EP2435038A1

EP2435038A1 - Combination therapy for the treatment of multiple myeloma using cep-18770 together with bortezomib or mephalan

Info

Publication number: EP2435038A1
Application number: EP09788795A
Authority: EP
Inventors: James R. Berenson
Original assignee: Cephalon LLC
Current assignee: Cephalon LLC
Priority date: 2009-05-27
Filing date: 2009-06-09
Publication date: 2012-04-04
Also published as: WO2010138101A1; NZ596541A; JP5665862B2; JP2012528151A

Abstract

The present invention provides a method for treating multiple myeloma in a subject, comprising the step of administering to the subject a combination of COMPOUND 1 and bortezomib. The invention further provides a method for treating multiple myeloma in a subject, comprising the step of administering to the subject a combination of COMPOUND 1 and melphalan.

Description

COMBINATION THERAPY FOR THE TREATMENT OF MULTIPLE MYELOMA USING CEP-18770 TOGETHER WITH BORTEZOMIB OR

MEPHALAN

TECHNICAL FIELD

Combination drug therapy for multiple myeloma.

BACKGROUND

Multiple myeloma (MM), a plasma cell neoplasm, comprises approximately 10% of all hematologic malignancies (1). The clinical success of the proteasome inhibitor (PI) bortezomib in MM has validated the ubiquitin-proteasome system (UPS) as a compelling target for drug development (2). The proteasome is a multi-subunit protein complex responsible for degrading misfolded and damaged proteins as well as intracellular signaling intermediates (3). Because of their dysregulated signaling pathways, neoplastic cells rely heavily on the UPS, and therefore are particularly sensitive to proteasome inhibition (4). Apoptosis of MM cells following proteasome inhibition occurs through multiple mechanisms, including down-regulation of prosurvival NF-κB signaling, inhibition of angiogenesis, activation of a misfolded protein stress response, induction of intrinsic and extrinsic cell death pathways, and inhibition of MM cell adhesion to the bone marrow stromal cells (5-8).

The first PI in clinical development, bortezomib (also known as PS-341 or [(lJ?)-3- methyl-l-({(25)-3-phenyl-2-[(pyrazin-2-ylcarbonyl)amino]propanoyl}amino)butyl] boronic acid), was approved by the FDA in 2003 following two successful single-agent phase II trials in relapsed MM (9,10). Bortezomib also shows remarkable activity in combination with other agents. In preclinical studies, subtoxic concentrations of bortezomib overcame the resistance of MM cells to chemotherapeutic drugs, including melphalan, doxorubicin, or mitoxantrone (11-13). In addition, bortezomib potentiates the activity of novel therapies for MM, including lenalidomide, arsenic trioxide, and inhibitors of histone deacetylase or PKC, as well as second-generation PIs (14-18). Synergistic in vitro activity has translated to enhanced in vivo efficacy in clinical studies testing bortezomib-based combination therapies. In the phase III VISTA trial evaluating melphalan and prednisone (MP) with or without bortezomib (V), VMP was associated with a 3-year overall survival rate of 72%, compared with 59% for MP therapy (P = 0.003) (19). Notably, the addition of bortezomib to a regimen can, in some cases, resensitize patients to failed therapies. For example, in a phase II study, 60% of MM patients who relapsed following melphalan treatment subsequently responded to bortezomib/melphalan combination therapy (20). Similarly, bortezomib combined with thalidomide and dexamethasone yielded a 63% overall response rate in a relapsed population of MM patients, 73% of whom had previous exposure to thalidomide (21).

Although the approval of bortezomib has transformed treatment of MM, a sizeable proportion of patients fail to respond to bortezomib therapy. The results of a recent study suggest that differing proteasome expression and activity levels may underlie the variable sensitivity of MM tumors to treatments with PIs (22). Furthermore, even patients who initially respond to bortezomib face almost-certain relapse. Growing evidence suggests that a small population of drug-resistant cancer stem cells may be responsible for recurrence of MM following remission (23-26). These cells express surface antigens characteristic of normal memory B cells, lack the plasma cell marker CD 138, and do not secrete antibody (24). Furthermore, when challenged with commonly used anti-myeloma drugs (e.g., dexamethasone, lenalidomide, cyclophosphamide) the CD138-negative stem cell population shows greater drug resistance than the rest of the malignant cell population (24). Single-agent bortezomib, for example, is active against MM cells that produce high amounts of immunoglobulin (27), but has little effect on growth of CD138-negative MM cells (24). These data highlight the need for new MM therapies that target cancer stem cells, as well as the remainder of the malignant plasma cell subtypes within the tumor population

A search for novel, more potent, or better-tolerated PIs resulted in the synthesis of COMPOUND 1 (also known as [(lR)-l-[[(2S,3R)-3-hydroxy-2-[6-phenyl-pyridine-2- carbonyl)amino]-l-oxobutyl]amino]-3-methylbutylboronic acid; Bernardini, et al., U.S. Application No. US 2005/0107307). Like bortezomib, COMPOUND 1 is a reversible PI in the peptide boronic acid class (28). In contrast to bortezomib, which is administered by intravenous (IV) bolus, COMPOUND 1 is active as an oral formulation in preclinical studies (28,29). Furthermore, COMPOUND 1 shows similar or better single-agent antitumor activity when compared with bortezomib, both in primary MM plasma cells in vitro and in RPMI8226 MM xenografts in vivo (29). COMPOUND 1 has the following chemical structure:

There remains a need for treatment options that can offer the best long-term outcome for multiple-myeloma patients. The need is especially urgent for novel therapies for patients with relapsed or refractory disease. Until the study disclosed herein, the combination therapy of COMPOUND 1 with either bortezomib or melphalan had never been investigated. These combination therapies offer attractive treatment options for MM patients, including those with relapsed or refractory disease.

All references cited are hereby incorporated by reference.

SUMMARY

Provided are methods for treating multiple myeloma in a subject with

COMPOUND 1. In one embodiment, the subject is administered a combination of COMPOUND 1 and bortezomib. Preferably, the bortezomib is administered as a prodrug. Preferably, the bortezomib is administered intravenously or orally.

Preferably, the bortezomib is administered at a dose in the range of about 0.5 mg/m² to about 2 mg/m². Preferably, the bortezomib is administered at a dose in the range of about 0.7 mg/m² to about 1.3 mg/m².

Preferably, the bortezomib is administered pursuant to a scheduled dosing cycle in which bortezomib is administered every 3 to 7 days for 2 to 4 weeks, followed by a rest period of about 7 to 21 days during which bortezomib is not administered. Preferably, the bortezomib is administered pursuant to a scheduled dosing cycle in which bortezomib is administered on days 1, 4, 8 and 11 of a 21 day cycle. Preferably, the bortezomib is administered pursuant to a scheduled dosing cycle in which bortezomib is administered on days 1, 4, 8 and 11 of a 28 day cycle. Preferably, the scheduled cycle is repeated at least once. In another embodiment, the subject is administered a combination of COMPOUND 1 and melphalan. Preferably, the melphalan is administered as a prodrug. Preferably, the melphalan is administered orally or intravenously.

Preferably, the melphalan is administered at a dose in the range of about 0.025 mg/kg to about 0.5 mg/kg. Preferably, the melphalan is administered at a dose in the range of about 0.025 mg/kg to about 0.3 mg/kg.

Preferably, the melphalan is administered pursuant to a scheduled dosing cycle in which melphalan is administered every 3 to 7 days for 1 to 2 weeks, followed by a rest period of about 4-6 weeks during which melphalan is not administered. Preferably, the melphalan is administered pursuant to a scheduled dosing cycle in which melphalan is administered once-daily for about 4 to about 7 days, followed by a rest period of about 4-6 weeks. Preferably, the melphalan is administered pursuant to a scheduled dosing cycle in which melphalan is administered once-daily for about 4 to about 5 days, followed by a rest period of about 4-6 weeks. Preferably, the scheduled cycle is repeated at least once.

Preferably, the COMPOUND 1 is administered as a prodrug. Preferably, the

COMPOUND 1 prodrug is a pharmaceutically acceptable ester form of COMPOUND 1. Preferably, the COMPOUND 1 is administered intravenously or orally.

Preferably, the COMPOUND 1 is administered at a dose in the range of about 0.5 mg/m² to about 5 mg/m². Preferably, the COMPOUND 1 is administered at a dose in the range of about 1 mg/m² to about 3 mg/m². Preferably, the COMPOUND 1 is administered pursuant to a scheduled dosing cycle in which COMPOUND 1 is administered every 3 to 14 days for 2 to 4 weeks, followed by a rest period of about 7 to 21 days during which COMPOUND 1 is not administered.

Preferably, the COMPOUND 1 is administered pursuant to a scheduled dosing cycle in which COMPOUND 1 is administered on days 1, 4, 8 and 11 of a 21 day cycle. Preferably, the COMPOUND 1 is administered pursuant to a scheduled dosing cycle in which COMPOUND 1 is administered on days 1, 4, 8 and 11 of a 28 day cycle. Preferably, the COMPOUND 1 is administered pursuant to a scheduled dosing cycle in which COMPOUND 1 is administered on days 1 and 15 of a 21 day cycle. Preferably, the COMPOUND 1 is administered pursuant to a scheduled dosing cycle in which COMPOUND 1 is administered on days 1 and 15 of a 28 day cycle. Preferably, the scheduled cycle is repeated at least once.

Preferably, the COMPOUND 1 is administered on days 1, 5 and 9 of a 21 day cycle or a 28 day cycle, and bortezomib is administered on days 3, 8, and 12 of the 21 day cycle or the 28 day cycle. Preferably, the bortezomib is administered on days 1, 5 and 9 of a 21 day cycle or a 28 day cycle, and COMPOUND is administered on days 3, 8, and 12 of the 21 day cycle or the 28 day cycle.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1. COMPOUND 1 inhibits the viability of MM cell lines as a single agent or in combination with other anti-MM therapeutics. A, The viability of MMlS (triangles) and RPMI8226 (squares) was assessed by MTS assay following 48 hours of incubation with the indicated concentrations of COMPOUND 1. 2?, MMlS cells were exposed to vehicle control (black bar), COMPOUND 1 (white bars), bortezomib (striped bars), or both agents (hatched bars) at the concentrations indicated for 48 hours, and viability was quantified by MTS assay. C, RPMI8226 cells were exposed to vehicle control (black bar), melphalan (40 μM) (white bars), COMPOUND 1 (concentrations indicated) (striped bars), or both agents (hatched bars) for 48 hours, and viability was quantified by MTS assay. Data graphed are the mean ± standard error of the mean (SEM) using 6 replicates. In 2? and C, combination indices (CI) are displayed above the hatched bars. CI values below 0.9 indicate synergistic activity; CI values between 0.9 and 1.1 indicate additive activity, and CI values above 1.1 indicate antagonistic activity.

Figure 2. COMPOUND 1, alone or in combination with bortezomib, does not inhibit the viability of normal peripheral blood mononuclear cells (PBMCs). A, PBMCs from a healthy volunteer were incubated with vehicle control (black bar), COMPOUND 1 alone (3.0 nM) (white bars), bortezomib alone (indicated concentrations) (striped bars), or COMPOUND 1 (3.0 nM) + bortezomib (indicated concentrations) (hatched bars) for 48 hours, after which cell viability was determined with the MTS assay. B, PBMCs from the same volunteer as in A were incubated with vehicle control (black bar), bortezomib alone (3.0 nM) (white bars), COMPOUND 1 alone (indicated concentrations) (striped bars), or COMPOUND 1 (indicated concentrations) + bortezomib (3.0 nM) (hatched bars), after which cell viability was determined using the MTS assay. C, PBMCs from a second volunteer were incubated with vehicle control (black bar), COMPOUND 1 alone (3.0 nM) (white bars), bortezomib alone (indicated concentrations) (striped bars), or COMPOUND 1 (3.0 nM) + bortezomib (indicated concentrations) (hatched bars) for 48 hours, after which cell viability was determined with the MTS assay. D, PBMCs from 3 healthy volunteers were incubated with increasing concentrations of COMPOUND 1 for 48 hours, after which cell viability was determined with the MTS assay. Each graph (A-D) is representative of three independent experiments.

Figure 3. COMPOUND 1 combined with bortezomib induces apoptosis in MM cells. RPMI8226 cells were incubated with (A) vehicle control, (B) COMPOUND 1 (2.5 nM), (C) bortezomib (2.5 nM), or (D) COMPOUND 1 (2.5 nM) plus bortezomib (2.5 nM) for 30 hours, and the percentage of staining positive for propidium iodide (PrI) and annexin V was quantified using flow cytometric analysis. Cells in early apoptosis are PrI negative and annexin V positive.

Figure 4. COMPOUND 1 inhibits the growth of human MM tumors. A, B, starting on day 14, mice bearing human LAGK-IA tumors received vehicle control or the indicated doses of COMPOUND 1 administered by IV or with oral gavage twice weekly for the duration of the study. Each week thereafter, serum human immunoglobulin (IgG) levels were assessed by ELISA (A) and tumor volume was measured with calipers (B). C, starting on day 21, mice bearing human LAGK-IB tumors were treated twice weekly for the duration of the study with vehicle control or the indicated concentrations of

COMPOUND 1 , and tumor volume was assessed weekly. Data are presented as means ± standard error of the mean, with 7-8 mice per group.

Figure 5. COMPOUND 1 combined with bortezomib or melphalan markedly inhibits the growth of myeloma tumors. A, B, COMPOUND 1 combined with bortezomib prevents the growth of LAGK-IA tumors. Starting on day 7, mice bearing LAGK-IA tumors were treated twice weekly with vehicle control, COMPOUND 1 alone (1 mg/kg), bortezomib alone (0.5 mg/kg), or COMPOUND 1 (1 mg/kg IV) plus bortezomib (0.5 mg/kg IV). Each week thereafter, serum human IgG levels (A) and tumor volume (B) were measured. C, COMPOUND 1 combined with bortezomib delays progression of LAGK-IB tumor volume by 100%. Starting on day 7, mice bearing LAGK-IB tumors were treated twice weekly with vehicle control, COMPOUND 1 alone (1 mg/kg), bortezomib alone (0.5 mg/kg), or COMPOUND 1 (1 mg/kg IV) plus bortezomib (0.5 mg/kg IV). Each week thereafter, tumor volume was measured. D, E, COMPOUND 1 combined with melphalan inhibits the growth of LAGK-IA tumors. Starting on day 7, mice bearing LAGK-IA tumors were treated with vehicle control twice weekly, COMPOUND 1 alone twice weekly (1 mg/kg), melphalan alone weekly (1 mg/kg), or twice weekly COMPOUND 1 (1 mg/kg IV) plus weekly melphalan (1 mg/kg IP). Each week thereafter, serum human IgG levels (D) and tumor volume (E) were measured. F, COMPOUND 1 combined with melphalan produces more decreases in LAGK-IB tumor volume than either drug alone. Starting on day 7, mice bearing LAGK-IB tumors were treated with vehicle control twice weekly, COMPOUND 1 alone twice weekly (1 mg/kg), melphalan alone weekly (3 mg/kg), or twice weekly COMPOUND 1 (1 mg/kg IV) plus weekly melphalan (3 mg/kg IP). Each week thereafter, tumor volume was measured. Data in parts A-F are presented as means ± standard error of the mean, with 7-8 mice per group.

Figure 6. LAGK-IB tumors treated with COMPOUND 1 and bortezomib show increased expression of the apoptotic marker apoptosis-inducing factor (AIF). Tumors excised from LAGK- IB-bearing mice following treatment with vehicle control (A), COMPOUND 1 (1 mg/kg) alone (B), bortezomib (0.5 mg/kg) alone (C), or both agents (D) were sectioned and stained for AIF. E-H, Sections from the same tumors as A-D stained with isotype controls. Slides were stained simultaneously.

Figure 7. Oral COMPOUND 1 inhibits the growth of human MM tumors. Effect of orally administered COMPOUND 1 on tumor volume levels.

Figure 8. Oral COMPOUND 1 inhibits the growth of human MM tumors. Effect of orally administered COMPOUND 1 on IgG levels.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The term "about" as used herein when referring to a measurable value such as an amount, a temporal duration, and the like, is meant to encompass variations of ±10% from the specified value. For example, the phrase "about 50%" includes ±10% of 50, or from 45% to 55%. As used herein, the term "subject" includes warm blooded animals, preferably mammals, including humans. In a preferred embodiment, the subject is a primate. In an even more preferred embodiment, the subject is a human.

Provided are methods for treating multiple myeloma in a subject. In one embodiment, the subject is administered a combination of COMPOUND 1 and bortezomib. We have found that the method of treating multiple myeloma with a combination of COMPOUND 1 and bortezomib according to the present invention synergistically treats multiple myeloma. This is surprising because COMPOUND 1 and bortezomib are both reversible boronic acid proteasome inhibitors that induce cell death through activation of the extrinsic and intrinsic apoptotic signaling pathways (7,29).

Furthermore, both agents primarily target the proteasome 's chymotrypsin-like catalytic activity, with minor inhibition of the caspase-like and little inhibition of the trypsin-like activities (29,34). Thus, COMPOUND 1 and bortezomib appear to have similar mechanisms of action. In addition, the compounds have very similar chemical structures.

Bortezomib ([(lR)-3-methyl-l-({(2S)-3-phenyl-2-[(pyrazin-2- ylcarbonyl)amino]propanoyl} amino) butyljboronic acid; marketed by Millennium Pharmaceuticals under the trade name Velcade®) has the following chemical structure:

Thus, the means through which COMPOUND 1 and bortezomib together induce enhanced activity against MM cells in vitro and tumors, particularly nonsecretory tumors, in vivo is unclear.

In another embodiment, the subject is administered a combination of COMPOUND 1 and melphalan. We have found that the method of treating multiple myeloma with a combination of COMPOUND 1 and melphalan according to the present invention synergistically treats multiple myeloma.

Melphalan (4-[bis(2-chloroethyl)amino]-Z-phenylalanine; marketed by GlaxoSmithKline under the trade name Alkeran®) has the following chemical structure:

The COMPOUND 1 , bortezomib and/or melphalan used in the present invention may be administered in any suitable chemical form, including as prodrugs, such as a pharmaceutically acceptable salt form and/or pharmaceutically acceptable ester form of the parent compound. Preferably, the pharmaceutically acceptable salt or ester derivative of the parent compound converts to the parent compound upon administration. As used herein, "pharmaceutically acceptable salt" refers to a derivative of the parent compound in which the compound is modified by making an acid or base salt thereof. Examples of pharmaceutically acceptable salts include, but are not limited to, mineral or organic acid salts of basic residues such as amines; alkali or organic salts of acidic residues such as carboxylic acids or boronic acids; and the like. As used herein, "pharmaceutically acceptable ester" refers to a derivative of the parent compound in which an acid residue is modified by making an ester thereof. Examples of pharmaceutically acceptable esters include, for example, boronic esters, i.e., an ester derivative of a boronic acid compound, and cyclic boronic esters. Examples of cyclic boronic esters include, but are not limited to, pinanediol boronic ester, pinacol boronic ester, 1 ,2-ethanediol boronic ester, 1,3- propanediol boronic ester, 1 ,2-propanediol boronic ester, 2,3-butanediol boronic ester, 1,1,2,2-tetramethylethanediol boronic ester, 1 ,2-diisopropylethanediol boronic ester, 5,6- decanediol boronic ester, 1 ,2-dicyclohexylethanediol boronic ester, bicyclohexyl- 1,1 '- diol, and 1 ,2-diphenyl- 1,2-ethanediol boronic ester.

Therefore, in certain embodiments the COMPOUND 1 and/or bortezomib is administered as a boronic ester derivative of the parent compound. In one embodiment, the COMPOUND 1 is administered as a boronic ester derivative of COMPOUND 1. In one embodiment, the bortezomib is administered as a boronic ester derivative of bortezomib.

Any suitable method of administration may be used. Examples include injection (subcutaneous, intravenous, parenterally, intraperitoneally, intrathecal, etc.), oral, inhalation, and transdermal. When administered by injection, the injection can be bolus or continuous infusion. The COMPOUND 1 and bortezomib can be administered to the subject separately (e.g., as sequential injections, an injection and an oral administration, or separate oral administrations) or together as a mixture (e.g., in a single injection or a single oral administration, such as by administration of a single tablet containing both COMPOUND 1 and bortezomib). In the same way, the COMPOUND 1 and melphalan can be administered to the subject separately or together as a mixture. The proportion or concentration of a compound of the invention in a pharmaceutical composition can vary depending upon a number of factors including dosage, chemical characteristics (e.g., hydrophobicity), and the route of administration.

For example, bortezomib is suitable for oral administration or intravenous injection. For example, bortezomib is available under the trade name Velcade® from Millennium Pharmaceuticals as a sterile lyophilized powder in a single use vial, which contains 3.5 mg bortezomib and 35 mg of the bulking agent mannitol. The powder is reconstituted with 3.5 mL of 0.9% NaCl by the clinician for injection. The bortezomib is present as a mannitol boronic ester in the Velcade lyophilized formulation, and after reconstitution is present as the mannitol boronic ester in equilibrium with the parent boronic acid (42). Therefore, in one embodiment the bortezomib is administered by intravenous (IV) injection. In another embodiment, the bortezomib is administered orally, preferably in a tablet or capsule. In one embodiment, the bortezomib is administered by injection in the form of a prodrug, such as a boronic ester. In one embodiment, the bortezomib is administered orally in the form of a prodrug, such as a boronic ester.

For example, melphalan is suitable for oral administration or intravenous injection. For example, melphalan is available under the trade name Alkeran® from GlaxoSmithKline as either a film coated tablet for oral administration or a sterile lyophilized powder in a single use vial. The film coated tablet contains 2 mg melphalan, and the excipients colloidal silicon dioxide, crospovidone, hypromellose, macrogol/PEG 400, magnesium stearate, microcrystalline cellulose, and titanium dioxide. The lyophilized powder contains melphalan hydrochloride equivalent to 50 mg melphalan, and 20 mg povidone. The powder is reconstituted for injection using the vial of sterile diluent provided, which contains sodium citrate 0.2 g, propylene glycol 6.0 mL, ethanol (96%) 0.52 mL, and Water for Injection to a total of 10 mL (43). Therefore, in one embodiment the melphalan is administered by intravenous (IV) injection as the hydrochloride salt. In another embodiment, the melphalan is administered orally, preferably in a tablet or capsule.

For example, COMPOUND 1 is suitable for administration by IV injection or by oral dosage form, such as in a tablet or capsule (28, 29). For example, COMPOUND 1 is presently under evaluation in a first in man Phase I clinical study in patients with solid tumor or Non-Hodgkin's lymphoma. In the Phase I study, COMPOUND 1 is provided as a sterile lyophilized powder in a single use vial, which contains 4 mg COMPOUND 1, 196 mg of the bulking agent hydroxypropyl-β-cyclodextrin, and 156.8 mg of the bulking agent mannitol. The powder is reconstituted with either 5 mL or 10 mL (depending upon the intended dose) of either sterile Water for Injection, 0.9% NaCl, or 5% mannitol before injection. Therefore, in one embodiment the COMPOUND 1 is administered by intravenous (IV) injection. In another embodiment, the COMPOUND 1 is administered orally, preferably in a tablet or capsule. In one embodiment, the COMPOUND 1 is administered by injection in the form of a prodrug, such as a boronic ester. In one embodiment, the COMPOUND 1 is administered orally in the form of a prodrug, such as a boronic ester.

The combination of COMPOUND 1 and bortezomib or COMPOUND 1 and melphalan is preferably administered in an amount effective to treat multiple myeloma, e.g., effective to prevent, alleviate, or ameliorate symptoms of the disease, prolong survival of the subject being treated, prevent undesirable cell growth, or reduce the size of a pre-existing benign cell mass or malignant tumor in the subject. Determination of the effective amount of each agent in the combination is well within the capability of those skilled in the art in light of the detailed disclosure and examples provided herein. The effective amount can vary depending on such factors as the type of cell growth being treated or inhibited, the size of the subject, the severity of the cancer cell growth or tumor, the frequency of administration (e.g., daily vs. once every several days), the manner of administration of the compound, the health and co-morbid conditions of the patient, the judgment and experience of the prescribing physician (e.g., with the same or similar drugs), the mode of administration, the bioavailability characteristics of the dosage form administered, the dose regimen selected, and the kind of concurrent treatment (e.g., additional chemotherapeutic agents). U.S. Pat. No. 5,427,916, for example, describes method for predicting the effectiveness of antineoplastic therapy in individual patients, and illustrates certain methods which can be used in conjunction with the treatment protocols of the instant invention. For example, effective doses can be extrapolated from dose-response curves derived from in vitro or animal model test systems, and may be based on the surface area of the patient.

Treatment can be initiated with smaller dosages which are less than the optimum dose of the compound. Thereafter, the dosage can be increased by small increments until the optimum effect under the circumstances is reached. The total daily dosage may be divided and administered in portions during the day if desired. To optimize the dosing regimen, the effectiveness of a combination of COMPOUND 1 with bortezomib or COMPOUND 1 with melphalan to treat multiple myeloma can be monitored by comparing tumor measurements at two or more time points obtained from a patient undergoing anti-cancer treatment. In general, it is preferable to obtain the initial assessment of tumor burden from the patient prior to beginning therapy and one or more additional assessments at different time points during treatment. In such a use, a baseline determination of tumor burden prior to therapy is determined and then changes in the amount of cancer are determined during the course of therapy. Alternatively, two or more successive determinations can be made during treatment without the need of a pre- treatment baseline measurement of tumor burden, hi such a use, the first assessment of tumor burden should be made from the subject as a baseline level for determining whether the tumor burden is increasing or decreasing.

The regimen of administration, e.g., the timing and/or sequence of administration, of the COMPOUND 1 and bortezomib or COMPOUND 1 and melphalan can vary depending on such factors as the pharmacokinetics of each dosage form, the type of cell growth being treated or inhibited, the size of the subject, the severity of the cancer cell growth or tumor, and the effective dosage. The timing and sequence of administration of the COMPOUND 1 and bortezomib or COMPOUND 1 and melphalan can be readily varied by the treating physician to optimize efficacy and minimize side effects in light of the above considerations and the present detailed disclosure.

There is wide flexibility in the dosing schedules for COMPOUND 1 , bortezomib, and melphalan according to present invention. In certain embodiments, the dosing schedules can be adapted from dosing schedules known to be suitable for these drugs. For example, bortezomib (1.3 mg/m²) is approved to treat previously untreated multiple myeloma by administration as a 3-5 second bolus IV injection in combination with oral melphalan (9 mg/m²) and oral prednisone (60 mg/m²) for nine 6-week treatment cycles as shown in Table 1. In Cycles 1-4, bortezomib is administered twice weekly on days 1, 4, 8, 11, 22, 25, 29 and 32. In Cycles 5-9, bortezomib is administered once weekly on days 1, 8, 22 and 29 (42).

Table 1. Dosage Regimen for Patients with Previously Untreated Multiple Myeloma \

Twice Weekly Bortezomib (Cycles 1-4)

Once Weekly Bortezomib (Cycles 5-9 when used in combination with Melphalan and

Prednisone)

If significant drug-related toxicity is observed during the treatment regimen (e.g., hematological toxicity), subsequent bortezomib doses can be skipped and/or reduced (e.g., from 1.3 mg/m to 1 mg/m , and possibly to 0.7 mg/m ). Additionally or alternatively, melphalan doses can be reduced by 25% in the next cycle (42). As another example, bortezomib is approved to treat relapsed or refractory multiple myeloma by administration as a 3-5 second bolus IV injection on days 1, 4, 8, and 11 of a 3-week cycle followed by a 10-day rest period (days 12-21). For extended therapy of more than 8 cycles, bortezomib can be administered on the standard schedule or on a maintenance schedule of once weekly for 4 weeks (days 1, 8, 15 and 22) followed by a 13-day rest period (days 23-35) (42).

If significant drug-related toxicity is observed during the treatment regimen (e.g., hematological toxicity, neuropathic pain and/or peripheral neuropathy), subsequent bortezomib doses can be skipped and/or reduced (e.g., from 1.3 mg/m to 1 mg/m , and possibly to 0.7 mg/m²) (42).

For use in the combination of the present invention, the bortezomib regimen may be similar to or different from the approved multiple myeloma regimens, including those presented above. For example, the bortezomib may be administered more or less frequently than in the approved regimens, and may optionally be administered at higher or lower doses.

The bortezomib may be administered in conjunction with COMPOUND 1 at any suitable dose. Suitable bortezomib doses can be in the range of about 0.5 mg/m² to about 7 mg/m², such as about 0.5 mg/m² to about 5 mg/m², for example about 0.5 mg/m² to about 3 mg/m². A suitable bortezomib dose will typically range from about 0.5 mg/m² to about 2 mg/m². Preferably, the bortezomib dose is in the range of about 0.6 mg/m² to about 1.5 mg/m². More preferably, the bortezomib dose is in the range of about 0.7 mg/m² to about 1.3 mg/m². Preferred bortezomib doses include, but are not limited to, 0.7 mg/m², 1 mg/m , or 1.3 mg/m². The preceding doses are suitable for any method of bortezomib administration, and are especially suitable for subcutaneous or intravenous dosing, with intravenous dosing preferred. Oral doses of bortezomib will typically be at the high end of the preceding ranges, such as about 1 mg/m² to about 5 mg/m², about 1.5 mg/m² to about 4 mg/m , or about 2 mg/m² to about 3 mg/m².

The bortezomib may be administered at the above-described doses with COMPOUND 1 according to any suitable schedule. The bortezomib dose amounts may be constant or varied within the dosing schedule. Preferably, the bortezomib dose is maintained at a constant level during the schedule unless significant drug-related toxicity is observed, in which case subsequent doses can be reduced, for example by about 20- 30%. The bortezomib may be administered on the same or different days as the COMPOUND 1. In one embodiment, the bortezomib and COMPOUND 1 are administered on the same days during the schedule. A suitable bortezomib schedule will typically range from once-daily dosing to once-weekly dosing or even once-monthly dosing. Preferably, the bortezomib is administered less frequently than once-daily, such as one dose every 2-14 days. Preferably, the bortezomib is administered every 3 to 7 days, such as every 3 to 4 days. Preferably, the schedule includes, after treatment with bortezomib for one or more weeks, such as 2, 3, or 4 weeks, a period of at least 5 days during which bortezomib is not administered, such as a period of about 7 to 21 days.

Preferably, the rest period is about 10 to 17 days, such as about 10 days or about 17 days. For example, the bortezomib can be administered on days 1, 4, 8 and 11 of a 21 day cycle, wherein days 12-21 are a rest period. As another example, the bortezomib can be administered on days 1, 4, 8, and 11 of a 28 day cycle, wherein days 12-28 are a rest period. As another example, the bortezomib can be administered once weekly for 4 weeks (e.g., days 1, 8, 15 and 22 of a 35 day cycle) followed by a 13-day rest period (e.g., days 23 to 35 of the 35 day cycle). The scheduled dosing cycles can be repeated one or more times. For example, the scheduled cycle may be repeated until maximum response is observed, plus one or two additional cycles. As another example, the scheduled cycle may be repeated for 6 to 12 cycles. Optionally, after the initial cycles are completed, a "maintenance schedule" may be used in which the bortezomib is administered less frequency than in the initial schedule, such as once per week or once every two weeks. The maintenance schedule may be continued either for a fixed period of time, generally 1- 2 years, or indefinitely as long as the patient is continuing to show no signs of progressive disease and is tolerating the treatment without significant toxicity.

The COMPOUND 1 may be administered in conjunction with bortezomib at any suitable dose. Suitable COMPOUND 1 doses can be in the range of about 0.5 mg/m² to about 10 mg/m², such as about 0.5 mg/m to about 5 mg/m², or about 0.5 mg/m² to about 3 mg/mg². A suitable COMPOUND 1 dose will typically range from about 0.5 mg/m² to about 3 mg/m². Preferably, the COMPOUND 1 dose is in the range of about 1 mg/m² to about 3 mg/m². More preferably, the COMPOUND 1 dose is in the range of about 1.5 mg/m² to about 2.5 mg/m². Preferred COMPOUND 1 doses include, but are not limited to, 1.5 mg/m², 1.8 mg/m², 2.1 mg/m², or 2.4 mg/m². The preceding doses are suitable for any method of COMPOUND 1 administration, and are especially suitable for subcutaneous or intravenous dosing, with intravenous dosing preferred. Oral doses of COMPOUND 1 will typically be at the high end of the preceding ranges, such as about 1 mg/m² to about 7 mg/m². hi one embodiment, the oral dose of COMPOUND 1 is about 2 mg/m² to about 6 mg/m², such as about 3 mg/m² to about 5 mg/m². Exemplary oral COMPOUND 1 doses include, but are not limited to, 2 mg/m², 3 mg/m², 4 mg/m², 5 mg/m² or 6 mg/m².

The COMPOUND 1 may be administered at the above-described doses with bortezomib according to any suitable schedule. The COMPOUND 1 dose amounts may be constant or varied within the dosing schedule. Preferably, the COMPOUND 1 dose is maintained at a constant level during the schedule unless significant drug-related toxicity is observed, in which case subsequent doses can be reduced, for example by about 20- 30%. The COMPOUND 1 may be administered on the same or different days as the bortezomib. In one embodiment, the COMPOUND 1 and bortezomib are administered on the same days during the schedule. A suitable COMPOUND 1 schedule will typically range from once-daily dosing to once-weekly dosing or even once-monthly dosing. Preferably, the COMPOUND 1 is administered less frequently than once-daily, such as one dose every 2-14 days. Preferably, the COMPOUND 1 is administered every 3 to 28 days, such as every 7 to 21 days. For example, the COMPOUND 1 may be administered twice per week. In another example, COMPOUND 1 may be administered once per week. In another example, COMPOUND 1 may be administered once every two weeks. Preferably, the schedule includes, after treatment with COMPOUND 1 for one or more weeks, such as 2, 3, or 4 weeks, a period of at least 5 days during which COMPOUND 1 is not administered, such as a period of about 7 to 21 days. Preferably, the rest period is about 10 to 17 days, such as about 10 days or about 17 days. For example, the

COMPOUND 1 can be administered on days 1, 4, 8 and 11 of a 21 day cycle, wherein days 12-21 are a rest period. In another embodiment, the COMPOUND 1 can be administered on days 1, 4, 8, and 11 of a 28 day cycle, wherein days 12-28 are a rest period. In another embodiment, the COMPOUND 1 can be administered on days 1 and 8 of a 21 day cycle, wherein days 12-21 are a rest period. In another embodiment, the

COMPOUND 1 can be administered on days 1 and 8 of a 28 day cycle, wherein days 12- 28 are a rest period. In another embodiment, the COMPOUND 1 can be administered on days 1 and 15 of a 21 day cycle. In another embodiment, the COMPOUND 1 can be administered on days 1 and 15 of a 28 day cycle. As previously mentioned, the bortezomib can be administered on the same or different days of the schedule. For example, both the COMPOUND 1 and bortezomib can be administered on days 1, 4, 8 and 11 of a 21 day cycle. In another embodiment, both the COMPOUND 1 and bortezomib can be administered on days 1, 4, 8, and 11 of a 28 day cycle. In another embodiment, the bortezomib can be administered on days 1, 4, 8 and 11 of a 21 day cycle, and COMPOUND 1 can be administered on days 1 and 8 of the 21 day cycle. In another embodiment, the bortezomib can be administered on days 1, 4, 8 and 11 of a 28 day cycle, and COMPOUND 1 can be administered on days 1 and 8 of the 28 day cycle. In another embodiment, the bortezomib can be administered on days 1, 4, 8, and 11 of a 21 day cycle, and COMPOUND 1 can be administered on days 1 and 15 of the 21 day cycle. In another embodiment, the bortezomib can be administered on days 1, 4, 8, and 11 of a 28 day cycle, and COMPOUND 1 can be administered on days 1 and 15 of the 28 day cycle. In another embodiment, the COMPOUND 1 can be administered on days 1, 4, 8 and 11 of a 21 day cycle or a 28 day cycle, and bortezomib can be administered on days 2, 5, 9 and 12 of the- 21 day cycle or the 28 day cycle. In another embodiment, the bortezomib can be administered on days 1, 4, 8 and 11 of a 21 day cycle or a 28 day cycle, and COMPOUND 1 can be administered on days 2, 5, 9 and 12 of the 21 day cycle or the 28 day cycle. In another embodiment, the COMPOUND 1 can be administered on days 1 and 8 of a 21 day cycle or a 28 day cycle, and bortezomib can be administered on days 2, 5, 9 and 12 of the 21 day cycle or the 28 day cycle. In another embodiment, the bortezomib can be administered on days 1, 4, 8 and 11 of a 21 day cycle or a 28 day cycle, and COMPOUND 1 can be administered on days 2 and 9 of the 21 day cycle or the 28 day cycle. In another embodiment, the COMPOUND 1 can be administered on days 1 and 15 of a 21 day cycle or a 28 day cycle, and bortezomib can be administered on days 2, 5, 9, and 12 of the 21 day cycle or the 28 day cycle. In another embodiment, the bortezomib can be administered on days 1, 4, 8, and 11 of a 21 day cycle or a 28 day cycle, and COMPOUND 1 can be administered on days 2 and 16 of the 21 day cycle or the 28 day cycle. In another embodiment, the COMPOUND 1 can be administered on days 1 and 8 of a 21 day cycle or a 28 day cycle, and bortezomib can be administered on days 4 and 11 of the 21 day cycle or the 28 day cycle. In another embodiment, the bortezomib can be administered on days 1 and 8 of a 21 day cycle or a 28 day cycle, and COMPOUND 1 can be administered on days 4 and 11 of the 21 day cycle or the 28 day cycle. In another embodiment, the COMPOUND 1 can be administered on days 1, 5 and 9 of a 21 day cycle or a 28 day cycle, and bortezomib can be administered on days 3, 8, and 12 of the 21 day cycle or the 28 day cycle. In another embodiment, the bortezomib can be administered on days 1, 5 and 9 of a 21 day cycle or a 28 day cycle, and COMPOUND 1 can be administered on days 3, 8, and 12 of the 21 day cycle or the 28 day cycle. In another embodiment, the COMPOUND 1 can be administered on days 1 and 15 of a 21 day cycle or a 28 day cycle, and bortezomib can be administered on days 1, 6 and 11 of the 21 day cycle or the 28 day cycle. In another embodiment, the bortezomib can be administered on days 1 and 11 of a 21 day cycle or a 28 day cycle, and COMPOUND 1 can be administered on days 5 and 15 of the 21 day cycle or the 28 day cycle. The scheduled dosing cycles can be repeated one or more times. For example, the scheduled cycle may be repeated until maximum response is observed, plus one or two additional cycles. As another example, the scheduled cycle may be repeated for 6 to 12 cycles. Optionally, after the initial cycles are completed, a "maintenance schedule" may be used in which the bortezomib and COMPOUND 1 are administered less frequency than in the initial schedule, such as once per week, once every two weeks, once every three weeks, or once every four weeks. The maintenance schedule may be continued either for a fixed period of time, generally 1-2 years, or indefinitely as long as the patient is continuing to show no signs of progressive disease and is tolerating the treatment without significant toxicity.

As previously mentioned, there is wide flexibility in the dosing schedules for COMPOUND 1 and melphalan according to present invention. In certain embodiments, the dosing schedules can be adapted from dosing schedules known to be suitable for these drugs. For example, oral melphalan (9 mg/m²) is approved to treat previously untreated multiple myeloma in combination with bortezomib (1.3 mg/m²) and oral prednisone (60 mg/m²) for nine 6-week treatment cycles as shown in Table 1 above. Melphalan is administered on days 1, 2, 3, and 4 of each 6-week cycle (42).

Oral melphalan is usually administered as a single agent at a dose of 6 mg daily. The dose is adjusted, as required, on the basis of blood counts done at approximately weekly intervals. After 2-3 weeks of treatment, the drug is discontinued for up to 4 weeks, during which time the blood count should be followed carefully. When the white blood cell and platelet counts are rising, a maintenance dose of 2 mg daily may be instituted (43). For use in the combination of the present invention, the melphalan regimen may be similar to or different from the approved multiple myeloma regimens, including those presented above. For example, the melphalan may be administered more or less frequently than in the approved regimens, and may optionally be administered at higher or lower doses.

The melphalan may be administered in conjunction with COMPOUND 1 at any suitable dose. Suitable melphalan doses can be in the range of about 0.025 mg/kg to about 0.5 mg/kg, such as about 0.05 mg/kg to about 0.3 mg/kg. A suitable melphalan dose will typically range from about 0.025 mg/kg to about 0.3 mg/kg. Preferably, the melphalan dose is in the range of about 0.05 mg/kg to about 0.25 mg/kg. More preferably, the melphalan dose is in the range of about 0.1 mg/kg to about 0.2 mg/kg. Preferred melphalan doses include, but are not limited to, 0.1 mg/kg, 0.15 mg/kg, 0.2 mg/kg, or 0.25 mg/kg. The preceding doses are suitable for any method of melphalan administration, and are especially suitable for subcutaneous, intravenous, or oral dosing, with oral dosing preferred.

The melphalan may be administered at the above-described doses with COMPOUND 1 according to any suitable schedule. The melphalan dose amounts may be constant or varied within the dosing schedule. Preferably, the melphalan dose is maintained at a constant level during the schedule unless significant drug-related toxicity is observed, in which case subsequent doses can be reduced, for example by about 20- 30%. The melphalan may be administered on the same or different days as the COMPOUND 1. A suitable melphalan schedule will typically occur on consecutive days for a period of days, followed by a rest period. Preferably, the melphalan is administered once-daily for about 3 to about 7 days, followed by a rest period of about 1-6 weeks. Preferably, the melphalan is administered once-daily for about 4 to about 7 days, followed by a rest period of about 4-6 weeks. Preferably, the melphalan is administered once-daily for about 4 to about 5 days, followed by a rest period of about 4-6 weeks. The schedules can be repeated one or more times.

The COMPOUND 1 may be administered in conjunction with melphalan at any suitable dose. Suitable COMPOUND 1 doses can be in the range of about 0.5 mg/m² to about 10 mg/m², such as about 0.5 mg/m² to about 5 mg/m², or about 0.5 mg/m² to about 3 mg/mg². A suitable COMPOUND 1 dose will typically range from about 0.5 mg/m² to about 3 mg/m². Preferably, the COMPOUND 1 dose is in the range of about 1 mg/m² to about 3 mg/m². More preferably, the COMPOUND 1 dose is in the range of about 1.5 mg/m² to about 2.5 mg/m². Preferred COMPOUND 1 doses include, but are not limited to, 1.5 mg/m², 1.8 mg/m², 2.1 mg/m², or 2.4 mg/m². The preceding doses are suitable for any method of COMPOUND 1 administration, and are especially suitable for subcutaneous or intravenous dosing, with intravenous dosing preferred. Oral doses of COMPOUND 1 will typically be at the high end of the preceding ranges, such as about 1 mg/m² to about 7 mg/m². hi one embodiment, the oral dose of COMPOUND 1 is about 2 mg/m² to about 6 mg/m², such as about 3 mg/m² to about 5 mg/m². Exemplary oral COMPOUND 1 doses include, but are not limited to, 2 mg/m², 3 mg/m², 4 mg/m², 5 mg/m² or 6 mg/m².

The COMPOUND 1 may be administered at the above-described doses with melphalan according to any suitable schedule. The COMPOUND 1 dose amounts may be constant or varied within the dosing schedule. Preferably, the COMPOUND 1 dose is maintained at a constant level during the schedule unless significant drug-related toxicity is observed, in which case subsequent doses can be reduced, for example by about 20- 30%. The COMPOUND 1 may be administered on the same or different days as the melphalan. A suitable COMPOUND 1 schedule will typically range from once-daily dosing to once-weekly dosing or even once-monthly dosing. Preferably, the COMPOUND 1 is administered less frequently than once-daily, such as one dose every 2- 14 days. Preferably, the COMPOUND 1 is administered every 3 to 28 days, such as every 7 to 21 days. For example, the COMPOUND 1 may be administered twice per week. In another example, COMPOUND 1 may be administered once per week. In another example, COMPOUND 1 may be administered once every two weeks. Preferably, the schedule includes a period of at least 5 days during which COMPOUND 1 is not administered, such as a period of about 7 to 21 days. Preferably, the rest period is about 10 to 17 days, such as about 10 days or about 17 days. For example, the COMPOUND 1 can be administered on days 1, 4, 8 and 11 of a 21 day cycle, wherein days 12-21 are a rest period. In another embodiment, the COMPOUND 1 can be administered on days 1, 4, 8, and 11 of a 28 day cycle, wherein days 12-28 are a rest period. In another embodiment, the COMPOUND 1 can be administered on days 1 and 8 of a 21 day cycle, wherein days 12-21 are a rest period. In another embodiment, the COMPOUND 1 can be administered on days 1 and 8 of a 28 day cycle, wherein days 12-28 are a rest period. In another embodiment, the COMPOUND 1 can be administered on days 1 and 15 of a 21 day cycle. In another embodiment, the COMPOUND 1 can be administered on days 1 and 15 of a 28 day cycle. In one embodiment, the COMPOUND 1 can be administered on days 1, 4, 8, 11, 22, 25, 29 and 32 of a 42 day cycle, and melphalan can be administered on days 1, 2, 3 and 4 of the 42 day cycle. In another embodiment, the COMPOUND 1 can be administered on days 1, 4, 8, 11, 22, 25, 29, 32, 43, 50, 64, and 71 of an 84 day cycle, and melphalan can be administered on days 1, 2, 3, 4, 43, 44, 45, and 46 of the 84 day cycle. In another embodiment, the melphalan can be administered on days 1, 2, 3, and 4, of a 28 day cycle, and COMPOUND 1 can be administered on days 1 and 15 of the 28 day cycle. In another embodiment, the melphalan can be administered on days 1, 2, 3, 4, and 5 of a 42 day cycle, and COMPOUND 1 can be administered on days 1, 8, 22 and 29 of the 42 day cycle. The schedules can be repeated one or more times.

One or more additional cancer treatments can be used in combination with the administration of the COMPOUND 1 and bortezomib or COMPOUND 1 and melphalan. Such treatments include cancer agents including, but not limited to, bortezomib, melphalan, dexamethasone and other steroids, doxorubicin, cyclophosphamide, thalidomide, lenalidomide, arsenic trioxide, and histone deacetylase inhibitors. Appropriate doses of these agents are well known in the art. In another aspect of the invention, an additional agent can be a granulocyte colony-stimulating factor (G-CSF) such as filgrastim. In a preferred embodiment, filgrastim is administered at a dose of about 5 μg/kg/day SC starting day 6 until neutrophil recovery to ANOlOOO. ANC is an abbreviation for "absolute neutrophil count."

The combination therapy of the present invention may be used as part of a treatment course further involving attempts to surgically remove part or all of a cancerous growth. For instance, the combination therapy may be administered after surgical treatment of a subject to treat any remaining neoplastic or metastasized cells. Treatment can also precede surgery, in an effort to shrink the size of the tumor to reduce the amount of tissue to be excised, thereby making the surgery less invasive and traumatic.

Treating multiple myeloma with the combination therapy of the presently disclosed subject matter can further include one or more treatment courses with a radiotherapeutic agent to induce DNA damage. Radiotherapeutic agents include, for example, gamma irradiation, X-rays, UV-irradiation, microwaves, electronic emissions, radioisotopes and the like. Therapy can be achieved by irradiating the localized tumor site with the above- described forms of radiation.

Another aspect of the invention relates to methods for purging bone marrow, i.e., removing cancer cells from bone marrow, by exposing the bone marrow cells to the combination therapy of the present invention. The purged bone marrow may then be placed back into the subject from whom the bone marrow was removed, or placed into a different subject.

MATERIALS AND METHODS

Reagents COMPOUND 1 (4 mg; Cephalon, Frazer, PA) was dissolved in propylene glycol

(800 μL) and added to 5% mannitol to generate a final stock concentration of 1 mg/mL; COMPOUND 1 stock solution was diluted to the indicated concentrations immediately before treatment. Bortezomib (Millennium Pharmaceuticals, Cambridge, MA) was obtained at 1 mg/mL and diluted as specified using 0.9% sodium chloride. Melphalan (Sigma, St. Louis, MO) was dissolved in 100 μL acid-EtOH (acid-EtOH: 47 μL concentrated HCl + 1 mL of 100% EtOH) and diluted to 1 mL with phosphate-buffered saline. Formulations were prepared weekly.

Cell lines and primary cells The human myeloma cell line RPMI8226 was obtained from American Type

Culture Collection (Rockville, MD). The MMlS myeloma cell line was provided by Dr. Steven Rosen (Northwestern University, Chicago, IL). Normal peripheral blood mononuclear cells (PBMCs) were isolated by Histopaque^® density gradient centrifugation, according to the manufacturer's protocol (Sigma- Aldrich, St. Louis, MO). Myeloma cell lines and PBMCs were maintained in RPMI 1640 (Omega Scientific, Tarzana, CA) supplemented with 10% fetal bovine serum, 2 mM L-glutamine, 100 IU/mL penicillin, 100 μg/mL streptomycin, and essential amino acids in an atmosphere of 5% carbon dioxide (CO₂) at 37°C.

Cell viability assay (MTS assay)

Cells were seeded at 10⁵ cells/100 μL/well in 96-well plates and incubated for 24 hours. RPMI8226 and MMlS cells were cultured in the presence of vehicle, COMPOUND 1, bortezomib, melphalan, COMPOUND 1 + bortezomib, or COMPOUND 1 + melphalan for 48 hours. After the incubation period, cell viability was quantified using the CellTiter 96^® AQueous Non-Radioactive Cell Proliferation Assay (Promega, Madison, WI). Each well was treated with MTS (3-(4, 5-dimethylthiazol-2-yl)-5-(3- carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt) for 1 to 4 hours, after which absorbance was recorded at 490 nm. The quantity of formazan product as measured by absorbance at 490 nm is directly proportional to the number of living cells in culture.

In vitro synergy between COMPOUND 1 and bortezomib or melphalan was assessed using the median effect method of Chou and Talalay (30). Combination indices (CIs) were calculated separately for each combination. Drug interactions were determined synergistic if the CI was less than 0.9 or antagonistic if the CI was greater than 1.1. CIs between 0.9 and 1.1 were considered to indicate additive drug effects (31).

Apoptotic assay by annexin V and propidium iodide staining

To quantify apoptosis in response to drug treatment, RPMI8226 cells (5 x 10⁵ cells per well) were incubated with vehicle or PIs at 37°C and 5% CO₂ for 30 hours. As a positive control, cells were incubated with 250 ng/mL of actinomycin D for 24 or 48 hours. Cells were then washed twice with phosphate-buffered saline, resuspended in binding buffer (100 mM HEPES/NaOH, pH 7.5 containing 1.4 M NaCl and 25 mM CaCl₂), and stained with fluorescein isothiocyanate (FITC)-conjugated annexin V and with the fluorescent dye propidium iodide (PrI), according to the manufacturer's protocol (Bio Vision, Mountain View, CA). For each drug treatment, 1 x 10⁵ gated events were recorded. Cells negative for both PI and annexin V staining were considered live; annexin V-positive, Prl-negative cells were considered early apoptotic; annexin V-positive, PrI- positive cells were considered late apoptotic. Flow cytometric analyses were performed using a Beckman Coulter FC500 cytometer with Cytomics CXP software (Beckman Coulter, Fullerton, CA).

SCID mice

Six- to 8-week-old male SCID mice were obtained from the Jackson Laboratory (Bar Harbor, ME) and maintained in a specific pathogen-free area in our animal resources facility. All animal studies were conducted according to protocols approved by the Institutional Animal Care and Use Committee. Animals were anesthetized with ketamine, xylazine, and isoflurane prior to surgery and were euthanized when tumors reached 2 cm in diameter.

Intramuscular tumor xenograft models

To establish the LAGK-IA tumor (sensitive to bortezomib and melphalan), a bone marrow biopsy was obtained from a female MM patient who had progressed while on lenalidomide treatment. Immediately subsequent to this biopsy, the patient was treated with a combination of melphalan and bortezomib and showed a response. Biopsy tissue was surgically implanted in the hind limbs of anesthetized SCID mice and passaged through succeeding generations (32). The LAGK-IB tumor (resistant to bortezomib and melphalan) originated from the same patient as LAGK-IA but was generated from a biopsy taken when the patient was progressing on bortezomib and melphalan (32).

Myeloma tumors (LAGK-IA or LAGK-IB) were excised from an anesthetized donor mouse, sectioned into 20 to 40 mm³ pieces, and surgically implanted into the left superficial gluteal muscle of anesthetized naive SCID mice. Recipient mice received weekly injections of anti-asialo GMl rabbit serum (Wako Bioproducts, Richmond, VA) to further suppress immune activity. Mice were blindly assigned to one of the experimental groups, and treatment was initiated 7 to 21 days after tumor implantation. COMPOUND 1 was administered twice weekly (W, F) via either IV injection (0.5-3.0 mg/kg) or oral gavage (10 mg/kg), as specified. Melphalan (1 mg/kg) was provided via weekly intraperitoneal (IP) injections (W). Bortezomib (0.5 mg/kg) was dispensed twice weekly (T, Th) via IV injection. Control treatment consisted of COMPOUND 1 diluent (3.2 mL 5% mannitol and 800 μL propylene glycol) alone.

Human immunoglobulin G (hlgG) enzyme-linked immunosorbent assay (ELISA)

Serum levels of MgG secreted by LAGK-IA tumors (LAGK-IB tumors do not secrete paraprotein) were quantified by ELISA as a protein marker of tumor growth. Mice bearing MM tumors underwent weekly retro-orbital bleeds. Resulting samples were spun at 13,000 rpm for 30 minutes to isolate serum. The hlgG ELISA kit (Bethyl Laboratories, Montgomery, TX) was used according to the manufacturer's specifications. Absorbance at 450 ran with a reference wavelength of 550 run was determined on a μQuant microplate spectrophotometer with KC Junior software (Bio-Tek Instruments, Winooski, VT). Data graphed are the mean ± SEM with n = 7-8 mice/group.

Determination of tumor volume

As a direct measurement of tumor growth, calipers were used to assess tumor volume weekly, and the formula for an ellipsoid volume was applied (4/3 π x [width/2]² x [length/2]).

Immunohistochemical analysis of apoptosis-inducing factor (AIF) expression in tumor cells

LAGK-IB tumors were fixed in 4% paraformaldehyde and cut into 5 μm sections. Briefly, sections were blocked with Tris-buffered saline with 0.05% Tween-20 (TBST) and 3% BSA for 1 hour at room temperature and then incubated overnight with a rabbit antibody against AIF (Sigma, St. Louis, MO). The sections were washed three times with TBST and treated with horse radish peroxidase(ARH)-conjugated anti-rabbit antibody (KPL, Gaithersburg, MD) diluted 1 :500 in TBST at room temperature for 2 hours. The slides were washed three times in TBST and placed in 3-amino-9-ethylcarbazole (AEC) buffer for 5 minutes, and color was detected using an AEC kit (Dako, Glostrup, Denmark). Staining was documented using an Olympus BX51 microscope (Olympus Imaging

America Inc., Center Valley, PA) and analyzed by Microsuite Biological Suite program (Olympus BX51).

Statistical analysis Tumor growth and hlgG levels were analyzed in terms of treatment group means and standard error. Student's t- test was applied to determine the statistical significance of differences between treatment groups. Minimal significance level was P < 0.05.

EXAMPLES

The data presented in the following Examples suggest that the combination therapy of the present invention may provide similar or greater efficacy in MM when COMPOUND 1 and bortezomib or COMPOUND 1 and melphalan are combined in low doses as compared with standard-dose single-agent therapy. In this way, drug-associated toxicities, such as peripheral neuropathy for bortezomib and myelosuppression for melphalan, may be reduced or avoided (40,41). In the experiments presented here, mice treated with combination therapies tolerated treatment well and experienced little or no tumor progression.

Example 1. COMPOUND 1 is cytotoxic to MM cells and synergistic when combined with anti-MM agents in vitro

RPMI8226 and MMlS cells were cultured in the presence of increasing concentrations of COMPOUND 1 (0.1-10 nM). After 48 hours, cell viability was assessed with the MTS assay. COMPOUND 1 induced concentration-dependent inhibition of viability in both cell lines (Fig. IA). Results were similar when cells were treated with COMPOUND 1 for 24 or 72 hours (data not shown).

We next examined cell viability in the presence of COMPOUND 1 plus the PI bortezomib or the chemotherapeutic agent melphalan. First, MMlS cells were incubated with a steady concentration of COMPOUND 1 (1.75 nM) and increasing concentrations of bortezomib (0.5-2.5 nM) for 48 hours. At bortezomib concentrations < 1.5 nM, the cytotoxic effects of COMPOUND 1 were enhanced. For example, as single agents, COMPOUND 1 (1.75 nM) and bortezomib at the lowest concentration (0.5 nM) each inhibited cell viability by approximately 16%. However, when COMPOUND 1 (1.75 nM) was combined with bortezomib (0.5 nM), cell viability decreased by approximately 43% (Fig. IB). Chou-Talalay equations were applied to confirm the synergy of this combination (CIs, 0.74-0.85) (30,31). Similar results were obtained when the experiment was repeated with RPMI8226 cells (data not shown).

When RPMI8226 cells were incubated with melphalan (40 μM) and concentrations of COMPOUND 1 >6.0 nM (IC₅₀ = 8.5 nM), synergistic inhibition of viability was observed (CIs, 0.78-0.87). For example, cell viability decreased by approximately 30% in the presence of single-agent melphalan (40 μM) and by 64% in the presence of single- agent COMPOUND 1 (9.0 nM). When both drugs were applied simultaneously, cell viability was reduced by 90% (Fig. 1C). Together, these results demonstrate that COMPOUND 1 combined with bortezomib or melphalan can synergistically suppress MM cell viability. Example 2. COMPOUND 1 and bortezomib are selectively cytotoxic for neoplastic cells

In order for therapy with two or more PIs to be feasible in vivo, the combination must spare non-neoplastic cells. Therefore, we tested the effects of COMPOUND 1 plus bortezomib on the viability of normal PBMCs. A healthy donor's PBMCs were cultured for 48 hours in the presence of COMPOUND 1 alone, bortezomib alone, or both agents together, and cell viability was quantified by MTS assay. Monotherapy with either PI near its IC₅o in MM cells only modestly inhibited the viability of PBMCs (approximately 75% and 85% viable cells when PBMCs were treated with 9 nM COMPOUND 1 and 9 nM bortezomib, respectively) (Figs. 2 A, B). Co-incubation with both PIs did not further decrease or slightly increased cell viability compared with administration of either agent alone (3%-23% decrease in cell viability when both PIs were administered at all concentrations tested) (Figs. 2A, B). Similar results were obtained with PBMCs derived* from a second healthy donor (Fig. 2C). To determine whether PBMCs were vulnerable to higher concentrations of PIs, PBMCs were cultured with COMPOUND 1 up to 120 nM. When compared with controls, no significant differences in cell viability were detected at any concentration tested (Fig. 2D). Similar results were obtained when PBMCs were incubated with concentrations of bortezomib up to 120 nM (data not shown). Therefore, the combination therapy of the present invention provides enhanced efficacy against MM without increasing toxicity to normal cells.

Example 3. COMPOUND 1 in combination with bortezomib induces apoptosis of MM cells

To determine whether the reduction in cell viability observed following treatment of MM cells with COMPOUND 1 and bortezomib was due to apoptosis, we incubated RPMI8226 cells with both agents (at 2.5 nM for each drug) for 30 hours and measured the fraction of cells stained with the viability dye PrI and the apoptosis marker annexin V. The proportion of cells in early apoptosis (PrI-/ Annexin V+) was greater following treatment with both PIs (38.9% of cells) than with either agent alone (10.4% and 17.5% of cells treated with 2.5 nM COMPOUND 1 or 2.5 nM bortezomib, respectively) (Fig. 3). The proportion of cells in late apoptosis (Prl+/Annexin V+) or necrosis (Prl+/Annexin V-) did not vary among treatment groups at this time point.

Example 4. Single-agent COMPOUND 1 inhibited human MM tumor growth in vivo

Because COMPOUND 1 demonstrates potent anti-MM effects as a single agent and in combination in vitro, we next conducted a series of in vivo studies. For these experiments, we utilized mice bearing LAGK-IA (bortezomib- and melphalan-sensitive) and LAGK-IB (bortezomib- and melphalan-resistant) tumors, both of which were originally derived from bone marrow biopsies of an MM patient. These tumors closely resemble human MM and have been passaged through multiple generations of mice with consistent growth and chemoresistance patterns. Following intramuscular implantation of tumor tissue, mice underwent twice-weekly treatment with COMPOUND 1 at escalating doses ranging from 0.1 to 3 mg/kg IV or 10 mg/kg orally. Control group mice received COMPOUND 1 diluent.

Administration of single-agent COMPOUND 1 IV yielded a dose-dependent decrease in paraprotein secretion from LAGK-IA tumors. Lower doses of COMPOUND 1 reduced tumor hlgG secretion, and higher doses rendered serum hlgG levels essentially undetectable (P = 0.0001 for 1 mg/kg and P = 0.0002 for 3 mg/kg IV COMPOUND 1 , compared with control at 28 days of drug treatment) (Fig. 4A). Unlike bortezomib, COMPOUND 1 also shows activity as an oral formulation (28,29). Within 2 weeks of treatment with oral COMPOUND 1 , serum hlgG levels were significantly lower than in control-treated animals (P = 0.0007). By 28 days of treatment with oral COMPOUND 1, serum hlgG levels were negligible (P = 0.0001, compared with control-treated animals) (Fig. 4A).

In addition to effects on paraprotein levels, single-agent COMPOUND 1 slowed increases in LAGK-IA tumor volume compared with vehicle-treated mice. After 4 weeks of drug treatment, COMPOUND 1 administered IV at 1 or 3 mg/kg resulted in an approximately 15-fold reduction in the volume of tumors, compared with control-treated xenografts at the same time point (P = 0.0001 for each dose compared with control) (Fig. 4B). COMPOUND 1 delivered orally also inhibited tumor growth. After only 14 days of treatment with oral COMPOUND 1 , a marked reduction in tumor volume, compared with control-treated tumors, was observed (P = 0.0002), a difference that persisted throughout the duration of the study (Fig. 4B).

The effect of COMPOUND 1 on tumor volume was also tested in mice bearing the bortezomib-resistant nonsecretory LAGK-IB tumor (Fig 4C). As with the LAGK-IA tumors, COMPOUND 1 inhibited tumor growth, both as an IV injection and as an oral formulation. Compared with control-treated mice, mice treated with 3 mg/kg IV or 10 mg/kg oral COMPOUND 1 showed tumors that were approximately 8 to 12 times smaller after 14 days of treatment (P = 0.0008 and P = 0.0028, respectively) (Fig 4C). Because LAGK-IB tumors used in these experiments are nonsecretory, mice bearing these tumors were not tested for serum hlgG levels.

Example 5. COMPOUND 1 in combination with bortezomib inhibits the growth of bortezontib-sensitive LA GK-IA MM tumors

Because COMPOUND 1 combined with bortezomib induces synergistic apoptosis of MM cells in vitro, we tested this combination on human MM tumors in vivo. We selected drug concentrations with suboptimal single-agent antitumor activity. As monotherapy, both COMPOUND 1 (1 mg/kg IV) and bortezomib (0.5 mg/kg IV) only partially inhibited serum MgG levels and volume of LAGK-IA tumors compared with vehicle control (Figs. 5 A, B). However, gradual progression of tumor growth, as measured by both paraprotein secretion and tumor volume, persisted despite treatment with single-agent COMPOUND 1 or bortezomib. In contrast, co-administration of COMPOUND 1 with bortezomib at the same doses eliminated detectable paraprotein secretion and increases in tumor volume. Differences in growth between control-treated and combination therapy-treated LAGK-IA tumors first became significant 28 days after the initiation of therapy (P = 0.0028 for serum hlgG levels and P - 0.0265 for tumor volume) (Figs. 5 A, B). Complete inhibition of tumor progression was maintained throughout the duration of the experiment (110 days). Furthermore, when mice treated with COMPOUND 1 plus bortezomib were euthanized, examination of excised hind limbs revealed only muscle mass and no tumor tissue. Tumors implanted at study initiation had regressed completely. Notably, the combination treatment was well tolerated without any obvious signs of toxicity.

In previous studies, changes in the volume of hlgG-secreting myeloma tumors were tightly correlated with changes in serum human paraprotein levels (15,32).

However, in these experiments, paraprotein secretion from tumors treated with single- agent COMPOUND 1 or bortezomib plateaued and then declined beginning on the 63rd day of treatment (study day 70); in contrast, tumor volumes continued to increase throughout the duration of the study (Figs. 5 A, B). Therefore, as monotherapy each agent suppressed increases in serum hlgG levels more effectively than tumor volume.

To verify these results, samples from day 70 onward were retested by ELISA, and decreasing hlgG levels were confirmed. The inverse relationship between hlgG levels and tumor volumes suggests that a population of nonsecretory, drug-resistant MM cells exist, perhaps derived from cancer stem cells. Thus, either bortezomib or COMPOUND 1 alone may act primarily against the antibody-secreting mature plasma cell component of MM (22), without affecting the small stem cell population responsible for delayed tumor growth (24).

In contrast, LAGK- 1 A-bearing mice that received a combination of COMPOUND

1 and bortezomib showed a marked and sustained lack of tumor growth, as assessed by both hlgG and tumor volume measurements, throughout the 110-day study. These data indicate that MM cells that proliferate without producing paraprotein in the presence of single-agent PIs are sensitive to the combination of COMPOUND 1 and bortezomib.

Example 6. Combination therapy with COMPOUND 1 and bortezomib overcomes drug resistance in bortezomib-resistant LAGK-IB tumors

LAGK-IB tumors are resistant to bortezomib; and, indeed, either PI alone (0.5 mg/kg IV bortezomib or 1 mg/kg IV COMPOUND 1) only modestly suppresses the growth of these tumors. In contrast, LAGK- IB-bearing mice treated with COMPOUND 1 plus bortezomib developed significantly smaller tumors than vehicle-treated mice after 21 days of therapy (P = 0.0014). Furthermore, after 28 days of treatment, tumors in mice receiving combination therapy were also smaller than those in mice treated with either PI alone (P = 0.0039 and P < 0.0001, for comparisons with COMPOUND 1 alone and bortezomib alone, respectively) (Fig. 5C). In order to determine the time to tumor progression, dosing of mice in the combination-therapy group continued. Compared with tumors treated with single-agent PIs, progression of tumor volume in the combination- therapy group was delayed by 100% (35 days to tumor progression for mice treated with single-agent PIs versus 70 days to tumor progression for mice treated with both PIs). Finally, the overall survival of each treatment group was documented. Compared with vehicle-treated mice, mice receiving combination therapy lived 150% longer (data not shown). Mice treated with either PI alone survived 20% longer than vehicle-treated mice (data not shown). Additional mouse survival data indicated that the tolerability of combination therapy with both PIs was similar to monotherapy (data not shown). Together, these data demonstrate that COMPOUND 1 combined with bortezomib can overcome bortezomib resistance in human MM in vivo.

Example 7. COMPOUND 1 combined with melphalan inhibits the growth of LAGK- IA and LAGK-IB tumors

Because COMPOUND 1 synergizes with melphalan to decrease viability in cultured MM cells, and bortezomib enhances the anti-MM effects of melphalan in both laboratory (11) and clinical studies (33), we evaluated the efficacy of this alkylating agent with COMPOUND 1 in vivo. Treatment with single-agent melphalan at a low dose (1 mg/kg IP) had no effect on serum hlgG levels or tumor volumes in LAGK- 1 A-bearing mice. Likewise, administration of single-agent COMPOUND 1 (1 mg/kg IV) resulted in a nonsignificant decrease in both paraprotein secretion and tumor volume. However, after 3 weeks of treatment, tumors exposed to both COMPOUND 1 and melphalan showed a marked reduction in both hlgG secretion (P = 0.0012) and tumor volume (P = 0.032) compared with vehicle-treated tumors (Figs. 5D, E). A similar result was obtained in mice bearing bortezomib- and melphalan-resistant LAGK-IB tumors. Single-agent melphalan at 3 mg/kg IP (3 times higher than the dose administered to LAGK- 1 A-bearing mice) or COMPOUND 1 at 1 mg/kg IV (the same dose administered to LAGK- 1 A-bearing mice) partially inhibited increases in tumor volume, but when COMPOUND 1 was combined with melphalan tumor volumes were reduced to practically undetectable levels (Fig. 5F). In contrast to single-agent treatment, tumor growth was prevented as long as combination therapy continued in mice bearing either tumor type (63 days of treatment in the LAGK-IA mice and 49 days of treatment in the LAGK-IB mice). Furthermore, the tolerability of combination therapy was similar to that of each agent alone (data not shown).

Example 8. Tumors from LAGK-IB mice treated with COMPOUND 1 and bortezomib show elevated expression of apoptosis-inducing factor

Tumors from LAGK- IB-bearing mice were excised post-treatment and stained with AIF, a marker of apoptosis. Tumors treated with single-agent COMPOUND 1 or bortezomib showed elevated AIF expression when compared with vehicle-treated tumors. However, AIF expression is further increased in tumors taken from animals treated with both PIs (Fig. 6). Tumors from LAGK- 1 A-bearing mice that received COMPOUND 1 plus bortezomib were not available for histological analysis due to lack of available xenograft samples following complete tumor regression in this treatment group.

Example 9. Single-agent oral COMPOUND 1 inhibited human MM tumor growth in vivo

These experiments were performed as described in Example 4 using mice bearing LAGK-IA tumors originally derived from bone marrow biopsies of a MM patient. Following intramuscular implantation of tumor tissue, mice underwent daily or twice- weekly treatment with COMPOUND 1 at escalating doses ranging from 0.5 to 5 mg/kg orally each day or 5 to 10 mg/kg orally twice per week. Control group mice received COMPOUND 1 diluent. \

COMPOUND 1 administered orally and daily at 3 mg/kg has moderate anti- myeloma activity for both human IgG levels and tumor volumes. When orally administered daily at 5 mg/kg COMPOUND 1 has statistically significant anti-myeloma activity (IgG levels and tumor volumes) (Figs. 7 and 8). At this schedule and dose (daily, 5 mg/kg), 87% of the mice survived to day 42. Orally administered COMPOUND 1 dosed twice weekly at 10 mg/kg also results in statistically significant anti -myeloma activity (IgG levels and tumor volumes), with 100% of the mice surviving to day 42. (Figs. 7 and 8)

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42. VELCADE® Full Prescribing Information

43. ALKERAN® Tablets Prescribing Information; ALKERAN® for Inj ection Prescribing Information

Claims

What is Claimed:

1. A method for treating multiple myeloma in a subject, comprising the step of administering to the subject a combination of COMPOUND 1 and bortezomib.

2. The method of claim 1, wherein the bortezomib is administered as a prodrug.

3. The method of claims 1 or 2, wherein the bortezomib is administered intravenously.

4. The method of claims 1 or 2, wherein the bortezomib is administered orally.

5. The method of any of claims 1 to 4, wherein the bortezomib is administered at a dose in the range of about 0.5 mg/m² to about 2 mg/m².

6. The method of claim 5, wherein the bortezomib is administered at a dose in the range of about 0.7 mg/m² to about 1.3 mg/m².

7. The method of any of claims 1 to 6, wherein the bortezomib is administered pursuant to a scheduled dosing cycle in which bortezomib is administered every 3 to 7 days for 2 to 4 weeks, followed by a rest period of about 7 to 21 days during which bortezomib is not administered.

8. The method of claim 7, wherein the bortezomib is administered pursuant to a scheduled dosing cycle in which bortezomib is administered on days 1, 4, 8 and 11 of a 21 day cycle.

9. The method of claim 7, wherein the bortezomib is administered pursuant to a scheduled dosing cycle in which bortezomib is administered on days 1, 4, 8 and 11 of a 28 day cycle.

10. The method of any of claims 7 to 9, wherein the scheduled cycle is repeated at least once.

11. A method for treating multiple myeloma in a subject, comprising the step of administering to the subject a combination of COMPOUND 1 and melphalan.

12. The method according to claim 11 , wherein the melphalan is administered as a prodrug.

13. The method according to claims 11 or 12, wherein the melphalan is administered orally.

14. The method according to claims 11 or 12, wherein the melphalan is administered intravenously.

15. The method of any of claims 11 to 14, wherein the melphalan is administered at a dose in the range of about 0.025 mg/kg to about 0.5 mg/kg.

16. The method of claim 15, wherein the melphalan is administered at a dose in the range of about 0.025 mg/kg to about 0.3 mg/kg.

17. The method of any of claims 11 to 16, wherein the melphalan is administered pursuant to a scheduled dosing cycle in which melphalan is administered every 3 to 7 days for 1 to 2 weeks, followed by a rest period of about 4-6 weeks during which melphalan is not administered.

18. The method of claim 17, wherein the melphalan is administered pursuant to a scheduled dosing cycle in which melphalan is administered once-daily for about 4 to about 7 days, followed by a rest period of about 4-6 weeks.

19. The method of claim 17, wherein the melphalan is administered pursuant to a scheduled dosing cycle in which melphalan is administered once-daily for about 4 to about 5 days, followed by a rest period of about 4-6 weeks.

20. The method of any of claims 17 to 19, wherein the scheduled cycle is repeated at least once.

21. The method of any of claims 1 to 20, wherein the COMPOUND 1 is administered as a prodrug.

22. The method of claim 21 , wherein the COMPOUND 1 prodrug is a pharmaceutically acceptable ester form of COMPOUND 1.

23. The method of any of claims 1 to 22, wherein the COMPOUND 1 is administered intravenously.

24. The method of any of claims 1 to 22, wherein the COMPOUND 1 is administered orally.

25. The method of any of claims 1 to 24, wherein the COMPOUND 1 is administered at a dose in the range of about 0.5 mg/m² to about 5 mg/m².

26. The method of claim 25, wherein the COMPOUND 1 is administered at a dose in the range of about 1 mg/m² to about 3 mg/m².

27. The method of any of claims 1 to 26, wherein the COMPOUND 1 is administered pursuant to a scheduled dosing cycle in which COMPOUND 1 is administered every 3 to 14 days for 2 to 4 weeks, followed by a rest period of about 7 to 21 days during which COMPOUND 1 is not administered.

28. The method of claim 27, wherein the COMPOUND 1 is administered pursuant to a scheduled dosing cycle in which COMPOUND 1 is administered on days 1 , 4, 8 and 11 of a 21 day cycle.

29. The method of claim 27, wherein the COMPOUND 1 is administered pursuant to a scheduled dosing cycle in which COMPOUND 1 is administered on days 1, 4, 8 and 11 of a 28 day cycle.

30. The method of claim 27, wherein the COMPOUND 1 is administered pursuant to a scheduled dosing cycle in which COMPOUND 1 is administered on days 1 and 15 of a 21 day cycle.

31. The method of claim 27, wherein the COMPOUND 1 is administered pursuant to a scheduled dosing cycle in which COMPOUND 1 is administered on days 1 and 15 of a 28 day cycle.

32. The method of any of claims 1 to 6, wherein the bortezomib is administered on days 1, 5 and 9 of a 21 day cycle, and COMPOUND 1 is administered on days 3, 8, and 12 of the 21 day cycle.

33. The method of any of claims 1 to 6, wherein the bortezomib is administered on days 1, 5 and 9 of a 28 day cycle, and COMPOUND 1 is administered on days 3, 8, and 12 of the 28 day cycle.

34. The method of any of claims 1 to 6, wherein the COMPOUND 1 is administered on days 1, 5 and 9 of a 21 day cycle, and bortezomib is administered on days 3, 8, and 12 of the 21 day cycle.

35. The method of any of claims 1 to 6, wherein the COMPOUND 1 is administered on days 1, 5 and 9 of a 28 day cycle, and bortezomib is administered on days 3, 8, and 12 of the 28 day cycle.

36. The method of any of claims 32 to 35, wherein the COMPOUND 1 is administered as a prodrug.

37. The method of claim 36, wherein the COMPOUND 1 prodrug is a pharmaceutically acceptable ester form of COMPOUND 1.

38. The method of any of claims 32 to 37, wherein the COMPOUND 1 is administered intravenously.

39. The method of any of claims 32 to 37, wherein the COMPOUND 1 is administered orally.

40. The method of any of claims 32 to 39, wherein the COMPOUND 1 is administered at a dose in the range of about 0.5 mg/m² to about 5 mg/m².

41. The method of claim 40, wherein the COMPOUND 1 is administered at a dose in the range of about 1 mg/m² to about 3 mg/m².

42. The method of any of claims 27 to 41, wherein the scheduled cycle is repeated at least once.