WO2009065098A1 - Use of cathepsin k antagonists in the treatment of bone cancer - Google Patents

Abstract

The invention regards the modulation of a proteolytic enzyme, Cathepsin K that results in increased bone production by bone-forming cells. Drugs that target this enzyme inhibit its activity represent a new class of therapies for multiple myeloma.

Description

USE OF CATHEPSIN K ANTAGONISTS IN THE TREATMENT

OF BONE CANCER

BACKGROUND OF THE INVENTION

This application claims priority to U.S. Provisional Application Serial No. 60/988,634, filed on November 16, 2007, which is incorporated herein by reference.

I. Field of the Invention

The present invention relates to the fields of molecular biology, oncology and medicine. More particularly, it relates to the field of cancer with bone involvement. Specifically, it deals with the use of Cathepsin K antagonists to treat multiple myeloma.

II. Related Art

Multiple myeloma (MM) is a B-lymphocyte malignancy characterized by the accumulation of malignant clonal plasma cells in the bone marrow. The clinical manifestations of the disease are due to the replacement of normal bone marrow components by abnormal plasma cells, with subsequent overproduction of a monoclonal immunoglobulin (M protein or M component), bone destruction, bone pain, anemia, hypercalcemia and renal dysfunction. The median age at diagnosis is 65 years, with only 3% of the patients being <40 years of age. The incidence of multiple myeloma is especially high in African- Americans, in whom it is the most common hematologic malignancy (world-wide-web at multiplemyeloma.org).

As distinct from other cancers that spread to the bone (e.g., breast, lung, thyroid, kidney, prostate), myeloma bone disease (MBD) is not a metastatic disease. Rather, myeloma cells are derived from the B-cells of the immune system that normally reside in the bone marrow and are therefore intimately associated with bone. Indeed, the bone marrow microenvironment plays an important role in the growth, survival and resistance to chemotherapy of the myeloma cells, which, in turn, regulate the increased bone loss associated with this disorder (world-wide-web at multiplemyeloma.org). Over 90% of myeloma patients have bone involvement, versus 40-60% of cancer patients who have bone metastasis, and over 80% have intractable bone pain. Additionally, approximately 30% of myeloma patients have hypercalcemia

80374471.1 1 that is a result of the increased osteolytic activity associated with this disease (Cavo et a/., 2006).

Unlike the osteolysis associated with other bone tumors, the MBD lesions are unique in that they do not heal or repair, despite the patients' having many years of complete remission (world- wide-web at multiplemyeloma.org; Terpos et ah, 2005). Mechanistically, this seems to be related to the inhibition and/or loss of the bone- forming osteoblast during disease progression. Indeed, bone marker studies and histomorphometry indicate that both the bone-resorbing osteoclast and osteoblast activity are increased, but balanced early in the disease, whereas overt MBD shows high osteoclast activity and low osteoblast activity (world- wide-web at multiplemyeloma.org). Thus, MBD is a disorder in which bone formation and bone loss are uncoupled and would benefit from therapies that both stimulate bone formation and retard its loss. To date, no such therapies exist.

80374471.1 SUMMARY OF THE INVENTION

Thus, in accordance with the present invention, there is provided a method of treating a subject with multiple myeloma comprising (i) selecting a first intracellular Cathepsin K inhibitor; and (ii) administering to a subject the first inhibitor of Cathepsin K. The inhibitor may be a biological or an organopharmaceutical small molecule. The biological may be a peptide, an siRNA, an antisense molecule or a single-chain antibody. The organopharmaceutical small molecule may be a structural variant of a known Cathepsin K inhibitor based on hydrophilic and lipophilic characteristics, spatial properties, or other information available from medicinal chemistry and chemical enzymology studies on these compounds. The organopharmaceutical may be an epoxysuccinamide, VEL-0230 or analog thereof. The first inhibitor may also prevent bone resorption or stimulate bone formation.

The method may further comprise contacting the subject with a second agent. The second agent may be a bisphosphonate, a PTH analog, or a second inhibitor of Cathepsin K that is distinct from the first inhibitor. The second inhibitor of Cathepsin K may be an extracellular inhibitor of Cathepsin K. The second agent may also be an anti-cancer agent, such as a chemotherapy, a radiotherapy, an immunotherapy, a cytokine therapy, a toxin therapy or a gene therapy. The multiple myeloma may be recurrent, metastatic or drug resistant. The first and/or second inhibitor may be formulated to increase transmembrane delivery. The first and/or second inhibitor may be formulated with a cell permeability factor. The first and/or second inhibitor may be formulated in a lipid delivery vehicle. The first and/or second inhibitor may be formulated to enhance its bioavailability. The first and/or second inhibitor may be administered to the subject more than once. The first and/or second inhibitor is administered to the subject by oral or intravenous routes, injection into the tumor or tumor vasculature, or administration local or regional to a tumor.

It is contemplated that any method or composition described herein can be implemented with respect to any other method or composition described herein. The use of the word "a" or "an" when used in conjunction with the term

"comprising" in the claims and/or the specification may mean "one," but it is also consistent with the meaning of "one or more," "at least one," and "one or more than one."

80374471.1 It is contemplated that any embodiment discussed in this specification can be implemented with respect to any method or composition of the invention, and vice versa. Furthermore, compositions and kits of the invention can be used to achieve methods of the invention. Throughout this application, the term "about" is used to indicate that a value includes the inherent variation of error for the device, the method being employed to determine the value, or the variation that exists among the study subjects.

80374471.1 BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings form part of the present specification and are included to further demonstrate certain aspects of the present invention. The invention may be better understood by reference to one or more of these drawings in combination with the detailed description of specific embodiments presented herein.

FIG. 1 - Structure of VEL-0230. VEL-0230 is an orally available small molecule (MW = 309.3 Da) that both stimulates human bone formation and inhibits bone loss. The chemical name for VEL-0230 is sodium (2 S, 3 S) -3[[1-(S)- isobutoxymethyl-3-methylbutyl]carbamoyl]oxirane-2-carboxylate. The VEL-0230 drug substance is an optically active compound that has 3 asymmetric carbons. It occurs as white crystalline powder, and it is hygroscopic and is gradually decomposed by humidity.

FIG. 2 - Analogs and Isomers of VEL-0230. VEL-0230 represents an active member of a family of epoxysuccinimides that may be modifies at a variety of sites to enhance potency, bioavailability, specificity or other factors affecting it usefulness as a therapeutic agent. These changes may be made by alterations of the sites as indicated by positions Rl to R4, or by utilizing any optical isomer thereof.

FIG. 3 - VEL-0230 Inhibition of Human Osteoclast Proteolytic Activity. Cells in upper panel were treated with 10 μM VEL-0230.

FIG. 4 - Velcura's Ex vivo Bone Formation Technology. A three- dimensional tissue like aggregate of human osteoblasts and bone collagen. Masson Stain.

FIG. 5 - Bone formation in tissue like aggregates of human osteoblasts. Indicated by Ca++ fluorescence (arrows).

FIG. 6 - Cathepsin K in Osteoblasts and Osteoclasts.

FIG. 7 - VEL-0230 Inhibition of Human Osteoclast Proteolytic Activity.

FIG. 8 - VEL-0230 Prevents Trabecular and Cortical Bone Loss. Cortical Bone and Cortical Thickness measurements (lower right). Doses of 15, 50 and 150 mg/kg are given BID. Values are mean + SEM (n = 7-8 per group), # # # p ≤ 0.001 vs. sham; * p ≤ 0.05 vs. OVX

FIG. 9 - VEL-0230 Restores BMD and Bone Strength. * p< 0.05.

80374471.1 FIG. 10 - Urinary CTx and Serum NTx in Vel-0230 Treated Normal Dogs. Left Panel: Urinary CTx. red bars, VEL-0230 treated; grey bars controls. Right Panel: Dashed lines, vehicle controls at each dose; solid lines VEL-0230 treated. Values are Mean ± SEM (n = 3-4 per group) ** p ≤ 0.01 vs. appropriate control, * p ≤ 0.05 vs. appropriate at each dose; solid lines VEL-0230 treated. Values are Mean ± SEM (n = 3-4 per group), ** p ≤ 0.01 vs. appropriate control, * p ≤ 0.05 vs. appropriate control.

FIG. 11 - VEL-0230 Reduces Urinary NTx levels in Estrogen-depleted monkeys. Values are mean ± SEM (n = 3-4 per group) ** p ≤ 0.01 vs. appropriate control, * p ≤ 0.05 vs. appropriate control.

FIG. 12 - BMD, BSAP & Urinary CTx Levels in VEL-0230-treated, Ovariectomized Primates.

80374471.1 DETAILED DESCRIPTION OF THE INVENTION

One of the inventors previously discovered a unique mechanism of action for Cathepsin K, a proteolytic enzyme previously thought to be involved only in bone degradation. Its role in modulating bone resorption is that of a classic proteolytic enzyme, functioning to degrade components of the extra-cellular compartment, particularly collagen (Bossard et al., 1996). Moreover, the prevalent viewpoint is that this enzyme functions solely and/or selectively in osteoclasts to degrade extracellular proteins and, as such, is targeted by anti-catabolic therapies that function to inhibit the bone-resorbing osteoclast (Yasuda et al., 2005; Grabowskal et al., 2005; Troen, 2004; Dodds, 2003; Zaidi et al., 2003). Recently, Cathepsin K was shown to be expressed by osteoblasts; however, this report still subscribed to the concept that Cathepsin K has an extracellular role and, further, did not test enzymatic function of this enzyme within osteoblasts (Mandelin et al., 2006).

An important feature of the present invention is that, within bone-forming cells Cathepsin K plays a role in bone formation as inhibition of the enzyme unexpectedly results in an increase in bone formation, as described below. The role of Cathepsin K in bone formation intracellular signaling networks is supported by three observations: (1) the inventor's Cathepsin K inhibitors stimulate bone formation both in vivo and in vitro; (2) RNA interference studies of Cathepsin K (RNAi; performed via small-interfering RNA (siRNA) treatment) demonstrate that inhibition of this message results in a bone-formation phenotype in treated human osteoblasts; and (3) stimulation of bone formation with multiple osteogenic growth factors decreases Cathepsin K message and activity within the osteoblast.

Numerous patents exist on the structure of Cathepsin K inhibitors and their use in treating the extracellular activity of the enzyme. WO 2005/049028 Al describes the use of Cathepsin K inhibitors to stimulate bone formation in a patient in need of such a treatment. However, the data therein does not demonstrate this effect in humans, nor do two related abstracts. Moreover, these references disclose and advocate the use of inhibitors in line with the conventional viewpoint of extracellular inhibition of osteoclast Cathepsin K. WO 2004/033445 also describes compounds that are cysteine protease inhibitors, in particular, extracellular inhibitors of cathepsins K, L, S and B, and are described as useful for treating diseases in which inhibition of bone resorption is indicated, such as osteoporosis and cancers including multiple

80374471.1 7 myeloma. The present invention, by way of contrast, proposes the use of intracellular inhibition of Cathepsin K to treat multiple myeloma, including myeloma bone disease.

I. Cathepsin K

Cathepsins are proteases that function in the normal physiological as well as pathological degradation of connective tissue. Cathepsins play a major role in intracellular protein degradation and turnover, bone remodeling, and prohormone activation (Marx, 1987). Cathepsin B, H, L and S are ubiquitously expressed lysosomal cysteine proteinases that belong to the papain superfamily. They are found at constitutive levels in many tissues in the human including kidney, liver, lung and spleen. Some pathological roles of cathepsins include an involvement in glomerulonephritis, arthritis, and cancer metastasis (Sloan and Honn, 1984). Greatly elevated levels of cathepsin L and B mRNA and protein are seen in tumor cells. Cathepsin L mRNA is also induced in fibroblasts treated with tumor promoting agents and growth factors (Kane and Gottesman, 1990).

Cathepsin K, a member of this protease family, is considered the primary protease responsible for the degradation of the bone matrix. Cathepsin K was discovered in 1994, is synthesized as a 37 kDa pre-pro enzyme, and is presumably autoactivated to the mature 27 kDa enzyme at low pH (McQueney et al, 1997; Littlewood-Evans et al, 1997; U.S. Patent 5,861,298). It is abundantly and relatively selectively expressed in osteoclasts, where it is localized in lysosomes in the ruffled border and in resorption lacunae on the bone surface. This cellular and extracellular localization suggests an important role in bone resorption, as does its recently characterized functional activity profile. The unique ability of Cathepsin K to degrade type I collagen both within and outside the helical regions and also type II collagens at the N-terminal of the triple helix, to act at an acidic and neutral pH, shows that Cathepsin K plays an important role in bone and cartilage break down.

II. Multiple Myeloma A. Symptoms

Because many organs can be affected by myeloma, the symptoms and signs vary greatly. A mnemonic for multiple myeloma is CRAB: C = Calcium (elevated), R = Renal failure, A = Anemia, B = Bone lesions. Myeloma has many possible

80374471.1 8 symptoms, and all symptoms may be due to other causes. They are presented here in decreasing order of incidence.

Myeloma bone pain usually involves the spine and ribs, and worsens with activity. Persistent localized pain may indicate a pathological fracture. Involvement of the vertebrae may lead to spinal cord compression. Myeloma bone disease is due to proliferation of tumor cells and release of IL-6, also known as osteoclast activating factor (OAF), which stimulates osteoclasts to break down bone. These bone lesions are lytic in nature and are best seen in plain radiographs, which may show a "punched-out" resorptive lesions. The breakdown of bone also leads to release of calcium into the blood, leading to hypercalcemia and its associated symptoms.

The most common infections occuring in MM are pneumonias and pyelonephritis. Common pneumonia pathogens include S. pneumoniae, S. aureus, and K. pneumoniae, while common pathogens causing pyelonephritis include E.coli and other gram-negative organisms. The increased risk of infection is due to immune deficiency resulting from diffuse hypogammaglobulinemia, which is due to decreased production and increased destruction of normal antibodies.

Renal failure may develop both acutely and chronically. It is commonly due to hypercalcemia (see above). It may also be due to tubular damage from excretion of light chains, also called Bence Jones proteins, which can manifest as the Fanconi syndrome (type II renal tubular acidosis). Other causes include glomerular deposition of amyloid, hyperuricemia, recurrent infections (pyelonephritis), and local infiltration of tumor cells.

The anemia found in myeloma is usually normocytic and normochromic. It results from the replacement of normal bone marrow by infiltrating tumor cells and inhibition of normal red blood cell production (erythropoiesis) by cytokines.

Common problems are weakness, confusion and fatigue due to hypercalcemia. Headache, visual changes and retinopathy may be the result of hyperviscosity of the blood depending on the properties of the paraprotein. Finally, there may be radicular pain, loss of bowel or bladder control (due to involvement of spinal cord leading to cord compression) or carpal tunnel syndrome and other neuropathies (due to infiltration of peripheral nerves by amyloid). It may give rise to paraplegia in late presenting cases.

80374471.1 B. Diagnosis

The presence of unexplained anemia, kidney dysfunction, a high erythrocyte sedimentation rate (ESR) and a high serum protein (especially raised immunoglobulin) may prompt further testing. A doctor will request protein electrophoresis of the blood and urine, which might show the presence of a paraprotein (monoclonal protein, or M protein) band, with or without reduction of the other normal immunoglobulins (known as immune paresis). One type of paraprotein is the Bence Jones protein, which is a urinary paraprotein composed of free light chains. Quantitative measurements of the paraprotein are necessary to establish a diagnosis and to monitor the disease. The paraprotein is an abnormal immunoglobulin produced by the tumor clone. Very rarely, the myeloma is non-secretory.

In theory, multiple myeloma can produce all classes of immunoglobulin, but IgG paraproteins are most common, followed by IgA and IgM. IgD and IgE myeloma are very rare. In addition, light and or heavy chains may be secreted in isolation: K- or λ- light chains or any of the five types of heavy chains (α-, γ-, δ-, ε- or μ-heavy chains). Additional findings include: a raised calcium and phosphorus (when osteoclasts are breaking down bone, releasing calcium and phosphorus into the bloodstream), raised serum creatinine due to reduced renal function, which may be due to paraprotein deposition in the kidney. The workup of suspected multiple myeloma includes a skeletal survey. This is a series of X-rays of the skull, axial skeleton and proximal long bones. Myeloma activity sometimes appear as "lytic lesions" (with local disappearance of normal bone due to resorption), and on the skull X-ray as "punched-out lesions" or "pepper pot skull." Magnetic resonance imaging (MRI) is more sensitive than simple X-ray in the detection of lytic lesions, and may supersede skeletal survey, especially when vertebral disease is suspected. Occasionally a CT scan is performed to measure the size of soft tissue plasmacytomas.

A bone marrow biopsy is usually performed to estimate the percentage of bone marrow occupied by plasma cells. This percentage is used in the diagnostic criteria for myeloma. Immunohisto chemistry (staining particular cell types using antibodies against surface proteins) can detect plasma cells which express immunoglobulin in the cytoplasm but usually not on the surface; myeloma cells are typically CD56⁺, CD38⁺, CD138⁺ and CD 19^" and CD45^". Cytogenetics may also be performed in myeloma for prognostic purposes.

80374471.1 10 Other useful laboratory tests include quantitative measurement of IgA, IgG, IgM (immunoglobulins) to look for immune paresis, and β2-microglobulin which provides prognostic information. On peripheral blood smears, the rouleaux formation of red blood cells is commonly seen. The recent introduction of a commercial immunoassay for measurement of free light chains potentially offers an improvement in monitoring disease progression and response to treatment, particularly where the paraprotein is difficult to measure accurately by electrophoresis (for example in light chain myeloma, or where the paraprotein level is very low). Initial research also suggests that measurement of free light chains may also be used, in conjunction with other markers, for assessment of the risk of progression from monoclonal gammopathy of undetermined significance (MGUS) to multiple myeloma.

C. Conventional Treatments

Treatment for multiple myeloma is focused on disease containment and suppression. If the disease is completely asymptomatic (i.e., there is a paraprotein and an abnormal bone marrow population but no end-organ damage), treatment may be deferred. Although allogeneic stem cell transplant might cure the cancer, it is considered investigational given the high treatment-related mortality of 5-10% associated with the procedure. In addition to direct treatment of the plasma cell proliferation, bisphosphonates (e.g., pamidronate or zoledronic acid) are routinely administered to prevent fractures and erythropoietin to treat anemia.

Initial treatment is aimed at treating symptoms and reducing disease burden. Commonly used induction regimens include dexamethasone with or without thalidomide and cyclophosphamide, and VAD (vincristine, adriamycin, and dexamethasone). Low-dose therapy with melphalan combined with prednisone can be used to palliate symptoms in patients who cannot tolerate aggressive therapy. Plasmapheresis can be used to treat symptomatic protein proliferation (hyperviscosity syndrome).

In younger patients, therapy may include high-dose chemotherapy, melphalan, and autologous stem cell transplantation. This can be given in tandem fashion, i.e., an autologous transplant followed by a second transplant. Non-myeloablative or "mini" allogeneic stem cell transplantation is being investigated as an alternative to autologous stem cell transplant, or as part of a tandem transplant following an autologous transplant (also known as an "auto-mini" tandem transplant).

80374471.1 1 1 A 2007 trial indicated that the addition of thalidomide to reduced-intensity chemotherapy (melphalan and prednisone, MP) in patients between 65-75 led to a marked prolongation (median 51 versus 33 months) in survival. Reduced intensity melphalan followed by a stem cell transplant was inferior to the MP -thalidomide regimen (median survival 38 months).

The natural history of myeloma is of relapse following treatment. Depending on the patient's condition, the prior treatment modalities used and the duration of remission, options for relapsed disease include re-treatment with the original agent, use of other agents (such as melphalan, cyclophosphamide, thalidomide or dexamethasone, alone or in combination), and a second autologous stem cell transplant. Later in the course of the disease, "treatment resistance" occurs. This may be a reversible effect, and some new treatment modalities may re-sensitize the tumor to standard therapy. For patients with relapsed disease, bortezomib (or Velcade®) is a recent addition to the therapeutic arsenal, especially as second line therapy. Bortezomib is a proteasome inhibitor. Finally, lenalidomide (or Revlimid®), a less toxic thalidomide analog, is showing promise for treating myeloma.

Renal failure in multiple myeloma can be acute (reversible) or chronic (irreversible). Acute renal failure typically resolves when the calcium and paraprotein levels are brought under control. Treatment of chronic renal failure is dependent on the type of renal failure and may involve dialysis.

D. Staging and Prognosis

The International Staging System (ISS) for myeloma was published by the International Myeloma Working Group in 2003 : Stage I: β₂-microglobulin (β2M) < 3.5 mg/L, albumin >= 3.5 g/dL

Stage II: β2M < 3.5 and albumin < 3.5; or β2M between 3.5 and 5.5 Stage III: β2M > 5.5

First published in 1975, the Durie-Salmon staging system is still in use, but has largely been superseded by the simpler ISS: Stage 1 : all of

Hb > lOg/dL

Normal calcium

Skeletal survey: normal or single plasmacytoma or osteoporosis

Serum paraprotein level < 5 g/dL if IgG, < 3 g/dL if IgA

80374471.1 12 Urinary light chain excretion < 4 g/24h Stage 2: fulfilling the criteria of neither 1 nor 3 Stage 3 : one or more of

Hb < 8.5g/dL High calcium > 12mg/dL

Skeletal survey: 3 or more lytic bone lesions Serum paraprotein >7g/dL if IgG, > 5 g/dL if IgA Urinary light chain excretion > 12g/24h

Stages 1, 2 and 3 of the Durie-Salmon staging system can be divided into A or B depending on serum creatinine:

A - serum creatinine < 2 mg/dL (< 177 μmol/L) B - serum creatinine > 2 mg/dL (> 177 μmol/L)

The International Staging System can help to predict survival, with a median survival of 62 months for stage 1 disease, 45 months for stage 2 disease, and 29 months for stage 3 disease. Cytogenetic analysis of myeloma cells may be of prognostic value, with deletion of chromosome 13, non-hyperdiploidy and the balanced translocations t(4;14) and t(14;16) conferring a poorer prognosis. The 1 Iql3 and 6p21 cytogenetic abnormalities are associated with a better prognosis. Prognostic markers such as these are always generated by retrospective analyses, and it is likely that new treatment developments will improve the outlook for those with traditionally

'poor-risk' disease.

E. Myeloma Bone Disease

The clinical manifestations of multiple myeloma are due to the replacement of normal bone marrow components by abnormal plasma cells, with subsequent overproduction of a monoclonal immunoglobulin (M protein or M component), bone destruction, bone pain, anemia, hypercalcemia and renal dysfunction. As distinct from other cancers that spread to the bone (e.g., breast, lung, thyroid, kidney, prostate), myeloma bone disease (MBD) is not a metastatic disease. Rather, myeloma cells are derived from the B-cells of the immune system that normally reside in the bone marrow and are therefore intimately associated with bone. Indeed, the bone marrow microenvironment plays an important role in the growth, survival and resistance to chemotherapy of the myeloma cells, which, in turn, regulate the increased bone loss

80374471.1 13 associated with this disorder. Myeloma-associated osteolysis is present in at least 80% of myeloma patients presenting as discrete osteolytic lesions and/or diffuse osteoporosis, and 75% of myeloma patients have bone pain. Additionally, approximately 30% of myeloma patients have hypercalcemia that is a result of the increased osteolytic activity associated with this disease.

As discussed above, unlike the osteolysis associated with other bone tumors, the MBD lesions are unique in that they do not heal or repair, despite the patients' having many years of complete remission. Mechanistically, this seems to be related to the inhibition and/or loss of the bone-forming osteoblast during disease progression. Indeed, bone marker studies and histomorphometry indicate that both the bone- resorbing osteoclast and osteoblast activity are increased, but balanced early in the disease, whereas overt MBD shows high osteoclast activity and low osteoblast activity. Thus, MBD is a disorder in which bone formation and bone loss are uncoupled and would benefit from therapies that both stimulate bone formation and retard its loss.

A number of therapeutic approaches have been used in MBD, with the endpoints of treating pain, hypercalcemia, or the reduction of skeletal related events (SRE). Many of these may present serious complications. Surgery, such as vertebroplasty or kyphoplasty, that is performed for stability and pain relief has the attendant surgical risks (e.g., infection) made worse by a compromised immune system and does not reverse existing skeletal defects. Radiation therapy and radioisotope therapy are both used to prevent/control disease progression and have the typical risks of irradiation therapies. More recently, drugs such as the bisphosphonates that inhibit osteoclast activity have become a standard of therapy for MBD, despite the fact that they work poorly in this disorder. In 9 major double-blind, placebo-controlled trials on bisphosphonates, only 66% of patients showed an effective reduction in pain; 56% showed a reduction in SRE and only 1 of the 9 demonstrated a survival benefit.

III. Multiple Myeloma Therapy Using Cathepsin K Antagonists

In one aspect, treatment of multiple myeloma by compounds of the present invention addresses bone loss by stimulating the production of new bone tissue. However, data also show that Cathepsin K inhibitors, particularly intracellular inhibitors, inhibit the function of osteoclasts with out killing them. This is distinct

80374471.1 14 from the effects of bisphosphonates that stimulate apoptosis, or from those resulting from Densoamab™, an antibody against RANK ligand that inhibits osteoclast formation. Both of those agents reduce osteoclast numbers, which can also have adverse effects. The compounds of the present invention do not reduce osteoclast number, so these important cells can still contribute to bone homeostasis by signaling osteoblasts. Additionally, compounds of the present invention prevent osteoclasts from forming "bone-pits" where the myeloma cells locate themselves, thus reducing the area in which tumor cells can live. Therefore, the physical presence of the non- resorbing osteoclasts, plus the lack of osteoclast-pits, both impeded myeloma cell growth as well as promoting bone growth and/or reducing bone loss since myeloma cells both inhibit the osteoblast and stimulate the osteoclasts. As such, disease progression (defined as myeloma growth, metastasis, bone disease, bone loss, and bone resportion) may slow, stop, and even be reversed. PCT Application US2007/069211, incorporated herein by reference, describes the use of Cathepsin K inhibitors of the present invention in treating various bone disease.

A. Antagonists

The U.S. Patents 5,843,992, 6,387,908 and 6,689,785, incorporated by reference, are drawn to the structures underlying VEL-0230 and its analogues as Cathepsin K. The only known activity of Cathepsin K antagonists is to modulate the extracellular activity of Cathepsin K. An agent of the present invention is one that is capable of inhibiting the extracellular function of Cathepsin K and also promoting the formation of bone in vitro and/or in vivo by the inhibition of intracellular Cathepsin K. In so doing, the agent will stimulate bone formation to restore lost bone in multiple myeloma, and inhibit osteoclasts in their anabolic action. The agent may also inhibit bone resorption and in so doing may inhibit further myeloma disease progression.

B. Combinations

Other agents may be used in combination with intracellular Cathepsin K inhibitors to effect greater inhibition of Cathepsin K, and thus provide a more effective therapy for multiple myeloma. More generally, these agents would be provided in a combined amount (along with the intracellular inhibitor) to produce or increase any of the effects discussed herein. This process may involve contacting the cell or subject with both agents at the same time. This may be achieved by contacting

80374471.1 15 the cell with a single composition or pharmacological formulation that includes both agents, or by contacting the cell or subject with two distinct compositions or formulations, at the same time, wherein one composition includes the intracellular Cathepsin K inhibitor and the other includes the second agent. Alternatively, one agent may precede or follow the other by intervals ranging from minutes to weeks. In embodiments where the agents are applied separately to the cell or subject, one would generally ensure that a significant period of time did not expire between the time of each delivery, such that the agents would still be able to exert an advantageously combined effect on the cell or subject. In such instances, it is contemplated that one may contact the cell with both modalities within about 12-24 h of each other and, more preferably, within about 6-12 h of each other. In some situations, it may be desirable to extend the time period for treatment significantly, however, where several days (2, 3, 4, 5, 6 or 7) to several weeks (1, 2, 3, 4, 5, 6, 7 or 8) lapse between the respective administrations. Another type of combination therapy involves the use of Cathepsin K inhibitors with tradition cancer therapies, including chemotherapy, radiotherapy, immunotherapy, hormone therapy, cytokine therapy, gene therapy, or toxin therapy.

Various combinations may be employed, the intracellular inhibitor of Cathepsin K is "A" and the other agent is "B":

A/B/A B/A/B B/B/A A/A/B A/B/B B/A/A A/B/B/B B/A/B/B B/B/B/A B/B/A/B A/A/B/B A/B/A/B A/B/B/A B/B/A/A B/A/B/A B/A/A/B A/A/A/B B/A/A/A A/B/A/A A/A/B/A

Administration protocols and formulation of such agents will generally follow those of standard pharmaceutical drugs, as discussed further below. Combination agents include bisphosphonates (Didronel , Fosamax and Actonel ), SERMs (Evista) or other hormone derivatives, and Parathyroid Hormone (PTH) analogs. In addition, U.S. Patents 6,642,239, 6,531,612, 6,462,076 and 6,274,336, as well as U.S. Publication Nos. 2006/0074092, 2006/0020001, 2005/0245596, 2005/0107616, 2005/0054819, and 2004/0249153, disclose other Cathepsin K inhibitors that work in an extracellular fashion. Other agents include, thalidomide cyclophosphamide, VAD (vincristine, adriamycin, and dexamethasone), low-dose therapy with melphalan combined with prednisone, plasmapheresis, dialysis, high-dose chemotherapy with

80374471.1 16 melphalan combined with autologous stem cell transplantation, thalidomide combined with reduced-intensity chemotherapy (melphalan and prednisone), cyclophosphamide, dexamethasone, bortezomib (or Velcade®) and lenalidomide (or Revlimid®).

IV. Pharmaceutical Formulations and Delivery A. Compositions and Routes

Pharmaceutical compositions of the present invention comprise an effective amount of one or more Cathepsin K antagonists dissolved or dispersed in a pharmaceutically acceptable carrier. The phrases "pharmaceutical or pharmacologically acceptable" refer to molecular entities and compositions that do not produce an adverse, allergic or other untoward reaction when administered to an animal, such as, for example, a human, as appropriate. The preparation of a pharmaceutical composition that contains at least one Cathepsin K antagonist, and optionally an additional active ingredient, will be known to those of skill in the art in light of the present disclosure, as exemplified by Remington's Pharmaceutical Sciences, 18th Ed. Mack Printing Company, 1990, incorporated herein by reference. Moreover, for animal (e.g., human) administration, it will be understood that preparations should meet sterility, pyrogenicity, general safety and purity standards as required by FDA Office of Biological Standards. As used herein, "pharmaceutically acceptable carrier" includes any and all solvents, dispersion media, coatings, surfactants, antioxidants, preservatives (e.g., antibacterial agents, antifungal agents), isotonic agents, absorption delaying agents, salts, preservatives, drugs, drug stabilizers, gels, binders, excipients, disintegration agents, lubricants, sweetening agents, flavoring agents, dyes, such like materials and combinations thereof, as would be known to one of ordinary skill in the art (see, for example, Remington's Pharmaceutical Sciences, 18th Ed., Mack Printing Company, 1990, pp. 1289-1329, incorporated herein by reference). Except insofar as any conventional carrier is incompatible with the active ingredient, its use in the pharmaceutical compositions is contemplated. The Cathepsin K antagonist may be admixed with different types of carriers depending on whether it is to be administered orally or by injection. The present invention can be administered buccally, intravenously, intradermally, transdermally, intrathecally, intraarterially, intraperitoneally, intranasally, intravaginally, intrarectally, topically, intramuscularly, intratumorally, into tumor vasculature,

80374471.1 17 subcutaneously, mucosally, orally, topically, locally, inhalation (e.g., aerosol inhalation), injection, infusion, continuous infusion, localized perfusion bathing target cells directly, via a catheter, via a lavage, in cremes, in lipid compositions (e.g., nanoparticles, liposomes), or by other method or any combination of the forgoing as would be known to one of ordinary skill in the art (see, for example, Remington's Pharmaceutical Sciences, 18th Ed. Mack Printing Company, 1990, incorporated herein by reference). In particular, the Cathepskin K antagonist is formulated into a syringeable composition for use in intravenous admiminstration.

The Cathepsin K antagonist may be formulated into a composition in a free base, neutral or salt form or ester. It may also be synthesized/formulated in a prodrug form. Pharmaceutically acceptable salts, include the acid addition salts, e.g., those formed with the free amino groups of a proteinaceous composition, or which are formed with inorganic acids such as for example, hydrochloric or phosphoric acids, or such organic acids as acetic, oxalic, tartaric, fumaric, or mandelic acid. Salts formed with the free carboxyl groups can also be derived from inorganic bases such as for example, sodium, potassium, ammonium, calcium or ferric hydroxides; or such organic bases as isopropylamine, trimethylamine, histidine or procaine. Upon formulation, solutions will be administered in a manner compatible with the dosage formulation and in such amount as is therapeutically effective. Further in accordance with the present invention, the composition of the present invention suitable for administration is provided in a pharmaceutically acceptable carrier with or without an inert diluent. The carrier should be assimilable and includes liquid, semi-solid, i.e., pastes, or solid carriers. Except insofar as any conventional media, agent, diluent or carrier is detrimental to the recipient or to the therapeutic effectiveness of the composition contained therein, its use in administrable composition for use in practicing the methods of the present invention is appropriate. Examples of carriers or diluents include fats, oils, water, saline solutions, lipids, liposomes, resins, binders, fillers and the like, or combinations thereof. The composition may also comprise various antioxidants to retard oxidation of one or more component. Additionally, the prevention of the action of microorganisms can be brought about by preservatives such as various antibacterial and antifungal agents, including but not limited to parabens (e.g., methylparabens, propylparabens), chlorobutanol, phenol, sorbic acid, thimerosal or combinations thereof.

80374471.1 18 In a specific embodiment of the present invention, the composition is combined or mixed thoroughly with a semi-solid or solid carrier. The mixing can be carried out in any convenient manner such as grinding. Stabilizing agents can be also added in the mixing process in order to protect the composition from loss of therapeutic activity, i.e., denaturation in the stomach. Examples of stabilizers for use in an the composition include buffers, amino acids such as glycine and lysine, carbohydrates such as dextrose, mannose, galactose, fructose, lactose, sucrose, maltose, sorbitol, mannitol, etc.

In further embodiments, the present invention may concern the use of a pharmaceutical lipid vehicle compositions that include Cathepsin K antagonist, one or more lipids, and an aqueous solvent. As used herein, the term "lipid" will be defined to include any of a broad range of substances that is characteristically insoluble in water and extractable with an organic solvent. This broad class of compounds are well known to those of skill in the art, and as the term "lipid" is used herein, it is not limited to any particular structure. Examples include compounds which contain long- chain aliphatic hydrocarbons and their derivatives. A lipid may be naturally- occurring or synthetic (i.e., designed or produced by man). Lipids are well known in the art, and include for example, neutral fats, phospholipids, phosphoglycerides, steroids, terpenes, lysolipids, glycosphingolipids, glycolipids, sulphatides, lipids with ether and ester-linked fatty acids and polymerizable lipids, and combinations thereof.

One of ordinary skill in the art would be familiar with the range of techniques that can be employed for dispersing a composition in a lipid vehicle. For example, the Cathepsin K antagonist may be dispersed in a solution containing a lipid, dissolved with a lipid, emulsified with a lipid, mixed with a lipid, combined with a lipid, covalently bonded to a lipid, contained as a suspension in a lipid, contained or complexed with a micelle or liposome, or otherwise associated with a lipid or lipid structure by any means known to those of ordinary skill in the art. The dispersion may or may not result in the formation of liposomes.

The actual dosage amount of a composition of the present invention administered to an animal patient can be determined by physical and physiological factors such as body weight, severity of condition, the type of disease being treated, previous or concurrent therapeutic interventions, idiopathy of the patient and on the route of administration. Depending upon the dosage and the route of administration, the number of administrations of a preferred dosage and/or an effective amount may

80374471.1 19 vary according to the response of the subject. The practitioner responsible for administration will, in any event, determine the concentration of active ingredient(s) in a composition and appropriate dose(s) for the individual subject.

In certain embodiments, Cathepsin K antagonist pharmaceutical compositions may comprise, for example, at least about 0.1% of the antagonist, about 0.5% of the antagonist, or about 1.0% of the antagonist. In other embodiments, the antagonist may comprise between about 2% to about 75% of the weight of the unit, or between about 25% to about 60%, for example, and any range derivable therein. Naturally, the amount of the antagonist in each therapeutically useful composition may be prepared is such a way that a suitable dosage will be obtained in any given unit dose of the compound. Factors such as solubility, bioavailability, biological half-life, route of administration, product shelf life, as well as other pharmacological considerations will be contemplated by one skilled in the art of preparing such pharmaceutical formulations, and as such, a variety of dosages and treatment regimens may be desirable.

In other non-limiting examples, a dose of a Cathepsin K antagonist may also comprise from about 0.1 microgram/kg/body weight, about 0.2 microgram/kg/body weight, about 0.5 microgram/kg/body weight, about 1 microgram/kg/body weight, about 5 microgram/kg/body weight, about 10 microgram/kg/body weight, about 50 microgram/kg/body weight, about 100 microgram/kg/body weight, about 200 microgram/kg/body weight, about 350 microgram/kg/body weight, about 500 microgram/kg/body weight, about 1 milligram/kg/body weight, about 5 milligram/kg/body weight, about 10 milligram/kg/body weight, about 50 milligram/kg/body weight, about 100 milligram/kg/body weight, about 200 milligram/kg/body weight, about 350 milligram/kg/body weight, about 500 milligram/kg/body weight, to about 1000 mg/kg/body weight or more per administration, and any range derivable therein. In non-limiting examples of a derivable range from the numbers listed herein, a range of about 5 mg/kg/body weight to about 100 mg/kg/body weight, about 5 microgram/kg/body weight to about 500 milligram/kg/body weight, etc., can be administered, based on the numbers described above.

In particular embodiments of the present invention, the Cathepsin K antagonists are formulated to be administered via an alimentary route. Alimentary routes include all possible routes of administration in which the composition is in

80374471.1 20 direct contact with the alimentary tract. Specifically, the pharmaceutical compositions disclosed herein may be administered orally, buccally, rectally, or sublingually. As such, these compositions may be formulated with an inert diluent or with an assimilable edible carrier, or they may be enclosed in hard- or soft- shell gelatin capsule, or they may be compressed into tablets, or they may be incorporated directly with the food of the diet.

In certain embodiments, the active compounds may be incorporated with excipients and used in the form of ingestible tablets, buccal tablets, troches, capsules, elixirs, suspensions, syrups, wafers, and the like (Mathiowitz et al., 1997; Hwang et al, 1998; U.S. Patents 5,641,515, 5,580,579 and 5,792, 451, each specifically incorporated herein by reference in its entirety). The tablets, troches, pills, capsules and the like may also contain the following: a binder, such as, for example, gum tragacanth, acacia, cornstarch, gelatin or combinations thereof; an excipient, such as, for example, dicalcium phosphate, mannitol, lactose, starch, magnesium stearate, sodium saccharine, cellulose, magnesium carbonate or combinations thereof; a disintegrating agent, such as, for example, corn starch, potato starch, alginic acid or combinations thereof; a lubricant, such as, for example, magnesium stearate; a sweetening agent, such as, for example, sucrose, lactose, saccharin or combinations thereof; a flavoring agent, such as, for example peppermint, oil of wintergreen, cherry flavoring, orange flavoring, etc. When the dosage unit form is a capsule, it may contain, in addition to materials of the above type, a liquid carrier. Various other materials may be present as coatings or to otherwise modify the physical form of the dosage unit. For instance, tablets, pills, or capsules may be coated with shellac, sugar, or both. When the dosage form is a capsule, it may contain, in addition to materials of the above type, carriers such as a liquid carrier. Gelatin capsules, tablets, or pills may be enterically coated. Enteric coatings prevent denaturation of the composition in the stomach or upper bowel where the pH is acidic. See, e.g., U.S. Patent 5,629,001, incorporated by reference. Upon reaching the small intestines, the basic pH therein dissolves the coating and permits the composition to be released and absorbed by specialized cells, e.g., epithelial enterocytes and Peyer's patch M cells. A syrup of elixir may contain the active compound sucrose as a sweetening agent methyl and propylparabens as preservatives, a dye and flavoring, such as cherry or orange flavor. Of course, any material used in preparing any dosage unit form should be pharmaceutically pure and substantially non-toxic in the amounts employed. In

80374471.1 21 addition, the active compounds may be incorporated into sustained-release preparation and formulations.

For oral administration, such as in the treatment of periodontal disease, the compositions of the present invention may alternatively be incorporated with one or more excipients in the form of a mouthwash, dentifrice, buccal tablet, oral spray, gel or sublingual orally-administered formulation. For example, a mouthwash may be prepared incorporating the active ingredient in the required amount in an appropriate solvent, such as a sodium borate solution (Dobell's Solution). Alternatively, the active ingredient may be incorporated into an oral solution such as one containing sodium borate, glycerin and potassium bicarbonate, or dispersed in a dentifrice, or added in a therapeutically-effective amount to a composition that may include water, binders, abrasives, flavoring agents, foaming agents, and humectants. Alternatively the compositions may be fashioned into a tablet, gel or solution form that may be placed under the tongue, along the gum line, brushed on to teeth surfaces, or otherwise dissolved in the mouth. U.S. Patents 6,074,674 and 6,270,750, both incorporated by reference, describe topical, sustained release compositions for periodontal procedures.

In further embodiments, Cathepsin K antagonist may be administered via a parenteral route. As used herein, the term "parenteral" includes routes that bypass the alimentary tract. Specifically, the pharmaceutical compositions disclosed herein may be administered for example, but not limited to intravenously, intradermally, intramuscularly, intraarterially, intrathecally, subcutaneous, or intraperitoneally U.S. Patents 6,537,514, 6,613,308, 5,466,468, 5,543,158; 5,641,515; and 5,399,363 (each specifically incorporated herein by reference in its entirety). Solutions of the active compounds as free base or pharmacologically acceptable salts may be prepared in water suitably mixed with a surfactant, such as hydroxypropylcellulose. Dispersions may also be prepared in glycerol, liquid polyethylene glycols, and mixtures thereof and in oils. Under ordinary conditions of storage and use, these preparations contain a preservative to prevent the growth of microorganisms. The pharmaceutical forms suitable for injectable use include sterile aqueous solutions or dispersions and sterile powders for the extemporaneous preparation of sterile injectable solutions or dispersions (U.S. Patent 5,466,468, specifically incorporated herein by reference in its entirety). In all cases the form must be sterile and must be fluid to the extent that easy injectability exists. It must be stable under the conditions of manufacture and storage

80374471.1 22 and must be preserved against the contaminating action of microorganisms, such as bacteria and fungi. The carrier can be a solvent or dispersion medium containing, for example, water, ethanol, polyol (i.e., glycerol, propylene glycol, and liquid polyethylene glycol, and the like), suitable mixtures thereof, and/or vegetable oils. Proper fluidity may be maintained, for example, by the use of a coating, such as lecithin, by the maintenance of the required particle size in the case of dispersion and by the use of surfactants. The prevention of the action of microorganisms can be brought about by various antibacterial and antifungal agents, for example, parabens, chlorobutanol, phenol, sorbic acid, thimerosal, and the like. In many cases, it will be preferable to include isotonic agents, for example, sugars or sodium chloride. Prolonged absorption of the injectable compositions can be brought about by the use in the compositions of agents delaying absorption, for example, aluminum monostearate and gelatin.

For parenteral administration in an aqueous solution, for example, the solution should be suitably buffered if necessary and the liquid diluent first rendered isotonic with sufficient saline or glucose. These particular aqueous solutions are especially suitable for intravenous, intramuscular, subcutaneous, and intraperitoneal administration. In this connection, sterile aqueous media that can be employed will be known to those of skill in the art in light of the present disclosure. For example, one dosage may be dissolved in 1 ml of isotonic NaCl solution and either added to 1000 ml of hypodermoclysis fluid or injected at the proposed site of infusion, (see for example, "Remington's Pharmaceutical Sciences" 15th Edition, pages 1035-1038 and 1570-1580). Some variation in dosage will necessarily occur depending on the condition of the subject being treated. The person responsible for administration will, in any event, determine the appropriate dose for the individual subject. Moreover, for human administration, preparations should meet sterility, pyrogenicity, general safety and purity standards as required by FDA Office of Biologies standards.

Sustained release formulations for treating of bone conditions include U.S. Patents 4,722,948, 4,843,112, 4,975,526, 5,085,861, 5,162,114, 5,741,796 and 6,936,270, all of which are incorporated by reference. Methods and injectable compositions for bone repair are described in U.S. Patents 4,863,732, 5,531,791, 5,840,290, 6,281,195, 6,288,043, 6,485,754, 6,662,805 and 7,008,433, all of which are incorporated by reference.

80374471.1 23 Sterile injectable solutions are prepared by incorporating the active compounds in the required amount in the appropriate solvent with various of the other ingredients enumerated above, as required, followed by filtered sterilization. Generally, dispersions are prepared by incorporating the various sterilized active ingredients into a sterile vehicle which contains the basic dispersion medium and the required other ingredients from those enumerated above. In the case of sterile powders for the preparation of sterile injectable solutions, the preferred methods of preparation are vacuum-drying and freeze-drying techniques which yield a powder of the active ingredient plus any additional desired ingredient from a previously sterile- filtered solution thereof. A powdered composition is combined with a liquid carrier such as, e.g., water or a saline solution, with or without a stabilizing agent.

V. Examples

The following examples are included to demonstrate preferred embodiments of the invention. It should be appreciated by those of skill in the art that the techniques disclosed in the examples which follow represent techniques discovered by the inventor to function well in the practice of the invention, and thus can be considered to constitute preferred modes for its practice. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention.

EXAMPLE 1 - STIMULATION OF BONE FORMATION

Three-dimensional Osteoblast Development. Typically, the in vitro growth of calvarial or bone marrow-derived osteogenic cells on 2-dimensional (i.e., planar) surfaces eventually leads to a localized piling of confluent cells into "bone nodules" (i.e., 3-dimensional adherent cell arrays) that mineralize the surrounding ECM. Such observations strongly suggest that cell-density plays a role in the process of bone formation. Confirming and extending this finding, the inventors have demonstrated that serum- free TGF-βl treatment of human bone cells derived from multiple sources results in the formation of 3-dimensional tissue-like aggregates, the up-regulation of bone proteins such as osteonectin and alkaline phosphatase and the formation of human bone.

80374471.1 24 A core technology is the ability to rapidly grow human bone in tissue culture (also known as ex vivo bone formation). As shown in FIG. 4, this requires human bone cells (osteoblasts) to be grown as 3-dimensional tissue-like aggregates. In the presence of an osteogenic compound (small molecule or osteogenic growth factors), the osteoblasts then produce monophosphate- and carbonate-derivatized hydroxyapatite analogous to human bone. Together with this assay, the inventors have developed a number of in vitro assays to analyze the effects of VEL-0230. All assays utilize primary bone cells (preosteoblasts) harvested from human bone organ donors obtained from the National Disease Research Interchange (Philadelphia, PA.). These assays are performed in serum- free chemically defined media. Importantly, human osteoblasts treated with VEL-0230 recapitulate this process. Human osteoblasts form 3-dimensional tissue-like aggregates and micro crystalline bone. This bone-formation is detected in a variety of ways; a recent development is to visualize the calcium in the bone with a fluorescent probe (FIG. 5, arrows). Alizarin red S, an "industry standard" cytochemical stain that detects calcium phosphates (not shown) is also used.

EXAMPLE 2 - CATHEPSIN K IS IMPORTANT IN BONE FORMATION

The novel bone formation platform described above was used to identify an unexpected molecular target for bone formation: osteoblast-expressed Cathepsin K. Until now, Cathepsin K was understood to be the primary extracellular protease of the bone-resorbing osteoclast responsible for the degradation of type 1 collagen in bone (FIG. 6). It was discovered that this enzyme is expressed in human osteoblasts. Further, inhibition of Cathepsin K in these cells results in ex vivo bone formation. As a result of these observations and the preliminary data, a novel mechanism of action exists for VEL-0230 and other similar compounds. In the osteoclast resorption space, VEL-0230 acts as a prototypical Cathepsin K inhibitor, functioning to halt the enzyme's actions in the extra-cellular compartment. This prevents the degradation of type 1 collagen and reduces levels of the collagen telopeptides NTx and CTx. In the osteoblast, VEL-0230 has an intracellular effect in which inhibition of the enzyme unexpectedly results in an anabolic effect. The role of Cathepsin K in bone formation is supported by two observations: (1) siRNA knock-down of Cathepsin K results in a bone-formation phenotype in treated human osteoblasts and (2) stimulation of bone

80374471.1 25 formation with osteogenic growth factors decreases Cathepsin K message and activity within the osteoblast. These studies are corroborated by in vivo observations on Cathepsin K that implicate it in bone remodeling, but do not distinguish cellular targets. An important indication of a role for Cathepsin K is that mutations in this protease in humans caused pycnodysostosis, a rare form of osteopetrosis. Confirming this, Cathepsin K knock-out mice develop osteopetrosis, and Cathepsin K over expression in transgenic mice results in osteoporosis.

EXAMPLE 3 - CATHEPSIN K MECHANISM OF ACTION STUDIES

To better understand the molecular effects of Cathepsin K knock-down on osteoblasts, RNA profiling was performed on 4 independent osteoblast donors. Control, Non-RISC, and Non-targeting siRNA-treated osteoblast cultures do not demonstrate significantly altered gene expression when compared to untransfected controls (data not shown). Cathepsin K- silenced osteoblasts, however, demonstrate significant alteration of gene expression (data not shown). Genomic and comparative analyses of gene expression demonstrate that 110 genes that were previously identified as molecular signatures of bone formation are similarly regulated following siRNA-mediated silencing of Cathepsin K expression. Pathway mapping of these modulated genes has shown that down-regulation of cathepsin K demonstrates that siRNA against Cathepsin K results in activation of pathways required for bone formation. Lastly, Cathepsin-K siRNA-treated human osteoblasts form tissue-like aggregates and produce micro-crystalline human bone in a similar fashion to osteogenic growth factor-treated osteoblasts (not shown). Together, these data further validate the role of cathepsin K in bone formation.

EXAMPLE 4 - PREVENTION OF BONE LOSS

VEL-0230 Inhibition of Human Osteoclasts. The inhibitory activity of VEL- 0230 on human osteoclasts was demonstrated using morphometric analysis of osteoclast pit-formation and migration when adhered to slices of bovine bone.

Human osteoclasts were differentiated from low-density, human bone marrow mononuclear cells induced with M-CSF and Rank Ligand. Similar to controls, osteoclasts differentiated in VEL-0230 (10 μM) adhere to the bone, acidify the resorption space and demineralize bone. However, morphometric analysis

80374471.1 26 demonstrates that the osteoclasts fail to degrade the bone matrix as staining demonstrates that the osteoclasts do not migrate and form only shallow pits as compared to untreated osteoclasts (FIG. 7, upper left panel). Consistent with these morphological observations, VEL-0230 sharply reduced the release of the collagen telopeptide CTx, a marker of collagen degradation (FIG. 7 bottom panel).

VEL-0230 represents a member of a new class of cathepsin K inhibitors - compounds that inhibit the actions of this enzyme in both the extracellular and intracellular space. In the osteoclast resorption space, they function to inhibit collagen degradation and thus reduce NTx and CTx levels. Within the osteoblast, VEL-0230 unexpectedly results in an anabolic effect, increasing markers of bone formation (BSAP) and mineralization of bone matrix.

EXAMPLE 5 - IN VITRO STUDIES

Pharmacological studies in rats, intact beagle dogs, medically ovariectomized monkeys and surgically ovariectomized monkey models demonstrate that VEL-0230 both stimulates bone formation and retards its loss. A summary of these studies follows.

Rat Efficacy Studies. VEL-0230 was administered to ovariectomized (OVX) female rats or sham-operated (Sham) animals twice daily (BID) for 5 weeks (n = 7-8 in each group). A larger dose of VEL-0230 (150 mg/kg, BID) was administered to rats than to the dog (1, 3, 10 mg/kg QD) or non-human primate (3 or 10 mg/kg QD), due to large differences in metabolism of VEL-0230 in the rat and markedly different pharmacokinetic (PK) parameters. As expected, bone loss in ovariectomized rats results in reduced trabecular bone content, whereas treatment with VEL-0230 prevents this loss (data not shown). Measurement of the changes in cortical bone thickness also indicates a clear decrease in ovariectomized animals, in contrast to no loss of cortical bone in treated animals (FIG. 8 right & left panels). Confirming these observations, increases in bone mineral density (BMD) and bone strength of the proximal tibial metaphysis and the fifth lumbar vertebra are seen (FIG. 9 right & left panels, respectively). VEL-0230 also significantly inhibits rat urinary excretion of the urinary bone resorption markers (data not shown).

80374471.1 27 Dog Efficacy Studies. VEL-0230 treatment of normal dogs indicated VEL- 0230 significantly decreases markers of bone resorption. Animals treated for 3 days with VEL-0230 show significant decreases in urinary excretion of NTx (FIG. 10, left panel). Likewise, significant decreases of serum NTx levels are seen at 0.3 -1.0 mg/kg BID (FIG. 10, right panel). These changes thus show an inhibitory action of VEL-0230 on bone resorption in dogs. These changes thus show an inhibitory action of VEL-0230 on bone resorption in dogs.

Primate Efficacy Studies. Two studies of VEL-0230 in non-human primate osteopenia models were undertaken: short term medicinal estrogen-depletion, as well as long-term (16 months) treatment of surgically ovariectomized animals. Both studies demonstrated that daily treatment with VEL-0230 is well tolerated for treatment periods of up to 16 months. VEL-0230 also demonstrated affects on bone turnover, reducing markers of bone resorption and increasing markers of bone formation. In estrogen depleted animals, gonadotropin releasing hormone agonist (GnRHa) was injected intramuscularly into 4- to 5-year-old female Cynomolgus monkeys (n = 6 per group). After confirming estrogen depletion, VEL-0230 was orally administered BID for 3 days VEL-0230 dose-dependently and significantly reduced the urinary concentration NTx within 3 days of administration (FIG. 11).

VEL-0230-treated OVX animals show marked increases in the bone formation marker bone-specific alkaline phosphatase (FIG. 12, upper right panel). BSAP is markedly increased during the first 16 weeks of treatment with 10 mg/kg VEL-0230 and remains elevated (~ 120%) until study end. The increase in BSAP seen in the OVX animals is expected, as it is being driven by increased bone turnover; but the BMD of these animals indicates this is a net-negative turnover resulting in continued bone loss. VEL-0230-treated animals also show modulations of urinary CTx that is reduced in a dose-dependent fashion with respect to OVX animals, although the biological variability in these elderly animals complicates statistical interpretation (FIG. 12, bottom panel).

EXAMPLE 6 - SUMMARY

VEL-0230 treated, ovariectomized, elderly primates show changes in bone density and biochemical markers of bone turnover that are consistent with it having both anabolic and anti-resorptive activities. VEL-0230 increases BMD, increases

80374471.1 28 markers of bone formation and reduces markers of bone resorption. This is in sharp contrast to other anti-catabolic agents where markers of both formation and resorption decrease; or to anabolic agents such as PTH where both increase. The primate observations are supported by the rat and dog data. That is, in all animals so tested, there is a significant prevention of bone loss (as indicated by BMD); bone formation is increased (as marked by increased BSAP and BMD) and resorption decreased (reduced urinary CTx).

* * * * * * * * * * * * * * * *

All of the compositions and/or methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the compositions and methods of this invention have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the compositions and/or methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit and scope of the invention. More specifically, it will be apparent that certain agents which are both chemically and physiologically related may be substituted for the agents described herein while the same or similar results would be achieved. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the invention as defined by the appended claims.

80374471.1 29 VI. References

The following references, to the extent that they provide exemplary procedural or other details supplementary to those set forth herein, are specifically incorporated herein by reference.

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80374471.1 33

Claims

1. A method of treating a subject with multiple myeloma comprising:

(i) selecting an intracellular Cathepsin K inhibitor; and

(ii) administering to said subject said first inhibitor of Cathepsin K.

2. The method of claim 1, wherein said inhibitor is a biological inhibitor or an organopharmaceutical small molecule.

3. The method of claim 2, wherein said first inhibitor is a biological inhibitor.

4. The method of claim 3, wherein said biological inhibitor is a peptide, an siRNA, an antisense molecule or a single-chain antibody.

5. The method of claim 2, wherein said inhibitor is an organopharmaceutical small molecule.

6. The method of claim 5, wherein said inhibitor is an epoxysuccinamide and variants thereof.

7. The method of claim 5, wherein said inhibitor is VEL-0230 or analog thereof.

8. The method of claim 5, wherein said inhibitor is a non-epoxysuccinamide.

9. The method of claim 1, further comprising contacting said subject with a second agent.

10. The method of claim 9, wherein said second agent is a bisphosphonate, an osteoclast inhibitor such as a PTH analog, or a second inhibitor of Cathepsin K that is distinct from said first inhibitor.

11. The method of claim 10, wherein the second inhibitor of Cathepsin K is an extracellular inhibitor of Cathepsin K.

12. The method of claim 1, wherein said first inhibitor is formulated to increase transmembrane delivery.

13. The method of claim 12, wherein said first inhibitor is formulated with a cell permeability factor.

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14. The method of claim 12, wherein said first inhibitor is formulated in a lipid delivery vehicle.

15. The method of claim 12, wherein said first inhibitor is formulated to enhance its bioavailability.

16. The method of claim 1, wherein said subject is a human.

17. The method of claim 1 , wherein the subject is a non-human animal.

18. The method of claim 9, wherein said second agent is an anti-cancer agent.

19. The method of claim 18, wherein said anti-cancer agent is a chemotherapeutic, a radiotherapeutic, an immunotherapeutic, a hormone therapy, a cytokine therapy, a toxin therapy or a gene therapy.

20. The method of claim 1, wherein said first inhibitor also prevents bone resorption.

21. The method of claim 1, wherein said first inhibitor is administered to said subject more than once.

22. The method of claim 1, wherein said first inhibitor also stimulates bone formation.

23. The method of claim 22, wherein said first inhibitor is administered to said subject more than once.

24. The method of claim 1, wherein said first inhibitor is administered to said subject by oral, intravenous, intratumoral, or tumor vasculature routes.

25. The method of claim 1, wherein the multiple myeloma is recurrent, metastatic or drug resistant.

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