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  Pharmaceutical Patents  

 

Title:  ILK inhibitors for the treatment of renal disease
United States Patent: 
7,678,775
Issued: 
March 16, 2010

Inventors:
 Kretzler; Matthias (Ann Arbor, MI), Logan; Patricia (Vancouver, CA)
Assignee:
  QLT Inc. (Vancouver, British Columbia, CA)
Appl. No.:
 11/855,884
Filed:
 September 14, 2007


 

Woodbury College's Master of Science in Law


Abstract

The invention relates to the treatment of renal diseases using modulators of integrin linked kinase. Methods of treatment as well as therapeutic agents including antisense, small molecules, catalytic peptides and antibodies are disclosed. The agents of the invention may also be used in combination with traditional therapies for renal disease including ACE inhibitors. An advantage of the invention is that it treats one of the causes of renal disease, rather than just ameliorating symptoms, and can help prevent the progression of renal disease to the point of acute renal failure.

Description of the Invention

BACKGROUND

1. Technical Field

The invention relates to the treatment of renal diseases using modulators of integrin linked kinase.

Progressive renal disease is an increasingly common and economically burdensome disease. A significant portion of patients progress to acute renal failure, a life threatening illness whose mortality has remained high despite the introduction of its only nonsurgical treatment, hemodialysis, about 25 years ago. Conventional hemodialysis mimics the filtration function of the kidneys by circulating a patient's blood through or over a dialysate solution physically separated from the blood by a porous or permeable wall or membrane. The process results in the preferential diffusion of small molecules, such as urea, from the bloodstream into the dialysate solution.

Although dialysis has dramatically changed the prognosis of renal failure, it is not a complete replacement therapy, since it only provides filtration function and does not replace the homeostatic, regulatory, and endocrine functions of the kidney. Patients on dialysis continue to have major medical problems.

In the United States, kidney failure is experienced by more than 360,000 people who depend on dialysis or a kidney transplant to survive. The number of people with kidney failure has actually doubled over the past 10 years, and the pool of candidates is large. Conservatively estimated, 10.9 million Americans have kidney disease and face the possibility of a future on dialysis or with a kidney transplant. Even with these remarkable treatments, nearly 58,000 people with kidney failure died in 1997. Jones, C. A., et al., Serum creatinine levels in the US population: third national health and nutrition examination survey. American Journal of Kidney Diseases, vol. 32, no. 6, pp. 992-999, December 1998.

Chronic renal failure may result from any major cause of renal dysfunction. The most common cause of end-stage renal disease is diabetic nephropathy, followed by hypertensive nephroangiosclerosis and various primary and secondary glomerulopathies. Plasma concentrations of creatinine and urea (which are highly dependent on glomerular filtration) begin a nonlinear rise as the renal function diminishes. Changes in creatinine and urea concentrations are minimal early on; later levels increase rapidly and are usually associated with systemic manifestations. For substances that are excreted mainly through distal nephron secretion, e.g., K, adaptation usually produces a normal plasma concentration until advanced failure occurs.

Kidney function depends on an intact glomerular filtration unit, allowing the excretion of potentially hazardous small molecular substances but retaining essential macromolecules. The permselectivity of the glomerular filter is defined by a fenestrated endothelial cell layer, the glomerular basement membrane (GBM), and podocytes. The podocyte forms the filtration slit, an ultrastructural membrane bridging the delicate web of interdigitating podocyte foot processes.

In glomerular disease there is progressive podocyte damage and proteinurea. Although the mechanisms for the progression of renal impairment remain fully undetermined, available evidence indicate that renal glomerular hypertension is responsible in part for the development of renal injury. In renal disease, afferent arteriolar tone is reported to be reduced, while the augmented intrarenal angiotensin II serves to act as an efferent arteriolar constrictor, both of which result in an increase in glomerular capillary pressure. Angiotensin converting enzyme inhibitors (ACE-I) are established as the agent possessing both antihypertensive and renoprotective actions, which exert vasodilator action on efferent arterioles. Calcium antagonists are also reported to have salutary effect on renal disease, although their beneficial action varies depending on the antagonists used and the underlying disease. Chronic progression can be slowed for 6-12 months using these drugs, but there is no other treatment at this time besides dialysis and ultimately transplantation of the organ.

A long-term replacement therapy which replaces all of the functions of the kidney and which is less costly than current dialysis therapies is desirable.

2. Description of the Related Art

Integrin-linked kinase (ILK) is a receptor-proximal protein kinase regulating integrin-mediated signal transduction. The ILK sequence is described in U.S. Pat. No. 6,013,782, herein incorporated by reference. The presence of ILK mRNA in proteinurea models and puromycin-induced podocyte damage is disclosed by Teixeira et al. (2000) Kidney & Blood Pressure Research 23(3-5):231; Unschuld et al. (1999) Kidney & Blood Pressure Research 22(4-6):400; Kretzler et al. (1998) Kidney & Blood Pressure Research 21(2-4):145. The distribution and regulation of ILK in normal and diabetic kidneys is discussed by Guo et al. (2001) Am J Pathol 159:1735-1742.

BRIEF SUMMARY

The invention provides therapeutic compositions and methods for treatment of renal disease, specifically for modulating the activity of integrin linked kinase (ILK) to ameliorate glomerular renal disease states that may result in proteinuria, or states characterized by tubular or tubulo-interstitial damage. Treatment includes the administration of agents that interfere with the ILK signaling pathway, including integrin linked kinase (ILK) blocking agents; compounds that otherwise prevent the binding of natural ILK ligands to ILK; or compounds that prevent expression of, or signaling through, ILK. Such a treatment is used alone as single therapy or in combination with a second therapy as an adjunct to prevent, to reduce or to reverse the renal function.

DETAILED DESCRIPTION

In the subject methods, compounds that modulate the activity of integrin linked kinase (ILK) are administered systemically or locally to treat renal diseases, particularly those with underlying glomerular insufficiency, or tubular damage or insufficiency. Such a treatment is used alone as single therapy or in combination with a second therapy, including administration of angiotensin converting enzyme inhibitors as an adjunct to prevent, to reduce or to reverse the loss of renal function.

Animal and human proteinuric glomerulopathies evolve to terminal renal failure by a process leading to progressive parenchymal damage, which is relatively independent of the initial insult. The amount of urinary proteins, or proteinuria, correlates with the tendency of a given disease to progress. A constant feature of proteinuric nephritis is also the concomitant presence of tubulointerstitial inflammation. Biochemical events associated with tubular cell activation in response to protein stress include up-regulation of inflammatory and vasoactive genes such as MCP-1 and endothelins. The corresponding molecules formed in an excessive amount by renal tubuli are secreted toward the basolateral compartment of the cell and give rise to an inflammatory reaction that in most forms of glomerulonephritis consistently precedes renal scarring.

Causes of chronic renal failure include, without limitation, glomerulopathies, e.g., IgA nephropathy, focal glomerulosclerosis, membranous nephropathy, membranoproliferative glomerulonephritis, idiopathic crescentic glomerulonephritis, diabetes mellitus, postinfectious glomerulonephritis, systemic lupus erythematosus, Wegener's granulomatosis, hemolytic-uremic syndrome, amyloidosis; chronic tubulointerstitial nephropathies; hereditary nephropathies, e.g., polycistic kidney disease, Alport's syndrome, medullary cystic disease, Nail-patella syndrome; hypertension, e.g., nephroangiosclerosis, malignant glomerulosclerosis; renal macrovascular disease; and obstructive uropathy, e.g., ureteral obstruction, vesicoureteral reflux, benign prostatic hyperplasia; and the like.

Chronic renal failure (CRF) may result from any major cause of renal dysfunction. The functional effects of CRF can be categorized as diminished renal reserve, renal insufficiency (failure), and uremia. Plasma concentrations of creatinine and urea begin a nonlinear rise as the renal function diminishes. Na and water balance is well maintained by increased fractional excretion of Na and a normal response to thirst. Thus, the plasma Na concentration is typically normal and hypervolemia is infrequent despite unmodified dietary intake of Na. However, imbalances may occur if Na and water intakes are very restricted or excessive.

Patients with mildly diminished renal reserve are asymptomatic, and renal dysfunction can be detected only by laboratory testing. A patient with mild to moderate renal insufficiency may have only vague symptoms despite elevated BUN and creatinine; nocturia is noted, principally due to a failure to concentrate the urine during the night. Lassitude, fatigue, and decreased mental acuity often are the first manifestations of uremia.

Neuromuscular features include coarse muscular twitches, peripheral neuropathies with sensory and motor phenomena, muscle cramps, and convulsions. Anorexia, nausea, vomiting, stomatitis, and an unpleasant taste in the mouth are almost uniformly present. In advanced CRP, GI ulceration and bleeding are common. Hypertension is present in >80% of patients with advanced renal insufficiency and is usually related to hypervolemia and occasionally to activation of the renin-angiotensin-aldosterone system. Cardiomyopathy and renal retention of Na and water may lead to congestive heart failure or dependent edema. Pericarditis, usually seen in chronic uremia, may occur in acute, potentially reversible, uremia. Abnormalities with lipid metabolism also occur with CRF, on dialysis, and after renal transplantation. The primary finding in CRF and dialysis is hypertriglyceridemia; the total cholesterol level is usually normal.

Treatments useful as an adjunct to the present methods include diet for controlling hyperglycemia in diabetic nephropathy and hypertension, and protein restriction. Administration of ACE inhibitors, and angiotensin receptor blockers is also of interest.

ILK Modulating Agents

ILK is a 59 kDa serine/threonine kinase that associates with the cytoplasmic tails of .beta.1 and .beta.3 integrins. The enzymatic activity for ILK is modulated by the interaction of cells with the extracellular matrix component fibronectin, integrin clustering and a number of growth factors. Because of its intimate association with a wide variety of signaling pathways that have been directly or indirectly implicated in various pathological processes, ILK may represent a therapeutic target for a variety of clinical conditions including angiogenesis, cancer, inflammation and autoimmunity. The genetic sequence of human ILK is disclosed in U.S. Pat. Nos. 6,013,782; and 6,001,622, herein incorporated by reference.

Agents that block ILK activity are used in the treatment of renal disease relating to neovascularization. Numerous agents are useful in reducing ILK activity, including agents that directly modulate ILK expression, e.g., anti-sense specific for ILK, ILK specific antibodies and analogs thereof, small organic molecules that block ILK catalytic or binding activity, etc.; and agents that affect ILK activity through direct or indirect modulation of [PtdIns(3,4,5)P.sub.3] levels in a cell. For example, small molecule inhibitors of integrin linked kinase are described in U.S. Pat. No. 6,214,813. Antisense inhibitors of ILK are described in U.S. Pat. No. 6,177,273, each herein incorporated by reference.

Agents of interest for down-regulating ILK activity include direct blocking of [PtdIns(3,4,5)P.sub.3] binding sites through competitive binding, steric hindrance, etc. Of particular interest are antibodies that bind to the PH domains, thereby blocking the site. Antibodies include fragments, e.g., F(Ab), F(Ab)', and other mimetics of the binding site. Such antibodies can be raised by immunization with the protein or the specific domain. Mimetics are identified by screening methods. Analogs of [PtdIns(3,4,5)P.sub.3] that compete for binding sites but do not result in activation of ILK are also of interest.

Because ILK activity is upregulated by the presence of the lipid [PtdIns(3,4,5)P.sub.3], the activity of ILK can be manipulated by agents that affect cellular levels of [PtdIns(3,4,5)P.sub.3], or that block the binding of [Ptdins(3,4,5)P.sub.3] to ILK. The amino acid sequence of ILK contains a sequence motif found in pleckstrin homology (PH) domains, which are involved in the binding of phosphatidylinositol phosphates. The activity of ILK is also down-regulated by inhibiting the activity of PI(3) kinase, thereby decreasing cellular levels of [PtdIns(3,4,5)P.sub.3]. Agents of interest include inhibitors of PI(3) kinase, e.g., wortmannin, LY294002, etc. Physiologically effective levels of wortmannin range from about 10 to 1000 nM, usually from about 100 to 500 nM, and optimally at about 200 nM. Physiologically effective levels of LY294002 range from about 1 to 500 .mu.M, usually from about 25 to 100 gM, and optimally at about 50 .mu.M. The inhibitors are administered in vivo or in vitro at a dose sufficient to provide for these concentrations in the target tissue.

Drug screening can be used to identify agents that modulate ILK function. One can identify ligands or substrates that inhibit the action of ILK. A wide variety of assays may be used for this purpose, including labeled in vitro protein-protein binding assays, electrophoretic mobility shift assays, immunoassays for protein binding, and the like. Knowledge of the 3-dimensional structure of ILK, derived from crystallization of purified recombinant ILK protein, leads to the rational design of small drugs that specifically inhibit ILK activity. These drugs may be directed at specific domains of ILK, e.g., the kinase catalytic domain, ankyrin repeat domains, pleckstrin homology domains, etc. Among the agents of interest for drug screening are those that interfere with the binding of cytoplasmic integrin tails to ILK; the kinase activity of ILK; binding of [Ptdins(3,4,5)P.sub.3] to the PH domains of ILK and agents that inhibit the production of [PtdIns(3,4,5)P.sub.3] by P1 (3) kinase.

The term "agent" as used herein describes any molecule, e.g., protein or pharmaceutical, with the capability of altering the physiological function of ILK. Candidate agents encompass numerous chemical classes, though typically they are organic molecules, preferably small organic compounds having a molecular weight of more than 50 and less than about 2,500 daltons. Candidate agents comprise functional groups necessary for structural Interaction with proteins, particularly hydrogen bonding, and typically include at least an amine, carbonyl, hydroxyl or carboxyl group, preferably at least two of the functional chemical groups. The candidate agents often comprise cyclical carbon or heterocyclic structures and/or aromatic or polyaromatic structures substituted with one or more of the above functional groups. Candidate agents are also found among biomolecules including peptides, saccharides, fatty acids, steroids, purines, pyrimidines, derivatives, structural analogs or combinations thereof.

Assays of interest may detect agents that block ILK function, such as integrin binding, kinase activity, down regulation of E-cadherin, up regulation of LEF-1, binding properties, etc. For example, an expression construct comprising an ILK gene may be introduced into a cell line under conditions that allow expression. The level of ILK activity is determined by a functional assay, as previously described. In one screening assay, candidate agents are added, and the formation of fibronectin matrix is detected. In another assay, the ability of candidate agents to enhance ILK function is determined.

Methods of Treatment

The subject methods are used for prophylactic or therapeutic purposes to treat renal diseases, particularly to prevent, reduce or reverse the loss of glomerular function. As used herein, the term "treating" is used to refer to both prevention of disease, and treatment of pre-existing conditions. While treatment during early stages is desirable, the adverse symptoms of the disease may be at least partially alleviated by treatment during later stages.

Suitable animal models exist for determination of an effective dose of an ILK inhibitor, for example as set forth in the examples. However the efficacy of a therapeutic effect for different mammals varies widely; for example, doses typically are 20, 30 or even 40 times smaller (per unit body weight) in man than in the rat. Similarly the mode of administration can have a large effect on dosage. Formulation or treatment with an adjunct therapeutic agent or regimen may also affect the effective dose

In practicing the method of treatment or use of the present invention, a therapeutically effective amount of an ILK inhibitor is administered to a subject afflicted with a disease or disorder related to loss of renal function, particularly to glomerular insufficiency relating to progressive podocyte damage and proteinurea. The inhibitor may be administered in accordance with the method of the invention either alone or in combination with other known therapies. When co-administered with one or more other therapies, the inhibitor may be administered either simultaneously with the other treatment(s), or sequentially. If administered sequentially, the attending physician will decide on the appropriate sequence of administration, which may be before or after a second therapy.

In addition to dietary management, administration of ACE inhibitors is useful as adjunct therapy. ACE inhibitor include, but are not limited to, captopril, benazeprile, enalapril, fosinopril, lisinopril, quinapril, Ramipril, imidapril, perindopril, erbumine, and trandolapril. ACE receptor blockers may also be used in place of or as well as ACE inhibitors, and these include losartan, irbesartan, candesartan, cilexetil, and valsartan.

The dose of ILK inhibitor in the pharmaceutical composition of the present invention will depend upon the nature and severity of the condition being treated, and on the nature of prior treatments which the patent has undergone. Ultimately, the attending physician will decide the dose with which to treat each individual patient. Initially, the attending physician may administer low doses and observe the patient's response. Larger doses may be administered until the optimal therapeutic effect Is obtained for the patient, and at that point the dosage is not increased further.

The compounds of this invention can be incorporated into a variety of formulations for therapeutic administration. Administration of an ILK inhibitor may be by delivery using any appropriate means including, but not limited to, systemic, local, or even direct application to the target tissue. Local delivery of an ILK inhibitor provides a high local concentration while reducing the likelihood of non-specific anti-angiogenic or other undesirable side effects that may follow systemic administration of an ILK inhibitor.

The compounds of the present invention are formulated into pharmaceutical compositions by combination with appropriate, pharmaceutically acceptable carriers or diluents, and may be formulated into preparations in solid, semi-solid, liquid or gaseous forms, such as tablets, capsules, powders, granules, ointments, solutions, suppositories, injections, inhalants, gels, microspheres, and aerosols. As such, administration of the compounds can be achieved in various ways, including oral, buccal, rectal, parenteral, intraperitoneal, intradermal, transdermal, intracheal, etc., administration. The ILK may be systemic after administration or may be localized by the use of an implant that acts to retain the active dose at the site of implantation.

The compounds of the present invention can be administered alone, in combination with each other, or they can be used in combination with other known compounds and therapies. In pharmaceutical dosage forms, the compounds may be administered in the form of their pharmaceutically acceptable salts, or they may also be used alone or in appropriate association, as well as in combination with other pharmaceutically active compounds.

For oral preparations, the compounds can be used alone or in combination with appropriate additives to make tablets, powders, granules or capsules, for example, with conventional additives, such as lactose, mannitol, corn starch or potato starch; with binders, such as crystalline cellulose, cellulose derivatives, acacia, corn starch or gelatins; with disintegrators, such as corn starch, potato starch or sodium carboxymethylcellulose; with lubricants, such as talc or magnesium stearate; and if desired, with diluents, buffering agents, moistening agents, preservatives and flavoring agents.

The compounds can be formulated into preparations for injections by dissolving, suspending or emulsifying them in an aqueous or nonaqueous solvent, such as vegetable or other similar oils, synthetic aliphatic acid glycerides, esters of higher aliphatic acids or propylene glycol; and if desired, with conventional additives such as solubilizers, isotonic agents, suspending agents, emulsifying agents, stabilizers and preservatives.

Implants for sustained release formulations are well-known in the art. Implants are formulated as microspheres, slabs, etc. with biodegradable or non-biodegradable polymers. For example, polymers of lactic acid and/or glycolic acid form an erodible polymer that is well-tolerated by the host. The implant is placed in proximity to the site of Infection, so that the local concentration of active agent is increased relative to the rest of the body.

The term "unit dosage form," as used herein, refers to physically discrete units suitable as unitary dosages for human and animal subjects, each unit containing a predetermined quantity of compounds of the present invention calculated in an amount sufficient to produce the desired effect in association with a pharmaceutically acceptable diluent, carrier or vehicle. The specifications for the novel unit dosage forms of the present invention depend on the particular compound employed and the effect to be achieved, and the pharmacodynamics associated with each compound in the host.

The pharmaceutically acceptable excipients, such as vehicles, adjuvants, carriers or diluents, are readily available to the public. Moreover, pharmaceutically acceptable auxiliary substances, such as pH adjusting and buffering agents, tonicity adjusting agents, stabilizers, wetting agents and the like, are readily available to the public.

Those of skill will readily appreciate that dose levels can vary as a function of the specific compound, the severity of the symptoms and the susceptibility of the subject to side effects. Some of the specific compounds are more potent than others. Preferred dosages for a given compound are readily determinable by those of skill in the art by a variety of means. A preferred means is to measure the physiological potency of a given compound.
 

Claim 1 of 24 Claims

1. A method for treating a patient with renal dysfunction, the method comprising: administering an effective dose of an integrin linked kinase (ILK) inhibitor to said patient.

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If you want to learn more about this patent, please go directly to the U.S. Patent and Trademark Office Web site to access the full patent.
 

 

     
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