Patent Publication Number: US-2010113392-A1

Title: Methods of using saha and bortezomib for treating multiple myeloma

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from U.S. Provisional Application Ser. No. 60/856,462, filed on Nov. 3, 2006. 
    
    
     Each of the applications and patents cited in this text, as well as each document or reference cited in each of the applications and patents (including during the prosecution of each issued patent; “application cited documents”), and each of the U.S. and foreign applications or patents corresponding to and/or claiming priority from any of these applications and patents, and each of the documents cited or referenced in each of the application cited documents, are hereby expressly incorporated herein by reference. More generally, documents or references are cited in this text, either in a Reference List before the claims, or in the text itself; and, each of these documents or references (“herein-cited references”), as well as each document or reference cited in each of the herein-cited references (including any manufacturer&#39;s specifications, instructions, etc.), is hereby expressly incorporated herein by reference. Documents incorporated by reference into this text may be employed in the practice of the invention. 
     FIELD OF THE INVENTION 
     The present invention relates to a method of treating multiple myeloma by administering a histone deacetylase (HDAC) inhibitor such as suberoylanilide hydroxamic acid (SAHA) in combination with one or more anti-cancer agents, including Bortezomib. The combined amounts together can comprise a therapeutically effective amount. 
     BACKGROUND OF THE INVENTION 
     Multiple myeloma, a B-cell malignancy of plasma cells, represents the second most common hematological malignancy. The annual incidence in the United States is about four per 100,000. Approximately 13,600 cases of multiple myeloma are diagnosed each year. Approximately 11,200 deaths per year are due to the disease, representing approximately 2% of all cancer deaths. 
     Multiple myeloma is characterized by the neoplastic proliferation of a single clone of plasma cells engaged in the production of a monoclonal immunoglobulin. Although multiple myeloma cells are initially responsive to radiotherapy and chemotherapy, durable complete responses are rare and virtually all patients who respond initially ultimately relapse. As the disease progresses, morbidity and eventual mortality are caused by lowering resistance to infection, significant skeletal destruction (with bone pain, pathological fractures and hypercalcemia), anemia, renal failure and hyperviscosity. To date, conventional treatment approaches have not resulted in long-term disease-free survival, which highlights the importance of developing new drug treatment for this incurable disease. 
     Cancer therapy is often being attempted by the induction of terminal differentiation of the neoplastic cells (M. B., Roberts, A. B., and Driscoll, J. S. (1985) in  Cancer: Principles and Practice of Oncology , eds. Hellman, S., Rosenberg, S. A., and DeVita, V. T., Jr., Ed. 2, (J. B. Lippincott, Philadelphia), P. 49). In cell culture models, differentiation has been reported by exposure of cells to a variety of stimuli, including: cyclic AMP and retinoic acid (Breitman, T. R., Selonick, S. E., and Collins, S. J. (1980)  Proc. Natl. Acad. Sci. USA  77: 2936-2940; Olsson, I. L. and Breitman, T. R. (1982)  Cancer Res.  42: 3924-3927), aclarubicin and other anthracyclines (Schwartz, E. L. and Sartorelli, A. C. (1982)  Cancer Res.  42: 2651-2655). There is abundant evidence that neoplastic transformation does not necessarily destroy the potential of cancer cells to differentiate (Sporn et al; Marks, P. A., Sheffery, M., and Rifkind, R. A. (1987)  Cancer Res.  47: 659; Sachs, L. (1978)  Nature  ( Lond .) 274: 535). 
     There are many examples of tumor cells which do not respond to the normal regulators of proliferation and appear to be blocked in the expression of their differentiation program, and yet can be induced to differentiate and cease replicating. A variety of agents can induce various transformed cell lines and primary human tumor explants to express more differentiated characteristics. Histone deacetylase inhibitors such as suberoylanilide hydroxamide acid (SAHA), belong to this class of agents that have the ability to induce tumor cell growth arrest, differentiation, and/or apoptosis (Richon, V. M., Webb, Y., Merger, R., et al. (1996)  PNAS  93:5705-8). These compounds are targeted towards mechanisms inherent to the ability of a neoplastic cell to become malignant, as they do not appear to have toxicity in doses effective for inhibition of tumor growth in animals (Cohen, L. A., Amin, S., Marks, P. A., Rifkind, R. A., Desai, D., and Richon, V. M. (1999)  Anticancer Research  19:4999-5006). 
     The HDACs exert their targeted action during post-translational acetylation of core nucleosomal histones, which affects chromatin structure, thereby regulating gene expression. DNA that is wrapped around condensed, non-acetylated histones is transcriptionally inactive, whereas acetylation of N-terminal histone lysine residues exposes DNA to important transcription factors that promote transcriptional activity (Workman and Kingston, 1998; Arts et al., 2003). The dynamic equilibrium between histone acetylation and deacetylation is regulated by histone acetyltransferases (HATS) and HDACs. The action of HDACs on nucleosomal histones leads to tight coiling of chromatin and silencing of expression of various genes, including those implicated in the regulation of cell survival, proliferation, differentiation, and apoptosis (Jones and Baylin, 2002). The effects of HDACs are not limited to histone deacetylation. HDACs also act as members of a protein complex to recruit transcription factors to the promoter region of genes, including those of tumor suppressors, and they affect the acetylation status of specific cell cycle regulatory proteins (Arts et al., 2003). 
     Accumulating evidence has demonstrated the effectiveness of HDAC inhibitors in combination with several other agents in vitro. For example, the combination of SAHA and DNA hypomethylating agents (5-azacytidine or decitabine) acts synergistically to induce apoptosis, differentiation, and/or cell growth arrest in various cancer cell lines (Tabe et al., 2002; Zhu and Otterson, 2003). Further, when SAHA was combined with the anti-metabolite 5-fluorouracil, a supra-additive to additive antiproliferative effect in wild type and mutant-p53 colorectal cancer cells was observed (Di Gennaro et al., 2003). SAHA with Gleevec® may be effective in chronic myelogenous leukemia (CML) cells that resist Gleevec® through increased Bcr-Abl expression (Nimmanapalli et al., 2003; Yu et al., 2003). These studies suggest that SAHA in combination with certain anti-cancer agents may be effectively combined to achieve desired therapeutic efficacy. 
     Besides the aim to increase the therapeutic efficacy, another purpose of combination treatment is the potential decrease of the doses of the individual components in the resulting combinations in order to decrease unwanted or harmful side effects caused by higher doses of the individual components. Thus, there is an urgent need to discover suitable methods for the treatment of cancer, such as for example multiple myeloma, including combination treatments that result in decreased side effects and that are effective at treating and controlling malignancies. 
     SUMMARY OF THE INVENTION 
     The present invention is based on the discovery that histone deacetylase (HDAC) inhibitors, for example suberoylanilide hydroxamic acid (SAHA), can be used in combination with Bortezomib, to provide additive or synergistic therapeutic effects. Bortezomib is sold under the name Velcade®. 
     The invention relates to a method for treating multiple myeloma comprising administering to a subject in need thereof an amount of an HDAC inhibitor, e.g., SAHA, and an amount of another anti-cancer agent, e.g., Bortezomib. In particular aspects of this invention, SAHA, or a pharmaceutically acceptable salt or hydrate thereof is orally administered at 200 mg to 800 mg per day for at least one treatment cycle on days 4-11 of a 21 day cycle, and Bortezomib or a pharmaceutically acceptable salt or hydrate thereof, is intravenously administered 0.7-1.3 mg/m 2  per day for at least one treatment cycle on days 1, 4, 8 and 11 of a 21 day cycle. In particular embodiment, multiple myeloma is relapsed and refractory multiple myeloma. 
     The invention further relates to pharmaceutical combinations useful for the treatment of multiple myeloma comprising an amount of an HDAC inhibitor, e.g., SAHA, and an amount of an anti-cancer agent, e.g., Bortezomib. 
     In further embodiments, the treatment procedures are performed sequentially in any order, alternating in any order, simultaneously, or any combination thereof. In particular, the administration of an HDAC inhibitor, e.g., SAHA, and the administration of the anti-cancer agent, e.g., Bortezomib, can be performed concurrently, consecutively, or, for example, alternating concurrent and consecutive administration. 
     The invention further relates to methods for selectively inducing terminal differentiation, cell growth arrest, and/or apoptosis of neoplastic cells, thereby inhibiting proliferation of such cells in a subject by administering to the subject an amount of an HDAC inhibitor, e.g., SAHA, an amount of an anti-cancer agent, e.g. Bortezomib, wherein the HDAC inhibitor and Bortezomib are administered in amounts effective to induce terminal differentiation, cell growth arrest, or apoptosis of the cells. 
     In one embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 100 mg for at least one treatment period of days 4-11 out of 21 days. 
     In another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 200 mg for at least one treatment period of days 4-11 out of 21 days. 
     In another particular embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 300 mg for at least one treatment period of days 4-11 out of 21 days. 
     In another particular embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered once daily at a dose of 400 mg for at least one treatment period of days 4-11 out of 21 days. 
     In yet another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 400 mg for at least one treatment period of days 4-11 out of 21 days. 
     In another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered once daily at a dose of 500 mg for at least one treatment period of days 4-11 out of 21 days. 
     In another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered once daily at a dose of 600 mg for at least one treatment period of days 4-11 out of 21 days. 
     In yet another embodiment, administration of SAHA or pharmaceutically acceptable salt or hydrate thereof is repeated for up to eight treatment periods of days 4-11 out of 21 days. 
     In another aspect of this invention, Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered once daily at a dose of 1 mg/m 2  on days 1, 4, 8, and 11 out of 21 days. 
     In yet another aspect of this invention, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 100 mg or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.0 mg/m 2 . 
     In yet another aspect of this invention, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 100 mg or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.3 mg/m 2 . 
     In yet another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 100 mg and Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.3 mg/m 2 . 
     In yet another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 200 mg and Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.3 mg/m 2 . 
     In another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 300 mg and or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.3 mg/m 2 . 
     In yet another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 400 mg and Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.3 mg/m 2 . 
     In yet another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered once daily at a dose of 400 mg and Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.3 mg/m 2 . 
     In yet another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered once daily at a dose of 500 mg and Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.3 mg/m 2 . 
     In another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered once daily at a dose of 600 mg and Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.3 mg/m 2 . 
     In yet another embodiment, the method of treatment of multiple myeloma with SAHA and Bortezomib further comprises orally administering dexamethasone or a pharmaceutically acceptable salt or hydrate thereof wherein the dexamethasone or pharmaceutically acceptable salt or hydrate thereof is administered once daily at a dose of 20 mg for at least one treatment period of 5 out of 21 days. 
     In further embodiment, the method of treatment of multiple myeloma comprises orally administering dexamethasone once daily at a dose of 20 mg for at least one treatment period of days 4-8 out of 21 days. 
     In yet another embodiment, SAHA is orally administered once daily at 400 mg per day for at least one treatment cycle on days 4-11 of a 21 day cycle, and Bortezomib is intravenously administered at 1.3 mg/m 2  per day for at least one treatment cycle on days 1, 4, 8 and 11 of a 21 day cycle. 
     Unless otherwise defined, 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 pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are expressly incorporated by reference in their entirety. In cases of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples described herein are illustrative only and are not intended to be limiting. 
     Other features and advantages of the invention will be apparent from and are encompassed by the following detailed description and claims. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     It has been unexpectedly discovered that the combination treatment procedure that includes administration of an HDAC inhibitor, SAHA, as described herein, and Bortezomib, as described herein, can provide synergistic therapeutic effects. Each of the treatments (administration of an HDAC inhibitor and administration of the Bortezomib) is used to provide a therapeutically effective treatment. 
     The invention further relates to a method of treating multiple myelomas, in a subject in need thereof, by administering to a subject in need thereof an amount of suberoylanilide hydroxamic acid (SAHA) or a pharmaceutically acceptable salt or hydrate thereof, in a treatment procedure, and an amount of antimetabolic agent, such as Bortezomib, in another treatment procedure, wherein the amounts can comprise a therapeutically effective amount. The cancer treatment effect of SAHA and the Bortezomib can be, e.g., additive or synergistic. 
     In one aspect, the method comprises administering to a patient in need thereof a first amount of SAHA or a pharmaceutically acceptable salt or hydrate thereof, in a first treatment procedure, and another amount of Bortezomib. The invention further relates to pharmaceutical combinations useful for the treatment cancer or other disease. In one aspect, the pharmaceutical combination comprises a first amount of an HDAC inhibitor, e.g., SAHA or a pharmaceutically acceptable salt or hydrate thereof, and another amount of anti-cancer agents, such as Bortezomib or a pharmaceutically acceptable salt or hydrate thereof. The first and second amounts can comprise a therapeutically effective amount. 
     The invention further relates to methods for selectively inducing terminal differentiation, cell growth arrest, and/or apoptosis of neoplastic cells, thereby inhibiting proliferation of such cells in a subject by administering to the subject an amount of an HDAC inhibitor, e.g., SAHA, an amount of an anti-cancer agent, e.g. Bortezomib, wherein the HDAC inhibitor and Bortezomib are administered in amounts effective to induce terminal differentiation, cell growth arrest, or apoptosis of the cells. 
     The invention further relates to in vitro methods for selectively inducing terminal differentiation, cell growth arrest, and/or apoptosis of neoplastic cells, thereby inhibiting proliferation of such cells, by contacting the cells with an amount of an HDAC inhibitor, e.g., SAHA, an amount of an anti-cancer agent, e.g. Bortezomib, wherein the HDAC inhibitor and second (and optional third and/or fourth) anti-cancer agent are administered in amounts effective to induce terminal differentiation, cell growth arrest, or apoptosis of the cells. 
     The combination therapy of the invention provides a therapeutic advantage in view of the differential toxicity associated with the two treatment modalities. For example, treatment with HDAC inhibitors can lead to a particular toxicity that is not seen with the anti-cancer agent, and vice versa. As such, this differential toxicity can permit each treatment to be administered at a dose at which said toxicities do not exist or are minimal, such that together the combination therapy provides a therapeutic dose while avoiding the toxicities of each of the constituents of the combination agents. Furthermore, when the therapeutic effects achieved as a result of the combination treatment are enhanced or synergistic, for example, significantly better than additive therapeutic effects, the doses of each of the agents can be reduced even further, thus lowering the associated toxicities to an even greater extent. 
     DEFINITIONS 
     The term “treating” in its various grammatical forms in relation to the present invention refers to preventing (i.e. chemoprevention), curing, reversing, attenuating, alleviating, minimizing, suppressing or halting the deleterious effects of a disease state, disease progression, disease causative agent (e.g., bacteria or viruses) or other abnormal condition. For example, treatment may involve alleviating a symptom (i.e., not necessary all symptoms) of a disease or attenuating the progression of a disease. Because some of the inventive methods involve the physical removal of the etiological agent, the artisan will recognize that they are equally effective in situations where the inventive compound is administered prior to, or simultaneous with, exposure to the etiological agent (prophylactic treatment) and situations where the inventive compounds are administered after (even well after) exposure to the etiological agent. 
     Treatment of cancer, as used herein, refers to partially or totally inhibiting, delaying or preventing the progression of cancer including cancer metastasis; inhibiting, delaying or preventing the recurrence of cancer including cancer metastasis; or preventing the onset or development of cancer (chemoprevention) in a mammal, for example a human. In addition, the method of the present invention is intended for the treatment of chemoprevention of human patients with cancer. However, it is also likely that the method would be effective in the treatment of cancer in other mammals. 
     The “anti-cancer agents” of the invention encompass those described herein, including any pharmaceutically acceptable salts or hydrates of such agents, or any free acids, free bases, or other free forms of such agents, and as non-limiting examples: A) Polar compounds (Marks et al. (1987); Friend, C., Scher, W., Holland, J. W., and Sato, T. (1971)  Proc. Natl. Acad. Sci . (USA) 68: 378-382; Tanaka, M., Levy, J., Terada, M., Breslow, R., Rifkind, R. A., and Marks, P. A. (1975)  Proc. Natl. Acad. Sci . ( USA ) 72: 1003-1006; Reuben, R. C., Wife, R. L., Breslow, R., Rifkind, R. A., and Marks, P. A. (1976)  Proc. Natl. Acad. Sci . ( USA ) 73: 862-866); B) Derivatives of vitamin D and retinoic acid (Abe, E., Miyaura, C., Sakagami, H., Takeda, M., Konno, K., Yamazaki, T., Yoshika, S., and Suda, T. (1981)  Proc. Natl. Acad. Sci . (USA) 78: 4990-4994; Schwartz, E. L., Snoddy, J. R., Kreutter, D., Rasmussen, H., and Sartorelli, A. C. (1983)  Proc. Am. Assoc. Cancer Res.  24: 18; Tanenaga, K., Hozumi, M., and Sakagami, Y. (1980)  Cancer Res.  40: 914-919); C) Steroid hormones (Lotem, J. and Sachs, L. (1975)  Int. J. Cancer  15: 731-740); D) Growth factors (Sachs, L. (1978)  Nature  (Lond.) 274: 535, Metcalf, D. (1985)  Science,  229: 16-22); E) Proteases (Scher, W., Scher, B. M., and Waxman, S. (1983)  Exp. Hematot  11: 490-498; Scher, W., Scher, B. M., and Waxman, S. (1982)  Biochem . &amp;  Biophys. Res. Comm.  109: 348-354); F) Tumor promoters (Huberman, E. and Callaham, M. F. (1979)  Proc. Natl. Acad. Sci . (USA) 76: 1293-1297; Lottem, J. and Sachs, L. (1979)  Proc. Natl. Acad. Sci . (USA) 76: 5158-5162); and G) Inhibitors of DNA or RNA synthesis (Schwartz, E. L. and Sartorelli, A. C. (1982)  Cancer Res.  42: 2651-2655, Terada, M., Epner, E., Nudel, U., Salmon, J., Fibach, E., Rifkind, R. A., and Marks, P. A. (1978)  Proc. Natl. Acad. Sci . (USA) 75: 2795-2799; Morin, M. J. and Sartorelli, A. C. (1984)  Cancer Res.  44: 2807-2812; Schwartz, E. L., Brown, B. J., Nierenberg, M., Marsh, J. C., and Sartorelli, A. C. (1983)  Cancer Res.  43: 2725-2730; Sugano, H., Furusawa, M., Kawaguchi, T., and Ikawa, Y. (1973)  Bibl. Hematol.  39: 943-954; Ebert, P. S., Wars, I., and Buell, D. N. (1976)  Cancer Res.  36: 1809-1813; Hayashi, M., Okabe, J., and Hozumi, M. (1979)  Gann  70: 235-238). 
     As used herein, the term “therapeutically effective amount” is intended to qualify the combined amount of treatments in the combination therapy. The combined amount will achieve the desired biological response. In the present invention, the desired biological response is partial or total inhibition, delay or prevention of the progression of cancer including cancer metastasis; inhibition, delay or prevention of the recurrence of cancer including cancer metastasis; or the prevention of the onset or development of cancer (chemoprevention) in a mammal, for example a human. 
     As used herein, the terms “combination treatment”, “combination therapy”, “combined treatment,” or “combinatorial treatment”, used interchangeably, refer to a treatment of an individual with at least two different therapeutic agents. According to one aspect of the invention, the individual is treated with a first therapeutic agent, e.g., SAHA or another HDAC inhibitor as described herein. The second therapeutic agent may be another HDAC inhibitor, or may be any clinically established anti-cancer agent (such as Bortezomib) as defined herein. A combinatorial treatment may include a third or even further therapeutic agent (such as dexamethasone, as defined here). The combination treatments may be carried out consecutively or concurrently. 
     As recited herein, “HDAC inhibitor” (e.g., SAHA) encompasses any synthetic, recombinant, or naturally-occurring inhibitor, including any pharmaceutical salts or hydrates of such inhibitors, and any free acids, free bases, or other free forms of such inhibitors. “Hydroxamic acid derivative,” as used herein, refers to the class of histone deacetylase inhibitors that are hydroxamic acid derivatives. Specific examples of inhibitors are provided herein. 
     A “retinoid” or “retinoid agent” (e.g., 3-methyl TTNEB) as used herein encompasses any synthetic, recombinant, or naturally-occurring compound that binds to one or more retinoid receptors, including any pharmaceutically acceptable salts or hydrates of such agents, and any free acids, free bases, or other free forms of such agents. 
     An “adjunctive agent” refers to any compound used to enhance the effectiveness of an anti-cancer agent or to prevent or treat conditions associated with an anti-cancer agent such as low blood counts, neutropenia, anemia, thrombocytopenia, hypercalcemia, mucositis, bruising, bleeding, toxicity, fatigue, pain, nausea, and vomiting. 
     “Patient” or “subject” as the terms are used herein, refer to the recipient of the treatment. Mammalian and non-mammalian patients are included. In a specific embodiment, the patient is a mammal, such as a human, canine, murine, feline, bovine, ovine, swine, or caprine. In a particular embodiment, the patient is a human. 
     The terms “intermittent” or “intermittently” as used herein means stopping and starting at either regular or irregular intervals. 
     The term “hydrate” includes but is not limited to hemihydrate, monohydrate, dihydrate, trihydrate, and the like. 
     Histone Deacetylases and Histone Deacetylase Inhibitors 
     Histone deacetylases (HDACs) include enzymes that catalyze the removal of acetyl groups from lysine residues in the amino terminal tails of the nucleosomal core histones. As such, HDACs together with histone acetyl transferases (HATs) regulate the acetylation status of histones. Histone acetylation affects gene expression and inhibitors of HDACs, such as the hydroxamic acid-based hybrid polar compound suberoylanilide hydroxamic acid (SAHA) induce growth arrest, differentiation, and/or apoptosis of transformed cells in vitro and inhibit tumor growth in vivo. 
     HDACs can be divided into three classes based on structural homology. Class I HDACs (HDACs 1, 2, 3, and 8) bear similarity to the yeast RPD3 protein, are located in the nucleus and are found in complexes associated with transcriptional co-repressors. Class II HDACs (HDACs 4, 5, 6, 7 and 9) are similar to the yeast HDA1 protein, and have both nuclear and cytoplasmic subcellular localization. Both Class I and II HDACs are inhibited by hydroxamic acid-based HDAC inhibitors, such as SAHA. Class III HDACs form a structurally distant class of NAD dependent enzymes that are related to the yeast SIR2 proteins and are not inhibited by hydroxamic acid-based HDAC inhibitors. 
     Histone deacetylase inhibitors or HDAC inhibitors are compounds that are capable of inhibiting the deacetylation of histones in vivo, in vitro or both. As such, HDAC inhibitors inhibit the activity of at least one histone deacetylase. As a result of inhibiting the deacetylation of at least one histone, an increase in acetylated histone occurs and accumulation of acetylated histone is a suitable biological marker for assessing the activity of HDAC inhibitors. Therefore, procedures that can assay for the accumulation of acetylated histones can be used to determine the HDAC inhibitory activity of compounds of interest. It is understood that compounds that can inhibit histone deacetylase activity can also bind to other substrates and as such can inhibit other biologically active molecules such as enzymes. It is also understood that the compounds of the present invention are capable of inhibiting any of the histone deacetylases set forth above, or any other histone deacetylases. 
     For example, in patients receiving HDAC inhibitors, the accumulation of acetylated histones in peripheral mononuclear cells as well as in tissue treated with HDAC inhibitors can be determined against a suitable control. 
     HDAC inhibitory activity of a particular compound can be determined in vitro using, for example, an enzymatic assay which shows inhibition of at least one histone deacetylase. Further, determination of the accumulation of acetylated histones in cells treated with a particular composition can be determinative of the HDAC inhibitory activity of a compound. 
     Assays for the accumulation of acetylated histones are well known in the literature. See, for example, Marks, P. A. et al.,  J. Natl. Cancer Inst.,  92:1210-1215, 2000, Butler, L. M. et al.,  Cancer Res.  60:5165-5170 (2000), Richon, V. M. et al.,  Proc. Natl. Acad. Sci ., USA, 95:3003-3007, 1998, and Yoshida, M. et al.,  J. Biol. Chem.,  265:17174-17179, 1990. 
     For example, an enzymatic assay to determine the activity of an HDAC inhibitor compound can be conducted as follows. Briefly, the effect of an HDAC inhibitor compound on affinity purified human epitope-tagged (Flag) HDAC1 can be assayed by incubating the enzyme preparation in the absence of substrate on ice for about 20 minutes with the indicated amount of inhibitor compound. Substrate ([ 3 H]acetyl-labeled murine erythroleukemia cell-derived histone) can be added and the sample can be incubated for 20 minutes at 37° C. in a total volume of 30 μL. The reaction can then be stopped and released acetate can be extracted and the amount of radioactivity release determined by scintillation counting. An alternative assay useful for determining the activity of an HDAC inhibitor compound is the “HDAC Fluorescent Activity Assay; Drug Discovery Kit-AK-500” available from BIOMOL® Research Laboratories, Inc., Plymouth Meeting, Pa. 
     In vivo studies can be conducted as follows. Animals, for example, mice, can be injected intraperitoneally with an HDAC inhibitor compound. Selected tissues, for example, brain, spleen, liver etc, can be isolated at predetermined times, post administration. Histones can be isolated from tissues essentially as described by Yoshida et al.,  J. Biol. Chem.  265:17174-17179, 1990. Equal amounts of histones (about 1 μg) can be electrophoresed on 15% SDS-polyacrylamide gels and can be transferred to Hybond-P filters (available from Amersham). Filters can be blocked with 3% milk and can be probed with a rabbit purified polyclonal anti-acetylated histone H4 antibody (αAc—H4) and anti-acetylated histone H3 antibody (αAc—H3) (Upstate Biotechnology, Inc.). Levels of acetylated histone can be visualized using a horseradish peroxidase-conjugated goat anti-rabbit antibody (1:5000) and the SuperSignal chemiluminescent substrate (Pierce). As a loading control for the histone protein, parallel gels can be run and stained with Coomassie Blue (CB). 
     In addition, hydroxamic acid-based HDAC inhibitors have been shown to up regulate the expression of the p21 WAF1  gene. The p21 WAF1  protein is induced within 2 hours of culture with HDAC inhibitors in a variety of transformed cells using standard methods. The induction of the p21 WAF1  gene is associated with accumulation of acetylated histones in the chromatin region of this gene. Induction of p21 WAF1  can therefore be recognized as involved in the G1 cell cycle arrest caused by HDAC inhibitors in transformed cells. 
     U.S. Pat. Nos. 5,369,108, 5,932,616, 5,700,811, 6,087,367 and 6,511,990, issued to some of the present inventors, disclose compounds useful for selectively inducing terminal differentiation of neoplastic cells, which compounds have two polar end groups separated by a flexible chain of methylene groups or a by a rigid phenyl group, wherein one or both of the polar end groups is a large hydrophobic group. Some of the compounds have an additional large hydrophobic group at the same end of the molecule as the first hydrophobic group which further increases differentiation activity about 100 fold in an enzymatic assay and about 50 fold in a cell differentiation assay. Methods of synthesizing the compounds used in the methods and pharmaceutical compositions of this invention are fully described the aforementioned patents, the entire contents of which are incorporated herein by reference. 
     Thus, the present invention includes within its broad scope compositions comprising HDAC inhibitors which are 1) hydroxamic acid derivatives; 2) Short-Chain Fatty Acids (SCFAs); 3) cyclic tetrapeptides; 4) benzamides; 5) electrophilic ketones; and/or any other class of compounds capable of inhibiting histone deacetylases, for use in inhibiting histone deacetylase, inducing terminal differentiation, cell growth arrest and/or apoptosis in neoplastic cells, and/or inducing differentiation, cell growth arrest and/or apoptosis of tumor cells in a tumor. 
     Non-limiting examples of such HDAC inhibitors are set forth below. It is understood that the present invention includes any salts, crystal structures, amorphous structures, hydrates, derivatives, metabolites, stereoisomers, structural isomers, and prodrugs of the HDAC inhibitors described herein. 
     A. Hydroxamic Acid Derivatives such as Suberoylanilide hydroxamic acid (SAHA) (Richon et al.,  Proc. Natl. Acad. Sci. USA  95, 3003-3007 (1998)); m-Carboxycinnamic acid bishydroxamide (CBHA) (Richon et al., supra); Pyroxamide; Trichostatin analogues such as Trichostatin A (TSA) and Trichostatin C (Koghe et al. 1998 . Biochem. Pharmacol.  56: 1359-1364); Salicylbishydroxamic acid (Andrews et al.,  International J. Parasitology  30, 761-768 (2000)); Suberoyl bishydroxamic acid (SBHA) (U.S. Pat. No. 5,608,108); Azelaic bishydroxamic acid (ABHA) (Andrews et al., supra); Azelaic-1-hydroxamate-9-anilide (AAHA) (Qiu et al.,  Mol. Biol. Cell  11, 2069-2083 (2000)); 6-(3-Chlorophenylureido) carpoic hydroxamic acid (3CI-UCHA); Oxamflatin [(2E)-5-[3-[(phenylsulfonyl)amino]phenyl]-pent-2-en-4-ynohydroxamic acid] (Kim et al.  Oncogene,  18: 2461 2470 (1999)); A-161906, Scriptaid (Su et al. 2000  Cancer Research,  60: 3137-3142); PXD-101 (Prolifix); LAQ-824; CHAP; MW2796 (Andrews et al., supra); MW2996 (Andrews et al., supra); or any of the hydroxamic acids disclosed in U.S. Pat. Nos. 5,369,108, 5,932,616, 5,700,811, 6,087,367, and 6,511,990. 
     B. Cyclic Tetrapeptides such as Trapoxin A (TPX)-cyclic tetrapeptide (cyclo-(L-phenylalanyl-L-phenylalanyl-D-pipecolinyl-L-2-amino-8-oxo-9,10-epoxy decanoyl)) (Kijima et al.,  J. Biol. Chem.  268, 22429-22435 (1993)); FR901228 (FK 228, depsipeptide) (Nakajima et al.,  Ex. Cell Res.  241, 126-133 (1998)); FR225497 cyclic tetrapeptide (H. Mori et al., PCT Application WO 00/08048 (17 Feb. 2000)); Apicidin cyclic tetrapeptide [cyclo(N-β-methyl-L-tryptophanyl-L-isoleucinyl-D-pipecolinyl-L-2-amino-8-oxodecanoyl)] (Darkin-Rattray et al.,  Proc. Natl. Acad. Sci. USA  93, 13143-13147 (1996)); Apicidin Ia, Apicidin Ib, Apicidin Ic, Apicidin IIa, and Apicidin Iib (P. Dulski et al., PCT Application WO 97/11366); CHAP, HC-toxin cyclic tetrapeptide (Bosch et al.,  Plant Cell  7, 1941-1950 (1995)); WF27082 cyclic tetrapeptide (PCT Application WO 98/48825); and Chlamydocin (Bosch et al., supra). 
     C. Short chain fatty acid (SCFA) derivatives such as: Sodium Butyrate (Cousens et al.,  J. Biol. Chem.  254, 1716-1723 (1979)); Isovalerate (McBain et al.,  Biochem. Pharm.  53: 1357-1368 (1997)); Valerate (McBain et al., supra); 4-Phenylbutyrate (4-PBA) (Lea and Tulsyan, Anticancer Research, 15, 879-873 (1995)); Phenylbutyrate (PB) (Wang et al.,  Cancer Research,  59, 2766-2799 (1999)); Propionate (McBain et al., supra); Butyramide (Lea and Tulsyan, supra); Isobutyramide (Lea and Tulsyan, supra); Phenylacetate (Lea and Tulsyan, supra); 3-Bromopropionate (Lea and Tulsyan, supra); Tributyrin (Guan et al.,  Cancer Research,  60, 749-755 (2000)); Valproic acid, Valproate, and Pivanex™. 
     D. Benzamide derivatives such as CI-994; MS-275 [N-(2-aminophenyl)-4-[N-(pyridin-3-yl methoxycarbonyl)aminomethyl]benzamide] (Saito et al.,  Proc. Natl. Acad. Sci. USA  96, 4592-4597 (1999)); and 3′-amino derivative of MS-275 (Saito et al., supra). 
     E. Electrophilic ketone derivatives such as Trifluoromethyl ketones (Frey et al.,  Bioorganic  &amp;  Med. Chem. Lett . (2002), 12, 3443-3447; U.S. Pat. No. 6,511,990) and α-keto amides such as N-methyl-α-ketoamides. 
     F. Other HDAC Inhibitors such as natural products, psammaplins, and Depudecin (Kwon et al. 1998. PNAS 95: 3356-3361). 
     Hydroxamic acid based HDAC inhibitors include suberoylanilide hydroxamic acid (SAHA), m-carboxycinnamic acid bishydroxamate (CBHA) and pyroxamide. SAHA has been shown to bind directly in the catalytic pocket of the histone deacetylase enzyme. SAHA induces cell cycle arrest, differentiation, and/or apoptosis of transformed cells in culture and inhibits tumor growth in rodents. SAHA is effective at inducing these effects in both solid tumors and hematological cancers. It has been shown that SAHA is effective at inhibiting tumor growth in animals with no toxicity to the animal. The SAHA-induced inhibition of tumor growth is associated with an accumulation of acetylated histones in the tumor. SAHA is effective at inhibiting the development and continued growth of carcinogen-induced (N-methylnitrosourea) mammary tumors in rats. SAHA was administered to the rats in their diet over the 130 days of the study. Thus, SAHA is a nontoxic, orally active antitumor agent whose mechanism of action involves the inhibition of histone deacetylase activity. 
     HDAC inhibitors include those disclosed in U.S. Pat. Nos. 5,369,108, 5,932,616, 5,700,811, 6,087,367, and 6,511,990, issued to some of the present inventors disclose compounds, the entire contents of which are incorporated herein by reference, non-limiting examples of which are set forth below: 
     Specific HDAC inhibitors include suberoylanilide hydroxamic acid (SAHA; N-Hydroxy-N′-phenyl octanediamide), which is represented by the following structural formula: 
     
       
         
         
             
             
         
       
     
     Other examples of such compounds and other HDAC inhibitors can be found in U.S. Pat. No. 5,369,108, issued on Nov. 29, 1994, U.S. Pat. No. 5,700,811, issued on Dec. 23, 1997, U.S. Pat. No. 5,773,474, issued on Jun. 30, 1998, U.S. Pat. No. 5,932,616, issued on Aug. 3, 1999 and U.S. Pat. No. 6,511,990, issued Jan. 28, 2003, all to Breslow et al.; U.S. Pat. No. 5,055,608, issued on Oct. 8, 1991, U.S. Pat. No. 5,175,191, issued on Dec. 29, 1992 and U.S. Pat. No. 5,608,108, issued on Mar. 4, 1997, all to Marks et al.; as well as Yoshida, M., et al.,  Bioassays  17, 423-430 (1995); Saito, A., et al.,  PNAS USA  96, 4592-4597, (1999); Furamai R. et al.,  PNAS USA  98 (1), 87-92 (2001); Komatsu, Y., et al.,  Cancer Res.  61(11), 4459-4466 (2001); Su, G. H., et al.,  Cancer Res.  60, 3137-3142 (2000); Lee, B. I. et al.,  Cancer Res.  61(3), 931-934; Suzuki, T., et al.,  J. Med. Chem.  42(15), 3001-3003 (1999); published PCT Application WO 01/18171 published on Mar. 15, 2001 to Sloan-Kettering Institute for Cancer Research and The Trustees of Columbia University; published PCT Application WO 02/246144 to Hoffmann-La Roche; published PCT Application WO 02/22577 to Novartis; published PCT Application WO 02/30879 to Prolifix; published PCT Applications WO 01/38322 (published May 31, 2001), WO 01/70675 (published on Sep. 27, 2001) and WO 00/71703 (published on Nov. 30, 2000) all to Methylgene, Inc.; published PCT Application WO 00/21979 published on Oct. 8, 1999 to Fujisawa Pharmaceutical Co., Ltd.; published PCT Application WO 98/40080 published on Mar. 11, 1998 to Beacon Laboratories, L.L.C.; and Curtin M. (Current patent status of HDAC inhibitors  Expert Opin. Ther. Patents  (2002) 12(9): 1375-1384 and references cited therein). 
     SAHA or any of the other HDACs can be synthesized according to the methods outlined in the Experimental Details Section, or according to the method set forth in U.S. Pat. Nos. 5,369,108, 5,700,811, 5,932,616 and 6,511,990, the contents of which are incorporated by reference in their entirety, or according to any other method known to a person skilled in the art. 
     Specific non-limiting examples of HDAC inhibitors are provided in the Table below. It should be noted that the present invention encompasses any compounds which are structurally similar to the compounds represented below, and which are capable of inhibiting histone deacetylases. 
     
       
         
           
               
               
             
               
                   
               
               
                 Name 
                 Structure 
               
               
                   
               
             
            
               
                 MS-275 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 DEPSIPEPTIDE 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 CI-994 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 Apicidin 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 A-161906 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 Scriptaid 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 PXD-101 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 CHAP 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 LAQ-824 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 Butyric Acid 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 Depudecin 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 Oxamflatin 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 Trichostatin 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     Stereochemistry 
     Many organic compounds exist in optically active forms having the ability to rotate the plane of plane-polarized light. In describing an optically active compound, the prefixes D and L or R and S are used to denote the absolute configuration of the molecule about its chiral center(s). The prefixes d and l or (+) and (−) are employed to designate the sign of rotation of plane-polarized light by the compound, with (−) or meaning that the compound is levorotatory. A compound prefixed with (+) or d is dextrorotatory. For a given chemical structure, these compounds, called stereoisomers, are identical except that they are non-superimposable mirror images of one another. A specific stereoisomer can also be referred to as an enantiomer, and a mixture of such isomers is often called an enantiomeric mixture. A 50:50 mixture of enantiomers is referred to as a racemic mixture. 
     Many of the compounds described herein can have one or more chiral centers and therefore can exist in different enantiomeric forms. If desired, a chiral carbon can be designated with an asterisk (*). When bonds to the chiral carbon are depicted as straight lines in the formulas of the invention, it is understood that both the (R) and (S) configurations of the chiral carbon, and hence both enantiomers and mixtures thereof, are embraced within the formula. As is used in the art, when it is desired to specify the absolute configuration about a chiral carbon, one of the bonds to the chiral carbon can be depicted as a wedge (bonds to atoms above the plane) and the other can be depicted as a series or wedge of short parallel lines is (bonds to atoms below the plane). The Cahn-Inglod-Prelog system can be used to assign the (R) or (S) configuration to a chiral carbon. 
     When the HDAC inhibitors of the present invention contain one chiral center, the compounds exist in two enantiomeric forms and the present invention includes both enantiomers and mixtures of enantiomers, such as the specific 50:50 mixture referred to as a racemic mixtures. The enantiomers can be resolved by methods known to those skilled in the art, for example by formation of diastereoisomeric salts which may be separated, for example, by crystallization (see, CRC Handbook of Optical Resolutions via Diastereomeric Salt Formation by David Kozma (CRC Press, 2001)); formation of diastereoisomeric derivatives or complexes which may be separated, for example, by crystallization, gas-liquid or liquid chromatography; selective reaction of one enantiomer with an enantiomer-specific reagent, for example enzymatic esterification; or gas-liquid or liquid chromatography in a chiral environment, for example on a chiral support for example silica with a bound chiral ligand or in the presence of a chiral solvent. It will be appreciated that where the desired enantiomer is converted into another chemical entity by one of the separation procedures described above, a further step is required to liberate the desired enantiomeric form. Alternatively, specific enantiomers may be synthesized by asymmetric synthesis using optically active reagents, substrates, catalysts or solvents, or by converting one enantiomer into the other by asymmetric transformation. 
     Designation of a specific absolute configuration at a chiral carbon of the compounds of the invention is understood to mean that the designated enantiomeric form of the compounds is in enantiomeric excess (ee) or in other words is substantially free from the other enantiomer. For example, the “R” forms of the compounds are substantially free from the “S” forms of the compounds and are, thus, in enantiomeric excess of the “S” forms. Conversely, “S” forms of the compounds are substantially free of “R” forms of the compounds and are, thus, in enantiomeric excess of the “R” forms. Enantiomeric excess, as used herein, is the presence of a particular enantiomer at greater than 50%. For example, the enantiomeric excess can be about 60% or more, such as about 70% or more, for example about 80% or more, such as about 90% or more. In a particular embodiment when a specific absolute configuration is designated, the enantiomeric excess of depicted compounds is at least about 90%. In a more particular embodiment, the enantiomeric excess of the compounds is at least about 95%, such as at least about 97.5%, for example, at least 99% enantiomeric excess. 
     When a compound of the present invention has two or more chiral carbons it can have more than two optical isomers and can exist in diastereoisomeric forms. For example, when there are two chiral carbons, the compound can have up to 4 optical isomers and 2 pairs of enantiomers ((S,S)/(R,R) and (R,S)/(S,R)). The pairs of enantiomers (e.g., (S,S)/(R,R)) are mirror image stereoisomers of one another. The stereoisomers which are not mirror-images (e.g., (S,S) and (R,S)) are diastereomers. The diastereoisomeric pairs may be separated by methods known to those skilled in the art, for example chromatography or crystallization and the individual enantiomers within each pair may be separated as described above. The present invention includes each diastereoisomer of such compounds and mixtures thereof. 
     As used herein, “a,” an” and “the” include singular and plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “an active agent” or “a pharmacologically active agent” includes a single active agent as well a two or more different active agents in combination, reference to “a carrier” includes mixtures of two or more carriers as well as a single carrier, and the like. 
     This invention is also intended to encompass pro-drugs of the HDAC inhibitors disclosed herein. A prodrug of any of the compounds can be made using well known pharmacological techniques. 
     This invention, in addition to the above listed compounds, is intended to encompass the use of homologs and analogs of such compounds. In this context, homologs are molecules having substantial structural similarities to the above-described compounds and analogs are molecules having substantial biological similarities regardless of structural similarities. 
     Alkylating Agents 
     Examples of alkylating agents include, but are not limited to, bischloroethylamines (nitrogen mustards, e.g., Chlorambucil, Cyclophosphamide, Ifosfamide, Mechlorethamine, Melphalan, uracil mustard), aziridines (e.g., Thiotepa), alkyl alkone sulfonates (e.g., Busulfan), nitrosoureas (e.g., Carmustine, Lomustine, Streptozocin), nonclassic alkylating agents (Altretamine, Dacarbazine, and Procarbazine), platinum compounds (Carboplastin and Cisplatin). These compounds react with phosphate, amino, hydroxyl, sulfihydryl, carboxyl, and imidazole groups. 
     Cisplatin (e.g., Platinol®-AQ, Bristol-Myers Squibb Co., Princeton, N.J.) is a heavy metal complex containing a central atom of platinum surrounded by two chloride atoms and two ammonia molecules in the cis position. The anticancer mechanism of Cisplatin is not clearly understood, but it is generally accepted that it acts through the formation of DNA adducts. Cisplatin is believed to bind to nuclear DNA and interfere with normal transcription and/or DNA replication mechanisms. Where Cisplatin-DNA adducts are not efficiently processed by cell machinery, this leads to cell death. Cells may die through apoptosis or necrosis, and both mechanisms may function within a population of tumor cells. The chemical name for Cisplatin is cis-diamminedichloroplatinum (e.g., cis-diamminedichloroplatinum (II)), as represented by the structure: 
     
       
         
         
             
             
         
       
     
     Cyclophosphamide (e.g., Cytoxan®, Baxter Healthcare Corp., Deerfield, Ill.) is chemically related to the nitrogen mustards. Cyclophosphamide is transformed to active alkylating metabolites by a mixed function microsomal oxidase system. These metabolites can interfere with the growth of rapidly proliferating malignant cells. The mechanism of action is thought to involve cross-linking of tumor cell DNA. The chemical name for Cyclophosphamide monohydrate available as Cytoxan® is 2-[bis(2-chloroethyl)amino]tetrahydro-2H-1,3,2-oxazaphosphorine 2-oxide monohydrate as represented by the structure: 
     
       
         
         
             
             
         
       
     
     Oxaliplatin (e.g., Eloxatin™, Sanofi-Synthelabo, Inc., New York, N.Y.) is an organoplatinum complex in which the platinum atom is complexed with 1,2-diaminocyclohexane (DACH) and with an oxalate ligand as a leaving group. Oxaliplatin undergoes nonenzymatic conversion in physiologic solutions to active derivatives which form inter- and intrastrand platinum-DNA crosslinks. Crosslinks are formed between the N7 positions of two adjacent guanines (GG), adjacent adenine-guanines (AG), and guanines separated by an intervening nucleotide (GNG). These crosslinks inhibit DNA replication and transcription in cancer and non-cancer cells. The chemical name for Oxaliplatin is of cis-[(1R,2R)-1,2-cyclohexanediamine-N,N′] [oxalato(2-)-O,O′] platinum, as represented by the structure: 
     
       
         
         
             
             
         
       
     
     Under physiological conditions, these drugs ionize and produce positively charged ion that attach to susceptible nucleic acids and proteins, leading to cell cycle arrest and/or cell death. The alkylating agents are cell cycle phase nonspecific agents because they exert their activity independently of the specific phase of the cell cycle. The nitrogen mustards and alkyl alkone sulfonates are most effective against cells in the G1 or M phase. Nitrosoureas, nitrogen mustards, and aziridines impair progression from the G1 and S phases to the M phases. Chabner and Collins eds. (1990) “Cancer Chemotherapy: Principles and Practice”, Philadelphia: JB Lippincott. 
     The alkylating agents are active against wide variety of neoplastic diseases, with significant activity in the treatment of leukemias and lymphomas as well as solid tumors. Clinically this group of drugs is routinely used in the treatment of acute and chronic leukemias; Hodgkin&#39;s disease; non-Hodgkin&#39;s lymphoma; multiple myeloma; primary brain tumors; carcinomas of the breast, ovaries, testes, lungs, bladder, cervix, head and neck, and malignant melanoma. 
     Antibiotic Agents 
     Antibiotics (e.g., cytotoxic antibiotics) act by directly inhibiting DNA or RNA synthesis and are effective throughout the cell cycle. Examples of antibiotic agents include anthracyclines (e.g., Doxorubicin, Daunorubicin, Epirubicin, Idarubicin, and Anthracenedione), Mitomycin C, Bleomycin, Dactinomycin, Plicatomycin. These antibiotic agents interfere with cell growth by targeting different cellular components. For example, anthracyclines are generally believed to interfere with the action of DNA topoisomerase II in the regions of transcriptionally active DNA, which leads to DNA strand scissions. 
     Idarubicin (e.g., Idamycin PFS®, Pharmacia &amp; Upjohn Co., Kalamazoo, Mich.) is a DNA-intercalating analog of daunorubicin which has an inhibitory effect on nucleic acid synthesis and interacts with the enzyme topoisomerase II. The chemical name for idarubicin hydrochloride is 5,12-naphthacenedione, 9-acetyl-7-[(3-amino-2,3,6-trideoxy-α-L-lyxo-hexopyranosyl)oxy]-7,8,9,10-tetrahydro-6,9,11-trihydroxyhydrochloride, (7S-cis) as represented by the structure: 
     
       
         
         
             
             
         
       
     
     Doxorubicin (e.g., Adriamycin®, Ben Venue Laboratories, Inc., Bedford, Ohio) is a cytotoxic anthracycline antibiotic isolated from cultures of  Streptomyces peucetius  var.  caesius . Doxorubicin binds to nucleic acids, presumably by specific intercalation of the planar anthracycline nucleus with the DNA double helix. Doxorubicin consists of a naphthacenequinone nucleus linked through a glycosidic bond at ring atom 7 to an amino sugar, daunosamine. The chemical name for Doxorubicin hydrochloride is (8S,10S)-10-[(3-Amino-2,3,6-trideoxy-a-L-lyxo-hexopyranosyl)-oxy]-8-glycoloyl-7,8,9,10-tetrahydro-6,8,11-trihydroxy-1-methoxy-5,12-naphthacenedione hydrochloride as represented by the structure: 
     
       
         
         
             
             
         
       
     
     Bleomycin is generally believed to chelate iron and forms an activated complex, which then binds to bases of DNA, causing strand scissions and cell death. 
     The antibiotic agents have been used as therapeutics across a range of neoplastic diseases, including carcinomas of the breast, lung, stomach and thyroids, lymphomas, myelogenous leukemias, myelomas, and sarcomas. 
     Antimetabolic Agents 
     Antimetabolic agents (i.e., antimetabolites) are a group of drugs that interfere with metabolic processes vital to the physiology and proliferation of cancer cells. Actively proliferating cancer cells require continuous synthesis of large quantities of nucleic acids, proteins, lipids, and other vital cellular constituents. 
     Many of the antimetabolites inhibit the synthesis of purine or pyrimidine nucleosides or inhibit the enzymes of DNA replication. Some antimetabolites also interfere with the synthesis of ribonucleosides and RNA and/or amino acid metabolism and protein synthesis as well. By interfering with the synthesis of vital cellular constituents, antimetabolites can delay or arrest the growth of cancer cells. Antimitotic agents are included in this group. Examples of antimetabolic agents include, but are not limited to, Fluorouracil (5-FU), Floxuridine (5-FUdR), Methotrexate, Leucovorin, Hydroxyurea, Thioguanine (6-TG), Mercaptopurine (6-MP), Cytarabine, Pentostatin, Fludarabine Phosphate, Cladribine (2-CDA), Asparaginase, and Gemcitabine. 
     Gemcitabine (e.g., Gemzar® HCl, Eli Lilly and Co., Indianapolis, Ind.) is a nucleoside analogue that exhibits antitumor activity. Gemcitabine exhibits cell phase specificity, primarily killing cells undergoing DNA synthesis (S-phase) and also blocking the progression of cells through the GUS-phase boundary. Gemcitabine is metabolized intracellularly by nucleoside kinases to the active diphosphate (dFdCDP) and triphosphate (dFdCTP) nucleosides. The cytotoxic effect of Gemcitabine is attributed to a combination of two actions of the diphosphate and the triphosphate nucleosides, which leads to inhibition of DNA synthesis. Gemcitabine induces internucleosomal DNA fragmentation, one of the characteristics of programmed cell death. The chemical name for Gemcitabine hydrochloride is 2′-deoxy-2′,2′-difluorocytidine monohydrochloride (β-isomer) as represented by the structure: 
     
       
         
         
             
             
         
       
     
     Bortezomib (e.g., Velcade®, Millennium Pharmaceuticals, Inc., Cambridge, Mass.) is a modified dipeptidyl boronic acid. Bortezomib is a reversible inhibitor of the 26S proteasome in mammalian cells. Inhibition of the 26S proteasome prevents targeted proteolysis, which can affect multiple signaling cascades within the cell. This disruption of normal homeostatic mechanisms can lead to cell death. Experiments have demonstrated that Bortezomib is cytotoxic in vitro and causes a delay in cell growth in vivo. The chemical name for Bortezomib, the monomeric boronic acid, is [(1R)-3-methyl-1-[[(2S)-1-oxo-3-phenyl-2-[(pyrazinylcarbonyl)amino]propyl]amino]butyl] boronic acid, as represented by the following structure: 
     
       
         
         
             
             
         
       
     
     Pemetrexed (e.g., Altima®, Eli Lilly and Co., Indianapolis, Ind.) is an antifolate agent that exerts its action by disrupting folate-dependent metabolic processes essential for cell replication. In vitro studies have shown that Pemetrexed inhibits thymidylate synthase (TS), dihydrofolate reductase (DHFR), and glycinamide ribonucleotide formyltransferase (GARFT), all folate-dependent enzymes involved in the de novo biosynthesis of thymidine and purine nucleotides. Pemetrexed disodium heptahydrate has the chemical name L-glutamic acid, N-[4-[2-(2-amino-4,7-dihydro-4-oxo-1H-pyrrolo[2,3-d]pyrimidin-5-yl)ethyl]benzoyl]-, disodium salt, heptahydrate, as represented by the structure: 
     
       
         
         
             
             
         
       
     
     Azacitidine (e.g., Vidaza™, Pharmion Corp., Boulder, Colo.) is a pyrimidine nucleoside analog of cytidine which causes hypermethylation of DNA and direct cytotoxicity on abnormal hematopoietic cells in bone marrow. Hypermethylation may restore normal function to genes that are involved in differentiation and proliferation without causing major suppression of DNA synthesis. The cytotoxic effects of Azacitidine cause the death of rapidly dividing cells, including cells that are non longer sensitive to normal growth control mechanisms. The chemical name for Azacitidine is 4-amino-1β-D-ribofuranosyl-s-trianzin-2(1H)-one, as represented by the structure: 
     
       
         
         
             
             
         
       
     
     Flavopiridol (e.g., L86-8275; Alvocidib; Aventis Pharmaceuticals, Inc., Bridgewater, N.J.) is a synthetic flavone that acts as an inhibitor of the cyclin-dependent kinases (CDKs). The activation of CDKs is required for transit of the cell between the different phases of the cell cycle, including G1 to S and G2 to M. Flavopiridol has been shown to block cell cycle progression at G1-S and G2-M stages and to induce apoptosis in vitro. The chemical formula for Flavopiridol as found in Alvocidib is (−)-2-(2-chlorophenyl)-5,7-dihydroxy-8-[(3R,4S)-3-hydroxy-1-methyl-4-piperidinyl]-4H-1-benzopyran-4-one hydrochloride, as represented by the structure: 
     
       
         
         
             
             
         
       
     
     Fluorouracil (e.g., Fluorouracil Injection, Gensia Sicor Pharmaceuticals, Inc., Irvine, Calif.; Adrucil®, SP Pharmaceuticals Albuquerque, N. Mex.) is a fluorinated pyrimidine. The metabolism of fluorouracil in the anabolic pathway may block the methylation reaction of deoxyuridylic acid to thymidylic acid. In this manner, fluorouracil can interfere with the synthesis of DNA and to a lesser extent inhibits the formation of ribonucleic acid (RNA). Since DNA and RNA are essential for cell division and growth, the effect of fluorouracil may be to create a thymine deficiency which provokes unbalanced growth and death of the cell. The effects of DNA and RNA inhibition are most marked on those cells which grow more rapidly and which take up fluorouracil at a more rapid rate. The chemical formula for Fluorouracil is 5-fluoro-2,4 (1H,3H)-pyrimidinedione, as represented by the structure: 
     
       
         
         
             
             
         
       
     
     Antimetabolic agents have been widely used to treat several common forms of cancer including carcinomas of colon, rectum, breast, liver, stomach and pancreas, malignant melanoma, acute and chronic leukemia and hair cell leukemia. 
     Hormonal Agents 
     The hormonal agents are a group of drug that regulate the growth and development of their target organs. Most of the hormonal agents are sex steroids and their derivatives and analogs thereof, such as estrogens, progestogens, anti-estrogens, androgens, anti-androgens and progestins. These hormonal agents may serve as antagonists of receptors for the sex steroids to down regulate receptor expression and transcription of vital genes. Examples of such hormonal agents are synthetic estrogens (e.g., Diethylstibestrol), antiestrogens (e.g., Tamoxifen, Toremifene, Fluoxyrnesterol, and Raloxifene), antiandrogens (e.g., Bicalutamide, Nilutamide, and Flutamide), aromatase inhibitors (e.g., Aminoglutethimide, Anastrozole, and Tetrazole), luteinizing hormone release hormone (LHRH) analogues, Ketoconazole, Goserelin Acetate, Leuprolide, Megestrol Acetate, and Mifepristone. 
     Prednisone (e.g., Deltasone®, Pharmacia &amp; Upjohn Co., Kalamazoo, Mich.) is an adrenocortical steroid and a synthetic glucocorticoid which is readily absorbed in the gastrointestinal tract. Glucocorticoids modify the body&#39;s immune responses to diverse stimuli. Synthetic glucocorticoids are primarily used for their anti-inflammatory effects and management of leukemias and lymphomas, and other hematological disorders such as thrombocytopenia, erythroblastopenia, and anemia. The chemical name for Prednisone is pregna-1,4-diene-3,11,20-trione, 17,21-dihydroxy- (also, 1,4-pregnadiene-17α,21-diol-3,11,20-trione; 1-Cortisone; 17α,21-dihydroxy-1,4-pregnadiene-3,11,20-trione; and dehydrocortisone), as represented by the structure: 
     
       
         
         
             
             
         
       
     
     Hormonal agents are used to treat breast cancer, prostate cancer, melanoma, and meningioma. Because the major action of hormones is mediated through steroid receptors, 60% receptor-positive breast cancer responded to first-line hormonal therapy; and less than 10% of receptor-negative tumors responded. The main side effect associated with hormonal agents is flare. The frequent manifestations are an abrupt increase of bone pain, erythema around skin lesions, and induced hypercalcemia. 
     Specifically, progestogens are used to treat endometrial cancers, since these cancers occur in women that are exposed to high levels of oestrogen unopposed by progestogen. 
     Antiandrogens are used primarily for the treatment of prostate cancer, which is hormone dependent. They are used to decrease levels of testosterone, and thereby inhibit growth of the tumor. 
     Hormonal treatment of breast cancer involves reducing the level of oestrogen-dependent activation of oestrogen receptors in neoplastic breast cells. Anti-oestrogens act by binding to oestrogen receptors and prevent the recruitment of coactivators, thus inhibiting the oestrogen signal. 
     LHRH analogues are used in the treatment of prostate cancer to decrease levels of testosterone and so decrease the growth of the tumor. 
     Aromatase inhibitors act by inhibiting the enzyme required for hormone synthesis. In post-menopausal women, the main source of oestrogen is through the conversion of androstenedione by aromatase. 
     Plant-Derived Agents 
     Plant-derived agents are a group of drugs that are derived from plants or modified based on the molecular structure of the agents. They inhibit cell replication by preventing the assembly of the cell&#39;s components that are essential to cell division. 
     Examples of plant derived agents include vinca alkaloids (e.g., Vincristine, Vinblastine, Vindesine, Vinzolidine, and Vinorelbine), podophyllotoxins (e.g., Etoposide (VP-16) and Teniposide (VM-26)), and taxanes (e.g., Paclitaxel and Docetaxel). These plant-derived agents generally act as antimitotic agents that bind to tubulin and inhibit mitosis. Podophyllotoxins such as Etoposide are believed to interfere with DNA synthesis by interacting with topoisomerase II, leading to DNA strand scission. 
     Vincristine (e.g., Vincristine sulfate, Gensia Sicor Pharmaceuticals, Irvine, Calif.) is an alkaloid obtained from a common flowering herb, the periwinkle plant ( Vinca rosea  Linn). Vincristine was originally identified as Leurocristine, and has also been referred to as LCR and VCR. The mechanism of action of Vincristine has been related to the inhibition of microtubule formation in the mitotic spindle, resulting in an arrest of dividing cells at the metaphase stage. Vincristine sulfate is vincaleukoblastine, 22-oxo-, sulfate (1:1) (salt) as represented by the structure: 
     
       
         
         
             
             
         
       
     
     Etoposide (e.g., VePesid®, Bristol-Myers Squibb Co., Princeton, N.J., also commonly known as VP-16) is a semisynthetic derivative of podophyllotoxin. Etoposide has been shown to cause metaphase arrest and G2 arrest in mammalian cells. At high concentrations, Etoposide triggers lysis of cells entering mitosis. At low concentrations, Etoposide inhibits entry of cells into prophase. The predominant macromolecular effect of Etoposide appears to be the induction of DNA strand breaks by an interaction with DNA topoisomerase II or the formation of free radicals. Etoposide phosphate (e.g., Etopophos®, Bristol-Myers Squibb Co., Princeton, N.J.) is a water soluble ester of Etoposide. The chemical name for Etoposide phosphate is 4′-demethylepipodophyllotoxin 9-[4,6-O-(R)-ethylidene-b-D-glucopyranoside], 4′-(dihydrogen phosphate), as represented by the structure: 
     
       
         
         
             
             
         
       
     
     The chemical name for Etoposide is 4′-demethylepipodophyllotoxin 9-[4,6-O-(R)-ethylidene-b-D-glucopyranoside] as represented by the structure: 
     
       
         
         
             
             
         
       
     
     Plant-derived agents are used to treat many forms of cancer. For example, Vincristine is used in the treatment of the leukemias, Hodgkin&#39;s and non-Hodgkin&#39;s lymphoma, and the childhood tumors neuroblastoma, rhabdomyosarcoma, and Wilms&#39; tumor. Vinblastine is used against the lymphomas, testicular cancer, renal cell carcinoma, mycosis fungoides, and Kaposi&#39;s sarcoma. Doxetaxel has shown promising activity against advanced breast cancer, non-small cell lung cancer (NSCLC), and ovarian cancer. 
     Etoposide is active against a wide range of neoplasms, of which small cell lung cancer, testicular cancer, and NSCLC are most responsive. 
     Biologic Agents 
     Biologic agents are a group of biomolecules that elicit cancer/tumor regression when used alone or in combination with chemotherapy and/or radiotherapy. Examples of biologic agents include immunomodulating proteins such as cytokines, monoclonal antibodies against tumor antigens, tumor suppressor genes, and cancer vaccines. 
     Cytokines possess profound immunomodulatory activity. Some cytokines such as interleukin-2 (IL-2, Aldesleukin) and interferon-α (IFN-α) demonstrated antitumor activity and have been approved for the treatment of patients with metastatic renal cell carcinoma and metastatic malignant melanoma. IL-2 is a T-cell growth factor that is central to T-cell-mediated immune responses. The selective antitumor effects of IL-2 on some patients are believed to be the result of a cell-mediated immune response that discriminate between self and nonself. 
     Interferon-α includes more than 23 related subtypes with overlapping activities. IFN-α has demonstrated activity against many solid and hematologic malignancies, the later appearing to be particularly sensitive. 
     Examples of interferons include interferon-α, interferon-β (fibroblast interferon) and interferon-γ (fibroblast interferon). Examples of other cytokines include erythropoietin (Epoietin-α), granulocyte-CSF (Filgrastin), and granulocyte, macrophage-CSF (Sargramostim). Other immuno-modulating agents other than cytokines include  bacillus  Calmette-Guerin, levamisole, and octreotide, a long-acting octapeptide that mimics the effects of the naturally occurring hormone somatostatin. 
     Furthermore, the anti-cancer treatment can comprise treatment by immunotherapy with antibodies and reagents used in tumor vaccination approaches. The primary drugs in this therapy class are antibodies, alone or carrying e.g. toxins or chemostherapeutics/cytotoxics to cancer cells. Monoclonal antibodies against tumor antigens are antibodies elicited against antigens expressed by tumors, particularly tumor-specific antigens. For example, monoclonal antibody HERCEPTIN® (Trastuzumab) is raised against human epidermal growth factor receptor2 (HER2) that is overexpressed in some breast tumors including metastatic breast cancer. Overexpression of HER2 protein is associated with more aggressive disease and poorer prognosis in the clinic. HERCEPTIN® is used as a single agent for the treatment of patients with metastatic breast cancer whose tumors over express the HER2 protein. 
     Another example of monoclonal antibodies against tumor antigens is RITUXAN® (Rituximab) that is raised against CD20 on lymphoma cells and selectively deplete normal and malignant CD20+ pre-B and mature B cells. 
     RITUXAN is used as single agent for the treatment of patients with relapsed or refractory low-grade or follicular, CD20+, B cell non-Hodgkin&#39;s lymphoma. MYELOTARG® (Gemtuzumab Ozogamicin) and CAMPATH® (Alemtuzumab) are further examples of monoclonal antibodies against tumor antigens that may be used. 
     Endostatin is a cleavage product of plasminogen used to target angiogenesis. 
     Tumor suppressor genes are genes that function to inhibit the cell growth and division cycles, thus preventing the development of neoplasia. Mutations in tumor suppressor genes cause the cell to ignore one or more of the components of the network of inhibitory signals, overcoming the cell cycle checkpoints and resulting in a higher rate of controlled cell growth-cancer. Examples of the tumor suppressor genes include Duc-4, NF-1, NF-2, RB, p53, WTI, BRCA1, and BRCA2. 
     DPC4 is involved in pancreatic cancer and participates in a cytoplasmic pathway that inhibits cell division. NF-1 codes for a protein that inhibits Ras, a cytoplasmic inhibitory protein. NF-1 is involved in neurofibroma and pheochromocytomas of the nervous system and myeloid leukemia. NF-2 encodes a nuclear protein that is involved in meningioma, schwanoma, and ependymoma of the nervous system. RB codes for the pRB protein, a nuclear protein that is a major inhibitor of cell cycle. RB is involved in retinoblastoma as well as bone, bladder, small cell lung and breast cancer. P53 codes for p53 protein that regulates cell division and can induce apoptosis. Mutation and/or inaction of p53 is found in a wide range of cancers. WTI is involved in Wilms&#39; tumor of the kidneys. BRCA1 is involved in breast and ovarian cancer, and BRCA2 is involved in breast cancer. The tumor suppressor gene can be transferred into the tumor cells where it exerts its tumor suppressing functions. 
     Cancer vaccines are a group of agents that induce the body&#39;s specific immune response to tumors. Most of cancer vaccines under research and development and clinical trials are tumor-associated antigens (TAAs). TAAs are structures (i.e., proteins, enzymes, or carbohydrates) that are present on tumor cells and relatively absent or diminished on normal cells. By virtue of being fairly unique to the tumor cell, TAAs provide targets for the immune system to recognize and cause their destruction. Examples of TAAs include gangliosides (GM2), prostate specific antigen (PSA), α-fetoprotein (AFP), carcinoembryonic antigen (CEA) (produced by colon cancers and other adenocarcinomas, e.g., breast, lung, gastric, and pancreatic cancers), melanoma-associated antigens (MART-1, gapl 00, MAGE 1,3 tyrosinase), papillomavirus E6 and E7 fragments, whole cells or portions/lysates of autologous tumor cells and allogeneic tumor cells. 
     Retinoids or retinoid agents for use with the invention include all natural, recombinant, and synthetic derivatives or mimetics of vitamin A, for example, retinyl palmitate, retinoyl-beta-glucuronide (vitamin A1 beta-glucuronide), retinyl phosphate (vitamin A1 phosphate), retinyl esters, 4-oxoretinol, 4-oxoretinaldehyde, 3-dehydroretinol (vitamin A2), 11-cis-retinal (11-cis-retinaldehyde, 11-cis or neo b vitamin A1 aldehyde), 5,6-epoxyretinol (5,6-epoxy vitamin A1 alcohol), anhydroretinol (anhydro vitamin A1) and 4-ketoretinol (4-keto-vitamin A1 alcohol), all-trans retinoic acid (ATRA; Tretinoin; vitamin A acid; 3,7-dimethyl-9-(2,6,6,-trimethyl-1-cyclohenen-1-yl)-2,4,6,8-nonatetraenoic acid [CAS No. 302-79-4]), lipid formulations of all-trans retinoic acid (e.g., ATRA-IV), 9-cis retinoic acid (9-cis-RA; Alitretinoin; Panretin©; LGD1057), (e)-4-[2-(5,6,7,8-tetrahydro-2-naphthalenyl)-1-propenyl]-benzoic acid, 3-methyl-(E)-4-[2-(5,6,7,8-tetrahydro-2-naphthalenyl)-1-propenyl]-benzoic acid, Fenretinide (N-(4-hydroxyphenyl)retinamide; 4-HPR), Etretinate (2,4,6,8-nonatetraenoic acid), Acitretin (Ro 10-1670), Tazarotene (ethyl 6-[2-(4,4-dimethylthiochroman-6-yl)-ethynyl]nicotinate), Tocoretinate (9-cis-tretinoin tocoferil), Adapalene (6-[3-(1-adamantyl)-4-methoxyphenyl]-2-naphthoic acid), Motretinide (trimethylmethoxyphenyl-N-ethyl retinamide), and retinaldehyde. 
     Also included as retinoids are retinoid related molecules such as CD437 (also called 6-[3-(1-adamantyl)-4-hydroxphenyl]-2-naphthalene carboxylic acid and AHPN), CD2325, ST1926 ([E-3-(4′-hydroxy-3′-adamantylbiphenyl-4-yl)acrylic acid), ST1878 (methyl 2-[3-[2-[3-(2-methoxy-1,1-dimethyl-2-oxoethoxy)phenoxy]ethoxy]phenoxy]isobutyrate), ST2307, ST1898, ST2306, ST2474, MM11453, MM002 (3-CI-AHPC), MX2870-1, MX3350-1, MX84, and MX90-1 (Garattini et al., 2004 , Curr. Pharmaceut. Design  10:433-448; Garattini and Terao, 2004 , J. Chemother.  16:70-73). Included for use with the invention are retinoid agents that bind to one or more RXR. Also included are retinoid agents that bind to one or more RXR and do not bind to one or more RAR (i.e., selective binding to RXR; rexinoids), e.g., docosahexanoic acid (DHA), phytanic acid, methoprene acid, LG100268 (LG268), LG100324, LGD1057, SR11203, SR11217, SR11234, SR11236, SR11246, AGN194204 (see, e.g., Simeone and Tari, 2004 , Cell Mol. Life Sci.  61:1475-1484; Rigas and Dragnev, 2005 , The Oncologist  10:22-33; Ahuja et al., 2001 , Mol. Pharmacol.  59:765-773; Gorgun and Foss, 2002, Blood 100:1399-1403; Bischoff et al., 1999 , J. Natl. Cancer Inst.  91:2118-2123; Sun et al., 1999 , Clin. Cancer Res.  5:431-437; Crow and Chandraratna, 2004 , Breast Cancer Res.  6:R546-R555). Further included are derivatives of 9-cis-RA. Particularly included are 3-methyl TTNEB and related agents, e.g., Targretin®; Bexarotene; LGD1069; 4-[1-(5,6,7,8-tetrahydro-3,5,5,8,8-pentamethyl-2-naphthalenyl)ethenyl] benzoic acid, or a pharmaceutically acceptable salt or hydrate thereof. 
     The use of all of these approaches in combination with HDAC inhibitors, e.g. SAHA, is within the scope of the present invention. 
     Other Agents 
     Other agents may also be useful for use with the present invention, for example, for adjunct therapies. Such adjunctive agents can be used to enhance the effectiveness of anticancer agents or to prevent or treat conditions associated with anticancer agents such as low blood counts, hypersensitivity reactions, neutropenia, anemia, thrombocytopenia, hypercalcemia, mucositis, bruising, bleeding, toxicity (e.g., Leucovorin), fatigue, pain, nausea, and vomiting. Antiemetic agents (e.g., 5-HT receptor blockers or benzodiazepines), anti-inflammatory agents (e.g., adrenocortical steroids or antihistamines), dietary supplements (e.g., folic acid), vitamins (e.g., Vitamin E, Vitamin C, Vitamin B 6 , Vitamin B 12 ), and acid reducing agents (e.g., H 2  receptor blockers) can be useful for increasing patient tolerance to cancer therapy. Examples of H 2  receptor blockers include Ranitidine, Famotidine, and Cimetidine. Examples of antihistamines include Diphenhydramine, Clemastine, Chlorpheniramine, Chlorphenamine, Dimethindene maleate, and Promethazine. Examples of steroids include Dexamethasone, Hydrocortisone, and Prednisone. Other agents include growth factors such as epoetin alpha (e.g., Procrit®, Epogen®) for stimulating red blood cell production, G-CSF (granulocyte colony-stimulating factor; filgrastim, e.g., Neupogen®) for stimulating neutrophil production, GM-CSF (granulocyte-macrophage colony-stimulating factor) for stimulating production of several white blood cells, including macrophages, and IL-11 (interleukin-11, e.g., Neumega®) for stimulating production of platelets. 
     Leucovorin (e.g., Leucovorin calcium, Roxane Laboratories, Inc., Columbus, Ohio; also called folinic acid, calcium folinate, citrovorum factor) can be used as an antidote to folic acid antagonists, and can also potentiate the activity of certain drugs, such as Fluorouracil. Leucovorin calcium is the calcium salt of N-[4-[[(2-amino-5-formyl-1,4,5,6,7,8-hexahydro-4-oxo-6-pteridinyl)methyl]amino]benzoyl]-L-glutamic acid. 
     Dexamethasone (e.g., Decadron®; Merck &amp; Co., Inc., Whitehouse Station, N.J.) is a synthetic adrenocortical steroid that can be used as an anti-inflammatory agent to control allergic reactions, e.g., drug hypersensitivity reactions. Further, dexamethasone is used to sensitize the cells to the cytotoxic activity of anti-cancer agents. Dexamethasone tablets for oral administration comprise 9-fluoro-1′-beta,17,21-trihydroxy-16-alpha-methylpregna-1,4-diene-3,20-dione, as represented by the structure: 
     
       
         
         
             
             
         
       
     
     Dexamethasone phosphate for intravenous administration comprises 9-fluoro-11β,17-dihydroxy-16α-methyl-2′-(phosphonooxy)pregna-1,4-diene-3,20-dione disodium salt, as represented by the structure: 
     
       
         
         
             
             
         
       
     
     Diphenhydramine (e.g., Benadryl®; Parkedale Pharmaceuticals, Inc., Rochester, Mich.) is an antihistamine drug used for amelioration of allergic reactions. Diphenhydramine hydrochloride (e.g., Diphenhydramine HCl for injection) is 2-(diphenylmethoxy)-N,N-dimethylethylamine hydrochloride, as represented by the structure: 
     
       
         
         
             
             
         
       
     
     Ranitidine (e.g., Zantac®; GlaxoSmithKline, Research Triangle Park, N.C.) is a competitive inhibitor of histamine at histamine Hz-receptors, and can be used to reduce stomach acid. Ranitidine hydrochloride (e.g., tablets or injection) is N[2-[[[5-[(dimethylamino)methyl]-2-furanyl]methyl]thio]ethyl]-N′-methyl-2-nitro-1,1-ethenediamine, HCl, as represented by the structure: 
     
       
         
         
             
             
         
       
     
     Cimetidine (e.g., Tagamet®; GlaxoSmithKline, Research Triangle Park, N.C.) is also a competitive inhibitor of histamine at histamine H2 receptors, and can be used to reduce stomach acid. Cimetidine is N″-cyano-N-methyl-N′-[2-[[(5-methyl-1H-imidazol-4-yl)methyl]thio]-ethyl]-guanidine, as represented by the structure: 
     
       
         
         
             
             
         
       
     
     Aprepitant (e.g., EMEND®; Merck &amp; Co., Inc.) is a substance P/neurokinin 1 (NK1) receptor antagonist and antiemetic. Aprepitant is 5-[[(2R,3S)-2-[(1R)-1-[3,5-bis(trifluoromethyl)phenyl]ethoxy]-3-(4-fluorophenyl)-4-morpholinyl]methyl]-1,2-dihydro-3H-1,2,4-triazol-3-one, as represented by the structure: 
     
       
         
         
             
             
         
       
     
     Ondansetron (e.g., Zofran®; GlaxoSmithKline, Research Triangle Park, N.C.) is a selective blocking agent of 5-HT3 serotonin receptor and antiemetic. Ondansetron hydrochloride (e.g., for injection) is (±)1,2,3,9-tetrahydro-9-methyl-3-[(2-methyl-1H-imidazol-1-yl)methyl]-4H-carbazol-4-one, monohydrochloride, dihydrate, as represented by the structure: 
     
       
         
         
             
             
         
       
     
     Lorazepam (e.g., Lorazepam Injection; Baxter Healthcare Corp., Deerfield, Ill.), is a benzodiazepine with anticonvulsant effects. Lorazepam is 7-chloro-5(2-chlorophenyl)-1,3-dihydro-3-hydroxy-2H-1,4-benzodiazepin-2-one, as represented by the structure: 
     
       
         
         
             
             
         
       
     
     The present invention also contemplates the addition of dexamethasone to combination of SAHA and Bortezomib to increase the response rate and to sensitize the cells to the cytotoxic activity of anti-myeloma agents. Dexamethasone is an important drug in the therapy of multiple myeloma. The addition of dexamethasone is done to increase the response rate by at least 20%. In one aspect of the invention, patients who completed 2 cycles of SAHA/Bortezomib and who experience less than a partial remission and no organ damaged defined as worsening anemia, worsening renal failure, signs and symptoms of heperviscosity syndrome, may be treated with dexamethasone 20 mg by mouth daily on five days (Days 4-8). 
     Administration of the MAC Inhibitor 
     Routes of Administration 
     The HDAC inhibitor (e.g. SAHA), can be administered by any known administration method known to a person skilled in the art. Examples of routes of administration include but are not limited to oral, parenteral, intraperitoneal, intravenous, intraarterial, transdermal, topical, sublingual, intramuscular, rectal, transbuccal, intranasal, liposomal, via inhalation, vaginal, intraoccular, via local delivery by catheter or stent, subcutaneous, intraadiposal, intraarticular, intrathecal, or in a slow release dosage form. SAHA or any one of the HDAC inhibitors can be administered in accordance with any dose and dosing schedule that, together with the effect of the anti-cancer agent, achieves a dose effective to treat disease. 
     Of course, the route of administration of SAHA or any one of the other HDAC inhibitors is independent of the route of administration of the anti-cancer agent. A particular route of administration for SAHA is oral administration. Thus, in accordance with this embodiment, SAHA is administered orally, and the second agent (anti-cancer agent) can be administered orally, parenterally, intraperitoneally, intravenously, intraarterially, transdermally, sublingually, intramuscularly, rectally, transbuccally, intranasally, liposomally, via inhalation, vaginally, intraoccularly, via local delivery by catheter or stent, subcutaneously, intraadiposally, intraarticularly, intrathecally, or in a slow release dosage form. 
     As examples, the HDAC inhibitors of the invention can be administered in such oral forms as tablets, capsules (each of which includes sustained release or timed release formulations), pills, powders, granules, elixirs, tinctures, suspensions, syrups, and emulsions. Likewise, the HDAC inhibitors can be administered by intravenous (e.g., bolus or infusion), intraperitoneal, subcutaneous, intramuscular, or other routes using forms well known to those of ordinary skill in the pharmaceutical arts. A particular route of administration of the HDAC inhibitor is oral administration. 
     The HDAC inhibitors can also be administered in the form of a depot injection or implant preparation, which may be formulated in such a manner as to permit a sustained release of the active ingredient. The active ingredient can be compressed into pellets or small cylinders and implanted subcutaneously or intramuscularly as depot injections or implants. Implants may employ inert materials such as biodegradable polymers or synthetic silicones, for example, Silastic, silicone rubber or other polymers manufactured by the Dow-Corning Corporation. 
     The HDAC inhibitor can also be administered in the form of liposome delivery systems, such as small unilamellar vesicles, large unilamellar vesicles and multilamellar vesicles. Liposomes can be formed from a variety of phospholipids, such as cholesterol, stearylamine, or phosphatidylcholines. Liposomal preparations of tyrosine kinase inhibitors may also be used in the methods of the invention. Liposome versions of tyrosine kinase inhibitors may be used to increase tolerance to the inhibitors. 
     The HDAC inhibitors can also be delivered by the use of monoclonal antibodies as individual carriers to which the compound molecules are coupled. 
     The HDAC inhibitors can also be prepared with soluble polymers as targetable drug carriers. Such polymers can include polyvinyl pyrrolidone, pyran copolymer, polyhydroxy-propyl-methacrylamide-phenol, polyhydroxyethyl-aspartamide-phenol, or polyethyleneoxide-polylysine substituted with palmitoyl residues. Furthermore, the HDAC inhibitors can be prepared with biodegradable polymers useful in achieving controlled release of a drug, for example, polylactic acid, polyglycolic acid, copolymers of polylactic and polyglycolic acid, polyepsilon caprolactone, polyhydroxy butyric acid, polyorthoesters, polyacetals, polydihydropyrans, polycyanoacrylates and cross linked or amphipathic block copolymers of hydrogels. 
     In a specific embodiment, the HDAC inhibitor, e.g. SAHA, is administered orally in a gelatin capsule, which can comprise excipients such as microcrystalline cellulose, croscarmellose sodium and magnesium stearate. 
     Dosages and Dosage Schedules 
     The dosage regimen utilizing the HDAC inhibitors can be selected in accordance with a variety of factors including type, species, age, weight, sex and the type of disease being treated; the severity (i.e., stage) of the disease to be treated; the route of administration; the renal and hepatic function of the patient; and the particular compound or salt thereof employed. A dosage regiment can be used, for example, to prevent, inhibit (fully or partially), or arrest the progress of the disease. 
     In accordance with the invention, an HDAC inhibitor (e.g., SAHA or a pharmaceutically acceptable salt or hydrate thereof) can be administered by continuous or intermittent dosages. For example, intermittent administration of an HDAC inhibitor may be administration one to six days per week or it may mean administration in cycles (e.g. daily administration for two to eight consecutive weeks, then a rest period with no administration for up to one week) or it may mean administration on alternate days. The compositions may be administered in cycles, with rest periods in between the cycles (e.g. treatment for two to eight weeks with a rest period of up to a week between treatments). 
     For example, SAHA or any one of the HDAC inhibitors can be administered in a total daily dose of up to 800 mg. The HDAC inhibitor can be administered once daily (QD), or divided into multiple daily doses such as twice daily (BID), and three times daily (TID). The HDAC inhibitor can be administered at a total daily dosage of up to 800 mg, e.g., 200 mg, 300 mg, 400 mg, 600 mg, or 800 mg, which can be administered in one daily dose or can be divided into multiple daily doses as described above. In specific aspects, the administration is oral. 
     SAHA or any one of the HDAC inhibitors can be administered in accordance with any dose and dosing schedule that, together with the effect of the anti-cancer agent, achieves a dose effective to treat cancer. The HDAC inhibitors can be administered in a total daily dose that may vary from patient to patient, and may be administered at varying dosage schedules. For example, SAHA or any of the HDAC inhibitors can be administered to the patient at a total daily dosage of between 25-4000 mg/m 2 . In particular, SAHA or any one of the HDAC inhibitors can be administered in a total daily dose of up to 800 mg, especially by oral administration, once, twice or three times daily, continuously (every day) or intermittently (e.g., 3-5 days a week). In addition, the administration can be continuous, i.e., every day, or intermittently. 
     The one aspect of this invention relates to a method for treating multiple myeloma comprising administering to a subject in need thereof an amount of an HDAC inhibitor, e.g., SAHA, and an amount of another anti-cancer agent, e.g., Bortezomib. In particular aspects of this invention, SAHA, or a pharmaceutically acceptable salt or hydrate thereof is orally administered at 200 mg to 800 mg per day for at least one treatment cycle on days 4-11 of a 21 day cycle, and Bortezomib or a pharmaceutically acceptable salt or hydrate thereof, is intravenously administered 0.7-1.3 mg/m 2  per day for at least one treatment cycle on days 1, 4, 8 and 11 of a 21 day cycle. In particular embodiment, multiple myeloma is relapsed and refractory multiple myeloma. 
     In one embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 100 mg for at least one treatment period of days 4-11 out of 21 days. 
     In another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 200 mg for at least one treatment period of days 4-11 out of 21 days. 
     In another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 300 mg for at least one treatment period of days 4-11 out of 21 days. 
     In yet another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 400 mg for at least one treatment period of days 4-11 out of 21 days. 
     In another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered once daily at a dose of 400 mg for at least one treatment period of days 4-11 out of 21 days. 
     In another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered once daily at a dose of 500 mg for at least one treatment period of days 4-11 out of 21 days. 
     In another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered once daily at a dose of 600 mg for at least one treatment period of days 4-11 out of 21 days. 
     In yet another embodiment, administration of SAHA or pharmaceutically acceptable salt or hydrate thereof is repeated for up to eight treatment periods of days 4-11 out of 21 days. 
     In another aspect of this invention, Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered once daily at a dose of 1 mg/m 2  on days 1, 4, 8, and 11 out of 21 days. 
     In yet another aspect of this invention, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 100 mg or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.0 mg/m 2 . 
     In yet another aspect of this invention, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 100 mg or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.0 mg/m 2 . 
     In yet another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 100 mg and Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.3 mg/m 2 . 
     In yet another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 200 mg and Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.3 mg/m 2 . 
     In another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 300 mg and or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.3 mg/m 2 . 
     In yet another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 400 mg and Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.3 mg/m 2 . 
     In yet another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered once daily at a dose of 400 mg and Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.3 mg/m 2 . 
     In yet another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered once daily at a dose of 500 mg and Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.3 mg/m 2 . 
     In another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered once daily at a dose of 600 mg and Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.3 mg/m 2 . 
     In yet another embodiment, the method of treatment of multiple myeloma with SAHA and Bortezomib further comprises orally administering dexamethasone or a pharmaceutically acceptable salt or hydrate thereof wherein the dexamethasone or pharmaceutically acceptable salt or hydrate thereof is administered once daily at a dose of 20 mg for at least one treatment period of 5 out of 21 days. 
     In further embodiment, the method of treatment of multiple myeloma comprises orally administering dexamethasone once daily at a dose of 20 mg for at least one treatment period of days 4-8 out of 21 days. 
     In yet another embodiment, SAHA is orally administered once daily at 400 mg per day for at least one treatment cycle on days 4-11 of a 21 day cycle, and Bortezomib is intravenously administered at 1.3 mg/m 2  per day for at least one treatment cycle on days 1, 4, 8 and 11 of a 21 day cycle. 
     In addition, the HDAC inhibitor may be administered according to any of the schedules described above, consecutively for a few weeks, followed by a rest period. For example, the HDAC inhibitor may be administered according to any one of the schedules described above from two to eight weeks, followed by a rest period of one week, or twice daily at a dose of 300 mg for three to five days a week. In another particular embodiment, the HDAC inhibitor is administered three times daily for two consecutive weeks, followed by one week of rest. 
     Intravenously or subcutaneously, the patient would receive the HDAC inhibitor in quantities sufficient to deliver between about 3-1500 mg/m 2  per day, for example, about 3, 30, 60, 90, 180, 300, 600, 900, 1200 or 1500 mg/m 2  per day. Such quantities may be administered in a number of suitable ways, e.g. large volumes of low concentrations of HDAC inhibitor during one extended period of time or several times a day. The quantities can be administered for one or more consecutive days, intermittent days or a combination thereof per week (7 day period). Alternatively, low volumes of high concentrations of HDAC inhibitor during a short period of time, e.g. once a day for one or more days either consecutively, intermittently or a combination thereof per week (7 day period). For example, a dose of 300 mg/m 2  per day can be administered for 5 consecutive days for a total of 1500 mg/m 2  per treatment. In another dosing regimen, the number of consecutive days can also be 5, with treatment lasting for 2 or 3 consecutive weeks for a total of 3000 mg/m 2  and 4500 mg/m 2  total treatment. 
     Typically, an intravenous formulation may be prepared which contains a concentration of HDAC inhibitor of between about 1.0 mg/mL to about 10 mg/mL, e.g. 2.0 mg/mL, 3.0 mg/mL, 4.0 mg/mL, 5.0 mg/mL, 6.0 mg/mL, 7.0 mg/mL, 8.0 mg/mL, 9.0 mg/mL and 10 mg/mL and administered in amounts to achieve the doses described above. In one example, a sufficient volume of intravenous formulation can be administered to a patient in a day such that the total dose for the day is between about 300 and about 1500 mg/m 2 . 
     Subcutaneous formulations can be prepared according to procedures well known in the art at a pH in the range between about 5 and about 12, which include suitable buffers and isotonicity agents, as described below. They can be formulated to deliver a daily dose of HDAC inhibitor in one or more daily subcutaneous administrations, e.g., one, two or three times each day. 
     The HDAC inhibitors can also be administered in intranasal form via topical use of suitable intranasal vehicles, or via transdermal routes, using those forms of transdermal skin patches well known to those of ordinary skill in that art. To be administered in the form of a transdermal delivery system, the dosage administration will, or course, be continuous rather than intermittent throughout the dosage regime. 
     It is apparent to a person skilled in the art that any one or more of the specific dosages and dosage schedules of the HDAC inhibitors are also applicable to any one or more of the anti-cancer agents to be used in the combination treatment. Moreover, the specific dosage and dosage schedule of the anti-cancer agent can further vary, and the optimal dose, dosing schedule, and route of administration can be determined based upon the specific anti-cancer agent that is being used. Further, the various modes of administration, dosages, and dosing schedules described herein merely set forth specific embodiments and should not be construed as limiting the broad scope of the invention. Any permutations, variations, and combinations of the dosages and dosing schedules are included within the scope of the present invention. 
     Administration of Anti-Cancer Agents 
     Any one or more of the specific dosages and dosage schedules of the HDAC inhibitors, is also applicable to any one or more of the anti-cancer agents to be used in the combination treatment. 
     Moreover, the specific dosage and dosage schedule of the anti-cancer agent can further vary, and the optimal dose, dosing schedule and route of administration will be determined based upon the specific anti-cancer agent that is being used. 
     Of course, the route of administration of SAHA or any one of the other HDAC inhibitors is independent of the route of administration of the anti-cancer agent. A particular route of administration for SAHA is oral administration. Thus, in accordance with this embodiment, SAHA is administered orally, and the other anti-cancer agent can be administered orally, parenterally, intraperitoneally, intravenously, intraarterially, transdermally, sublingually, intramuscularly, rectally, transbuccally, intranasally, liposomally, via inhalation, vaginally, intraoccularly, via local delivery by catheter or stent, subcutaneously, intraadiposally, intraarticularly, intrathecally, or in a slow release dosage form. 
     In addition, the HDAC inhibitor and anti-cancer agent may be administered by the same mode of administration, i.e. both agents administered orally, by IV, etc. However, it is also within the scope of the present invention to administer the HDAC inhibitor by one mode of administration, e.g. oral, and to administer the anti-cancer agent by another mode of administration, e.g. IV, or any other ones of the administration modes described hereinabove. 
     Commonly used anti-cancer agents and daily dosages usually administered include but are not restricted to: 
     
       
         
           
               
               
               
               
             
               
                   
               
             
            
               
                 Antimetabolites: 
                 Methotrexate: 
                 20-40 
                 mg/m 2  i.v. 
               
               
                   
                 Methotrexate: 
                 4-6 
                 mg/m 2  p.o. 
               
               
                   
                 Methotrexate: 
                 12000 
                 mg/m 2  high dose therapy 
               
               
                   
                 6-Mercaptopurine: 
                 100 
                 mg/m 2   
               
               
                   
                 6-Thioguanine: 
                 1-2 × 80 
                 mg/m 2  p.o. 
               
               
                   
                 Pentostatin 
                 4 
                 mg/m 2  i.v. 
               
               
                   
                 Fludarabinphosphate: 
                 25 
                 mg/m 2  i.v. 
               
               
                   
                 Cladribine: 
                 0.14 
                 mg/kg BW i.v. 
               
               
                   
                 5-Fluorouracil 
                 500-2600 
                 mg/m 2  i.v. 
               
               
                   
                 Capecitabine: 
                 1250 
                 mg/m 2  p.o. 
               
               
                   
                 Cytarabin: 
                 200 
                 mg/m 2  i.v. 
               
               
                   
                 Cytarabin: 
                 3000 
                 mg/m 2  i.v. high dose therapy 
               
               
                   
                 Gemcitabine: 
                 800-1250 
                 mg/m 2  i.v. 
               
               
                   
                 Hydroxyurea: 
                 800-4000 
                 mg/m 2  p.o. 
               
               
                   
                 Pemetrexed 
                 250-500 
                 mg/m 2  i.v. 
               
               
                 Antimitotic agents and 
                 Vincristine 
                 1.5-2 
                 mg/m 2  i.v. 
               
               
                 Plant-derived agents: 
                 Vinblastine 
                 4-8 
                 mg/m 2  i.v. 
               
               
                   
                 Vindesine 
                 2-3 
                 mg/m 2  i.v. 
               
               
                   
                 Etoposide (VP16) 
                 100-200 
                 mg/m 2  i.v. 
               
               
                   
                 Etoposide (VP16) 
                 100 
                 mg p.o. 
               
               
                   
                 Teniposide (VM26) 
                 20-30 
                 mg/m 2  i.v. 
               
               
                   
                 Paclitaxel (Taxol) 
                 175-250 
                 mg/m 2  i.v. 
               
               
                   
                 Docetaxel (Taxotere) 
                 100-150 
                 mg/m 2  i.v. 
               
               
                 Antibiotics: 
                 Actinomycin D 
                 0.6 
                 mg/m2 i.v. 
               
               
                   
                 Daunorubicin 
                 45-6.0 
                 mg/m 2  i.v. 
               
               
                   
                 Doxorubicin 
                 45-60 
                 mg/m 2  i.v. 
               
               
                   
                 Epirubicin 
                 60-80 
                 mg/m 2  i.v. 
               
               
                   
                 Idarubicin 
                 10-12 
                 mg/m 2  i.v. 
               
               
                   
                 Idarubicin 
                 35-50 
                 mg/m 2  p.o. 
               
               
                   
                 Mitoxantron 
                 10-12 
                 mg/m 2  i.v. 
               
               
                   
                 Bleomycin 
                 10-15 
                 mg/m 2  i.v., i.m., s.c. 
               
               
                   
                 Mitomycin C 
                 10-20 
                 mg/ 2  i.v. 
               
               
                   
                 Irinotecan (CPT-11) 
                 350 
                 mg/m 2  i.v. 
               
               
                   
                 Topotecan 
                 1.5 
                 mg/m 2  i.v. 
               
               
                 Alkylating Agents: 
                 Mustargen 
                 6 
                 mg/m 2  i.v. 
               
               
                   
                 Estramustinphosphate 
                 150-200 
                 mg/m 2  i.v. 
               
               
                   
                 Estramustinphosphate 
                 480-550 
                 mg/m 2  p.o. 
               
               
                   
                 Melphalan 
                 8-10 
                 mg/m 2  i.v. 
               
               
                   
                 Melphalan 
                 15 
                 mg/m 2  i.v. 
               
               
                   
                 Chlorambucil 
                 3-6 
                 mg/m 2  i.v. 
               
               
                   
                 Prednimustine 
                 40-100 
                 mg/m 2  p.o. 
               
               
                   
                 Cyclophosphamide 
                 750-1200 
                 mg/m 2  i.v. 
               
               
                   
                 Cyclophosphamide 
                 50-100 
                 mg/m 2  p.o. 
               
               
                   
                 Ifosfamide 
                 1500-2000 
                 mg/m 2  i.v. 
               
               
                   
                 Trofosfamide 
                 25-200 
                 mg/m 2  p.o. 
               
               
                   
                 Busulfan 
                 2-6 
                 mg/m 2  p.o. 
               
               
                   
                 Treosulfan 
                 5000-8000 
                 mg/m 2  i.v. 
               
               
                   
                 Treosulfan 
                 750-1500 
                 mg/m 2  p.o. 
               
               
                   
                 Thiotepa 
                 12-16 
                 mg/m 2  i.v. 
               
               
                   
                 Carmustin (BCNU) 
                 100 
                 mg/m 2  i.v. 
               
               
                   
                 Lomustin (CCNU) 
                 100-130 
                 mg/m 2  p.o. 
               
               
                   
                 Nimustin (ACNU) 
                 90-100 
                 mg/m 2  i.v. 
               
               
                   
                 Dacarbazine (OTIC) 
                 100-375 
                 mg/m 2  i.v. 
               
               
                   
                 Procarbazine 
                 100 
                 mg/m 2  p.o. 
               
               
                   
                 Cisplatin 
                 20-120 
                 mg/m 2  i.v. 
               
               
                   
                 Carboplatin 
                 300-400 
                 mg/m 2  i.v. 
               
               
                 Hormones, Cytokines 
                 Interferon-a 
                 2-10 × 10 6   
                 IU/m 2   
               
               
                 and Vitamins: 
                 Prednisone 
                 40-100 
                 mg/m 2  p.o. 
               
               
                   
                 Dexamethasone 
                 8-24 
                 mg p.o. 
               
               
                   
                 G-CSF 
                 5-20 
                 μg/kg BW s.c. 
               
               
                   
                 all-trans Retinoic Acid 
                 45 
                 mg/m 2   
               
               
                   
                 Interleukin-2 
                 18 × 10 6   
                 IU/m 2   
               
               
                   
                 GM-CSF 
                 250 
                 mg/m 2   
               
               
                   
                 Erythropoietin 
                 150 
                 IU/kg tiw 
               
               
                   
               
            
           
         
       
     
     The dosage regimens utilizing the anti-cancer agents described herein (or any pharmaceutically acceptable salts or hydrates of such agents, or any free acids, free bases, or other free forms of such agents) can follow the exemplary dosages herein, including those provided for HDAC inhibitors. The dosage can be selected in accordance with a variety of factors including type, species, age, weight, sex and the type of disease being treated; the severity (i.e., stage) of the disease to be treated; the route of administration; the renal and hepatic function of the patient; and the particular compound or salt thereof employed. A dosage regiment can be used, for example, to treat, for example, to prevent, inhibit (fully or partially), or arrest the progress of the disease. 
     In another embodiment, Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered once daily intravenous at a dose of 0.7-1.3 mg/m 2  on Days 1, 4, 8 and 11 out of 21 days. In other embodiments, Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered once daily at a dose of 1.0 mg/m 2  on Days 1, 4, 8 and 11 out of 21 days. In yet another embodiments, Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered once daily at a dose of 1.3 mg/m 2  on Days 1, 4, 8 and 11 out of 21 days. 
     Combination Administration 
     In accordance with the invention, HDAC inhibitors and anti-cancer agents can be used in the treatment of multiple myeloma, including but not limited to relapsed and refractory multiple myeloma. 
     Multiple myeloma is characterized by the neoplastic proliferation of a single clone of plasma cells engaged in the production of a monoclonal immunoglobulin (Kyle, Multiple Myeloma and Other Plasma Cell Disorders in  Hematology: Basic Principles and Practice . Second edition. 1995). Although multiple myeloma cells are initially responsive to radiotherapy and chemotherapy, durable complete responses are rare and virtually all patients who respond initially ultimately relapse and die from the disease. To date, conventional treatment approaches have not resulted in long-term disease-free survival, which highlights the importance of developing new drug treatment for this incurable disease (NCCN Proceedings. Oncology. November 1998). 
     In various aspects of the invention, the treatment procedures are performed sequentially in any order, simultaneously, or a combination thereof. For example, the first treatment procedure, e.g., administration of an HDAC inhibitor, can take place prior to the second treatment procedure, e.g., the anti-cancer agent, after the second treatment with the anticancer agent, at the same time as the second treatment with the anticancer agent, or a combination thereof. 
     In one aspect of the invention, a total treatment period can be decided for the HDAC inhibitor. The anti-cancer agent can be administered prior to onset of treatment with the HDAC inhibitor or following treatment with the HDAC inhibitor. In addition, the anti-cancer agent can be administered during the period of HDAC inhibitor administration but does not need to occur over the entire HDAC inhibitor treatment period. Similarly, the HDAC inhibitor can be administered prior to onset of treatment with the anti-cancer agent or following treatment with the anti-cancer agent. In addition, the HDAC inhibitor can be administered during the period of anti-cancer agent administration but does not need to occur over the entire anti-cancer agent treatment period. Alternatively, the treatment regimen includes pre-treatment with one agent, either the HDAC inhibitor or the anti-cancer agent, followed by the addition of the other agent(s) for the duration of the treatment period. 
     In a particular embodiment, the combination of the HDAC inhibitor and anti-cancer agent is additive, i.e., the combination treatment regimen produces a result that is the additive effect of each constituent when it is administered alone. In accordance with this embodiment, the amount of HDAC inhibitor and the amount of the anti-cancer together constitute an effective amount to treat cancer. 
     In another embodiment, the combination of the HDAC inhibitor and anti-cancer agent is considered therapeutically synergistic when the combination treatment regimen produces a significantly better anticancer result (e.g., cell growth arrest, apoptosis, induction of differentiation, cell death) than the additive effects of each constituent when it is administered alone at a therapeutic dose. Standard statistical analysis can be employed to determine when the results are significantly better. For example, a Mann-Whitney Test or some other generally accepted statistical analysis can be employed. 
     The combination therapy can act through the induction of cancer cell differentiation, cell growth arrest, and/or apoptosis. The combination of therapy is particularly advantageous, since the dosage of each agent in a combination therapy can be reduced as compared to monotherapy with the agent, while still achieving an overall anti-tumor effect. 
     In one embodiment of the present invention, the HDAC inhibitor can be administered in combination with an antimetabolic agent. Specifically, in one embodiment, SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 100 mg and Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.0 mg/m 2 . 
     In another embodiment the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 100 mg and Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.3 mg/m 2 . 
     In yet another embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 200 mg and Bortezomib or a pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.3 mg/m 2 . 
     In another specific embodiment, SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 300 mg and Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.3 mg/m 2 . 
     In yet another specific embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered twice daily at a dose of 400 mg and Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.3 mg/m 2 . 
     In another specific embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered once daily at a dose of 400 mg and Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.3 mg/m 2 . 
     In another specific embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered once daily at a dose of 500 mg and Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.3 mg/m 2 . 
     In another specific embodiment, the SAHA or pharmaceutically acceptable salt or hydrate thereof is administered once daily at a dose of 600 mg and Bortezomib or pharmaceutically acceptable salt or hydrate thereof is administered at a total daily dose of 1.3 mg/m 2 . 
     In yet another embodiment, SAHA is orally administered once daily at 400 mg per day for at least one treatment cycle on days 4-11 of a 21 day cycle, and Bortezomib is intravenously administered at 1.3 mg/m 2  per day for at least one treatment cycle on days 1, 4, 8 and 11 of a 21 day cycle. 
     Pharmaceutical Compositions 
     As described above, the compositions comprising the HDAC inhibitor and/or the anti-cancer agent can be formulated in any dosage form suitable for oral, parenteral, intraperitoneal, intravenous, intraarterial, transdermal, sublingual, intramuscular, rectal, transbuccal, intranasal, liposomal, via inhalation, vaginal, or intraocular administration, for administration via local delivery by catheter or stent, or for subcutaneous, intraadiposal, intraarticular, intrathecal administration, or for administration in a slow release dosage form. 
     The HDAC inhibitor and the anti-cancer agent can be formulated in the same formulation for simultaneous administration, or they can be in two separate dosage forms, which may be administered simultaneously or sequentially as described above. 
     The invention also encompasses pharmaceutical compositions comprising pharmaceutically acceptable salts of the HDAC inhibitors and/or the anti-cancer agents. 
     Suitable pharmaceutically acceptable salts of the compounds described herein and suitable for use in the method of the invention, are conventional non-toxic salts and can include a salt with a base or an acid addition salt such as a salt with an inorganic base, for example, an alkali metal salt (e.g., lithium salt, sodium salt, potassium salt, etc.), an alkaline earth metal salt (e.g., calcium salt, magnesium salt, etc.), an ammonium salt; a salt with an organic base, for example, an organic amine salt (e.g., triethylamine salt, pyridine salt, picoline salt, ethanolamine salt, triethanolamine salt, dicyclohexylamine salt, N,N&#39;-dibenzylethylenediamine salt, etc.) etc.; an inorganic acid addition salt (e.g., hydrochloride, hydrobromide, sulfate, phosphate, etc.); an organic carboxylic or sulfonic acid addition salt (e.g., formate, acetate, trifluoroacetate, maleate, tartrate, methanesulfonate, benzenesulfonate, p-toluenesulfonate, etc.); a salt with a basic or acidic amino acid (e.g., arginine, aspartic acid, glutamic acid, etc.) and the like. 
     The invention also encompasses pharmaceutical compositions comprising hydrates of the HDAC inhibitors and/or the anti-cancer agents. 
     In addition, this invention also encompasses pharmaceutical compositions comprising any solid or liquid physical form of SAHA or any of the other HDAC inhibitors. For example, The HDAC inhibitors can be in a crystalline form, in amorphous form, and have any particle size. The HDAC inhibitor particles may be micronized, or may be agglomerated, particulate granules, powders, oils, oily suspensions or any other form of solid or liquid physical form. 
     For oral administration, the pharmaceutical compositions can be liquid or solid. Suitable solid oral formulations include tablets, capsules, pills, granules, pellets, and the like. Suitable liquid oral formulations include solutions, suspensions, dispersions, emulsions, oils, and the like. 
     Any inert excipient that is commonly used as a carrier or diluent may be used in the formulations of the present invention, such as for example, a gum, a starch, a sugar, a cellulosic material, an acrylate, or mixtures thereof. The compositions may further comprise a disintegrating agent and a lubricant, and in addition may comprise one or more additives selected from a binder, a buffer, a protease inhibitor, a surfactant, a solubilizing agent, a plasticizer, an emulsifier, a stabilizing agent, a viscosity increasing agent, a sweetener, a film forming agent, or any combination thereof. Furthermore, the compositions of the present invention may be in the form of controlled release or immediate release formulations. 
     The HDAC inhibitors can be administered as active ingredients in admixture with suitable pharmaceutical diluents, excipients or carriers (collectively referred to herein as “carrier” materials or “pharmaceutically acceptable carriers”) suitably selected with respect to the intended form of administration. As used herein, “pharmaceutically acceptable carrier” is intended to include any and all solvents, dispersion media, coatings, antibacterial and antifungal agents, isotonic and absorption delaying agents, and the like, compatible with pharmaceutical administration. Suitable carriers are described in the most recent edition of Remington&#39;s Pharmaceutical Sciences, a standard reference text in the field, which is incorporated herein by reference. 
     For liquid formulations, pharmaceutically acceptable carriers may be aqueous or non-aqueous solutions, suspensions, emulsions or oils. Examples of non-aqueous solvents are propylene glycol, polyethylene glycol, and injectable organic esters such as ethyl oleate. Aqueous carriers include water, alcoholic/aqueous solutions, emulsions, or suspensions, including saline and buffered media. Examples of oils are those of petroleum, animal, vegetable, or synthetic origin, for example, peanut oil, soybean oil, mineral oil, olive oil, sunflower oil, and fish-liver oil. Solutions or suspensions can also include the following components: a sterile diluent such as water for injection, saline solution, fixed oils, polyethylene glycols, glycerine, propylene glycol or other synthetic solvents; antibacterial agents such as benzyl alcohol or methyl parabens; antioxidants such as ascorbic acid or sodium bisulfite; chelating agents such as ethylenediaminetetraacetic acid (EDTA); buffers such as acetates, citrates or phosphates, and agents for the adjustment of tonicity such as sodium chloride or dextrose. The pH can be adjusted with acids or bases, such as hydrochloric acid or sodium hydroxide. 
     Liposomes and non-aqueous vehicles such as fixed oils may also be used. The use of such media and agents for pharmaceutically active substances is well known in the art. Except insofar as any conventional media or agent is incompatible with the active compound, use thereof in the compositions is contemplated. Supplementary active compounds can also be incorporated into the compositions. 
     Solid carriers/diluents include, but are not limited to, a gum, a starch (e.g., corn starch, pregelatinized starch), a sugar (e.g., lactose, mannitol, sucrose, dextrose), a cellulosic material (e.g., microcrystalline cellulose), an acrylate (e.g., polymethylacrylate), calcium carbonate, magnesium oxide, talc, or mixtures thereof. 
     In addition, the compositions may further comprise binders (e.g., acacia, cornstarch, gelatin, carbomer, ethyl cellulose, guar gum, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, povidone), disintegrating agents (e.g., cornstarch, potato starch, alginic acid, silicon dioxide, croscarmellose sodium, crospovidone, guar gum, sodium starch glycolate, Primogel), buffers (e.g., tris-HCl, acetate, phosphate) of various pH and ionic strength, additives such as albumin or gelatin to prevent absorption to surfaces, detergents (e.g., Tween 20, Tween 80, Pluronic F68, bile acid salts), protease inhibitors, surfactants (e.g., sodium lauryl sulfate), permeation enhancers, solubilizing agents (e.g., glycerol, polyethylene glycerol), a glidant (e.g., colloidal silicon dioxide), anti-oxidants (e.g., ascorbic acid, sodium metabisulfite, butylated hydroxyanisole), stabilizers (e.g., hydroxypropyl cellulose, hyroxypropylmethyl cellulose), viscosity increasing agents (e.g., carbomer, colloidal silicon dioxide, ethyl cellulose, guar gum), sweeteners (e.g., sucrose, aspartame, citric acid), flavoring agents (e.g., peppermint, methyl salicylate, or orange flavoring), preservatives (e.g., Thimerosal, benzyl alcohol, parabens), lubricants (e.g., stearic acid, magnesium stearate, polyethylene glycol, sodium lauryl sulfate), flow-aids (e.g., colloidal silicon dioxide), plasticizers (e.g., diethyl phthalate, triethyl citrate), emulsifiers (e.g., carbomer, hydroxypropyl cellulose, sodium lauryl sulfate), polymer coatings (e.g., poloxamers or poloxamines), coating and film forming agents (e.g., ethyl cellulose, acrylates, polymethacrylates) and/or adjuvants. 
     In one embodiment, the active compounds are prepared with carriers that will protect the compound against rapid elimination from the body, such as a controlled release formulation, including implants and microencapsulated delivery systems. Biodegradable, biocompatible polymers can be used, such as ethylene vinyl acetate, polyanhydrides, polyglycolic acid, collagen, polyorthoesters, and polylactic acid. Methods for preparation of such formulations will be apparent to those skilled in the art. The materials can also be obtained commercially from Alza Corporation and Nova Pharmaceuticals, Inc. Liposomal suspensions (including liposomes targeted to infected cells with monoclonal antibodies to viral antigens) can also be used as pharmaceutically acceptable carriers. These can be prepared according to methods known to those skilled in the art, for example, as described in U.S. Pat. No. 4,522,811. 
     It is especially advantageous to formulate oral compositions in dosage unit form for ease of administration and uniformity of dosage. Dosage unit form as used herein refers to physically discrete units suited as unitary dosages for the subject to be treated; each unit containing a predetermined quantity of active compound calculated to produce the desired therapeutic effect in association with the required pharmaceutical carrier. The specification for the dosage unit forms of the invention are dictated by and directly dependent on the unique characteristics of the active compound and the particular therapeutic effect to be achieved, and the limitations inherent in the art of compounding such an active compound for the treatment of individuals. 
     The pharmaceutical compositions can be included in a container, pack, or dispenser together with instructions for administration. 
     The preparation of pharmaceutical compositions that contain an active component is well understood in the art, for example, by mixing, granulating, or tablet-forming processes. The active therapeutic ingredient is often mixed with excipients that are pharmaceutically acceptable and compatible with the active ingredient. For oral administration, the active agents are mixed with additives customary for this purpose, such as vehicles, stabilizers, or inert diluents, and converted by customary methods into suitable forms for administration, such as tablets, coated tablets, hard or soft gelatin capsules, aqueous, alcoholic, or oily solutions and the like as detailed above. 
     The amount of the compound administered to the patient is less than an amount that would cause toxicity in the patient. In the certain embodiments, the amount of the compound that is administered to the patient is less than the amount that causes a concentration of the compound in the patient&#39;s plasma to equal or exceed the toxic level of the compound. In particular embodiments, the concentration of the compound in the patient&#39;s plasma is maintained at about 10 nM. In another embodiment, the concentration of the compound in the patient&#39;s plasma is maintained at about 25 nM. In another embodiment, the concentration of the compound in the patient&#39;s plasma is maintained at about 50 nM. In another embodiment, the concentration of the compound in the patient&#39;s plasma is maintained at about 100 nM. In another embodiment, the concentration of the compound in the patient&#39;s plasma is maintained at about 500 nM. In another embodiment, the concentration of the compound in the patient&#39;s plasma is maintained at about 1,000 nM. In another embodiment, the concentration of the compound in the patient&#39;s plasma is maintained at about 2,500 nM. In another embodiment, the concentration of the compound in the patient&#39;s plasma is maintained at about 5,000 nM. The optimal amount of the compound that should be administered to the patient in the practice of the present invention will depend on the particular compound used and the type of cancer being treated. 
     The percentage of the active ingredient and various excipients in the formulations may vary. For example, the composition may comprise between 20 and 90%, or specifically between 50-70% by weight of the active agent. 
     For IV administration, Glucuronic acid, L-lactic acid, acetic acid, citric acid or any pharmaceutically acceptable acid/conjugate base with reasonable buffering capacity in the pH range acceptable for intravenous administration can be used as buffers. Sodium chloride solution wherein the pH has been adjusted to the desired range with either acid or base, for example, hydrochloric acid or sodium hydroxide, can also be employed. Typically, a pH range for the intravenous formulation can be in the range of from about 5 to about 12. A particular pH range for intravenous formulation comprising an HDAC inhibitor, wherein the HDAC inhibitor has a hydroxamic acid moiety, can be about 9 to about 12. 
     Subcutaneous formulations can be prepared according to procedures well known in the art at a pH in the range between about 5 and about 12, which include suitable buffers and isotonicity agents. They can be formulated to deliver a daily dose of the active agent in one or more daily subcutaneous administrations. The choice of appropriate buffer and pH of a formulation, depending on solubility of the HDAC inhibitor to be administered, is readily made by a person having ordinary skill in the art. Sodium chloride solution wherein the pH has been adjusted to the desired range with either acid or base, for example, hydrochloric acid or sodium hydroxide, can also be employed in the subcutaneous formulation. Typically, a pH range for the subcutaneous formulation can be in the range of from about 5 to about 12. A particular pH range for subcutaneous formulation of an HDAC inhibitor a hydroxamic acid moiety can be about 9 to about 12. 
     The compositions of the present invention can also be administered in intranasal form via topical use of suitable intranasal vehicles, or via transdermal routes, using those forms of transdermal skin patches well known to those of ordinary skill in that art. To be administered in the form of a transdermal delivery system, the dosage administration will, or course, be continuous rather than intermittent throughout the dosage regime. 
     The present invention also provides in-vitro methods for selectively inducing terminal differentiation, cell growth arrest and/or apoptosis of neoplastic cells, thereby inhibiting proliferation of such cells, by contacting the cells with a first amount of suberoylanilide hydroxamic acid (SAHA) or a pharmaceutically acceptable salt or hydrate thereof, and a second amount of an anti-cancer agent, wherein the first and second amounts together comprise an amount effective to induce terminal differentiation, cell growth arrest of apoptosis of the cells. 
     Although the methods of the present invention can be practiced in vitro, it is contemplated that a particular embodiment for the methods of selectively inducing terminal differentiation, cell growth arrest and/or apoptosis of neoplastic cells will comprise contacting the cells in vivo, i.e., by administering the compounds to a subject harboring neoplastic cells or tumor cells in need of treatment. 
     As such, the present invention also provides methods for selectively inducing terminal differentiation, cell growth arrest and/or apoptosis of neoplastic cells, thereby inhibiting proliferation of such cells in a subject by administering to the subject a first amount of suberoylanilide hydroxamic acid (SAHA) or a pharmaceutically acceptable salt or hydrate thereof, in a first treatment procedure, and a second amount of an anti-cancer agent in a second treatment procedure, wherein the first and second amounts together comprise an amount effective to induce terminal differentiation, cell growth arrest of apoptosis of the cells. 
     The invention is illustrated in the examples that follow. This section is set forth to aid in an understanding of the invention but is not intended to, and should not be construed to limit in any way the invention as set forth in the claims which follow thereafter. 
     EXAMPLES 
     The examples are presented in order to more fully illustrate the various embodiments of the invention. These examples should in no way be construed as limiting the scope of the invention recited in the appended claims. 
     Example 1 
     Phase I Clinical Trial of Oral SAHA in Combination with Bortezonub in Patients with Relapsed and Refractory Multiple Myeloma 
     The aim of the study was to determine the maximum tolerated dose (MTD), pharmacokinetic and pharmacodynamic profiles for the combination of oral. Vorinostat plus Bortezomib in patients with advanced multiple myeloma. Further, the dexamethasone was added to the combination of Vorinostat and Bortezomib in: 
     a) patients with less than a partial remission 
     b) patients with stable disease 
     c) patients with progression of disease only if there is no significant end organ damage defined as worsening anemia, worsening renal failure, signs and symptoms of hyperviscosity syndrome. 
     Furthermore, the study was used to assess the safety and tolerability of the combination regimen of Vorinostat and Bortezomib, to estimate response rate, time to response, and response and duration and time to progression for Vorinostat and Bortezomib when used in combination. 
     This was a multicenter, open label, escalating dose, Phase I study of Vorinostat in combination with intravenous Bortezomib injection in patients eligible for Bortezomib therapy. In this non-randomized trial, patients were treated with Vorinostat on days 4-11 for a 21-day treatment cycle for up to 8 cycles. Patients on Dose Levels 1-5 were administered Bortezomib as an intravenous (IV) bolus on Days 1, 4, 8 and 11. Patients who completed at least 2 cycles of treatment with Vorinostat in combination with Bortezomib and then experienced progressive disease were treated with dexamethasone 20 mg p.o. daily on Days 4-8 of each cycle along with Vorinostat and Bortezomib as scheduled. 
     At the beginning of the study, five 3-patient cohorts were evaluated at various dose levels as outlined in the Table 1 and Table 2 below. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Dose Escalation Schedule 1 
               
            
           
           
               
               
               
            
               
                   
                 Dose* 
                   
               
            
           
           
               
               
               
               
            
               
                   
                   
                 SAHA (mg) 
                 Bortezomib 
               
               
                   
                 Dose Level 
                 Days 4-11 
                 (mg/m2) days 1, 4, 8, 11 
               
               
                   
                   
               
               
                   
                 Level 1 
                 100 mg BID 
                 1.0 
               
               
                   
                 Level 1 
                 100 mg BID 
                 1.3 
               
               
                   
                 Level 2 
                 200 mg BID 
                 1.3 
               
               
                   
                 Level 3 
                 300 mg BID 
                 1.3 
               
               
                   
                 Level 4 
                 400 mg BID 
                 1.3 
               
               
                   
                 Level 5 
                 600 mg once daily 
                 1.3 
               
               
                   
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Dose Escalation Schedule 2 
               
            
           
           
               
               
               
            
               
                   
                 Dose* 
                   
               
            
           
           
               
               
               
               
            
               
                   
                   
                 SAHA (mg) 
                 Bortezomib 
               
               
                   
                 Dose Level 
                 Days 4-11 
                 (mg/m2) days 1, 4, 8, 11 
               
               
                   
                   
               
               
                   
                 Level 1 
                 100 mg BID 
                 1.0 
               
               
                   
                 Level 1 
                 100 mg BID 
                 1.3 
               
               
                   
                 Level 2 
                 200 mg BID 
                 1.3 
               
               
                   
                 Level 3 
                 400 mg once daily 
                 1.3 
               
               
                   
                 Level 4 
                 500 mg once daily 
                 1.3 
               
               
                   
                 Level 5 
                 600 mg once daily 
                 1.3 
               
               
                   
                   
               
            
           
         
       
     
     The median patients age was fifty five years (range 38-79). Median time from Multiple Myeloma diagnosis to study entry was 5.3 years (range: 1.5-15 years). Multiple myeloma isotype included IgG (n=10), IgA (n=5), light chain (n=4), and nonsecretory (n=2). 
     In the absence of treatment delays due to adverse events, treatment continued for 8-cycles or until one of the following criteria applied:
         a) disease progression   b) intercurrent illness that prevents further administration of treatment   c) unacceptable adverse events   d) patient decides to withdraw from the study   e) general or specific changes in the patient&#39;s condition render the patient unacceptable for further treatment in the judgment of the investigator.   f) if the patient achieves a complete remission, they continue on the study for a total of 8 cycles.       

     Further studies enrolled up to 40 adult patients with multiple myeloma, relapsed or refractory disease. One treatment cycle was 3 weeks or 21 days. The Vorinostat capsules were given orally (p.o.) b.i.d. on days 4-11 and Bortezomib injections were administered as an intravenous (IV) bolus twice weekly for two weeks in each cycle. On days where Vorinostat and Bortezomib were administered concurrently, the Vorinostat dose was given prior to the Bortezomib administration. Although the current FDA approved Bortezomib dose for relapsed myeloma patients to be 1.0 mg/m 2 , if toxicity occurred, the subsequent dose of Bortezomib was going to be decreased to 0.7 mg/m 2 . If the combination therapy was found to be safe, then dose escalation would proceed. Other Bortezomib dose to be tested was 1.3 mg/m 2 . 
     At study entry, 12 patients had a complex karyotype; 19 patients had PD on the last prior therapy with a median of 20 days (15-39) between last therapy and study entry. Only 2 patients were in first relapse on thalidomide maintenance. The MTD was defined for cycle 1 in 2 patients with Vorinostat 500 mg daily as grade 4 prolonged QT interval and grade 4 fatigue. After cycle 2, several grade 3-4 toxicities were observed that include myelo-suppression and thrombocytopenia requiring transfusional support and growth factors. Also, non-hematological toxicities grade 2 and higher included fatigue (n=5), diarrhea (n=3), atrial fibrillation (n=1), shingles (n=1) and pneumonia (n=2, bacterial and RSV) were observed. In fifteen patients evaluated for response, there was 1 nCR and 5 PR (overall response of 40%). Further, six patients had stable disease and three patients had PD. The dexamethasone was administered to the patients in the study with no upgrade in response. 
     The pharmacokinetics of Vorinostat after a single oral dose were linear from 100-500 mg with mean AUC (0.7±0.45-4.4±0.07), Cmax (0.3±0.14-1.2±0.06) and Tmax (1.3±0.4-2.3±2.5). In the study, ten patients had CD-138+ myeloma cells isolated from bone marrow before study entry (median of 1.8×10 6 , range: 0.2-42.6) and on day 11 of the first cycle [median 0.9×10 6 , range: 0.4-5.4]; pharmacodynamic data was presented. As summarized in the Table 3 below, the MTD for Vorinostat plus Bortezomib was 400 mg daily×8 days plus 1.3 mg/m 2  days 1, 4, 8 and 11. The study found that Vorinostat administration after Bortezomib did not affect pharmacokinetics. In view of the promising results, the regimen is planned to be evaluated in a phase II trial. 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 3 
               
               
                   
               
               
                   
                 Bort 
                 Vorinostat 
                 No of 
                   
                   
               
               
                 Cohort 
                 (mg/m 2 ) 
                 (mg) 
                 pts 
                 No of cycles 
                 Best response 5 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 1 
                 1 
                 100 bid 
                 3 
                 5, 7, 5 
                 SD, SD, SD 
               
               
                 2 
                 1.3 
                 100 bid 
                 3 
                 5, 6, 3 
                 SD, PR, PD 
               
               
                 3 
                 1.3 
                 200 bid 
                 3 
                 8, 3, 8 
                 nCR, SD, PR 
               
               
                 4 
                 1.3 
                 400 daily 
                 3 
                 5, 3, 3 
                 SD, PD, PR 
               
               
                 5 
                 1.3 
                 500 daily 
                 3 
                 7, 1, 1 
                 PR, NE, NE 
               
               
                   
                   
                   
                   
                   
                 “MTD with the 
               
               
                   
                   
                   
                   
                   
                 first cycle” 
               
               
                 MTD 
                 1.3 
                 400 daily 
                  6* 
                 4, 3, “2, 2, 1, 
                 PD, PR, “early 
               
               
                   
                   
                   
                   
                 1” 
                 for response 
               
               
                   
                   
                   
                   
                   
                 evaluation” 
               
               
                   
               
               
                 Bortezomib was given on days d 1, 4, 8, and 11 of 21 day cycle plus Vorinostat on days 4-11. 
               
               
                 Patients received up to 8 cycles. Dexamethasone was added at cycle 2 for nonresponders. 
               
               
                 *Six patients are treated at MTD to better define toxicity and response. 
               
            
           
         
       
     
     While this invention has been particularly shown and described with references to particular embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the meaning of the invention described. The scope of the invention encompasses the claims that follow.