WO2006036956A2 - Therapeutic regimen for treating cancer using quassinoids and other chemotherapeutic agents - Google Patents

Abstract

The invention provides a method for treating cancer in a mammal comprising administering a dose of a first pharmaceutical composition comprising a pharmaceutically acceptable carrier and an effective amount of a chemotherapeutic other than a quassinoid, at least once in a therapeutic period comprising up to about 10 weeks, and a dose of a second pharmaceutical composition comprising a pharmaceutically acceptable carrier and an effective amount of a quassinoid. The invention also provides a composition and a kit comprising a dose of a chemotherapeutic other than a quassinoid and a dose of a quassinoid.

Description

THERAPEUTIC REGIMEN FOR TREATING CANCER USING QUASSINOIDS AND OTHER CHEMOTHERAPEUTIC AGENTS

[0001] This application claims priority to U.S. patent application no. 60/613,353, filed September 27, 2004, which is hereby incorporated by reference.

FIELD OF THE INVENTION

[0002] This invention pertains to a method for treating cancer in a mammal and related compositions.

BACKGROUND OF THE INVENTION

[0003] The primary goal of cancer research is the identification of therapeutics effective against one or more types of cancers. Yet, despite extensive research into the mechanisms underlying cancer development and progression, identifying such therapeutics remain elusive.

[0004] For many cancer types, standard therapy involves the administration of one or more chemotherapeutic agents to the patient. The diterpenoid molecules paclitaxel (Taxol^®), extracted in 1971 from the western yew tree, Taxus brevifolia, and docetaxel (Taxotere^®) currently are in clinical use for the treatment of breast cancer, ovarian cancer, non-small cell lung carcinoma, and Kaposi's sarcoma. At the molecular level, paclitaxel exerts its antitumor activity through the stabilization of microtubule assemblies thus interrupting mitosis and the cell division process. The taxol- induced stabilized microtubules have been shown to be resistant to depolymerization. Paclitaxel also has been shown to induce cancer cell apoptosis and radiosensitivity (see, e.g., O'Donnell et al., Cancer Biother. Radiopharm. , 13, 351-361 (1998), and Distefano et al., Int. J. Cancer, 72, 844-850 (1997)).

[0005] Quassinoids are a family of bitter terpenoid substances isolated from the bark of trees within the family Simaroubaceae. Quassinoids have been found to exhibit diverse biologic activity, including anti-neoplastic activity (see, e.g., U.S. Patent Nos. 5,639,712, 5,965,493, and 6,573,296). In this respect, recent research had demonstrated that quassinoids induce apoptosis (cell death) in lymphoma, myeloma, and leukemic cancer cells (see, for example, Kupchan et al., /. Med. Chem., 19(9): 1130-1133 (1976), Cassady et al. (Eds. ) Anticancer Agents Based on Natural Product Models, Academic Press, New York (1980), and Cuendet et al., Clinical Cancer Research, 10, 1170-1179 (2004)). Possible mechanisms by which quassinoids exert their apoptotic effects include, for example, C- MYC downregulation, caspase activation, BID and PARP cleavage, and mitochondrial membrane depolarization (see, e.g., Cuendet et al., supra). [0006] Despite the efficacy with which chemotherapeutic agents kill tumor cells, many chemotherapeutic agents cause extensive damage to normal, healthy tissue, thereby inducing severe side effects in patients. In addition, cancer cells often acquire resistance to chemotherapeutic drugs, primarily through activation of the multi-drug resistance (MDR) mechanism within the cancer cells.

[0007] Accordingly, there remains a need for more effective methods for treating cancer in humans. In particular, there remains a need for a method that optimizes the local effects of chemotherapeutic agents, while minimizing toxicity to healthy tissue. The invention provides such a method. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.

BRIEF SUMMARY OF THE INVENTION

[0008] The invention provides a method for treating cancer in a mammal. The method comprises (a) administering to the mammal a dose of a first pharmaceutical composition comprising a pharmaceutically acceptable carrier and an effective amount of a chemotherapeutic other than a quassinoid, at least once in a therapeutic period comprising up to about 10 weeks, and (b) administering to the mammal a dose of a second pharmaceutical composition comprising a pharmaceutically acceptable carrier and an effective amount of a quassinoid or a derivative thereof, at least once in the therapeutic period.

[0009] The invention also provides a composition comprising a dose of a chemotherapeutic other than a quassinoid, a dose of the aforementioned quassinoid, and a pharmaceutically acceptable carrier. Further provided is a kit comprising a first pharmaceutical composition comprising a pharmaceutically acceptable carrier and the aforementioned chemotherapeutic, and a second pharmaceutical composition comprising a pharmaceutically acceptable carrier and a quassinoid.

BRIEF DESCRIPTION OF THE DRAWINGS

[Oθiθ] Figure 1 is a graph illustrating the average tumor volume over time in HCT-116 colon cancer xenografts treated with 0.05 mg/ml (data denoted with "■") or 0.025 mg/ml (data denoted with "A") of the quassinoid TPI-273 once a day for 5 days. The control data are denoted with "♦."

DETAILED DESCRIPTION OF THE INVENTION

[0011] This invention is predicated, at least in part, on the discovery that the combination of a chemotherapeutic agent (other than a quassinoid compound) and a quassinoid, when administered to a human tumor, inhibits tumor growth while limiting toxicity to normal cells. Various aspects of the inventive method are discussed below. Although each parameter is discussed separately, the inventive method comprises combinations of the parameters set forth below to treat a mammal (e.g., a human) for cancer. Accordingly, any combination of parameters can be used according to the inventive method.

[0012] The inventive method comprises administering to a mammal a dose of a first pharmaceutical composition comprising an effective amount of a chemotherapeutic. In the context of the invention, the term "chemotherapeutic" refers to any chemotherapeutic known in the art other than a quassinoid compound as described herein. In this respect, any suitable chemotherapeutic can be used in the inventive method. Suitable chemotherapeutics include, but are not limited to, adriamycin, asparaginase, bleomycin, busulphan, cisplatin, carboplatin, carmustine, capecitabine, chlorambucil, cytarabine, cyclophosphamide, camptothecin, dacarbazine, dactinomycin, daunorubicin, dexrazoxane, docetaxel, doxorubicin, epothilones (e.g., epothilone B), etoposide, floxuridine, fludarabine, fluorouracil, gemcitabine, hydroxyurea, idarubicin, ifosfamide, irinotecan, lomustine, mechlorethamine, mercaptopurine, meplhalan, methotrexate, mitomycin, mitotane, mitoxantrone, nitrosurea, paclitaxel, pamidronate, pentostatin, plicamycin, procarbazine, rituximab, streptozocin, teniposide, thioguanine, thiotepa, vinblastine, vincristine, vinorelbine, transplatinum, anti- vascular endothelial growth factor compounds ("anti- VEGFs"), anti-epidermal growth factor receptor compounds ("anti-EGFRs"), 5- fluorouracil, and the like. In one embodiment of the invention, the chemotherapeutic is a mitotic inhibitor. Mitotic inhibitors are known in the art and include, for example, paclitaxel, docetaxel, etoposide (VP16), teniposide, vinblastine, vincristine, and vinorelbine. In one embodiment of the invention, the chemotherapeutic is a taxane. Any suitable taxane can be used in the context of the inventive method. Suitable taxanes include paclitaxel (e.g., Taxol^®, Bristol-Myers Squibb) and the semi-synthetic paclitaxel analog docetaxel (e.g., Taxotere^®, Aventis). Suitable chemotherapeutics are further described in, for example, Bast et al. (eds.), Cancer Medicine, 5^th edition, BC. Decker Inc., Hamilton, Ontario (2000), and U.S. Patent Application Publication No. 2003/0082685 Al. [0013] A dose of one or more chemotherapeutics can be administered according to the inventive method. The type and number of chemotherapeutics used in the inventive method will depend on the standard chemotherapeutic regimen for a particular tumor type. In other words, while a particular cancer may be routinely treated with a single chemotherapeutic agent, another may be routinely treated with a combination of chemotherapeutic agents. Any suitable dose of the chemotherapeutic can be administered to the mammal. Suitable doses of the chemotherapeutics described above are known in the art, and are described in, for example, Bast et al., supra, and U.S. Patent Application Publication No. 2003/0082685 Al.

[0014] When chemotherapy is administered over a period of time with treatment-free intervals, then the patient can recuperate from its effects, and the effects of the therapy can be realized. For example, chemotherapy can be administered on 5 consecutive days, and not administered on 2 days, for each week of treatment, thereby allowing 2 days of rest per week. However, chemotherapy can be administered 1 day/week, 2 days/week, 3 days/week, 4 days/week, 5 days/week, 6 days/week, or all 7 days/week, depending on the response of the patient to therapy and any potential side effects. [0015] The inventive method further comprises administering a dose of a second pharmaceutical composition comprising an effective amount of a quassinoid. The majority of quassinoids, which are sometimes referred to as simaroubolides, are heavily oxygenated lactones that include the following carbon skeleton called "type I":

(D

Quassinoids of type I are conventionally termed picrasane and can be further divided into Groups A, B, and C (Cassady et al. (Eds. ) Anticancer Agents Based on Natural Product Models, Academic Press, New York (1980)). In one embodiment, the present invention includes the use of a quassinoid comprising a core structure of type I (i.e., formula (I)), and in particular, a quassinoid comprising a core structure of Group A or B.

Group A Group B [0016] Many variant ring structures and sidechains, particularly at the C-15 position, are known for quassinoid compounds comprising the core structure of formula (I) and Groups A and B (see e.g., Polonsky, "Quassinoid Bitter Principles II", Fortschr.Chem.Org Naturst, Progress in the Chemistry of Organic Natural Products, 47, 221 (1985)). Any suitable quassinoid compound can be used in the inventive method. The quassinoid can be naturally isolated or synthetically derived. Suitable quassinoids include, for example, chaparrinone, peninsularinone, bruceantin, bruceolide, brusatol, bruceantinol, glaucarubinone, glaucorubolone, ailanthinone, and derivatives thereof (e.g., holocanthone, castelanone, glaucarubolone-15-esters (e.g., glaucarubolone-15-octanoate, glaucarubolone- 15-benzoate), and glaucarubolone-15-tiglate). Quassinoid compounds and derivatives thereof suitable for use in the inventive method are further described in, for example, U.S. Patent Nos. 5,639,712, 5,849,748, 5,965,493, 6,573,296, U.S. Patent Application Publication No. 2003/0158088 Al, Cassady et al., supra, Kupchan et al. (J. Med. Chem., 19(9): 1130-1133 (1976), and Bhatnagar et al. (Tetrahedron, 43(15): 3471-3480 (1987)). [0017] In an embodiment of the invention, the quassinoid is glaucorubolone or a derivative thereof. In this respect, an exemplary quassinoid is represented by the formula (II):

(H) wherein Y can be hydrogen, alkyl, hydroxyalkyl, carboxyl, substituted aryl, alkenyl, cycloalkyl, cycloalkenyl, a glycosaccharide, a water soluble side chain, amino acid, a peptide, a polypeptide, or a protein.

[0018] In another embodiment, Y is hydrogen, alkyl having from 2 to 3 carbons, alkyl having more than 4 carbons, hydroxyalkyl having less than 4 carbons, hydroxyalkyl having more than 4 carbons, carboxyl (excluding glaucarubinone-2'-acetate), substituted aryl, alkenyl having less than 4 carbons, alkenyl having greater than 4 carbons, cycloalkyl, cycloalkenyl, a glycosaccharide, a water soluble side chain, amino acid, a peptide, a polypeptide, or a protein. In one embodiment of the invention, Y is represented by the formula (III)

(IH) wherein R₁, R₂, and R₃ taken separately or together represent hydrogen, alkyl, hydroxyl, hydroxyalkyl, carboxyl, aryl, alkenyl, cycloalkyl, cycloalkenyl, glycinyl, a glycosaccharide, a water soluble side chain, amino acid, a peptide, a polypeptide, a protein, or any of the foregoing attached to the central carbon by an ether, ester, carbonyl, or glycosidic linkage. It will be understood by one of ordinary skill in the art that the carbon alpha to the parent quassinoid structure has four valencies such that two hydrogens are bonded thereto. In some embodiments, however, the hydrogens can be substituted with other substituents of any suitable moiety (e.g., alkyl, hydroxyl, halo, cycloalkyl, aryl). [0019] In a particular embodiment of the invention, the quassinoid compound has a structure of formula (II) in which Y is a compound of formula (III), wherein R₁ is a hydroxyl group, R₂ is an isopropyl group, and R₃ is an isopropyl group. This exemplary quassinoid has the structure

and also is referred to as TPI-273.

[0020] In another embodiment, the quassinoid is bruceantin or a derivative thereof. In this respect, an exemplary quassinoid is represented by the formula (IV)

(IV) wherein R₄, R₅, and R₆ are independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, carboxyl, carbonyl, hydroxyalkyl, alkoxyalkyl, -OR₉, and -NRioRπ, wherein R₇ and R₈ are independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, and arylalkyl, or wherein R₇ and R₈ taken together form C₃-C₁O alkylene or alkenylene, or wherein R₇ and R₈ taken together form (C=O), wherein R9 is selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, and -C(O)R₁₂, wherein Ri₂ is selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, -OR₁₃, and

wherein R₁₃ is selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, and arylalkyl, and wherein R₁O and R₁₁ are independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, and arylalkyl, or R_1O and R₁₁ can be taken together to form a 5-7 membered heterocyclic ring with the nitrogen to which they are bonded.

[0021] In one embodiment of the invention, the quassinoid of formula (IV) has R₄ and Rs are isopropyl and R₆ is hydroxyl or R₆ is -(CH₂)_nORg, wherein n is an integer of 1-10. In another embodiment of the invention, the compound of formula (IV) is one in which (a) R₄, R₅, and R₆ are not all hydrogen, (b) when R₆ is hydroxyl then R₄ and R₅ are not both methyl, (c) if R₄ is methyl then R₅ is not hydrogen and R₆ is not trifluoromethyl, or (d) when R₄ is isopropyl then R₅ is not hydrogen and R₆ is not methyl. [0022] In a particular embodiment of the invention, the compound of formula (IV) has the structure

[0023] The quassinoid can also be a bruceantin compound of the formula (V)

(V) wherein R₁₄, R₁₅, and R₁₆ are independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, carboxyl, carbonyl, hydroxyalkyl, alkoxyalkyl, and -OR₁₇, wherein R₁₇ is selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, and -C(O)R₁₈, wherein R₁₈ is selected from the group consisting of alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, -OR₁Ci, and -NR₂₀R₂₁, wherein R1₉ is selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, and arylalkyl, wherein R₂₀ and R₂₁ are independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, and arylalkyl, or R₂₀ and R₂₁ can be taken together to form a 5-7 membered heterocyclic ring with the nitrogen to which they are bonded.

[0024] In one embodiment of the invention, the compound of formula (V) has R₁₄, R₁₅, and R₁₆ are methyl or R₁₄ and R₁₅ are methyl and R₁₆ is hydroxyl or R₁₄ and R₁₅ are isopropyl and R₁₆ is hydroxyl. In another embodiment, R₁₆ is -(CH₂)_nORi₇, wherein n is an integer of 1-10. Also, in another embodiment, the compound of formula (V) is bruceantin. [0025] Referring now to terminology used generically herein, the term "alkyl" means a straight-chain or branched alkyl substituent containing from, for example, about 1 to about 12 carbon atoms, preferably from about 1 to about 8 carbon atoms, more preferably from about 1 to about 6 carbon atoms. Examples of such substituents include methyl, ethyl, propyl, isopropyl, /ϊ-butyl, sec-butyl, isobutyl, tert-butyl, pentyl, isoamyl, hexyl, octyl, dodecanyl, and the like. The term "hydroxyalkyl" means an alkyl group as described herein that is substituted with one or more hydroxyl (-OH) groups. [0026] The term "alkenyl," as used herein, means a linear alkenyl substituent containing at least one carbon-carbon double bond and from, for example, about 2 to about 12 carbon atoms (branched alkenyls are about 3 to about 12 carbons atoms), preferably from about 2 to about 8 carbon atoms (branched alkenyls are preferably from about 3 to about 8 carbon atoms), more preferably from about 3 to about 6 carbon atoms. Examples of such substituents include propenyl, isopropenyl, n-butenyl, sec-butenyl, isobutenyl, tert- butenyl, pentenyl, isopentenyl, hexenyl, octenyl, dodecenyl, and the like. [0027] The term "alkynyl," as used herein, means a linear alkynyl substituent containing at least one carbon-carbon triple bond and from, for example, about 2 to about 12 carbon atoms (branched alkynyls are about 3 to about 12 carbons atoms), preferably from about 2 to about 8 carbon atoms (branched alkynyls are preferably from about 3 to about 8 carbon atoms), more preferably from about 3 to about 6 carbon atoms. Examples of such substituents include propynyl, isopropynyl, ra-butynyl, sec-butynyl, isobutynyl, tert- butynyl, pentynyl, isopentynyl, hexynyl, octynyl, dodecynyl, and the like. [0028] The term "cycloalkyl," as used herein, means a cyclic alkyl substituent containing from, for example, about 3 to about 30 carbon atoms, preferably from about 5 to about 14 carbon atoms, more preferably from about 5 to about 10 carbon atoms, and most preferably from about 5 to about 7 carbon atoms. Examples of such substituents include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like. The term "cycloalkenyl," as used herein, means the same as the term "cycloalkyl," however one or more double bonds are present. Examples of such substituents include cyclopentenyl and cyclohexenyl. [0029] The term "halo" or "halogen," as used herein, means a substituent selected from Group VIIA, such as, for example, fluorine, bromine, chlorine, and iodine. In one embodiment of the invention, the halo is bromine or iodine.

[0030] The term "aryl" refers to an unsubstituted or substituted aromatic carbocyclic substituent, as commonly understood in the art, and includes monocyclic and polycyclic aromatics such as, for example, phenyl, biphenyl, toluenyl, anisolyl, naphthyl, anthracenyl and the like. An aryl substituent generally contains from, for example, about 3 to about 30 carbon atoms, preferably from about 6 to about 18 carbon atoms, more preferably from about 6 to about 14 carbon atoms and most preferably from about 6 to about 10 carbon atoms. It is understood that the term aryl applies to cyclic substituents that are planar and comprise 4n+2 π electrons, according to Huckel's Rule. The term "arylalkyl" means an alkyl group as described herein that is substituted with one or more aryl groups as described herein.

[0031] The term "alkoxy" embraces linear or branched alkyl groups that are attached to divalent oxygen. The alkyl group is the same as described herein. Examples of such substituents include methoxy, ethoxy, t-butoxy, and the like. The term "alkoxyalkyl" refers to an alkyl group that is substituted with one or more alkoxy groups. The alkyl and alkoxy groups are as described herein.

[0032] The term "carboxyl" refers to the group -C(O)OH. The term "carboxyalkyl" refers to the group -RC(O)OH that is connected to the compound through the alkyl R group. The term "carboxyalkyloxy" refers to the group -ORC(O)OH, in which the R is an alkyl (e.g., (CH₂)_n alkylene group, n is 1 to 12) group. [0033] The term "amino acid" refers to substituents that include both a carboxyl group (C(O)OH) and an amino group (NH₂). Commonly, such substituents have the generic formula, -RCH(NH₂)COaH, in which the substituent bonds to the ester group at the C- 15 position through the R group. Examples of an amino acid include one of the 20 naturally occurring, such as glycinyl, alaninyl, and leucinyl. The term "peptide" refers to a substituent that includes two or more amino acids joined by an amide bond. A substituent comprising two or more peptide bonds is a polypeptide and includes shorter polypeptide units such as a dipeptide and tripeptide. The term "protein" refers to a substituent comprising a very long string of amino acids linked together through peptide bonds. [0034] The water soluble side chain is any moiety that enables the quassinoid compound to become soluble or more soluble in water. The waters soluble side chain contains, for example, a hydroxyl, an amino, an ammonium salt, a phosphate, a sulfate, a carboxylic acid, or a carboxylic acid salt.

[0035] The quassinoid compound can be isolated, purified, and/or synthesized using methods known in the art, such as those described in, for example, U.S. Patent Nos. 5,639,712, 5,849,748, 5,965,493, 6,573,296, and U.S. Patent Application Publication No. 2003/0158088 Al. As those skilled in the art will appreciate, isolation of novel quassinoids for use in the inventive method is possible from the roots of Castela peninsularis, and from other Castela species, subspecies, or varieties, and from related members of the family Simaroubaceae. Purification and separation of novel quassinoids may proceed from the use of solvent extracts such as methanol, ethanol, aromatic solvents, or other suitable extracting agents. Synthesis embraces everything from minor sidechain additions or subtractions from the picrasane carbon skeleton, to complete synthesis as disclosed in, for example, Grieco et al., /. Am. Chem. Soc, 115, 6078-6093 (1993). Numerous compounds having sidechain modifications at the C- 15 site have been naturally isolated or synthesized, as have certain ring structure modifications or varying substituents at the C-4 position, all of which are contemplated as being within the scope of the present invention. [0036] The first pharmaceutical composition and the second pharmaceutical composition comprises an effective amount of a chemotherapeutic and a quassinoid, respectively. An "effective amount" means an amount sufficient to show a meaningful benefit in an individual, e.g., promoting at least one aspect of tumor cell cytotoxicity, or treatment, healing, prevention, or amelioration of other relevant medical conditions) associated with a particular cancer. Effective amounts may vary depending upon the biological effect desired in the individual, condition to be treated, and/or the specific characteristics of the quassinoid and/or the chemotherapeutic, and the individual. In this respect, any suitable dose of a quassinoid can be administered to the mammal, according to the type of cancer to be treated. The dose of quassinoid desirably comprises about 0.1 mg per kilogram (kg) of the body weight of the mammal (mg/kg) to about 400 mg/kg (e.g., about 0.75 mg/kg, about 5 mg/kg, about 30 mg/kg, about 75 mg/kg, about 100 mg/kg, about 200 mg/kg, or about 300 mg/kg). In another embodiment, the dose of quassinoid comprises about 0.5 mg/kg to about 300 mg/kg (e.g., about 0.75 mg/kg, about 5 mg/kg, about 50 mg/kg, about 100 mg/kg, or about 200 mg/kg), about 10 mg/kg to about 200 mg/kg (e.g., about 25 mg/kg, about 75 mg/kg, or about 150 mg/kg), or about 50 mg/kg to about 100 mg/kg (e.g., about 60 mg/kg, about 70 mg/kg, or about 90 mg/kg). When the chemotherapeutic is paclitaxel and/or docetaxel, any suitable dose can be administered to the mammal, according to the type of cancer and dosing schedule envisioned by the clinician. A single dose of paclitaxel and/or docetaxel desirably comprises about 20 mg per m² of body surface area of the patient (i.e., mg/m²) to about 400 mg/m² (e.g., about 40 mg/m , about 100 mg/m , about 150 mg/m , about 200 mg/m , about 250 mg/m , or about 300 mg/m²). In another embodiment, the dose of paclitaxel and/or docetaxel preferably comprises about 30 mg/m² to about 300 mg/m² (e.g., about 50 mg/m², about 100 mg/m², or about 200 mg/m²), about 60 mg/m² to about 200 mg/m² (e.g., about 75 mg/m², about 125

0 0 0 0 mg/m , or about 175 mg/m ), or about 100 mg/m to about 200 mg/m (e.g., about 150 mg/m²). Of course, the dose of paclitaxel and/or docetaxel administered to the mammal will depend upon the length of time with which the paclitaxel and/or docetaxel is administered (e.g., infused) to the patient. Examples of typical infusion times include about 1 to about 6 hours every 21 days, and about 24 hours every 21 days. [0037] In some embodiments, it may be advantageous to employ a method of administering the chemotherapeutic and/or the quassinoid wherein a dose is continuously administered to the patient over a prolonged period of time. For example, continuous infusion of the patient with the chemotherapeutic and/or quassinoid the may be desirable. In this regard, the duration of the administration of the dose of the first and/or second pharmaceutical composition may be any suitable length of time. Standard infusion rates for the chemotherapeutics described herein are known in the art and can be used in the inventive method, or modified in any suitable manner according to the nature of the disease. For example, when the inventive method is practiced using 5-FU as a chemotherapeutic, a typical infusion rate is about 96 hours per treatment week (i.e., 5 days per week). Other aspects of cancer chemotherapy and dosing schedules are described in, for example, Bast et al. supra.

[0038] In one embodiment, the inventive method is used to treat cancer in a mammal. The inventive method can be used to treat cancer in any mammal (e.g., mouse, rat, monkey, or human). In one embodiment of the invention, the inventive method is used to treat cancer in a human. The first pharmaceutical composition and the second pharmaceutical composition each preferably contact a tumor associated with the cancer, resulting in the destruction of tumor cells within the tumor. The tumor can be a solid tumor or a tumor associated with soft tissue (i.e., soft tissue sarcoma), in a mammal. The term "tumor" refers to both tumor cells and associated stromal cells. The tumor can be associated with cancers of (i.e., located in) the oral cavity and pharynx, the digestive system, the respiratory system, bones and joints (e.g., bony metastases), soft tissue, the skin (e.g., melanoma and squamous cell carcinoma), breast, the genital system, the urinary system, the eye and orbit, the brain and nervous system (e.g., glioma), or the endocrine system (e.g., thyroid) and is not necessarily the primary tumor. Indeed, the tumor can be a metastasis of a primary tumor located in a different tissue or organ. Tissues associated with the oral cavity include, but are not limited to, the tongue and tissues of the mouth. Cancer can arise in tissues of the digestive system including, for example, the esophagus, stomach, small intestine, colon, rectum, anus, liver, gall bladder, and pancreas. Cancers of the respiratory system can affect the larynx, lung, and bronchus and include, for example, non-small cell lung carcinoma. Tumors can arise in the uterine cervix, uterine corpus, ovary, vulva, vagina, prostate, testis, and penis, which make up the male and female genital systems, and the urinary bladder, kidney, renal pelvis, and ureter, which comprise the urinary system. The target tissue also can be located in lymphatic or hematopoietic tissues. For example, the tumor can be associated with lymphoma (e.g., Hodgkin's disease and Non-Hodgkin's lymphoma), multiple myeloma, or leukemia (e.g., acute lymphocytic leukemia, chronic lymphocytic leukemia, acute myeloid leukemia, chronic myeloid leukemia, and the like). Preferably, the cancer to be treated is selected from the group consisting of breast cancer, ovarian cancer, non-small cell lung carcinoma, Kaposi's sarcoma, leukemia, and colorectal carcinoma. [0039] The tumor can be at any stage. The term "tumor stage" is used in the art to describe the tumor type and the degree of tumor spread. Several tumor staging systems are known in the art, and any suitable staging system can be used to determine the stage of the tumor to be treated. For example, the TNM (Tumor, Node, Metastasis) system is an internationally accepted system that is used frequently to determine tumor stage. In this regard "T" describes the size, depth, and area of the primary tumor. "TX" indicates that the primary tumor cannot be assessed. "TO" indicates that there is no evidence of a primary tumor. "Tis" indicates carcinoma in situ (i.e., the malignant cells are confined to the epithelial layer of the tissue). "Tl" indicates a localized tumor two centimeters (cm) or less in diameter and confined to the organ of origin. "T2" indicates a localized tumor less than 5 cm in diameter that extends into adjacent tissue of the same organ. "T3" indicates an advanced tumor greater than 5 cm in diameter with greater involvement of adjacent tissue of the same organ, and "T4" indicates a massive tumor that extends into nerves, blood vessels, bone, or another organ. "N" describes whether the cancer has spread to regional lymph nodes. In this respect, "NX" indicates that regional lymph nodes cannot be assessed. "NO" indicates that there is no evidence of metastases to regional lymph nodes, and stages "Nl," "N2," and "N3" indicate increasing involvement of regional lymph nodes. The "M" classification describes the presence or absence of distant metastases. In this regard, "MX" indicates that distant metastases cannot be assessed. "MO" indicates that there is no evidence of metastases, and "Ml" indicates the presence of distant metastases. Once a tumor has been classified according to the TNM system, each classification can be combined, and an overall stage of I, II, III, or IV can then be assigned to the tumor. While the above description of the TNM system applies generally to most tumor types, the specific definition of each level can vary depending on the type of cancer. Further information about tumor staging is described in, for example, AJCC Cancer Staging Manual, 6th ed., American College of Surgeons, Lippincott-Raven. Philadelphia (2002). [0040] The inventive method also is useful in treating tumors of any grade. The "grade" of a tumor refers to the degree of differentiation of tumor cells. Tumor grade is typically assessed by histological characterization of a tumor sample and determination of the growth rate of the tumor cells (such as by measuring the mitotic index). In general, tumor cells that are well-differentiated resemble normal cells and are of a lower grade (e.g., Grade 1 or 2), while undifferentiated tumor cells are typically more aggressive and are of a higher grade (e.g., Grade 3 or 4).

[0041] The tumor can be subjected to different therapies. In this regard, the inventive method is useful in treating tumors (i.e., destruction of tumor cells or reduction in tumor size) that have been proven to be resistant to other forms of cancer therapy, such as radiation-resistant tumors. The tumor also can be of any size. Ideally, in treating the mammal for cancer, the inventive method results in cancerous (tumor) cell death and/or reduction in tumor size. It will be appreciated that tumor cell death can occur without a substantial decrease in tumor size due to, for instance, the presence of supporting cells, vascularization, fibrous matrices, etc. Accordingly, while reduction in tumor size is preferred, it is not required in the treatment of cancer.

[0042] The tumor can be amenable to surgical removal (i.e., "resection"). In this respect, the inventive method can be used following surgical resection to eliminate any residual tumor cells. Alternatively, the target tissue can be a tumor that is surgically unresectable. In this case, the inventive method can be used to effect shrinkage of the tumor, thereby facilitating surgical resection.

[0043] The first and second pharmaceutical compositions of the inventive method comprise a chemotherapeutic and a quassinoid, respectively, as well as a pharmaceutically acceptable carrier. Any suitable pharmaceutically acceptable carrier can be used within the context of the invention, and such carriers are well known in the art. The choice of carrier will be determined, in part, by the particular site to which the pharmaceutical compositions are to be administered and the particular method used to administer the pharmaceutical compositions.

[0044] Suitable formulations include aqueous and non-aqueous solutions, isotonic sterile solutions, which can contain anti-oxidants, buffers, bacteriostats, and solutes that render the formulation isotonic with the blood or other bodily fluid of the intended recipient, and aqueous and non-aqueous sterile suspensions that can include suspending agents, solubilizers, thickening agents, stabilizers, and preservatives. In one embodiment, the pharmaceutically acceptable carrier is a liquid that contains a buffer and a salt. The formulations can be presented in unit-dose or multi-dose sealed containers, such as ampules and vials, and can be stored in a freeze-dried (lyophilized) condition requiring only the addition of the sterile liquid carrier, for example, water, immediately prior to use. Extemporaneous solutions and suspensions can be prepared from sterile powders, granules, and tablets. In one embodiment, the pharmaceutically acceptable carrier is a buffered saline solution.

[0045] Further carriers include sustained-release preparations, such as semipermeable matrices of solid hydrophobic polymers containing the active agent, which matrices are in the form of shaped articles (e.g., films, liposomes, or microparticles). [0046] The pharmaceutical composition comprising the chemotherapeutic or the quassinoid can include carriers, thickeners, diluents, buffers, preservatives, surface active agents and the like. The pharmaceutical compositions can also include one or more additional active ingredients, such as antimicrobial agents, anti- inflammatory agents, anesthetics, and the like.

[0047] The pharmaceutical compositions comprising the chemotherapeutic and the quassinoid, respectively, can be formulated for any suitable route of administration, depending on whether local or systemic treatment is desired, and on the area to be treated. Desirably, the pharmaceutical compositions are formulated for parenteral administration, such as intravenous, intraperitoneal, intramuscular, or intratumoral injection. Injectables can be prepared in conventional forms, either as liquid solutions or suspensions, solid forms suitable for suspension in liquid prior to injection, or as emulsions. Additionally, parental administration can involve the preparation of a slow-release or sustained-release system, such that a constant dosage is maintained. Preparations for parenteral administration include sterile aqueous or non-aqueous solutions, suspensions, and emulsions. Examples of non-aqueous solvents are propylene glycol, polyethylene glycol, vegetable oils, such as olive oil, and injectable organic esters, such as ethyl oleate. Aqueous carriers include water, alcoholic/aqueous solutions, emulsions or suspensions, including saline and buffered media. Parenteral vehicles include sodium chloride solution, Ringer's dextrose, dextrose and sodium chloride, lactated Ringer's, or fixed oils. Intravenous vehicles include fluid and nutrient replenishers, electrolyte replenishers (such as those based on Ringer's dextrose), and the like. Preservatives and other additives also can be present such as, for example, antimicrobials, anti-oxidants, chelating agents, and inert gases and the like. [0048] The pharmaceutical compositions also can be administered orally. Oral compositions can be in the form of powders or granules, suspensions or solutions in water or non-aqueous media, capsules, sachets, or tablets. Thickeners, flavorings, diluents, emulsifiers, dispersing aids, or binders may be desirable.

[0049] The pharmaceutical compositions can potentially be administered as a pharmaceutically acceptable acid- or base- addition salt, formed by reaction with inorganic acids, such as hydrochloric acid, hydrobromic acid, perchloric acid, nitric acid, thiocyanic acid, sulfuric acid, and phosphoric acid, and organic acids such as formic acid, acetic acid, propionic acid, glycolic acid, lactic acid, pyruvic acid, oxalic acid, malonic acid, succinic acid, maleic acid, and fumaric acid, or by reaction with an inorganic base, such as sodium hydroxide, ammonium hydroxide, potassium hydroxide, and organic bases, such as mono-, di-, trialkyl, and aryl amines and substituted ethanolamines.

[0050] Suitable carriers and their formulations are further described in A.R. Gennaro, ed., Remington: The Science and Practice of Pharmacy (19th ed.), Mack Publishing Company, Easton, PA (1995).

[0051] The pharmaceutical compositions comprising the chemotherapeutic and the quassinoid, respectively, can be administered in any suitable manner depending on whether local or systemic treatment is desired, and on the area to be treated. Desirably, the pharmaceutical compositions are administered parenterally, most preferably by intravenous, intraperitoneal, intramuscular, or intratumoral injection. By the term "injecting," it is meant that the pharmaceutical composition is forcefully introduced into the target tissue. Although more than one route can be used to administer the pharmaceutical composition, a particular route can provide a more immediate and more effective reaction than another route. For regional delivery, the first and/or second pharmaceutical composition can be administered intraarterially or intravenously, e.g., via the hepatic artery for delivery to the liver or the carotid artery for delivery to the brain. For administration to the brain, the first and/or second pharmaceutical composition can be introduced into tumor tissue using an intratumoral delivery catheter, ventricular shunt catheter attached to a reservoir (e.g., Ommaya reservoir), infusion pump, or introduced into a tumor resection cavity (such as Gliasite, Proxima Therapeutics). Tumor tissue in the brain also can be contacted by administering the first and/or second pharmaceutical composition via convection using a continuous infusion catheter or through cerebrospinal fluid. Alternatively, the pharmaceutical composition can be administered to the pleural cavity for delivery to the lung or the peritoneal cavity for mesothelioma. In addition, the lymphatic system can be accessed, for example, following intratumoral injection, for delivery to lymph nodes. For regional delivery, the first and/or second pharmaceutical composition is preferably delivered directly into an artery feeding the target tissue.

[0052] The first and/or second pharmaceutical composition can be administered in or on a device that allows controlled or sustained release of the chemotherapeutic and/or the quassinoid, such as a sponge, biocompatible meshwork, mechanical reservoir, or mechanical implant. Implants (see, e.g., U.S. Patent 5,443,505), devices (see, e.g., U.S. Patent 4,863,457), such as an implantable device, e.g., a mechanical reservoir or an implant or a device comprised of a polymeric composition, are particularly useful for administration of the active agents. The pharmaceutical compositions of the inventive method also can be administered in the form of sustained-release formulations (see, e.g., U.S. Patent 5,378,475) comprising, for example, gel foam, hyaluronic acid, gelatin, chondroitin sulfate, a polyphosphoester, such as bis-2-hydroxyethyl-terephthalate (BHET), and/or a polylactic- glycolic acid.

[0053] The pharmaceutical composition also can be incorporated into or coat other materials, such as glass or magnetic beads, that are subsequently administered to a patient. For example, the FDA has approved study of the use of radioactive glass beads to deliver concentrated radiation therapy to hidden tissues (e.g., invasive cancers, tumors deep within the body cavity, etc.). Such beads can contain or be coated with the first and/or second pharmaceutical composition. Alternatively, magnetic beads coated with the first and/or second pharmaceutical composition can be administered to a patient, and directed to target tissue by placement of a magnet in the vicinity of a tumor. While beads are likely to remain lodged in the body unless forcibly removed, biodegradable delivery devices dissolve into non-toxic end products that are naturally removed from the body. The Gliadel^® wafer, for example, is currently used to deliver chemotherapeutic drugs to the site of glioblastoma. Such biodegradation matrices, once implanted, can release the first and/or second pharmaceutical composition through degradation of the matrix, thereby delivering the therapeutic agent to the relevant site without clinician intervention. [0054] Of course, administration of the pharmaceutical compositions can be accomplished via any route that efficiently delivers the active agents to the target tissue. [0055] Two timing issues exist with respect to the inventive method: the total therapeutic period, in other words, the entire length of time over which treatment occurs, and the time between the administration of the dose of the first pharmaceutical composition and the dose of the second pharmaceutical composition. In one embodiment of the invention, the therapeutic period is not longer than about 10 weeks in length, such as a therapeutic period comprising about 1-10 weeks in length, although it can be shorter than 1 week (e.g., 1, 2, 3, 4, 5, or 6 day(s)) or longer than 10 weeks (e.g., 12, 14, 16, or 18 weeks). In another embodiment, the therapeutic period is from about 2-9 weeks (Le., about 2, 3, 4, 5, 6, 7, 8, or 9 weeks in length), more preferably about 3-8 weeks (e.g., 4-7 weeks). [0056] With respect to the administration of the dose of the first pharmaceutical composition and the dose of the second pharmaceutical composition, the doses can be administered simultaneously (Le., concurrently), or sequentially in any order. In a particularly embodiment, the dose of the first pharmaceutical composition is to be administered to the mammal prior to the dose of the second pharmaceutical composition. Alternatively, the dose of the second pharmaceutical composition can be administered to the mammal prior to the dose of the first pharmaceutical composition. When the dose of the first pharmaceutical composition and the dose of the second pharmaceutical composition are administered sequentially, the time between the administrations of each dose must be such that the anti-cancer effects of the quassinoid and the chemotherapeutic agent can be achieved. In this regard, the administration of the dose of the first pharmaceutical composition and the administration of the dose of the second pharmaceutical composition are separated by any suitable amount of time, so long as the therapeutic efficacy of the quassinoid or the chemotherapeutic is not significantly diminished before administration of the second or first pharmaceutical composition, respectively. Administration of the dose of the first pharmaceutical composition and the dose of the second pharmaceutical composition can be separated by about 6 hours to about 10 days (e.g., 24 hours, about 2 days, about 5 days, or about 7 days). In another embodiment, administration of the dose of the first pharmaceutical composition and the dose of the second pharmaceutical composition is separated by about 2 days to about 7 days (e.g., about 2, 3, 4, 5, 6, or 7 days). In yet another embodiment, administration of the dose . of the first pharmaceutical composition and the dose of the second pharmaceutical composition is separated by about 3 days to about 5 days (e.g., about 3, 4, or 5 days). For example, in some embodiments, the first pharmaceutical composition is administered first, and the second pharmaceutical composition is administered 2, 3, 4, 5, 6, or 7 days later. In other embodiments, the second pharmaceutical composition is administered first, and the first pharmaceutical composition is administered 2, 3, 4, 5, 6, or 7 days later. [0057] When the doses of the first and second pharmaceutical compositions are administered sequentially, the first and second pharmaceutical compositions can be administered more than once in order to achieve a desired biological effect in the mammal. In this embodiment, for example, administration of one dose of the first pharmaceutical composition followed by administration of one dose of the second pharmaceutical composition (or vice versa) is considered one treatment "cycle" in accordance with the inventive method. The inventive method can thus comprise multiple cycles of treatment, depending upon the type and severity of the cancer, and the condition of the patient before and during treatment. In one embodiment, a dose of the first pharmaceutical composition is administered, followed by a dose of the second pharmaceutical composition, which is followed by a second dose of the first pharmaceutical composition, all with appropriate time intervals between each dose.

[0058] In some embodiments, it may be advantageous to employ a method of administering the first and second pharmaceutical compositions wherein a dose is continuously administered to the target tissue over a prolonged period of time. For example, continuous perfusion of the target tissue with the pharmaceutical composition may be desirable. Accordingly, the inventive method can comprise contacting a tumor at least once during the therapeutic period. In other words, a dose of the first and/or second pharmaceutical composition is delivered over a prolonged period of time such as, for example, 1-10 weeks in length, although it can be shorter than 1 week (e.g., 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 2 weeks, 3 weeks, 4 weeks, 5 weeks, 6 weeks, 7 weeks, 8 weeks, or 9 weeks) or longer than 10 weeks (e.g., 12, 14, 16, or 18 weeks). Such a delivery strategy can be accomplished through, for instance, incorporation of the pharmaceutical composition in a sustained-release device or reservoir and implantation into the patient. [0059] The inventive method can be performed in combination with other anti-cancer therapeutic methods to achieve a desired biological effect in a patient. In one embodiment, radiation therapy can be used before, during, or after the inventive method as an adjuvant method for further reducing the size of one or more tumors in the mammal. Any type of radiation can be administered to a patient, so long as the dose of radiation is tolerated by the patient without significant negative side effects. Suitable types of radiotherapy include, for example, ionizing (electromagnetic) radiotherapy (e.g., X-rays or gamma rays) or particle beam radiation therapy (e.g., high linear energy radiation). In another embodiment, the first and second pharmaceutical compositions are administered before, during, or after surgical resection of a tumor. Complete surgical removal of tumor tissue is often complicated by invasion of the tumor tissue into surrounding tissues and indefinite margins of the mass. As described herein, treatment of a tumor using the inventive method leads to tumor shrinkage, which will facilitate resection. Ideally, surgical resection of a tumor is performed after completion of the therapeutic period. Surgical resection of a tumor can be performed at any time after completion of the therapeutic period, so long as the patient is allowed sufficient time to recover from the administration of the first and second pharmaceutical compositions.

[0060] Also provided by the invention is a composition comprising (a) a dose of a chemotherapeutic, (b) a dose of a quassinoid or a derivative thereof (e.g., a compound represented by the formula (I), (II), (IV) or (V)), and (c) a pharmaceutically acceptable carrier. Descriptions of the chemotherapeutic, the quassinoid, the pharmaceutically acceptable carrier, and components thereof, set forth above in connection with embodiments of the inventive method also are applicable to those same aspects of the aforesaid composition.

[0061] In one embodiment, the quassinoid compound in the composition has a structure of formula (II) in which Y is a compound of formula (III), wherein R₁ is a hydroxyl group, R₂ is an isopropyl group, and R₃ is an isopropyl group, according to the following structure

TPI-273

[0062] The chemotherapeutic in the composition can be paclitaxel or docetaxel. In a particular embodiment of the invention, the chemotherapeutic is paclitaxel. [0063] The composition can be in any form known in the art that is suitable for administration to a mammal, such as those described above. The composition preferably is in a form that can be administered orally (e.g., a tablet, capsule, or oral solution), parenterally (e.g., an injectable), or topically (e.g., a lotion, cream, or transdermal patch). In one embodiment of the invention, the composition can be a controlled-release dosage form, in which the quassinoid and the chemotherapeutic are sequentially released from the dosage form. In this embodiment, for example, the composition can be a controlled-release multilayer tablet, in which the dose of the chemotherapeutic is contained within an outer layer of the tablet, and the dose of the quassinoid is contained within an inner layer of the tablet. In this manner, the chemotherapeutic can be released immediately upon ingestion of the tablet, while release of the quassinoid is delayed. Alternatively, the dose of the quassinoid and the dose of the chemotherapeutic can be formulated in a composition such that both agents are subject to immediate release from the composition, or are subject to controlled release when administered to a mammal.

[0064] The invention further provides a kit comprising a dose of a first pharmaceutical composition comprising a pharmaceutically acceptable carrier and a chemotherapeutic as described above, and a dose of a second pharmaceutical composition comprising a pharmaceutically acceptable carrier and a quassinoid. Descriptions of the chemotherapeutic, the quassinoid, the pharmaceutically acceptable carrier, and components thereof, set forth above in connection with embodiments of the inventive method also are applicable to those same aspects of the aforesaid kit. [0065] The kit desirably is a multicompartment kit. In one embodiment, a multicompartment kit comprises at least two separate components. A first compartment of the kit comprises a first pharmaceutical composition comprising a chemotherapeutic and a pharmaceutically acceptable carrier. This first pharmaceutical composition can, for example, be in the form of an emulsion, powder, solution, suspension, gel or paste. A second compartment of the kit can comprise a second pharmaceutical composition comprising the aforementioned quassinoid or a derivative thereof (e.g., a compound of formula (I), (II), (IV), or (V)) and a pharmaceutically acceptable carrier. This second pharmaceutical composition in the second compartment can, for example, be in the form of an emulsion, powder, solution, suspension, gel or paste. It will be appreciated that the first and second pharmaceutical compositions can be in the same form, or can be in different forms when included as part of a multicompartment kit. One of ordinary skill in the art, based on the stability of the compositions and the application envisaged, will be able to determine how the compositions and/or multicompartment compositions should be stored and mixed. The kit optionally contains written instruction describing how the first and second pharmaceutical compositions are to be stored, administered, and/or discarded. [0066] The following examples further illustrate the invention but, of course, should not be construed as in any way limiting its scope.

EXAMPLES Cell Lines

[0067] The following cell lines, with the exception of the JNPSRLT and DP-FAI cell lines, were obtained from the ATCC (Manassas, Virginia): JNPSRLT (desmoplastic small round cell tumor), MSTO-211H (lung mesothelioma), NCI-H22 (lung mesothelioma), SHP-77 (small cell lung carcinoma), SK-N-AS (neuroblastoma), SK-N-DZ (neuroblastoma), MO59K (glioblastoma), MO59J (glioblastoma), U-87 (glioblastoma), DP- FAI (fibroblast), BNR-Il (fibroblast), SCC25 (tongue squamous cell carcinoma), FADU (pharynx squamous cell carcinoma), HUTU-80 (duodenal adenocarcinoma), PL-45 (pancreatic cancer), HT-29 (colorectal carcinoma), LS-174T (colon carcinoma), MCF7 (breast carcinoma), NCI-AR (breast carcinoma), and MES-Sar (uterine carcinoma). Cells were cultured in sextuplicate microwells at 37 ⁰C and 5% CO₂ in humidified air and in 10% FBS in Eagles MEM.

EXAMPLE l

[0068] This example demonstrates a method of killing tumor cells by administering a quassinoid to tumor cells in vitro. [0069] The following human tumor cell lines were obtained and cultured as described above: JNPSRLT, MSTO-211H, NCI-H22, SK-N-AS, SK-N-DZ, MO59J, HT-29, and LS- 174T. Cells from each cell line were separately treated with an amount of the quassinoid bruceantin (see Table 1) and an amount of the glaucorubolone derivative TPI-273. Cells were exposed to each drug for one hour, rinsed with drug-free media, and incubated for an additional five days. The number of viable cells was measured using an MTT (3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay (see, e.g., Mosmann, J. Immunol. Methods, 65(1-2), 55-63 (1983)).

[0070] The cytotoxicity of each drug was determined and expressed as the dose of drug required to kill 50% of the treated cells ("EDso")- The results of this analysis are set forth in Table 1.

Table 1

[0071] These results demonstrate that 10- to 20-fold lower amounts of TPI-273 are required to induce tumor cell cytotoxicity in vitro, as compared to the amount of bruceantin.

EXAMPLE 2

[0072] This example demonstrates the effects of cell cycling by administering a quassinoid and a taxane in combination to tumor cells in vitro.

[0073] The SK-N-AS cell line was cultured as described above. Cells were exposed to the quassinoid TPI-273 (0.075 μg/ml) and to the taxane paclitaxel (Ptx) (0.1 μg/ml) or docetaxel (Doc) (0.1 μg/ml) concurrently or sequentially. The cells were exposed to each drug for 1 hour. When administered sequentially, the second drug was added to the cell culture approximately 12 hours prior to collection and fixation of cells. Following drug exposure, cells were harvested and fixed at different time points. The cell cycle phases of the cells were determined using flow cytometry. The results of this analysis are set forth in Tables 2 and 3.

Table 2

% Cells in Cell Cycle Phase

Time of %

Fixation Apoptotic

Treatment G0/G1 G2/M

(hours post Cells treatment)

42 76.92 19.37 3.7 2.65

Control 54 79.18 17.46 3.36 3.7

66 76.98 20.23 2.79 2.16

Mean Value 77.69 19.02 3.28 2.83

Concurrent 43 66.95 25.05 8 2.43 TPI-273 and 54 63.13 28.87 8 1.14

Ptx 66 71.25 20.75 8 2.62 Mean Value 67.1 24.89 8 2.06

42 75.07 19.33 5.59 0.71

TPI-273 Prior 54 63.03 28.97 8 1.36 to Ptx 66 70.57 22.25 7.19 0.8

Mean Value 69.55 23.51 6.92 0.95

42 58.5 33.5 8 26.72

Ptx Prior to 54 67.32 TPI-273 24.68 8 26.58 66 68.95 23.52 7.53 27.58

Mean Value 64.92 27.23 7.84 26.96 [0074] This example demonstrates that sequential administration of the quassinoid TPI- 273 prior to, or concurrently with a taxane abrogates apoptosis of tumor cells in vitro.

EXAMPLE 3

[0075] This example demonstrates the safety and tolerability of administration of a quassinoid and paclitaxel in vivo.

[0076] To ascertain the potential toxicity of the combined administration of the quassinoid TPI-273 and paclitaxel in vivo, both drugs were administered to mice. In particular, a dose of TPI-273 (0.75 mg/kg) and a dose of paclitaxel (20 mg/kg) were administered via intraperitoneal (i.p.) injection to healthy mice concurrently or sequentially. Lethality occurred in mice immediately following concurrent administration of TPI-273 and paclitaxel, and where TPI-273 administration was followed by paclitaxel administration within 48 hours. In contrast, initial administration of paclitaxel followed by TPI-273 resulted in attenuated lethality as compared to the other treatment groups. The results of this analysis are set forth in Table 4.

Table 4

[0077] This example demonstrates the safety of administration of paclitaxel prior to the quassinoid TPI-273 in mice.

EXAMPLE 4

[0078] This example demonstrates a method of inhibiting tumor growth comprising administering a pharmaceutical composition comprising a dose of a quassinoid to mice in vivo.

[0079] Human tumor xenografts were grown in nude mice. Specifically, tumors derived from the multiple myeloma cell line RPMI-8226 and the colorectal carcinoma cell line HCT-15, which overexpresses the multi-drug resistance gene MDR-I, were grown in nude mice using xenotransplantation methods known in the art. The maximum tolerated dose (MTD) of TPI-273 (0.9 mg/kg every 7 days) was administered to mice harboring each type of tumor once a week for four weeks. The chemotherapeutics irinotecan and doxorubicin also were separately administered to xenotransplanted nude mice. Tumor volume was measured 28 days after treatment. The results of this analysis are set forth in Table 5. Table 5

[0080] To investigate the effects of lower doses of TPI-273 in vivo, TPI-273 also was administered at a dose of 0.05 mg/ml and 0.025 mg/ml to HCT- 116 colon cancer xenografts in nude mice. Each dose of TPI-273 was administered via intraperitoneal injection once a day for 5 days. Tumor volume was measured at various time points after administration. Both the 0.05 mg/ml dose and the 0.025 mg/ml dose of TPI-273 were effective in reducing tumor size (see Figure 1).

[0081] This example demonstrates a method for inhibiting tumor growth in vivo comprising administering a pharmaceutical composition comprising a quassinoid.

[0082] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0083] The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to,") unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. [0084] Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims

WHAT IS CLAIMED IS:

1. A method for treating cancer in a mammal, which method comprises:

(a) administering to the mammal a dose of a first pharmaceutical composition comprising a pharmaceutically acceptable carrier and an effective amount of a chemotherapeutic other than a quassinoid, at least once in a therapeutic period comprising up to about 10 weeks, and

(b) administering to the mammal a dose of a second pharmaceutical composition comprising a pharmaceutically acceptable carrier and an effective amount of a quassinoid or a derivative thereof, at least once in the therapeutic period.

2. A method for treating cancer in a mammal, which method comprises:

(a) administering to the mammal a dose of a first pharmaceutical composition comprising a pharmaceutically acceptable carrier and an effective amount of a chemotherapeutic other than a quassinoid, at least once in a therapeutic period comprising up to about 10 weeks, and

(b) administering to the mammal a dose of a second pharmaceutical composition comprising a pharmaceutically acceptable carrier and an effective amount of a quassinoid or a derivative thereof, at least once in the therapeutic period, wherein the quassinoid comprises a core structure of the formula (I):

(I)

3. A method for treating cancer in a mammal, which method comprises:

(a) administering to the mammal a dose of a first pharmaceutical composition comprising a pharmaceutically acceptable carrier and an effective amount of a chemotherapeutic other than a quassinoid, at least once in a therapeutic period comprising up to about 10 weeks, and

(b) administering to the mammal a dose of a second pharmaceutical composition comprising a pharmaceutically acceptable carrier and an effective amount of a quassinoid or a derivative thereof, at least once in the therapeutic period, wherein the quassinoid is of the formula (II):

(H) , wherein Y is hydrogen, alkyl, hydroxyalkyl, carboxyl, substituted aryl, alkenyl, cycloalkyl, cycloalkenyl, a glycosaccharide, a water soluble side chain, amino acid, a peptide, a polypeptide, or a protein.

4. The method of claim 3, wherein Y is hydrogen, alkyl having from 2 to 3 carbons, alkyl having more than 4 carbons, hydroxyalkyl having less than 4 carbons, hydroxyalkyl having more than 4 carbons, carboxyl (excluding glaucarubinone-2'-acetate), substituted aryl, alkenyl having less than 4 carbons, alkenyl having greater than 4 carbons, cycloalkyl, cycloalkenyl, a glycosaccharide, a water soluble side chain, amino acid, a peptide, a polypeptide, or a protein.

5. The method of claim 3 or 4, wherein Y is the formula (III)

(in) wherein R_t1R₂, R₃ taken separately or together represent hydrogen, alkyl, hydroxyl, hydroxyalkyl, carboxyl, aryl, alkenyl, cycloalkyl, cycloalkenyl, glycinyl, a glycosaccharide, a water soluble side chain, amino acid, a peptide, a polypeptide, a protein, or any of the foregoing attached to the central carbon by an ether, ester, carbonyl, or glycosidic linkage.

6. The method of claim 5, wherein R₁ is a hydroxyl group, R₂ is an isopropyl group, and R₃ is an isopropyl group.

7. A method for treating cancer in a mammal, which method comprises:

(a) administering to the mammal a dose of a first pharmaceutical composition comprising a pharmaceutically acceptable carrier and an effective amount of a chemotherapeutic other than a quassinoid, at least once in a therapeutic period comprising up to about 10 weeks, and

(b) administering to the mammal a dose of a second pharmaceutical composition comprising a pharmaceutically acceptable carrier and an effective amount of a quassinoid or a derivative thereof, at least once in the therapeutic period, wherein the quassinoid is of the formula (IV)

(IV) , wherein R₄, R₅, and R₆ are independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, carboxyl, carbonyl, hydroxyalkyl, alkoxyalkyl, -OR₉, and -NR_1OR₁₁, wherein R₇ and Rs are independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, and arylalkyl, or wherein R₇ and R₈ taken together form C₃-C_1O alkylene or alkenylene, or wherein R₇ and R₈ taken together form (C=O), wherein R₉ is selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, and -C(O)R₁₂, wherein R₁₂ is selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, -OR₁₃, and -NR₉R₁₀, wherein R₁₃ is selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, and arylalkyl, wherein R_1O and R₁₁ are independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, and arylalkyl, or R₁O and R₁₁ can be taken together to form a 5-7 membered heterocyclic ring with the nitrogen to which they are bonded.

8. The method of claim 7, wherein R₄ and R₅ are isopropyl and R₆ is hydroxyl.

9. A method for treating cancer in a mammal, which method comprises:

(a) administering to the mammal a dose of a first pharmaceutical composition comprising a pharmaceutically acceptable carrier and an effective amount of a chemotherapeutic other than a quassinoid, at least once in a therapeutic period comprising up to about 10 weeks, and

(b) administering to the mammal a dose of a second pharmaceutical composition comprising a pharmaceutically acceptable carrier and an effective amount of a quassinoid or a derivative thereof, at least once in the therapeutic period, wherein the quassinoid is of the formula (V)

(V) , wherein R₁₄, R₁₅, and R₁₆ are independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, carboxyl, carbonyl, hydroxyalkyl, alkoxyalkyl, and -OR₁₇, wherein R₁₇ is selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, and -C(O)R₁₈, wherein R₁₈ is selected from the group consisting of alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, -OR₁₉, and -NR₂₀R₂₁, wherein R₁₉ is selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, and arylalkyl, wherein R₂o and R₂₁ are independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, and arylalkyl, or R₂o and R₂₁ can be taken together to form a 5-7 membered heterocyclic ring with the nitrogen to which they are bonded.

10. The method of any of claims 1-9, wherein the chemotherapeutic is selected from the group consisting of adriamycin, asparaginase, bleomycin, busulphan, cisplatin, carboplatin, carmustine, capecitabine, chlorambucil, cytarabine, cyclophosphamide, camptothecin, dacarbazine, dactinomycin, daunorubicin, dexrazoxane, docetaxel, doxorubicin, etoposide, floxuridine, fludarabine, fluorouracil, gemcitabine, hydroxyurea, idarubicin, ifosfamide, irinotecan, lomustine, mechlorethamine, mercaptopurine, meplhalan, methotrexate, mitomycin, mitotane, mitoxantrone, nitrosurea, paclitaxel, pamidronate, pentostatin, plicamycin, procarbazine, rituximab, streptozocin, teniposide, thioguanine, thiotepa, vinblastine, vincristine, vinorelbine, taxol, transplatinum, and 5-fluorouracil.

11. The method of any of claims 1-10, wherein the chemotherapeutic is a mitotic inhibitor.

12. The method of any of claims 1-11, wherein the chemotherapeutic is paclitaxel or docetaxel.

13. The method of any of claims 1-12, wherein the first pharmaceutical composition and the second pharmaceutical composition contact a tumor, and tumor cells within the tumor are destroyed.

14. The method of claim 13, wherein the tumor is located in the breast, brain, lung, colon, pancreas, skin, lymphoid tissue, hematopoietic tissue, or soft tissue.

15. The method of any of claims 1-14, wherein the dose of the first pharmaceutical composition and the dose of the second pharmaceutical composition are administered via intravenous, intraperitoneal, intramuscular, or intratumoral administration.

16. The method of any of claims 1-15, wherein the dose of the first pharmaceutical composition and the dose of the second pharmaceutical composition are administered simultaneously.

17. The method of any of claims 1-15, wherein the dose of the first pharmaceutical composition and the dose of the second pharmaceutical composition are administered sequentially.

18. The method of claim 17, wherein the dose of the first pharmaceutical composition is administered to the mammal prior to the dose of the second pharmaceutical composition.

19. The method of claim 17, wherein the dose of the second pharmaceutical composition is administered to the mammal prior to the dose of the first pharmaceutical composition.

20. The method of any of claims 1-19, wherein the mammal is a human.

21. A composition comprising:

(a) a dose of a chemotherapeutic other than a quassinoid,

(b) a dose of a quassinoid or a derivative thereof, and

(c) a pharmaceutically acceptable carrier.

22. A composition comprising:

(a) a dose of a chemotherapeutic other than a quassinoid,

(b) a dose of a quassinoid comprising the core structure

(I) (c) a pharmaceutically acceptable carrier.

23. A composition comprising:

(a) a dose of a chemotherapeutic other than a quassinoid,

(b) a dose of a quassinoid represented by the formula (II):

(H) wherein Y is hydrogen, alkyl, hydroxyalkyl, carboxyl, substituted aryl, alkenyl, cycloalkyl, cycloalkenyl, a glycosaccharide, a water soluble side chain, amino acid, a peptide, a polypeptide, or a protein, and

(c) a pharmaceutically acceptable carrier.

24. The composition of claim 23, wherein Y is hydrogen, alkyl having from 2 to 3 carbons, alkyl having more than 4 carbons, hydroxyalkyl having less than 4 carbons, hydroxyalkyl having more than 4 carbons, carboxyl (excluding glaucarubinone-2'-acetate), substituted aryl, alkenyl having less than 4 carbons, alkenyl having greater than 4 carbons, cycloalkyl, cycloalkenyl, a glycosaccharide, a water soluble side chain, amino acid, a peptide, a polypeptide, or a protein.

25. The composition of claim 23 or 24, wherein Y is the formula (III)

(HI) wherein R₁, R₂, and R₃ taken separately or together represent hydrogen, alkyl, hydroxyl, hydroxyalkyl, carboxyl, aryl, alkenyl, cycloalkyl, cycloalkenyl, glycinyl, a glycosaccharide, a water soluble side chain, amino acid, a peptide, a polypeptide, a protein, or any of the foregoing attached to the central carbon by an ether, ester, carbonyl, or glycosidic linkage.

26. The composition of claim 25, wherein R₁ is a hydroxyl group, R₂ is an isopropyl group, and R₃ is an isopropyl group.

27. A composition comprising:

(a) a dose of a chemotherapeutic other than a quassinoid,

(b) a dose of a quassinoid represented by the formula (IV)

(IV) , wherein R₄, R₅, and R₆ are independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, carboxyl, carbonyl, hydroxyalkyl, alkoxyalkyl, -OR9, and -NR₁OR₁₁, wherein R₇ and R₈ are independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, and arylalkyl, or wherein R₇ and R₈ taken together form C₃-C₁O alkylene or alkenylene, or wherein R₇ and R₈ taken together form (C=O), wherein Rg is selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, and -C(O)R₁₂, wherein R₁₂ is selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, -OR₁₃, and

-NR₉R₁₀, wherein R₁₃ is selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, and arylalkyl, wherein R_1O and R₁₁ are independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, and arylalkyl, or R₁₀ and R₁₁ can be taken together to form a 5-7 membered heterocyclic ring with the nitrogen to which they are bonded, and

(c) a pharmaceutically acceptable carrier.

28. The composition of claim 27, wherein R₄ and R₅ are isopropyl and R₆ is hydroxyl.

29. A composition comprising:

(a) a dose of a chemotherapeutic other than a quassinoid,

(b) a dose of a quassinoid represented by the formula (V)

(V) , wherein R₁₄, R₁₅, and R₁₆ are independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, carboxyl, carbonyl, hydroxyalkyl, alkoxyalkyl, and -OR₁₇, wherein Ri₇ is selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, and -C(O)R₁₈, wherein R₁₈ is selected from the group consisting of alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, -OR₁₉, and -NR₂QR₂₁, wherein R19 is selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, and arylalkyl, wherein R20 and R_2I are independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, and arylalkyl, or R2₀ and R₂₁ can be taken together to form a 5-7 membered heterocyclic ring with the nitrogen to which they are bonded, and

(c) a pharmaceutically acceptable carrier.

30. The composition of any of claims 21-29, wherein the chemotherapeutic is selected from the group consisting of adriamycin, asparaginase, bleomycin, busulphan, cisplatin, carboplatin, carmustine, capecitabine, chlorambucil, cytarabine, cyclophosphamide, camptothecin, dacarbazine, dactinomycin, daunorubicin, dexrazoxane, docetaxel, doxorubicin, etoposide, floxuridine, fludarabine, fluorouracil, gemcitabine, hydroxyurea, idarubicin, ifosfamide, irinotecan, lomustine, mechlorethamine, mercaptopurine, meplhalan, methotrexate, mitomycin, mitotane, mitoxantrone, nitrosurea, paclitaxel, pamidronate, pentostatin, plicamycin, procarbazine, rituximab, streptozocin, teniposide, thioguanine, thiotepa, vinblastine, vincristine, vinorelbine, taxol, transplatinum, and 5-fluorouracil.

31. The composition of any of claims 21-30, wherein the chemotherapeutic is a mitotic inhibitor.

32. The composition of any of claims 21-31, wherein the chemotherapeutic is paclitaxel or docetaxel.

33. A kit comprising:

(a) a dose of a first pharmaceutical composition comprising a pharmaceutically acceptable carrier and a chemotherapeutic other than a quassinoid, and

(b) a dose of a second pharmaceutical composition comprising a pharmaceutically acceptable carrier and a quassinoid or a derivative thereof.

34. A kit comprising:

(a) a dose of a first pharmaceutical composition comprising a pharmaceutically acceptable carrier and a chemotherapeutic other than a quassinoid, and

(b) a dose of a second pharmaceutical composition comprising a pharmaceutically acceptable carrier and a quassinoid comprising a core structure of the formula (I)

(I)

35. A kit comprising:

(a) a dose of a first pharmaceutical composition comprising a pharmaceutically acceptable carrier and a chemotherapeutic other than a quassinoid, and

(b) a dose of a second pharmaceutical composition comprising a pharmaceutically acceptable carrier and a quassinoid represented by the formula (II):

(H) , wherein Y is hydrogen, alkyl, hydroxyalkyl, carboxyl, substituted aryl, alkenyl, cycloalkyl, cycloalkenyl, a glycosaccharide, a water soluble side chain, amino acid, a peptide, a polypeptide, or a protein.

36. The kit of claim 35, wherein Y is hydrogen, alkyl having from 2 to 3 carbons, alkyl having more than 4 carbons, hydroxyalkyl having less than 4 carbons, hydroxyalkyl having more than 4 carbons, carboxyl (excluding glaucarubinone-2-acetate), substituted aryl, alkenyl having less than 4 carbons, alkenyl having greater than 4 carbons, cycloalkyl, cycloalkenyl, a glycosaccharide, a water soluble side chain, amino acid, a peptide, a polypeptide, or a protein.

37. The kit of claim 35 or 36, wherein Y is the formula (III)

(HI) wherein R₁, R₂, and R₃ taken separately or together represent hydrogen, alkyl, hydroxyalkyl, carboxyl, aryl, alkenyl, cycloalkyl, cycloalkenyl, glycinyl, a glycosaccharide, a water soluble side chain, amino acid, a peptide, a polypeptide, a protein, or any of the foregoing attached to the central carbon by an ether, ester, carbonyl, or glycosidic linkage.

38. The kit of claim 37, wherein R₁ is a hydroxyl group, R₂ is an isopropyl group, and R₃ is an isopropyl group.

39. A kit comprising:

(a) a dose of a first pharmaceutical composition comprising a pharmaceutically acceptable carrier and a chemotherapeutic other than a quassinoid, and

(b) a dose of a second pharmaceutical composition comprising a pharmaceutically acceptable carrier and a quassinoid represented by the formula (IV)

(IV) , wherein R₄, Rs, and R₆ are independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, carboxyl, carbonyl, hydroxyalkyl, alkoxyalkyl, -OR9, and -NR₁₀R₁1, wherein R₇ and R₈ are independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, and arylalkyl, or wherein R₇ and R₈ taken together form C₃-C_1O alkylene or alkenylene, or wherein R₇ and R₈ taken together form (C=O), wherein R₉ is selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, and -C(O)R₁₂, wherein R₁₂ is selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, -OR₁₃, and -NR₉Ri₀, wherein R₁₃ is selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, and arylalkyl, wherein Rio and R₁₁ are independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, and arylalkyl, or R_1O and R₁₁ can be taken together to form a 5-7 membered heterocyclic ring with the nitrogen to which they are bonded.

40. The kit of claim 39, wherein R₄ and R₅ are isopropyl and R₆ is hydroxyl.

41. A kit comprising:

(a) a dose of a first pharmaceutical composition comprising a pharmaceutically acceptable carrier and a chemotherapeutic other than a quassinoid, and

(b) a dose of a second pharmaceutical composition comprising a pharmaceutically acceptable carrier and a quassinoid represented by the formula (V)

(V) , wherein R₁₄, R₁₅, and R₁₆ are independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, carboxyl, carbonyl, hydroxyalkyl, alkoxyalkyl, and -OR₁₇, wherein R₁₇ is selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, and -C(O)R₁₈, wherein Ri₈ is selected from the group consisting of alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, -OR₁₉, and -NR₂₀R₂₁, wherein R₁₉ is selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, and arylalkyl, wherein R₂o and R₂₁ are independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkenyl, aryl, and arylalkyl, or R₂₀ and R₂₁ can be taken together to form a 5-7 membered heterocyclic ring with the nitrogen to which they are bonded.