agents compared with monoculture of CLL cells. In particular, strong protective effects of PKC-βWT cells were observed in CLL cells treated with venetoclax and fludarabine. These protective effects were lost or reduced in CLL cell co-culture with PKC-βKO cells under all treatments (Figure 4). Example 3

[0057] PKC-β inhibitors synergize with venetoclax Approximately 20,000 wild-type bone marrow-derived stromal cells were seeded in tissue culture wells and then co-cultured with approximately 200,000 CLL patient cells. After 24 hours, the co-cultures were treated with enzastaurin, sotrastaurin or midostaurin (1.25 μM, 2.5 μM, 5 μM) before treatment with venetoclax. The co-cultures were then treated with venetoclax (5 nM, 10 nM, 20 nM) for 24 hours. Cell viability was then assessed using flow cytometry analysis. Synergy was calculated using Compusyn Software (CRUK) within the Bliss Independence model (Figure 5).

[0058] result Combination therapy of venetoclax with enzastaurin, sotrastaurin, or midostaurin produced synergistic effects, indicating that PKC-β inhibitors can chemosensitize malignant B cells to cytotoxic agents. Example 4

[0059] Expression of PKC-β in MSCs is essential for normal B1 cell development Generation of chimeric mice Bone marrow was isolated from age-matched mice of CD45.2+Prkcb+ / +, Prkcb- / -, and CD45.1+B6.SJL-Ptprca Pepcb / BoyJ (Jackson Laboratory, USA) and depleted for CD45- cells with purity >95% by flow cytometry (µCD45 microbeads; Miltenyi Biotec). 3*10 purified bone marrow cells from CD45.2+Prkcb- / - purified BM and CD45.1+B6.SJL-Ptprca Pepcb / BoyJ purified BM were used. 6 Each was injected intravenously into different CD45 recipients after irradiation (10 Gy) (i.e., CD45.1+BM into CD45.2 recipients and CD45.2+BM into CD45.1 recipients). CD45.2+Prkcb- / - BM was also injected into irradiated CD45.2+Prkcb- / - recipients as a control (Figure 6A). Chimerism was assessed by flow cytometry of CD45.1 and CD45.2 staining of peripheral blood collected by tail vein bleeding (Figure 6B). We investigated whether the lack of tumor cell engraftment in PKC-β KO mice was entirely due to a defect in MSCs or whether hematopoietic cells in the microenvironment also contributed. We also addressed whether the engraftment dependency on microenvironmental PKC-β signals reflected the properties of the cell of origin by generating mixed chimeras that differed only in the expression of PKC-β in the hematopoietic system. The cell of origin is thought to be CD5+ B cells in mice and humans, and most likely CD5+ B1 cells in mice, which are innate B cells responsible for the production of natural antibodies. We generated PKC-β chimeric mice by transplanting PKC-β WT CD45+ hematopoietic bone marrow cells into irradiated (10 Gy) KO animals (above). To assess chimerism, WT CD45.1+ bone marrow cells were transplanted into CD45.2+ KO recipient mice. As a control, KO CD45.2+ BM cells were transplanted into CD45.1+ WT recipient mice (Figure 6A). Ten weeks after transplantation, mixed chimerism was observed in the peripheral blood, where transplanted bone marrow cells predominated (WT(donor):WT(recipient)=72.0%±2.09%, WT:KO=73.7±7.11%, KO:WT=64.1%±1.13%; Fig. 6B). Deletion of PKC-β in the mouse germline induces immunodeficiency with a marked reduction in peritoneal B1 cells and a marked reduction in serum IgM and IgG3 (Non-Patent Document 12). Notably, in WT recipient animals, we found no difference in the number of peritoneal B1 cells derived from either PKC-βKO or WT donor cells. Conversely, the development of peritoneal B1 cells in KO recipient animals transplanted from WT bone marrow was significantly reduced compared to WT recipient animals. Notably, the number of peritoneal B1 cells was still higher than in PKC-βKO control recipients reconstituted with KO bone marrow (Fig. 6C). These data indicate that PKC-β is a critical extracellular factor for B cell development. Example 5

[0060] Pretreatment with enzastaurin enhances the efficacy of bendamustine 1 hour exposure to Enzastaurin Approximately 20,000 wild-type bone marrow-derived stromal cells were seeded in tissue culture wells and then co-cultured with approximately 200,000 CLL patient cells. After 24 h, co-culture with 5 μM enzastaurin was performed for 1 h at the indicated time points before treatment with bendamustine (Figure 7). Equivalent PKC-β inhibitor exposure was maintained by removal of the enzastaurin-treated co-cultures and subsequent washout. Before removal of the enzastaurin-containing medium, the co-cultures were centrifuged at 500 g for 5 min. After washout with cell culture medium, they were centrifuged for another 5 min at 500 g and the washed-out medium was replaced with fresh medium. Each co-culture was then treated with bendamustine (15 μM) for 24 h. Cell viability was then assessed by staining with Annexin-V-FITC and DAPI or 4',6-diamidino-2-phenylindole on a flow cytometer. Pretreatment with equivalent enzastaurin exposure enhanced bendamustine efficacy at 2-6 hours predose, with maximal effects observed at 3-6 hours (Figure 7). Continuous exposure to enzastaurin Approximately 20,000 wild-type bone marrow-derived stromal cells were seeded in tissue culture wells and then co-cultured with approximately 200,000 CLL patient cells. After 24 h, co-culture with 5 μM enzastaurin was performed at the indicated time points before treatment with bendamustine (Figure 8). Co-culture with bendamustine (15 μM) was then performed for 24 h. Cell viability was then assessed using Annexin V-FITC and DAPI staining on a flow cytometer (Figure 8). When enzastaurin was administered continuously from 1, 2, 3, 4, 6, or 8 hours before 24 hours prior to bendamustine administration, it was shown that the greatest effect was obtained when enzastaurin was preadministered 3 to 6 hours before bendamustine administration, but preadministration of enzastaurin before or after this reduced chemosensitization to bendamustine (Figure 8). Example 6

[0061] Pretreatment with midostaurin enhances the efficacy of bendamustine Continuous exposure to midostaurin Approximately 20,000 wild-type bone marrow-derived stromal cells were seeded in tissue culture wells and then co-cultured with approximately 200,000 CLL patient cells. After 24 hours, the co-cultures were treated with 1 μM midostaurin at the indicated time points prior to treatment with bendamustine (Figure 8). The co-cultures were then treated with bendamustine (15 μM) for 24 hours. Cell viability was then assessed using Annexin V-FITC and DAPI staining on a flow cytometer (Figure 9). Midostaurin was administered 1, 2, 3, 4, 6, or 8 hours before 24 hours prior to bendamustine administration, and then midostaurin administration was continued. It was shown that the effect of bendamustine was greatest when midostaurin was administered 3 to 8 hours prior to bendamustine administration (Figure 9). Example 7

[0062] Pretreatment with ruboxistaurin enhances efficacy of venetoclax 1-hour exposure to ruboxistaurin Approximately 20,000 wild-type bone marrow-derived stromal cells were seeded in tissue culture wells and then co-cultured with approximately 200,000 CLL patient cells. After 24 h, the co-cultures were treated with 5 μM ruboxistaurin for 1 h at the indicated time points before treatment with venetoclax (Figure 10A). Removal of the ruboxistaurin-treated co-cultures and subsequent washout maintained equivalent PKC-β inhibitor exposure. Co-cultures were centrifuged at 500 g for 5 min before removal of ruboxistaurin-containing medium. After washout with cell culture medium, they were centrifuged for an additional 5 min at 500 g and the washout medium was replaced with fresh medium. Each co-culture was then treated with venetoclax (5 nM) for 24 h. Cell viability was then assessed by staining with Annexin-V-FITC and DAPI or 4',6-diamidino-2-phenylindole on a flow cytometer (Figure 10B).

[0063] result Pretreatment with ruboxistaurin exposure demonstrated increased efficacy to venetoclax at time points 1 to 6 hours pre-dose, with the most significant effect observed between 1 and 4 hours (Figure 10B). References

[0064]

Table 1

Claims

1. 1. A pharmaceutical composition for use in the treatment of cancer comprising a protein kinase C (PKC) inhibitor and a cytotoxic agent, wherein in a subject, the PKC inhibitor reaches a peak concentration before the cytotoxic agent reaches a peak concentration, the peak concentration of the PKC inhibitor being the maximum concentration reached in the blood after the PKC inhibitor is administered to the subject, and the peak concentration of the cytotoxic agent being the maximum concentration reached in the blood after the cytotoxic agent is administered to the subject, wherein The PKC inhibitor is enzastaurin, sotrastaurin, midostaurin, ruboxistaurin, or a pharma- ceutically acceptable salt or solvate thereof; and A pharmaceutical composition wherein said cytotoxic agent is fludarabine, venetoclax, vincristine, dexamethasone, anthracycline, bendamustine, idealisib, ibrutinib, methotrexate, cyclophosphamide, a steroid or a monoclonal antibody targeting B cells, or a pharma- ceutically acceptable salt or solvate thereof.

2. The pharmaceutical composition of claim 1 , wherein the cancer is selected from the group consisting of lymphoma, leukemia, breast cancer, bile duct cancer, bladder cancer, gastric cancer, lung cancer, prostate cancer, colon cancer and colorectal cancer.

3. The pharmaceutical composition of claim 1 , wherein the cancer is selected from lymphoma and leukemia.

4. The pharmaceutical composition according to claim 3, wherein the cancer is selected from the group consisting of chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL), acute lymphoblastic leukemia (B-ALL), and acute myeloid leukemia (AML), follicular lymphoma, diffuse large B-cell lymphoma, and Burkitt's lymphoma.

5. The pharmaceutical composition described in any one of claims 1 to 4, wherein the PKC inhibitor is enzastaurin, or a pharma- ceutically acceptable salt or solvate thereof.

6. The pharmaceutical composition described in any one of claims 1 to 4, wherein the PKC inhibitor is ruboxistaurin, or a pharma- ceutically acceptable salt or solvate thereof.

7. The pharmaceutical composition described in any one of claims 1 to 6, wherein the cytotoxic agent is fludarabine, venetoclax, bendamustine, idealisib, ibrutinib, or a pharma- ceutically acceptable salt or solvate thereof.

8. The pharmaceutical composition of claim 7, wherein the cytotoxic agent is fludarabine, venetoclax, bendamustine, or a pharma- ceutically acceptable salt or solvate thereof.

9. The pharmaceutical composition of claim 1, wherein the PKC inhibitor reaches its peak concentration in the subject 30 minutes to 12 hours before the cytotoxic agent reaches its peak concentration.

10. The pharmaceutical composition of claim 9, wherein the PKC inhibitor reaches its peak concentration in the subject 1 to 8 hours or 2 to 6 hours before the cytotoxic agent reaches its peak concentration.

11. The pharmaceutical composition of claim 10, wherein the PKC inhibitor reaches its peak concentration 3 to 5 hours before the cytotoxic agent reaches its peak concentration.

12. 1. A pharmaceutical composition for use in the treatment of cancer comprising a composition comprising a PKC inhibitor and a cytotoxic agent, or a pharma- ceutically acceptable salt or solvate thereof, and a pharma- ceutically acceptable vehicle, wherein in a subject, the PKC inhibitor reaches a peak concentration before the cytotoxic agent reaches a peak concentration, the peak concentration of the PKC inhibitor being the maximum concentration reached in the blood after the PKC inhibitor is administered to the subject, and the peak concentration of the cytotoxic agent being the maximum concentration reached in the blood after the cytotoxic agent is administered to the subject, wherein The PKC inhibitor is enzastaurin, sotrastaurin, midostaurin, ruboxistaurin, or a pharma- ceutically acceptable salt or solvate thereof; and The pharmaceutical composition, wherein said cytotoxic agent is fludarabine, venetoclax, vincristine, dexamethasone, anthracycline, bendamustine, idealisib, ibrutinib, methotrexate, cyclophosphamide, a steroid or a monoclonal antibody targeting B cells, or a pharma- ceutically acceptable salt or solvate thereof.

13. 13. A method for preparing the pharmaceutical composition of claim 12, comprising contacting a therapeutically effective amount of said PKC inhibitor, or a pharma- ceutically acceptable salt or solvate thereof, and a cytotoxic agent, or a pharma- ceutically acceptable salt or solvate thereof, with a pharma- ceutically acceptable vehicle.

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