# Patent

## Title
Therapy for complications of diabetes

## Abstract

A method for enhancing glycemic control and/or insulin sensitivity in a human subject having diabetic nephropathy and/or metabolic syndrome comprises administering to the subject a selective endothelin A (ETA) receptor antagonist in a glycemic control and/or insulin sensitivity enhancing effective amount. A method for treating a complex of comorbidities in an elderly diabetic human subject comprises administering to the subject a selective ETA receptor antagonist in combination or as adjunctive therapy with at least one additional agent that is (i) other than a selective ETA receptor antagonist and (ii) effective in treatment of diabetes and/or at least one of said comorbidities other than hypertension. A therapeutic combination useful in such a method comprises a selective ETA receptor antagonist and at least one antidiabetic, anti-obesity or antidyslipidemic agent other than a selective ETA receptor antagonist.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 13/766,266, filed Feb. 13, 2013, which is a continuation of U.S. patent application Ser. No. 12/196,635, filed on Aug. 22, 2008, which claims the benefit of U.S. provisional application Ser. No. 60/957,300, filed on Aug. 22, 2007, the disclosure of each of which is incorporated herein by reference in its entirety.


FIELD OF THE INVENTION
The present invention relates to methods and therapeutic combinations useful for improving clinical outcomes in diabetic patients having complications of diabetes such as diabetic nephropathy and/or metabolic syndrome.
BACKGROUND OF THE INVENTION
Hyperglycemia in diabetes mellitus, if not controlled, over time causes certain irreversible morphologic changes including glomerular fibrosis in kidneys of affected subjects, a condition known as diabetic nephropathy that is associated with decline in renal function, eventually leading to end-stage renal disease. In type 1 (insulin-dependent) diabetes, glycemic control is usually achievable with chronic insulin therapy; however, in type 2 (non-insulin-dependent) diabetes, insulin alone may be ineffective in preventing hyperglycemia. Even in patients with type 1 diabetes, insulin sensitivity can be partially or completely lost. Insulin resistance, or loss of insulin sensitivity, is one of an array of physiological changes that occur in some individuals who are both obese and diabetic; such physiological changes are collectively known as metabolic syndrome. Diabetic nephropathy and metabolic syndrome are serious complications of diabetes that can dramatically reduce quality of life and survival time. A feature of both these complications is arterial hypertension, which superimposes risk of serious cardiac adverse events on the already high risk of chronic kidney failure arising from these complications.
Endothelins (ETs), particularly ET-1, are believed to play a role in mediating the damaging effects of hyperglycemia in the kidney and elsewhere. Expression of ET-1 in endothelial cells of the renal vasculature is upregulated by hyperglycemia; the potent profibrotic action of ET-1 thus generated in the kidney is believed to be involved in the morphologic changes seen in diabetic nephropathy. ET-1 acts via endothelin A (ETA) and endothelin B (ETB) receptors. Elevated plasma ET levels have been reported in patients with diabetes mellitus. See, for example, Takahashi et al. (1990) Diabetologia 33:306-310.
Elevated plasma ET levels have also been reported in patients with metabolic syndrome. See Ferri et al. (1997) Exp. Clin. Endocrinol. Diabetes 105:38-40. Metabolic syndrome (sometimes referred to as “syndrome X”) is characterized by coexistence of glucose intolerance, hypertension, dyslipidemia (specifically elevated LDL (low density lipoprotein) cholesterol and triglycerides and reduced HDL (high density lipoprotein) cholesterol), obesity and susceptibility to cardiovascular disease; these effects are thought to involve a common mechanism in which insulin resistance plays an important part.
The earliest clinical evidence of diabetic nephropathy is microalbuminuria, the appearance of low but abnormal levels (≧30 mg/day) of albumin in the urine. This early stage in development of the disease is known as incipient diabetic nephropathy. Without intervention, about 80% of subjects with type 1 diabetes who develop sustained microalbuminuria exhibit a progressive increase in urinary albumin, eventually (typically after 10-15 years) reaching clinical albuminuria (≧300 mg/day), a stage known as overt diabetic nephropathy. Accompanying the increase in albumin excretion is development of arterial hypertension. In subjects with overt diabetic nephropathy, without intervention, glomerular filtration rate (GFR) gradually falls over a period of 10-20 years, culminating in end-stage renal disease. See American Diabetes Association (2004) Diabetes Care 27(suppl. 1):S79-S83. Structural changes in diabetic nephropathy include, in the incipient stage, mesangial expansion and a thickening of the glomerular basement membrane (GBM). An increase in glomerular and kidney size is generally observed. Later, during the overt stage, mesangial nodules and tubular interstitial fibrosis develop.
Hocher et al. (2001) Nephron 87:161-169 reported that in rats with streptozotocin-induced diabetes, administration of either the selective ETA receptor antagonist LU 135252 (darusentan) or the nonselective ETA/ETB receptor antagonist LU 224332, in both cases at a dose of 100 mg/kg/day, normalized glomerular matrix protein deposition, indicating an antifibrotic effect. However, neither compound was found to influence serum glucose concentrations in the course of the study.
Dhien et al. (2000) J. Pharmacol. Exp. Therap. 293:351-359 reported that LU 135252 at 100 mg/kg/day partially or fully reversed various renal effects of streptozotocin-induced diabetes in rats, including increased glomerular diameter and deposition of eosinophilic material within the glomeruli, but that plasma glucose levels were unaffected by LU 135252.
Sorokin & Kohan (2003) Am. J. Physiol. Renal Physiol. 285:F579-F589 remarked that the stage was set for clinical trials of ET inhibitors in patients with glomerular disease characterized by increased ET-1 production and actions.
Avosentan, which may be classified as a selective ETA or dual ETA/ETB receptor antagonist, has been reported to be in Phase III clinical development for diabetic nephropathy. See Battistini et al. (2006) Exp. Biol. Med. 231:653-695.
U.S. Pat. No. 6,197,780 to Münter & Kirchengast reported that treatment of obese mice with “substance 23” (darusentan) at 50 mg/kg/day completely prevented increase in body weight. A method is claimed therein for treating a patient having hyperlipidemia, comprising administering a therapeutically effective amount of an ET antagonist (e.g., darusentan) to the patient.
Balsiger et al. (2002) Clin. Sci. 103(Suppl. 48):430S-433S reported that in a rat model of type 2 diabetes, BSF 208075 (said to be a selective ETA receptor antagonist) reduced plasma glucose levels and improved plasma glucose clearance rates in hyperglycemic rats.
On the other hand, Shaw et al. (2006) Exp. Biol. Med. 231:1101-1105 reported that in a mouse model of non-obese type 1 diabetes, the selective ETA receptor antagonist LU 208075 (ambrisentan) did not reduce the elevated plasma glucose levels seen in untreated animals.
According to Berthiaume et al. (2005) Metab. Clin. Exp. 54:735-740, some studies have shown desensitization by ET-1 of insulin signaling, leading to a decrease in glucose uptake, while other studies have shown opposite results. A study is reported therein of effects of the selective ETA receptor antagonist atrasentan in a rat model of insulin resistance. At a dose of 5 mg/kg/day, atrasentan was reported to significantly reduce 3-hour fasting insulin level but not 3-hour fasting glucose level, and to significantly reduce ΔAUC, a measure of incremental area under the curve induced by a meal tolerance test, for glucose, insulin and glucose-insulin index. These results were said to demonstrate an improvement in glucose tolerance and insulin sensitivity and to suggest that chronic endothelin antagonism may have benefits in treatment of insulin resistance and/or diabetes. It was further reported that ETA receptor blockade by atrasentan led to an increase rather than a decrease in plasma ET-1 levels.
Shaw & Boden (2005) Current Vascular Pharmacology 3:359-363 reviewed evidence on effects of ET-1 and proposed that chronically elevated ET-1 levels may be a cause of insulin resistance and impaired glucose tolerance in early stages of type 2 diabetes, obesity and metabolic syndrome. Recent data were said therein to indicate that combined ETA/ETB receptor antagonists may function as effectively as selective ETA blockers. A need was proposed for prospective trials to assess whether ET-1 antagonists, either alone or in combination, are superior to other more conventional treatments such as insulin sensitizers and to evaluate effects of combined therapies on development of insulin resistance and progression of diabetes.
Subjects having diabetic nephropathy and/or metabolic syndrome represent a particularly challenging subpopulation of diabetic patients, for whom therapies giving improved outcomes with respect to quality of life and survival time, through enhanced glycemic control and/or insulin sensitivity, would represent an important advance in the art.
Recognizing that elevated blood pressure occurs in both diabetic nephropathy and metabolic syndrome, and brings its own attendant risks to quality of life and survival time, an even more challenging patient population comprises subjects having at least one of these complications of diabetes and exhibiting inadequate blood pressure control by standard antihypertensive therapies. Subjects exhibiting resistance to a baseline antihypertensive therapy with one or more drugs include patients having clinically diagnosed resistant hypertension. Resistant hypertension is defined by the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7; Chobanian et al. (2003) Hypertension 42:1206-1252) as a failure to achieve goal blood pressure in patients who are adhering to full doses of an appropriate three-drug regimen that includes a diuretic. Further, resistant hypertension is diagnosed by many physicians on the basis of a patient's resistance to adequate, but less than full, doses of an appropriate three-drug regimen because of the risk or occurrence of adverse events associated with full doses. The terms “adequate” and “full” in the present context are defined hereinbelow.
For patients with serious or compelling conditions such as diabetes and chronic kidney disease, JNC 7 recommends a goal of systolic blood pressure (SBP) <130 mmHg and diastolic blood pressure (DBP) <80 mmHg. Despite intensive, multi-drug therapy, only about 50% of patients with diabetes or chronic kidney disease reach traditional blood pressure goals, with even fewer reaching the more stringent goals now recommended by JNC 7. Thus, resistant hypertension is particularly acute for segments of the population which exhibit complications of diabetes such as diabetic nephropathy or metabolic syndrome.
It should be noted that the British Hypertensive Society (BHD-IV; J. Human Hypertens. (2004) 18:139-185), the European Society of Hypertension/European Society of Cardiology (ESH/ESC; J. Hypertens. (2003) 21:1011-1053), and the World Health Organization/International Society of Hypertension (WHO/ISH; J. Hypertens. (2003) 21:1983-1992) guidelines propose similar but not identical blood pressure goals for diabetic patients.
In a news release dated Aug. 18, 2005 (http://stockjunction.com/modules.php?name=News&file=print&sid=7332), Myogen Inc. reported positive results in a clinical trial (DAR-201) evaluating darusentan in resistant hypertension. Among inclusion criteria for DAR-201 were subjects with diabetes and/or chronic kidney disease with mean systolic blood pressure≧130 mmHg (http://clinicaltrials.gov/ct/show/NCT00364026).
Weber et al. (2006) presented a poster, available at http://www.secinfo.com/dvjdn. vbz.d.htm, posted May 16, 2006, reporting, inter alfa, subject demographics in the DAR-201 study. Of 115 subjects enrolled, 70 had diabetes and/or chronic kidney disease, 55 had diabetes and 29 had chronic kidney disease.
Nakov et al. (2002) Am. J. Hypertens. 15:583-589 described a 392-patient study in which moderate hypertension was treated with darusentan at 10 to 100 mg/day. Exclusion criteria included concomitant medication with other antihypertensive drugs. Darusentan was reported to significantly reduce SBP and DBP by comparison with placebo.
German Patent No. DE 19744799 of Knoll mentions, in the abstract thereof, combinations of an endothelin antagonist, such as darusentan, and a diuretic said to show synergistic activity in treatment of hypertension, coronary artery disease, cardiac or renal insufficiency, renal or myocardial ischemia, subarachnoid hemorrhage, Raynaud's disease and peripheral arterial occlusion.
U.S. Pat. No. 6,352,992 to Kirchengast et al. proposes pharmaceutical combination preparations comprising a beta-receptor blocker and an endothelin antagonist for treatment of vasoconstrictive disorders. Among endothelin antagonists mentioned is darusentan.
German Patent No. DE 19743142 of Knoll proposes combinations of an endothelin antagonist, such as darusentan, and a calcium antagonist for treatment of cardiovascular disorders such as pulmonary hypertension and renal and myocardial ischemia.
U.S. Pat. No. 6,329,384 to Munter et al. proposes combinations of endothelin antagonists, such as darusentan, and renin-angiotensin system inhibitors, in particular angiotensin II antagonists and angiotensin converting enzyme (ACE) inhibitors for treatment of vasoconstrictive disorders such as hypertension, heart failure, ischemia or vasospasms.
German Patent No. DE 19743140 of Knoll proposes combinations of an endothelin antagonist, such as darusentan, and a vasodilator for treatment of cardiovascular disorders such as pulmonary hypertension, renal or myocardial ischemia, subarachnoid hemorrhage, Raynaud's disease, and peripheral arterial occlusion.
International Patent Publication No. WO 2004/082637 of Pharmacia proposes combinations of an aldosterone receptor antagonist with an endothelin receptor antagonist and/or an endothelin converting enzyme inhibitor, compositions thereof, and therapeutic methods for use in treatment of pathological conditions such as hypertension, cardiovascular disease and renal dysfunction.
Improved drug therapies for treatment of patients having complications of diabetes such as diabetic nephropathy and/or metabolic syndrome, especially such patients exhibiting resistance to a baseline antihypertensive therapy with one or more drugs, for example patients having clinically diagnosed resistant hypertension, would be highly desirable.
SUMMARY OF THE INVENTION
There is now provided a method for enhancing glycemic control and/or insulin sensitivity in a human subject having diabetic nephropathy and/or metabolic syndrome, comprising administering to the subject a selective endothelin A (ETA) receptor antagonist in a glycemic control and/or insulin sensitivity enhancing effective amount.
There is further provided a method for treating a complex of comorbidities in an elderly diabetic human subject, comprising administering to the subject a selective ETA receptor antagonist in combination or adjunctive therapy with at least one additional agent that is (i) other than a selective ETA receptor antagonist and (ii) effective in treatment of diabetes and/or at least one of said comorbidities other than hypertension. Optionally the combination or adjunctive therapy further comprises administration of at least one antihypertensive other than a selective ETA receptor antagonist.
There is still further provided a therapeutic combination comprising a selective ETA receptor antagonist and at least one antidiabetic, anti-obesity or antidyslipidemic agent other than a selective ETA receptor antagonist.
Other embodiments, including particular aspects of the embodiments summarized above, will be evident from the detailed description that follows.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of the clinical study described in Example 2 herein.



DETAILED DESCRIPTION
The term “diabetic nephropathy” as used herein will be understood to include both incipient and overt stages of diabetic nephropathy, whether diagnosed or not, but most typically as diagnosed by a clinician or physician. The term “metabolic syndrome” as used herein refers to a complex of obesity, hypertension, dyslipidemia and diabetes marked by a degree of insulin resistance. The existence of metabolic syndrome as a true clinical syndrome is not universally accepted; it will be understood that in the present context a patient having metabolic syndrome is one exhibiting a complex of conditions as itemized above, whether or not “metabolic syndrome” is formally diagnosed in the patient.
In one embodiment, the method of the invention is “for enhancing glycemic control and/or insulin sensitivity” in a human subject. Where glycemic control is enhanced, such enhancement can, but does not necessarily, arise from increased insulin sensitivity. Likewise, where insulin sensitivity is enhanced, such enhancement can, but does not necessarily, lead to improved glycemic control.
In one embodiment, practice of the method leads to enhancement of glycemic control, particularly in a subject having diabetic nephropathy and/or metabolic syndrome.
In another embodiment, practice of the method leads to enhancement of insulin sensitivity, particularly in a subject having diabetic nephropathy and/or metabolic syndrome. Insulin sensitivity may be measured by standard insulin models, such as HOMA-IR (homeostasis model assessment of insulin resistance).
In yet another embodiment, practice of the method leads to enhancement in both glycemic control and insulin sensitivity, particularly in a subject having diabetic nephropathy and/or metabolic syndrome.
Enhancement of glycemic control is typically manifested by a reduction in tendency for hyperglycemia. A fasting (e.g., preprandial) blood glucose level greater than about 140 mg/dl, or a bedtime blood glucose level greater than about 160 mg/dl, can be evidence of hyperglycemia. Any reduction in blood glucose level can be beneficial to a subject having hyperglycemia, for example a reduction by at least about 5, at least about 10, at least about 15 or at least about 20 mg/dl. Ideally, glucose level is brought into a goal range for healthy subjects of about 80 to about 120 mg/dl (preprandial) or about 100 to about 140 mg/dl (bedtime). Reduction of glucose level in urine can also provide evidence of enhanced glycemic control, but is less reliable than blood measurements because excretion of glucose in urine typically does not occur unless blood glucose level exceeds about 180 mg/dl.
For some purposes, a superior measure of glycemic control is the glycosylated hemoglobin (HbA1c) test. This test reflects blood glucose concentration over a period of time related to the life-span of red blood cells (about 120 days), and consequently is not affected by daily or hourly fluctuations in blood glucose level. A patient having an HbA1c test result greater than about 8% is normally considered hyperglycemic. Any reduction in HbA1c level can be beneficial to such a patient, for example a reduction by at least about 0.5, at least about 1, at least about 1.5 or at least about 2 percentage points. Ideally, HbA1c level is brought into a goal range for healthy subjects of about 4% to about 6%.
Subjects having diabetic nephropathy and/or metabolic syndrome can be of any age, but incidence of these complications of diabetes increases markedly with age. Older subjects can respond differently from younger subjects to treatment, and can have a different spectrum of adverse effects. It is contemplated herein that elderly subjects (i.e., subjects at least about 50, for example at least about 55, at least about 60 or at least about 65 years old) can benefit especially greatly from treatment according to the present method, in part because of the severity with which their quality of life and survival time are impacted by these complications of diabetes, and in part because the particular adverse side effects that have been noted for ET antagonists, including reproductive effects, are of lesser significance later in life.
In one embodiment the subject has incipient diabetic nephropathy.
In another embodiment the subject has overt diabetic nephropathy.
In a further embodiment the subject has incipient or overt diabetic nephropathy and practice of the method provides a further beneficial effect in one or more morphologic markers of diabetic nephropathy. A “morphologic marker” in the present context is any structural or histological feature of the kidney or a tissue thereof, whether observable macroscopically, by light microscopy or by electron microscopy. Such markers can be observable directly, for example by biopsy, or indirectly, through a secondary effect specific to the marker. Examples of morphologic markers of diabetic nephropathy include, without limitation, kidney size, kidney weight, GBM thickening, mesangial expansion, deposition of collagen, fibronectin and laminin, nephron density, nodular glomerulosclerosis, atherosclerosis of renal vasculature or a combination thereof.
In a still further embodiment the subject has incipient or overt diabetic nephropathy and practice of the method provides a further beneficial effect in one or more indicators of renal function, for example GFR, creatinine clearance, albuminuria or a combination thereof.
A “beneficial effect” of the present method can take the form of an improvement over baseline, i.e., an improvement over a measurement or observation made prior to initiation of therapy according to the method. For example, a reduction in amount of collagen deposited, an increase in GFR (in a subject having overt diabetic nephropathy) or a reduction in albuminuria by comparison with a baseline level would represent such an improvement.
A “beneficial effect” can also take the form of an arresting, slowing, retarding or stabilizing of a deleterious progression in any of the above markers or functional effects of diabetic nephropathy. For example, even if GFR is not increased or albuminuria is not reduced by comparison with baseline measurements, a reduction in the rate of decrease of GFR or the rate of increase of albuminuria would represent a beneficial effect of the present method.
Thus in one embodiment, practice of the invention leads to an arresting, slowing, retarding or stabilizing of the progression of diabetic nephropathy in the subject. Such arresting, slowing, retarding or stabilizing of progression of the disease can result in extension of the time to end-stage renal disease or chronic kidney failure, which in turn can extend survival time of the subject.
A selective ETA receptor antagonist useful herein exhibits an affinity (as expressed by dissociation constant Ki) for ETA not greater than about 10 nM and a selectivity for ETA over ETB (as expressed by the ratio Ki(ETB)/Ki(ETA)) of at least about 50. In various embodiments Ki(ETA) is not greater than about 5 nM, not greater than about 2 nM, not greater than about 1 nM, not greater than about 0.5 nM or not greater than about 0.2 nM. In various embodiments Ki(ETB)/Ki(ETA) is at least about 100, at least about 200, at least about 500 or at least about 1000.
Suitable selective ETA receptor antagonists can be identified by one of ordinary skill from literature on such antagonists, based on the disclosure herein, but a non-limiting list of such antagonists includes ambrisentan, atrasentan, avosentan, BMS 193884, BQ-123, CI-1020, clazosentan, darusentan, edonentan, S-0139, SB-209670, sitaxsentan, TA-0201, tarasentan, TBC 3711, tezosentan, YM-598, ZD-1611 and ZD-4054, as well as salts, esters, prodrugs, metabolites, tautomers, racemates and enantiomers thereof.
In one embodiment, the selective ETA receptor antagonist comprises darusentan ((+)-(S)-2-[(4,6-dimethoxy-2-pyrimidinyl)oxy]-3-methoxy-3,3-diphenylpropionic acid). This compound has the formula




Riechers et al. (1996) J. Med. Chem. 39:2123-2128 reported that 2-(4,6-dimethoxypyrimidin-2-yloxy)-3-methoxy-3,3-diphenylpropionic acid in racemic form has Ki(ETA) of 6 nM and Ki(ETB) of 371 nM, thus selectivity Ki(ETB)/Ki(ETA) for the racemate based on these data can be calculated as about 62. It was further reported therein that the pure enantiomers have an affinity for ETA of 3 nM and 150 nM. The more potent enantiomer was concluded to be the (S)-enantiomer.
More recently, Lip (2001) IDrugs 4(11):1284-1292 reported the (S)-enantiomer (darusentan) as having Ki(ETA) 1.4 nM and selectivity Ki(ETB)/Ki(ETA) about 160.
It has now been found that Ki(ETB)/Ki(ETA) for darusentan, when measured in a system that achieves steady-state binding, is much greater than previously reported.
To measure affinities of darusentan for ETA and ETB receptors in the same human tissue preparation, 125[I]-endothelin-1 receptor binding cold ligand competition curves were performed in human myocardial membranes prepared from failing and non-failing left ventricles, and cold ligand dissociation constants (Ki) for ETA and ETB receptors were determined by computer modeling. Assay conditions included 10 μM Gpp(NH)p (guanylyl-5′-imidodiphosphate) to eliminate high-affinity agonist binding, 18-point competition curves from 1 pM to 100 μM, and a 4-hour incubation time to achieve steady-state binding. Darusentan was found to have the following properties under these conditions (mean of 8 assays):
Ki(ETA): 0.178±0.055 nM
Ki(ETB): 216±85 nM
Ki(ETB)/Ki(ETA): 1181±148
According to the present method, the selective ETA receptor antagonist is administered “in a glycemic control and/or insulin sensitivity enhancing effective amount.” What constitutes such an effective amount will depend on the particular selective ETA receptor antagonist used, on the individual subject, on the dosage form and route of administration used and on other factors, and can be readily determined by one of skill in the art without undue experimentation based on the disclosure herein. Any dose that is effective for enhancing glycemic control and/or insulin sensitivity, up to a maximum that is tolerated by the subject without unacceptable adverse side effects, can be administered. Illustratively for darusentan, such a dose is likely to be about 1 to about 600 mg/day, for example about 5 to about 450 mg/day or about 10 to about 300 mg/day. Higher or lower doses can be useful in specific circumstances. Useful doses of other selective ETA receptor antagonists are doses that are therapeutically equivalent to such a dose of darusentan.
The desired daily dosage amount can be administered in any suitable number of individual doses, for example four times, three times, twice or once a day. With a dosage form having appropriate controlled release properties, a lower frequency of administration may be possible, for example once every two days, once a week, etc.
In one embodiment, the selective ETA receptor antagonist is administered according to a therapeutic regimen wherein dose and frequency of administration and duration of therapy are effective to lower blood glucose level by at least about 10 mg/dl and/or to lower HbA1c level by at least about 0.5 percentage points.
In another embodiment, the selective ETA receptor antagonist is administered according to a therapeutic regimen wherein dose and frequency of administration and duration of therapy are effective to achieve a goal preprandial blood glucose level of about 80 to about 120 mg/dl, a goal bedtime blood glucose level of about 100 to about 140 mg/dl and/or a goal HbA1c level not greater than about 7%.
Benefits of the present method may not be evident immediately upon initiating a therapeutic regimen as described herein. In particular, it can take some time for it to become evident that progression of a complication of diabetes such as diabetic neuropathy has been slowed. It is therefore contemplated that administration of a selective ETA receptor antagonist will in some cases continue for an extended period of time, typically at least about 1 month, more typically at least about 3 months. Duration of therapy in some embodiments can be at least about 1 year, at least about 5 years, or for as long as needed, which can be lifelong (i.e., from a time of initiation of treatment for substantially the remainder of the patient's life). In one embodiment duration of therapy is from a time of diagnosis of diabetic nephropathy (whether incipient or overt) at least to a time of progression of the diabetic nephropathy into end-stage renal disease. In some situations the method of this embodiment will be successful in preventing progression of the disease to end-stage; in such situations the treatment can be continued indefinitely. For example, administration of the selective ETA receptor antagonist can continue for as long as a therapeutic benefit is provided thereby and any adverse side effects thereof remain commensurate with the therapeutic benefit.
Selective ETA receptor antagonists are known to be useful as antihypertensive agents. Thus practice of the present method is likely to provide a benefit not only in glycemic control and/or insulin sensitivity as outlined above, but an additional benefit in lowering blood pressure. As hypertension is an important feature of both diabetic nephropathy and metabolic syndrome, these benefits can be mutually reinforcing.
Any one or more measures of blood pressure can be lowered by a method as described herein, including SBP and/or DBP as determined, for example, by sphygmomanometry. SBP and/or DBP can be measured, for example, in a sitting or ambulatory patient.
A “trough sitting” SBP or DBP is measured at a time point when serum concentration of a drug or drugs administered according to a method of the invention is expected to be at or close to its lowest in a treatment cycle, typically just before administration of a further dose. Illustratively, where the drug or drugs are administered once a day at a particular time, for example around 8 am, trough sitting systolic or diastolic blood pressure can be measured at that time, immediately before the daily administration. It is generally preferred to measure trough sitting SBP or DBP at around the same time of day for each such measurement, to minimize variation due to the natural diurnal blood pressure cycle.
A “24-hour ambulatory” SBP or DBP is an average of measurements taken repeatedly in the course of a 24-hour period, in an ambulatory patient.
A “maximum diurnal” SBP or DBP is a measure of highest SBP or DBP recorded in a 24-hour period, and often reflects the peak of the natural diurnal blood pressure cycle, typically occurring in the morning, for example between about 5 am and about 11 am. Commonly, a second peak occurs in the evening, for example between about 5 pm and 10 pm. Such a bimodal waveform diurnal ABP pattern may be especially characteristic of resistant hypertension.
A common feature of resistant hypertension is a nighttime (defined herein as 2200 to 0600) mean systolic ABP that is less than about 10% lower than the daytime (defined herein as 0600 to 2200) mean systolic ABP. The parameter herein termed “day/night ABP ratio” expressed as a percentage is calculated as (daytime mean−nighttime mean)/daytime mean×100. A diurnal ABP pattern having a day/night ABP ratio of less than about 10% is sometimes referred to as a “non-dipping ABP”.
The patient receiving therapy according to a method of the invention can be a patient exhibiting resistance to a baseline antihypertensive therapy with one or more drugs. A “baseline antihypertensive therapy” herein means a therapeutic regimen comprising administration of one or more drugs, not including a selective ETA receptor antagonist, with an objective (which can be the primary objective or a secondary objective of the regimen) of lowering blood pressure in the patient. Each drug according to the regimen is administered at least at a dose considered by an attending physician to be adequate for treatment of hypertension, taking into account the particular patient's medical condition and tolerance for the drug without unacceptable adverse side-effects. An “adequate” dose as prescribed by the physician can be less than or equal to a full dose of the drug. A “full” dose is the lowest of (a) the highest dose of the drug labeled for a hypertension indication; (b) the highest usual dose of the drug prescribed according to JNC 7, BHD-IV, ESH/ESC or WHO/ISH guidelines; or (c) the highest tolerated dose of the drug in the particular patient.
A baseline antihypertensive therapy illustratively comprises administering one or more diuretics and/or one or more antihypertensive drugs selected from (a) angiotensin converting enzyme inhibitors and angiotensin II receptor blockers, (b) beta-adrenergic receptor blockers, (c) calcium channel blockers, (d) direct vasodilators, (e) alpha-1-adrenergic receptor blockers, (f) central alpha-2-adrenergic receptor agonists and other centrally acting antihypertensive drugs, and (g) aldosterone receptor antagonists. Optionally drugs of still further classes can be included in the baseline therapy.
A patient who is “resistant” to a baseline antihypertensive therapy is one in whom hypertension is failing to respond adequately or at all to the baseline therapy. Typically, the patient receiving the baseline therapy is failing to reach an established blood pressure goal, as set forth for U.S. patients, for example, in JNC 7 or comparable standards in other countries (e.g., BHD-IV, ESH/ESC or WHO/ISH guidelines). Illustratively, the JNC 7 goal in a patient having a complicating condition such as diabetes and/or chronic kidney disease is <130 mmHg SBP and <80 mmHg DBP.
Patients resistant to a baseline antihypertensive therapy, especially such a therapy involving a plurality of drugs, clearly represent a very challenging population for treatment. Typically in such patients, increasing dosages of the baseline therapy are not an option because of resulting adverse side effects; furthermore this approach is often ineffective in providing a desired lowering of blood pressure.
A clinically meaningful lowering of blood pressure can be obtained in such patients by use of a selective ETA receptor antagonist such as darusentan. A reduction of at least about 3 mmHg in any blood pressure parameter can be considered clinically meaningful.
Accordingly, in one embodiment of the present invention, a method for enhancing glycemic control and/or insulin sensitivity and for lowering blood pressure in a patient exhibiting resistance to a baseline antihypertensive therapy comprises administering to the patient a selective ETA receptor antagonist, for example darusentan, at a dose and frequency effective to provide a reduction of at least about 3 mmHg in trough sitting SBP and/or DBP, 24-hour ambulatory SBP and/or DBP, and/or maximum diurnal SBP and/or DBP.
In patients exhibiting resistance to a baseline antihypertensive therapy with one or more drugs, administration of darusentan adjunctively with these same drugs is surprisingly well tolerated. Accordingly, in another embodiment of the present invention, a method for enhancing glycemic control and/or insulin sensitivity and for lowering blood pressure in a patient exhibiting resistance to a baseline antihypertensive therapy with one or more drugs comprises administering darusentan to the patient adjunctively with said one or more drugs.
While in certain embodiments the selective ETA receptor antagonist, for example darusentan, can be administered alone, i.e., in monotherapy, it is contemplated that in most cases combination therapy, for example but not necessarily with one or more drugs of the baseline therapy to which the patient has proved resistant, will be desirable. However, a benefit of the administration of darusentan can be that, at least in some circumstances, it can permit dose reduction, or even elimination, of at least one of the drugs in the baseline therapy.
Particularly when used at a full dose, many baseline antihypertensive therapy drugs can have undesirable, in some cases clinically unacceptable or even dangerous, adverse side effects.
For example, especially at full doses, potassium-sparing diuretic drugs can be associated with increased risk of hyperkalemia and related disorders. Overuse of loop diuretics can cause depletion of sodium resulting in hyponatremia and/or extracellular fluid volume depletion associated with hypotension, reduced GFR, circulatory collapse, and thromboembolic episodes. Further, loop diuretics can cause ototoxicity that results in tinnitus, hearing impairment, deafness and/or vertigo. Thiazide diuretics, similarly to loop diuretics, can have adverse effects related to abnormalities of fluid and electrolyte balance. Such adverse events include extracellular volume depletion, hypotension, hypokalemia, hyponatremia, hypochloremia, metabolic alkalosis, hypomagnesemia, hypercalcemia and hyperuricemia. Thiazide diuretics can also decrease glucose tolerance, and increase plasma levels of LDL cholesterol, total cholesterol, and total triglycerides.
Angiotensin converting enzyme (ACE) inhibitors are associated with cough and increased risk of angioedema. Beta-adrenergic receptor blockers are associated with increased risk of bronchospasm, bradycardia, heart block, excess negative inotropic effect, peripheral arterial insufficiency and sometimes male impotence. Calcium channel blockers are associated with increased risk of lower limb edema. Further information on adverse events associated with antihypertensive drugs can be found, for example, in standard reference works such as Goodman & Gilman's The Pharmaceutical Basis of Therapeutics, 13th ed.
In situations such as those outlined immediately above, dose reduction or elimination of a baseline therapy drug permitted by use of darusentan can result in a reduced risk or incidence of adverse events by comparison with the baseline therapy alone without such dose reduction or elimination.
“Adjunctive” administration of darusentan (or other selective ETA receptor antagonist) in the present context means that the darusentan is administered concomitantly with a baseline hypertensive therapy as defined above, with or without dose reduction of one or more drugs in the baseline therapy. For example, darusentan can be administered adjunctively with an adequate to full dose of each of the drugs in the baseline therapy. In adjunctive therapy, the dose and frequency of darusentan administration is, in one embodiment, effective in combination with the baseline therapy to provide a reduction of at least about 3 mmHg in trough sitting SBP and/or DBP, 24-hour ambulatory SBP and/or DBP, and/or maximum diurnal SBP and/or DBP.
A method of the present invention is especially beneficial where the patient has clinically diagnosed resistant hypertension. By definition herein, in general accordance with JNC 7, such a patient exhibits resistance to an antihypertensive regimen of at least three drugs including a diuretic. In one embodiment, the patient having resistant hypertension exhibits resistance to a baseline antihypertensive therapy that comprises at least the following:

    
    
        (1) one or more diuretics; and
        (2) two or more antihypertensive drugs, selected from at least two of the following classes:
        
            (a) ACE inhibitors and angiotensin II receptor blockers;
            (b) beta-adrenergic receptor blockers; and
            (c) calcium channel blockers.
        
        
    
    


In some cases, the patient is resistant to an even more comprehensive baseline therapy, further comprising, for example, one or more direct vasodilators, alpha-1-adrenergic blockers, central alpha-2-adrenergic agonists or other centrally acting antihypertensive drugs, and/or aldosterone receptor antagonists.
While in one embodiment the selective ETA receptor antagonist is administered orally, the invention is not limited to any route of administration, so long as the route selected results in effective delivery of the drug so that the stated benefits are obtainable. Thus administration of the darusentan can illustratively be parenteral (e.g., intravenous, intraperitoneal, subcutaneous or intradermal), transdermal, transmucosal (e.g., buccal, sublingual or intranasal), intraocular, intrapulmonary (e.g., by inhalation) or rectal. Most conveniently for the majority of patients, however, the selective ETA receptor antagonist is administered orally, i.e., per os (p.o.). Any suitable orally deliverable dosage form can be used for the selective ETA receptor antagonist, including without limitation tablets, capsules (solid- or liquid-filled), powders, granules, syrups and other liquids, etc.
Most antihypertensive medicines are suitable for once a day administration, and this is true also of darusentan. Thus, particularly where darusentan is being administered in adjunctive therapy with one or more other antihypertensive drugs, it is generally most convenient to administer the darusentan once a day in a dose as indicated above.
Most typically, where the patient has clinically diagnosed resistant hypertension, the selective ETA receptor antagonist is administered adjunctively with (1) one or more diuretics; and (2) two or more antihypertensive drugs, selected from (a) ACE inhibitors and angiotensin II receptor blockers; (b) beta-adrenergic receptor blockers; and (c) calcium channel blockers. Each of these diuretic and antihypertensive drugs is typically administered at an adequate to full dose. One of skill in the art can readily identify a suitable dose for any particular diuretic or antihypertensive drug from publicly available information in printed or electronic form, for example on the internet.
Mention of a particular diuretic or antihypertensive drug in the present specification and claims will be understood, except where the context demands otherwise, to include pharmaceutically acceptable salts, esters, prodrugs, metabolites, racemates and enantiomers of the drug, to the extent that such salts, esters, prodrugs, metabolites, racemates or enantiomers exist and are therapeutically effective.
Examples of drugs useful in combination or adjunctive therapy with a selective ETA receptor antagonist, for example darusentan, or as a component of a baseline antihypertensive therapy are classified and presented in several lists below. Some drugs are active at more than one target; accordingly certain drugs may appear in more than one list. Use of any listed drug in a combination or adjunctive therapy of the invention is contemplated herein, independently of its mode of action.
A suitable diuretic can illustratively be selected from the following list:
Organomercurials

    
    
        chlormerodrin
        chlorothiazide
        chlorthalidone
        meralluride
        mercaptomerin sodium
        mercumatilin sodium
        mercurous chloride
        mersalyl
    
    


Purines

    
    
        pamabrom
        protheobromine
        theobromine
    
    


Steroids

    
    
        canrenone
        oleandrin
        spironolactone
    
    


Sulfonamide Derivatives

    
    
        acetazolamide
        ambuside
        azosemide
        bumetanide
        butazolamide
        chloraminophenamide
        clofenamide
        clopamide
        clorexolone
        disulfamide
        ethoxzolamide
        furosemide
        mefruside
        methazolamide
        piretanide
        torsemide
        tripamide
        xipamide
    
    


Thiazides and Analogs

    
    
        althiazide
        bendroflumethiazide
        benzthiazide
        benzylhydrochlorothiazide
        buthiazide
        chlorthalidone
        cyclopenthiazide
        cyclothiazide
        ethiazide
        fenquizone
        hydrochlorothiazide
        hydroflumethiazide
        indapamide
        methyclothiazide
        metolazone
        paraflutizide
        polythiazide
        quinethazone
        teclothiazide
        trichlormethiazide
    
    


Uracils

    
    
        aminometradine
    
    


Unclassified

    
    
        amiloride
        Biogen BG 9719
        chlorazanil
        ethacrynic acid
        etozolin
        isosorbide
        Kiowa Hakko KW 3902
        mannitol
        muzolimine
        perhexyline
        Sanofi-Aventis SR 121463
        ticrynafen
        triamterene
        urea
    
    


In some embodiments, the diuretic if present comprises a thiazide or loop diuretic. Thiazide diuretics are generally not preferred where the patient has a complicating condition such as diabetes or chronic kidney disease, and in such situations a loop diuretic can be a better choice.
Particularly suitable thiazide diuretics, for example for use with darusentan, include chlorothiazide, chlorthalidone, hydrochlorothiazide, indapamide, metolazone, polythiazide and combinations thereof. Particularly suitable loop diuretics include bumetanide, furosemide, torsemide and combinations thereof.
A suitable ACE inhibitor can illustratively be selected from the following list:

    
    
        alacepril
        benazepril
        captopril
        ceronapril
        cilazapril
        delapril
        enalapril
        enalaprilat
        eosinopril
        fosinopril
        imidapril
        lisinopril
        moexipril
        moveltipril
        omapatrilat
        perindopril
        quinapril
        ramipril
        sampatrilat
        spirapril
        temocapril
        trandolapril
    
    


Particularly suitable ACE inhibitors, for example for use with darusentan, include benazepril, captopril, enalapril, fosinopril, lisinopril, moexipril, perindopril, quinapril, ramipril, trandolapril and combinations thereof.
A suitable angiotensin II receptor blocker can illustratively be selected from the following list:

    
    
        candesartan
        eprosartan
        irbesartan
        losartan
        olmesartan
        tasosartan
        telmisartan
        valsartan
    
    


A suitable beta-adrenergic receptor blocker can illustratively be selected from the following list:

    
    
        AC 623
        acebutolol
        alprenolol
        atenolol
        amosulalol
        arotinolol
        atenolol
        befunolol
        betaxolol
        bevantolol
        bisoprolol
        bopindolol
        bucindolol
        bucumolol
        bufetolol
        bufuralol
        bunitrolol
        bupranolol
        butidrine hydrochloride
        butofilolol
        carazolol
        carteolol
        carvedilol
        celiprolol
        cetamolol
        cloranolol
        dilevalol
        esmolol
        indenolol
        labetalol
        landiolol
        levobunolol
        mepindolol
        metipranolol
        metoprolol
        moprolol
        nadolol
        nadoxolol
        nebivolol
        nifenalol
        nipradilol
        oxprenolol
        penbutolol
        pindolol
        practolol
        pronethalol
        propranolol
        sotalol
        sulfinalol
        talinolol
        tertatolol
        tilisolol
        timolol
        toliprolol
        xibenolol
    
    


Particularly suitable beta-adrenergic receptor blockers, for example for use with darusentan, include acebutolol, atenolol, betaxolol, bisoprolol, carvedilol, labetalol, metoprolol, nadolol, penbutolol, pindolol, propranolol, timolol and combinations thereof.
A suitable calcium channel blocker can illustratively be selected from the following list:
Arylalkylamines

    
    
        bepridil
        clentiazem
        diltiazem
        fendiline
        gallopamil
        mibefradil
        prenylamine
        semotiadil
        terodiline
        verapamil
    
    


Dihydropyridine Derivatives

    
    
        amlodipine
        aranidipine
        barnidipine
        benidipine
        cilnidipine
        efonidipine
        elgodipine
        felodipine
        isradipine
        lacidipine
        lercanidipine
        manidipine
        nicardipine
        nifedipine
        nilvadipine
        nimodipine
        nisoldipine
        nitrendipine
        NZ 105
    
    


Piperazine Derivatives

    
    
        cinnarizine
        dotarizine
        flunarizine
        lidoflazine
        lomerizine
    
    


Unclassified

    
    
        bencyclane
        etafenone
        fantofarone
        monatepil
        perhexyline
    
    


Particularly suitable calcium channel blockers, for example for use with darusentan, include amlodipine, diltiazem, felodipine, isradipine, nicardipine, nifedipine, nisoldipine, verapamil and combinations thereof.
Optionally, one or more additional antihypertensive drugs can be administered. These can be selected, for example, from direct vasodilators, alpha-1-adrenergic receptor blockers, central alpha-2-adrenergic receptor agonists and other centrally acting antihypertensive drugs, and aldosterone receptor antagonists.
A suitable direct vasodilator can illustratively be selected from the following list:

    
    
        amotriphene
        benfurodil hemisuccinate
        benziodarone
        chloracizine
        chromonar
        clobenfurol
        clonitrate
        cloricromen
        dilazep
        droprenilamine
        efloxate
        erythrityl tetranitrate
        etafenone
        fendiline
        hexestrol bis(β-diethylaminoethyl ether)
        hexobendine
        hydralazine
        isosorbide dinitrate
        isosorbide mononitrate
        itramin tosylate
        khellin
        lidoflazine
        mannitol hexanitrate
        minoxidil
        nitroglycerin
        pentaerythritol tetranitrate
        pentrinitrol
        perhexyline
        pimethylline
        prenylamine
        propatyl nitrate
        trapidil
        tricromyl
        trimetazidine
        trolnitrate phosphate
        visnadine
    
    


Particularly suitable direct vasodilators, for example for use with darusentan, include hydralazine, minoxidil and combinations thereof.
A suitable alpha-1-adrenergic receptor blocker can illustratively be selected from the following list:

    
    
        amosulalol
        arotinolol
        carvedilol
        dapiprazole
        doxazosin
        ergoloid mesylates
        fenspiride
        idazoxan
        indoramin
        labetalol
        methyldopa
        monatepil
        naftopidil
        nicergoline
        prazosin
        tamsulosin
        terazosin
        tolazoline
        trimazosin
        yohimbine
    
    


Particularly suitable alpha-1-adrenergic receptor blockers, for example for use with darusentan, include carvedilol, doxazosin, labetalol, prazosin, terazosin and combinations thereof. It is noted that, of these, carvedilol and labetalol also function as beta-adrenergic receptor blockers.
A suitable central alpha-2-adrenergic receptor agonist or other centrally acting antihypertensive drug can illustratively be selected from the following list:

    
    
        clonidine
        guanabenz
        guanadrel
        guanfacine
        methyldopa
        moxonidine
        reserpine
    
    


A suitable aldosterone receptor antagonist can illustratively be selected from the following list:

    
    
        canrenone
        eplerenone
        spironolactone
    
    


Still further classes of drugs that can be useful in combination or adjunctive therapy with darusentan or in a baseline antihypertensive therapy include vasopeptidase inhibitors, NEP (neutral endopeptidase) inhibitors, prostanoids (particularly oral prostanoids), PDE5 (phosphodiesterase type 5) inhibitors, nitrosylated compounds and oral nitrates.
Illustrative vasopeptidase inhibitors include:

    
    
        fasidotril
        omapatrilat
        sampatrilat
    
    


Illustrative NEP inhibitors, some of which are also ACE inhibitors, include:

    
    
        candoxatril
        CGS 26582
        MDL 100173
        omapatrilat
        phosphoramidon
        sinorphan
        thiorphan
        Z13752A
    
    


Illustrative prostanoids include:

    
    
        beraprost
        cicaprost
        epoprostenol
        iloprost
        PGE1 
        PGI2 (pro stacyclin)
        NS-304
        treprostinil
    
    


Illustrative PDE5 inhibitors include:

    
    
        sildenafil
        tadalafil
        vardenafil
    
    


Other drugs that can be useful in combination or adjunctive therapy with darusentan or in a baseline antihypertensive therapy can illustratively be selected from the following unclassified list:

    
    
        ajmaline
        alfuzosin
        Alteon ALT 711
        γ-aminobutyric acid
        atrial natriuretic peptide
        azelnidipine
        bethanidine
        bietaserpine
        bosentan
        budralazine
        bufeniode
        bunazosin
        cadralazine
        carmoxirole
        CD 3400
        chlorisondamine chloride
        cicletanine
        ciclosidomine
        clevidipine
        debrisoquin
        denitronipradilol
        desacetylalacepril
        deserpidine
        diazoxide
        dihydralazine
        endralazine
        fenoldopam
        flosequinan
        guanethidine
        guanidine, N-cyano-N′-4-pyridinyl-N′′-(1,2,2-trimethylpropyl)-, monohydrate
        guanoxabenz
        guanoxan
        hexamethonium
        ketanserin
        LBI 45
        levcromakalim
        lofexidine
        magnesiocard
        mebutamate
        mecamylamine
        normopresil
        2-oxazolamine, N-(dicyclopropylmethyl)-4,5-dihydro-, (2E)-2-butenedioate
        pargyline
        pempidine
        pentamethonium bromide
        pentolinium tartrate
        pheniprazine
        phentolamine
        pildralazine
        pinacidil
        piperoxan
        protoveratrines
        3,5-pyridinedicarboxylic acid, 1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-, methyl 1-(phenylmethyl)-3-pyrrolidinyl ester
        raubasine
        rescimetol
        rescinnamine
        rilmenidine
        saralasin
        sodium niroprusside
        syrosingopine
        Takeda TAK 536
        TBC 3711
        tetrahydrolipstatin
        1,4-thiazepine-4(5H)-acetic acid, 6-[[1-(ethoxycarbonyl)-3-phenylpropyl]amino]-tetrahydro-5-oxo-2-(2-thienyl)
        tiamenidine
        todralazine
        tolonidine
        trimethaphan camsylate
        tyrosinase
        urapidil
        zofenopril
    
    


In one embodiment, the selective ETA receptor antagonist, more specifically darusentan, is administered concomitantly (e.g., in combination or adjunctive therapy) with one or more of

    
    
        (a) a diuretic selected from the group consisting of chlorothiazide, chlorthalidone, hydrochlorothiazide, indapamide, metolazone, polythiazide, bumetanide, furosemide, torsemide and combinations thereof;
        (b) an ACE inhibitor selected from the group consisting of benazepril, captopril, enalapril, fosinopril, lisinopril, moexipril, perindopril, quinapril, ramipril, trandolapril and combinations thereof, and/or an angiotensin II receptor blocker selected from the group consisting of candesartan, eprosartan, irbesartan, losartan, olmesartan, tasosartan, telmisartan, valsartan and combinations thereof;
        (c) a beta-adrenergic receptor blocker selected from the group consisting of acebutolol, atenolol, betaxolol, bisoprolol, carvedilol, labetalol, metoprolol, nadolol, penbutolol, pindolol, propranolol, timolol and combinations thereof;
        (d) a calcium channel blocker selected from the group consisting of amlodipine, diltiazem, felodipine, isradipine, nicardipine, nifedipine, nisoldipine, verapamil and combinations thereof;
        (e) a direct vasodilator selected from the group consisting of hydralazine, minoxidil and combinations thereof;
        (f) an alpha-1-adrenergic receptor blocker selected from the group consisting of carvedilol, doxazosin, labetalol, prazosin, terazosin and combinations thereof;
        (g) a central alpha-2-adrenergic receptor agonist or other centrally acting drug selected from the group consisting of clonidine, guanabenz, guanadrel, guanfacine, methyldopa, moxonidine, reserpine and combinations thereof; and
        (h) an aldosterone receptor antagonist selected from the group consisting of canrenone, eplerenone, spironolactone and combinations thereof.
    
    


More particularly, the selective ETA receptor antagonist, more specifically darusentan, can be administered in combination or adjunctive therapy with one or more of (a), (b), (c) and (d) above, optionally further with one or more of (e), (f), (g) and (h).
Still more particularly, the selective ETA receptor antagonist, more specifically darusentan, can be administered in combination or adjunctive therapy at least with (a) and any two of (b), (c) and (d).
As in the case of the selective ETA receptor antagonist, the one or more drugs constituting the baseline antihypertensive therapy and optionally administered in combination with the selective ETA receptor antagonist can be delivered by any suitable route of administration. Generally, such drugs are suitable for oral administration, and many are suitable for once a day oral administration. Thus in one embodiment at least one of the diuretic or antihypertensive drugs in the baseline therapy is orally administered once a day. In a particular embodiment, all drugs in the baseline therapy are orally administered once a day. According to this embodiment, it will generally be found convenient to administer all drugs in the regimen, i.e., the selective ETA receptor antagonist as well as the baseline therapy drugs, orally once a day.
Fixed-dose combinations of two or more drugs can be achieved in many cases by coformulation of the drugs in a single dosage unit such as a tablet or capsule. For example, coformulations of various drugs useful in a baseline antihypertensive therapy as defined herein are available, including:

    
    
        amiloride+hydrochlorothiazide;
        amlodipine+benazepril;
        atenolol+chlorthalidone;
        benazepril+hydrochlorothiazide;
        bisoprolol+hydrochlorothiazide;
        candesartan+hydrochlorothiazide;
        captopril+hydrochlorothiazide;
        enalapril+felodipine;
        enalapril+hydrochlorothiazide;
        eprosartan+hydrochlorothiazide;
        fosinopril+hydrochlorothiazide;
        irbesartan+hydrochlorothiazide;
        lisinopril+hydrochlorothiazide;
        losartan+hydrochlorothiazide;
        methyldopa+hydrochlorothiazide;
        metoprolol+hydrochlorothiazide;
        moexipril+hydrochlorothiazide;
        nadolol+hydrochlorothiazide;
        olmesartan+hydrochlorothiazide;
        propranolol+hydrochlorothiazide;
        quinapril+hydrochlorothiazide;
        reserpine+chlorothiazide;
        reserpine+chlorthalidone;
        reserpine+hydrochlorothiazide;
        spironolactone+hydrochlorothiazide;
        telmisartan+hydrochlorothiazide;
        timolol+hydrochlorothiazide;
        trandolapril+verapamil;
        triamterene+hydrochlorothiazide; and
        valsartan+hydrochlorothiazide.
    
    


It will be understood that combination or adjunctive therapies as indicated above, while of particular benefit in patients having resistant hypertension, are not limited to such patients. Hypertension (whether resistant or not) is a common feature of most complications of diabetes, including both diabetic nephropathy and metabolic syndrome, and it is contemplated that combination or adjunctive therapies of a selective ETA receptor antagonist with one or more antihypertensive drugs other than selective ETA receptor antagonists can be useful in many diabetic patients having these complications.
Another kind of combination or adjunctive therapy that can be useful according to the present invention includes a selective ETA receptor antagonist and one or more additional antidiabetic agents other than selective ETA receptor antagonists. Such additional antidiabetic agents can, for example, be selected from alpha-glucosidase inhibitors, biguanides, exendins, hormones and analogs thereof, meglitinides, sulfonylurea derivatives and thiazolidinediones.
A suitable antidiabetic can illustratively be selected from the following list:
Biguanides

    
    
        buformin
        metformin
        phenformin
    
    


Hormones and Analogs Thereof

    
    
        amylin
        insulin
        insulin aspart
        insulin detemir
        insulin glargine
        insulin glulisine
        insulin lispro
        liraglutide
        pramlintide
    
    


Sulfonylurea Derivatives

    
    
        acetohexamide
        carbutamide
        chlorpropamide
        glibornuride
        gliclazide
        glimepiride
        glipizide
        gliquidone
        glisoxepid
        glyburide
        glybuthiazole
        glybuzole
        glyhexamide
        glymidine
        tolazamide
        tolbutamide
        tolcyclamide
    
    


Thiazolidinediones

    
    
        pioglitazone
        rosiglitazone
        troglitazone
    
    


Unclassified

    
    
        acarbose
        exenatide
        miglitol
        mitiglinide
        muraglitazar
        nateglinide
        repaglinide
        sitagliptin
        tesaglitazar
        vildagliptin
        voglibose
    
    


Particularly suitable antidiabetics, for example for use with darusentan, include acarbose, exenatide, glimepiride, insulins, metformin, nateglinide, pioglitazone, pramlintide, rosiglitazone and combinations thereof.
For a subject with metabolic syndrome, a selective ETA receptor antagonist can be administered in combination or adjunctive therapy with one or more additional agents selected from antidiabetics (for example as listed above), antihypertensives (for example as listed above), anti-obesity agents and antidyslipidemics.
Suitable anti-obesity agents include anorexics, CB1 receptor blockers and lipase inhibitors.
A suitable anti-obesity agent can illustratively be selected from the following list:

    
    
        a minorex
        amphetamine
        benzphetamine
        chlorphentermine
        clobenzorex
        clortermine
        cyclexedrine
        dextroamphetamine
        diethylpropion
        N-ethylamphetamine
        fenbutrazate
        fenfluramine
        fenproporex
        levophacetoperane
        mazindol
        mefenorex
        methamphetamine
        norpseudoephedrine
        orlistat
        pentorex
        phendimetrazine
        phenmetrazine
        phentermine
        phenylpropanolamine
        rimonabant
        sibutramine
    
    


Particularly suitable anti-obesity agents, for example for use with darusentan, include benzphetamine, methamphetamine, orlistat, phendimetrazine, phentermine, rimonabant, sibutramine and combinations thereof.
Suitable antidyslipidemics include bile acid sequestrants, cholesterol absorption inhibitors, fibrates, HMG CoA reductase inhibitors (statins), nicotinic acid derivatives, and thyroid hormones and analogs thereof.
A suitable antidyslipidemic can illustratively be selected from the following list:
Bile Acid Sequestrants

    
    
        cholestyramine resin
        colesevelam
        colestilan
        colestipol
        polidexide
    
    


Fibrates

    
    
        bezafibrate
        binifibrate
        ciprofibrate
        clinofibrate
        clofibrate
        clofibric acid
        etofibrate
        fenofibrate
        gemfibrozil
        pirifibrate
        ronifibrate
        simfibrate
        theofibrate
    
    


HMG CoA Reductase Inhibitors

    
    
        atorvastatin
        cerivastatin
        fluvastatin
        lovastatin
        pitavastatin
        pravastatin
        rosuvastatin
        simvastatin
    
    


Nicotinic Acid Derivatives

    
    
        acipimox
        aluminum nicotinate
        niacin (nicotinic acid)
        niceritrol
        oxiniacic acid
    
    


Thyroid Hormones and Analogs Thereof

    
    
        dextrothyroxine
        etiroxate
        thyropropic acid
    
    


Unclassified

    
    
        acifran
        avasimibe
        benfluorex
        detaxtran
        eicosapentaenoic acid
        ezetimibe
        meglutol
        melinamide
        omega-3 acid ethyl esters
        γ-oryzanol
        pantethine
        pirozadil
        policonasol
        probucol
        β-sitosterol
        sultosilic acid
        tiadenol
        torcetrapib
        xenbucin
    
    


Particularly suitable antidyslipidemics, for example for use with darusentan, include atorvastatin, colesevelam, ezetimibe, fenofibrate, fluvastatin, lovastatin, niacin, rosuvastatin, simvastatin and combinations thereof.
It is further contemplated that the selective ETA receptor antagonist can itself have useful antidyslipidemic activity, for example secondary to its activity in enhancing glycemic control and/or insulin sensitivity.
When a selective ETA receptor antagonist is used in adjunctive therapy with one or more additional antidiabetics, antihypertensives, anti-obesity agents and/or antidyslipidemics, the selective ETA receptor antagonist and at least one additional antidiabetic, antihypertensive, anti-obesity agent and/or antidyslipidemic can be administered at different times or at about the same time (at exactly the same time or directly one after the other in any order). The selective ETA receptor antagonist and the at least one antidiabetic, antihypertensive, anti-obesity agent and/or antidyslipidemic can be formulated in one dosage form as a fixed-dose combination for administration at the same time, or in two or more separate dosage forms for administration at the same or different times.
Separate dosage forms can optionally be co-packaged, for example in a single container or in a plurality of containers within a single outer package, or co-presented in separate packaging (“common presentation”). As an example of co-packaging or common presentation, a kit is contemplated comprising, in separate containers, darusentan and at least one drug useful in combination or adjunctive therapy with darusentan, for example an antidiabetic, antihypertensive, anti-obesity agent or antidyslipidemic. In another example, darusentan and at least one drug useful in combination or adjunctive therapy with darusentan, for example an antidiabetic, antihypertensive, anti-obesity agent or antidyslipidemic, are separately packaged and available for sale independently of one another, but are co-marketed or co-promoted for use according to the invention. The separate dosage forms can also be presented to a patient separately and independently, for use according to the invention.
A further embodiment of the present invention provides a method for treating a complex of comorbidities in an elderly diabetic human subject. This method comprises administering to the subject a selective ETA receptor antagonist in combination or adjunctive therapy with

    
    
        (a) at least one additional agent that is (i) other than a selective ETA receptor antagonist and (ii) effective in treatment of diabetes and/or at least one of said comorbidities other than hypertension, and optionally
        (b) at least one antihypertensive other than a selective ETA receptor antagonist.
    
    


An “elderly” subject is as defined hereinabove.
A “comorbidity” is a disease condition present in the subject in addition to diabetes, that adds to the deleterious effects of the diabetes on the subject and/or affects the choice of therapy. Comorbidities can arise secondarily from the diabetes or from other comorbidities, or may arise independently. Among comorbidities commonly occurring in an elderly diabetic patient population are, illustratively, insulin resistance, chronic kidney disease, hypertension, dyslipidemia, obesity, cardiac insufficiency and sleep apnea.
A “complex” of comorbidities is defined herein as the presence of at least two such comorbidities, in addition to the underlying diabetes. In some embodiments the subject presents with at least three, or even four or more, such comorbidities. For example, in metabolic syndrome, a subject can exhibit diabetes with insulin resistance, hypertension, dyslipidemia and obesity.
“Treating” in the present context includes alleviating symptoms, enhancing glycemic control and/or insulin sensitivity, arresting, slowing, retarding or stabilizing progression of a condition or a physiological or morphological marker thereof, and/or improving clinical outcome, for example as measured by quality of life, incidence or severity of adverse cardiac events, time to end-stage renal disease or survival time.
The selective ETA receptor antagonist can illustratively be selected from those mentioned hereinabove. In one embodiment the selective ETA receptor antagonist comprises darusentan, for example at dosage amounts and frequencies of administration, by routes of administration and dosage forms, and for duration of treatment as indicated hereinabove.
Several of the comorbidities mentioned above as occurring in elderly diabetic patients have been individually reported in the literature (including literature cited herein) to be mediated by ET-1 and/or to be treatable with a selective ETA receptor antagonist. However, it has not hitherto been proposed to simultaneously address a complex of comorbidities of diabetes in an elderly patient by treatment with a selective ETA receptor antagonist such as darusentan; nor has it been proposed to combine such treatment, in adjunctive or combination therapy, with one or more additional agents effective in treatment of diabetes and/or at least one of said comorbidities other than hypertension. Given the spectrum of effects of selective ETA receptor antagonists but without being bound by theory, it is believed that the selective ETA receptor antagonist (e.g., darusentan) component of such adjunctive or combination therapy can contribute in a substantial way to clinical improvement in each of a plurality of comorbidities, for example supplementing the effect of, co-acting with, or permitting dose reduction (with potential benefits in reducing adverse side-effects) in at least one additional agent. However, even without such contribution by the selective ETA receptor antagonist to more than one comorbidity, the adjunctive or combination therapy of the present embodiment brings great benefit to the elderly diabetic patient by enabling a complex of comorbidities, as seen for example in diabetic nephropathy or metabolic syndrome, to be simultaneously addressed.
The at least one additional agent that is (i) other than a selective ETA receptor antagonist and (ii) effective in treatment of diabetes and/or at least one comorbidity other than hypertension can comprise, for example, one or more antidiabetics, anti-obesity agents and/or antidyslipidemics, including any such agents listed hereinabove. For example, one or more agents selected from acarbose, exenatide, glimepiride, insulins, metformin, nateglinide, pioglitazone, pramlintide, rosiglitazone, benzphetamine, methamphetamine, orlistat, phendimetrazine, phentermine, rimonabant, sibutramine, atorvastatin, colesevelam, ezetimibe, fenofibrate, fluvastatin, lovastatin, niacin, rosuvastatin, simvastatin and combinations thereof can be administered in adjunctive or combination therapy with a selective ETA receptor antagonist, for example darusentan.
Antihypertensive(s) optionally additionally present in the adjunctive or combination therapy can comprise, for example, agents of any class listed hereinabove, including diuretics, ACE inhibitors, angiotensin II receptor blockers, beta-adrenergic receptor blockers, calcium channel blockers, direct vasodilators, alpha-1-adrenergic receptor blockers, central alpha-2-adrenergic receptor agonists and other centrally acting antihypertensive drugs, aldosterone receptor antagonists, vasopeptidase inhibitors, NEP inhibitors, prostanoids, PDE5 inhibitors, nitrosylated compounds, oral nitrates and renin inhibitors, or combinations of agents from one or more than one such class. For example, where the subject has clinically diagnosed resistant hypertension as one of the comorbidities, the adjunctive or combination therapy can comprise administration of at least one diuretic and at least two antihypertensives selected from at least two of (a) ACE inhibitors and angiotensin II receptor blockers, (b) beta-adrenergic receptor blockers and (c) calcium channel blockers.
Illustratively antihypertensives for use in the method of the present embodiment can be selected from chlorothiazide, chlorthalidone, hydrochlorothiazide, indapamide, metolazone, polythiazide, bumetanide, furosemide, torsemide, benazepril, captopril, enalapril, fosinopril, lisinopril, moexipril, perindopril, quinapril, ramipril, trandolapril, candesartan, eprosartan, irbesartan, losartan, olmesartan, tasosartan, telmisartan, valsartan, acebutolol, atenolol, betaxolol, bisoprolol, carvedilol, labetalol, metoprolol, nadolol, penbutolol, pindolol, propranolol, timolol, amlodipine, diltiazem, felodipine, isradipine, nicardipine, nifedipine, nisoldipine, verapamil and combinations thereof.
A still further embodiment of the present invention provides a therapeutic combination comprising a selective ETA receptor antagonist and at least one antidiabetic, anti-obesity or antidyslipidemic agent other than a selective ETA receptor antagonist. Such a combination can have utility in a number of situations, not limited to methods described herein. However, a combination of this embodiment can be especially useful for treating a complex of comorbidities in an elderly diabetic human subject as described above.
The selective ETA receptor antagonist and the at least one antidiabetic, anti-obesity or antidyslipidemic agent can be present in the combination in two or more separate dosage forms, permitting administration at the same or different times. Such separate dosage forms can be formulated with one or more pharmaceutically acceptable excipients for administration via the same or different routes. In a particular embodiment all agents in the combination are formulated for oral administration; in an even more particular embodiment all agents are formulated for once-daily oral administration and can be administered at the same time each day. Where a treatment regimen includes administration of a plurality of drugs, as in the present instance, there are great benefits in convenience and compliance in standardizing route, frequency and timing of administration in this way.
As indicated hereinabove, separate dosage forms can optionally be co-packaged, for example in a single container or in a plurality of containers within a single outer package, or co-presented in separate packaging, for example as a kit comprising, in separate containers, a selective ETA receptor antagonist and at least one antidiabetic, anti-obesity or antidyslipidemic agent. The kit can optionally comprise separate labeling information for each agent, or a single product label having information on the therapeutic combination as a whole. In another example, the selective ETA receptor antagonist and the at least one antidiabetic, anti-obesity or antidyslipidemic agent are separately packaged and available for sale independently of one another, but are co-marketed or co-promoted for use according to the invention. The separate dosage forms can also be presented to a patient separately and independently, for use according to the invention.
In another embodiment, the selective ETA receptor antagonist and the at least one antidiabetic, anti-obesity or antidyslipidemic agent are coformulated with one or more pharmaceutically acceptable excipients in a single pharmaceutical composition as a fixed-dose combination.
A pharmaceutical composition comprising the selective ETA receptor antagonist, the at least one antidiabetic, anti-obesity or antidyslipidemic agent, and one or more pharmaceutically acceptable excipients is itself a still further embodiment of the present invention.
In a therapeutic combination or pharmaceutical composition of the invention, the selective ETA receptor antagonist can illustratively be selected from those mentioned hereinabove. In one embodiment the selective ETA receptor antagonist comprises darusentan, for example in a dosage amount as set forth hereinabove.
The combination or composition can comprise at least one antidiabetic, for example selected from alpha-glucosidase inhibitors, biguanides, exendins, hormones and analogs thereof, meglitinides, sulfonylurea derivatives and thiazolidinediones. In a particular embodiment the selective ETA receptor antagonist comprises darusentan and the at least one antidiabetic is selected from acarbose, exenatide, glimepiride, insulins, metformin, nateglinide, pioglitazone, pramlintide, rosiglitazone and combinations thereof.
The combination or composition can comprise at least one anti-obesity agent, for example selected from anorexics, CB1 receptor blockers and lipase inhibitors. In a particular embodiment the selective ETA receptor antagonist comprises darusentan and the at least one anti-obesity agent is selected from benzphetamine, methamphetamine, orlistat, phendimetrazine, phentermine, rimonabant, sibutramine and combinations thereof.
The combination or composition can comprise at least one antidyslipidemic, for example selected from bile acid sequestrants, cholesterol absorption inhibitors, fibrates, HMG CoA reductase inhibitors, nicotinic acid derivatives, and thyroid hormones and analogs thereof. In a particular embodiment the selective ETA receptor antagonist comprises darusentan and the at least one antidyslipidemic is selected from atorvastatin, colesevelam, ezetimibe, fenofibrate, fluvastatin, lovastatin, niacin, rosuvastatin, simvastatin and combinations thereof. For example, the combination or composition can comprise a selective ETA receptor antagonist such as darusentan, a cholesterol absorption inhibitor such as ezetimibe, and an HMG CoA reductase inhibitor (statin) such as atorvastatin, fluvastatin, lovastatin, rosuvastatin or simvastatin.
The combination or composition comprises, in one embodiment, a selective ETA receptor antagonist, at least one antidiabetic and at least one anti-obesity agent.
The combination or composition comprises, in another embodiment, a selective ETA receptor antagonist, at least one antidiabetic and at least one antidyslipidemic.
The combination or composition comprises, in yet another embodiment, a selective ETA receptor antagonist, at least one anti-obesity agent and at least one antidyslipidemic.
The combination or composition comprises, in a still further embodiment, a selective ETA receptor antagonist, at least one antidiabetic, at least one anti-obesity agent and at least one antidyslipidemic.
According to any embodiment mentioned above, the combination or composition optionally further comprises at least one antihypertensive. The at least one antihypertensive can comprise, for example, one or more agents of any class listed hereinabove or a combination of agents from more than one such class.
An illustrative combination or composition of the invention comprises:

    
    
        (a) darusentan as a selective ETA receptor antagonist;
        (b) one or more of:
        
            (i) at least one antidiabetic selected from acarbose, exenatide, glimepiride, insulins, metformin, nateglinide, pioglitazone, pramlintide, rosiglitazone and combinations thereof;
            (ii) at least one anti-obesity agent selected from benzphetamine, methamphetamine, orlistat, phendimetrazine, phentermine, rimonabant, sibutramine and combinations thereof; and/or
            (iii) at least one antidyslipidemic selected from atorvastatin, colesevelam, ezetimibe, fenofibrate, fluvastatin, lovastatin, niacin, rosuvastatin, simvastatin and combinations thereof; and
        
        
        (c) at least one antihypertensive selected from chlorothiazide, chlorthalidone, hydrochlorothiazide, indapamide, metolazone, polythiazide, bumetanide, furosemide, torsemide, benazepril, captopril, enalapril, fosinopril, lisinopril, moexipril, perindopril, quinapril, ramipril, trandolapril, candesartan, eprosartan, irbesartan, losartan, olmesartan, tasosartan, telmisartan, valsartan, acebutolol, atenolol, betaxolol, bisoprolol, carvedilol, labetalol, metoprolol, nadolol, penbutolol, pindolol, propranolol, timolol, amlodipine, diltiazem, felodipine, isradipine, nicardipine, nifedipine, nisoldipine, verapamil and combinations thereof.
    
    


EXAMPLES
The following examples are merely illustrative, and do not limit this disclosure in any way. Reference is made in the examples to statistical analysis. Such reference is made in the interest of full disclosure and does not constitute admission that statistical significance is a prerequisite for patentability of any claim herein.
Example 1
Summary
The following is a protocol for a Phase II double blind placebo-controlled randomized study to investigate the safety and the hemodynamic effects of three-week oral applications of different doses of darusentan on top of standard medication in congestive heart failure patients.
Objectives
The primary objective of this study was to assess the tolerability and safety profile of three-week oral applications of different doses of darusentan on top of established standard medicinal treatments in patients suffering from advanced chronic congestive heart failure NYHA functional class III. Secondary objective was the assessment of the short-term effects of three-week darusentan treatment on hemodynamic parameters by means of SWAN GANZ floating catheterization and thermodilution.
Methodology
This was a multinational, multicenter, prospective, double-blind, placebo-controlled, randomized clinical trial.
After a pre-investigational eligibility check, double-blind treatment was started for a period of three weeks, followed by a one-week double-blind follow-up period.
The safety and hemodynamic effects of three different dosages of darusentan were consecutively studied, starting with darusentan at 30 mg or placebo. The following dosages of 300 mg followed by 100 mg were selected after reviewing the results and experiences gleaned from evaluating the safety data of at least 15 patients who completed the entire three-week dosing period.
Patients
To obtain at least 24 evaluable patients per treatment group, it was expected to include a total number of 120 patients into the study. Actually, 157 patients were randomized (30 mg: n=36; 100 mg: n=39; 300 mg: n=49; placebo: n=33).
Male and female patients were selected based on the following profile: aged 18 years or older who needed to undergo SWAN GANZ floating catheterization for diagnostic reasons with clinical CHF signs of at least three months duration and for any underlying cause (except for primary organic valvular heart disease), present or recent history of NYHA functional class III and presenting with a left ventricular ejection fraction less than or equal to 35%, assessed by means of echocardiography or isotope ventriculography within seven days prior to investigational procedures. Continuation in the study was only possible, if at baseline pulmonary capillary wedge pressure (PCWP) was more than equal to 12 mmHg and cardiac index (CI) was less than or equal to 2.6 l/min/m2.
Test Product, Dose, Mode of Administration and Duration of Treatment
Tablets containing 30 mg, 100 mg or 300 mg darusentan.
Medication was taken orally once a day for 3 weeks
Reference Therapy, Dose, Mode of Administration and Duration of Treatment
Matching placebo tablets taken orally once a day for 3 weeks.
Criteria for Evaluation:
1. Efficacy
Changes in hemodynamic parameters from baseline focusing on CI (1/min/m2), and PCWP (mmHg). Furthermore, pharmacokinetic parameters and neurohormone plasma levels were assessed.
2. Safety
Adverse events, changes in systemic blood pressure, heart rate, ECG and clinical laboratory parameters were measured.
Statistical Methods
All treated patients were included in the safety analysis. Efficacy was analyzed primarily according to the intention-to-treat principle. Continuous data were described by statistical characteristics (m, mean, standard deviation, minimum, 1st quartile, median, 3rd quartile, maximum, number of missing values) for each time point, as well as for changes from baseline. For categorical data and adverse events, frequency and percentage were given. For the two primary efficacy parameters CI (1/min/m2) and PCWP (mmHg), analysis-of-covariance models were calculated.
Results:
During the course of this study blood glucose levels (mg/dl or mmol/l) were determined at patient visits. Only fasting blood glucose levels are shown below. “N/A” is used where either blood glucose level was not examined or the laboratory test was performed when the patient was not fasting.










Glucose Levels















Visit 1
Visit 2
Visit 3
Visit 4
Visit 5
Visit 6
Side Effects


















Patient 185
N/A
156
N/A
N/A
N/A
139
Increasing of Dyspnoea (3)









Increase of Body Weight (3)









Decrease of Diuresis (3)


Patient 152
N/A
11.4
8.6
6.4
11.1
5.2
Hyperglycemia (5)









Face Rush (3)









Pneumonia (3)









Headache each day (2)









Better Exercise Tolerance (2)


Patient 190
N/A
116
121
N/A
N/A
N/A
Sensations of Heat (3)









Head cephalgia (3)









Angina Pectoris (3)









Subjective feelings of unrest (3)









Sleep Disturbance (3)









Angina Pectoris with Dyspnoea (3)









Sensations of Abdominal Pressure (3)


Patient 215
N/A
97
92
N/A
N/A
N/A
CHF worsening (4)


Patient 216
N/A
127
141
N/A
N/A
104
Acute Left Heart Failure (5)









Decreasing Plueral Effusion


Patient 288
80
65
N/A
N/A
N/A
88
None Listed





Side Effect Relationship to Drug


(1) - Definite


(2) - Probable


(3) - Possible


(4) - Unlikely


(5) - Unrelated


**Non-survivor patients whose mordity was deemed to have an unlikely or unrelated relationship to darusentan by the clinician have been omitted.






Example 2
Summary
Hypertension clinical studies conducted over the last decade have indicated that proper control of systolic blood pressure (SBP) is equally as important as diastolic blood pressure (DBP) control in relationship to cardiovascular and renal outcomes; and SBP is more difficult to control than DBP, especially in patients over 50 years of age. Despite treatment with multiple antihypertensive drugs at therapeutic doses, a substantial number of patients, especially those with diabetes mellitus (diabetes) and/or chronic kidney disease (CKD), do not reach guideline-recommended blood pressure goals.
The following is the protocol for a phase 3 randomized, double-blind, placebo-controlled, multi-center, parallel group study to evaluate the efficacy and safety of fixed doses of darusentan in subjects with resistant systolic hypertension receiving combination therapy with three or more antihypertensive drugs, including a diuretic.










LIST OF ABBREVIATIONS


















ABPM
Ambulatory blood pressure monitoring



ACEI
Angiotensin converting enzyme inhibitor



AE
Adverse event



ALT
Alanine aminotransferase



ANCOVA
Analysis of covariance



ARB
Angiotensin receptor blocker



AST
Aspartate aminotransferase



AUC
Area-under-the-curve



AV
Atrioventricular



BMI
Body mass index



BNP
b-type natriuretic peptide



BP
Blood pressure



BUN
Blood urea nitrogen



CCB
Calcium channel blocker



Cmax
Peak plasma concentration



CHF
Chronic heart failure



CFR
Code of Federal Regulations



CKD
Chronic kidney disease



CNO
Certificate of non-objection



CRF
Case report form



DBP
Diastolic blood pressure



dL
Deciliters



DMC
Data Monitoring Committee



ECG
Electrocardiogram



eGFR
Estimated glomerular filtration rate



ET-1
Endothelin-1



ETA
Endothelin A receptor



ETB
Endothelin B receptor



ERA
Endothelin receptor antagonist



FDA
Food and Drug Administration



FSH
Follicle stimulating hormone



g
Grams



GCP
Good clinical practice



GDC
Global Data Collection



GGT
Gamma glutamyl aminotransferase



HbA1c
Glycosylated hemoglobin



HDL
High density lipoprotein



HIPAA
Health Insurance Portability and Accountability Act



HR
Heart rate



IB
Investigator's Brochure



ICD
Implantable cardioverter defibrillator



ICF
Informed Consent Form



ICH
International Conference on Harmonization



IEC
Independent ethics committee



IgM
Immunoglobulin M



IND
Investigational New Drug application



INR
International normalized ratio



IRB
Institutional review board



kg
Kilograms



Ki
Inhibition constant



LDH
Lactate dehydrogenase



LDL
Low density lipoprotein



LFT
Liver function test



LH
Luteinizing hormone



LLN
Lower limit of normal



LV
Left ventricular



LVIDD
Left ventricular internal diastolic diameter



m2
Meters squared



MDRD
Modification of Diet in Renal Disease



mg
Milligrams



min
Minutes



mL
Milliliters



mmHg
Millimeters of mercury



μg
Micrograms



nM
Nanomolar



NOTEL
No toxic effect level



NOAEL
No observed adverse effect level



NSAIDs
Non-steroidal anti-inflammatory drugs



P450
Cytochrome P450



PDC
Premature Discontinuation



PDE
Phosphodiesterase



PHI
Protected health information



PK
Pharmacokinetic



po
Per os (orally)



PT
Prothrombin time



PTT
Partial thromboplastin time



qd
Once daily



RBC
Red blood cell



RHTN
Resistant hypertension



SADR
Serious adverse drug reaction



SAE
Serious adverse event



SaO2
Arterial oxygen saturation



SBP
Systolic blood pressure



SCr
Serum creatinine



SSRIs
Selective serotonin reuptake inhibitors



SUSAR
Suspected unexpected serious adverse event



t1/2
Elimination half-life



TCA
Tricyclic antidepressants



TG
Triglycerides



TSH
Thyroid stimulating hormone



UACR
Urinary albumin-to-creatinine ratio



ULN
Upper limit of normal



WBC
White blood cell









Methods

Patients

Approximately 352 subjects will be randomized to one of three doses of darusentan (50, 100 or 300 mg po qd) or placebo in a ratio of 7:7:7:11 at approximately 160 investigative sites in North and South America, Europe, New Zealand, and Australia.
Eligible subjects will include men and women, 35-80 years old, treated with full doses of three or more antihypertensive drugs, including a diuretic, with RHTN as defined by contemporary clinical guidelines for the treatment of hypertension [1,2]. Subjects with diabetes and/or CKD must have a SBP ≧130 mmHg at Screening to be eligible for study entry. All other subjects must have a SBP of ≧140 mmHg. SBP at Screening must be <180 mmHg for all subjects. A BMI of 20 to 43 kg/m2 or an upper arm circumference <42 cm, and an eGFR ≧30 mL/min/1.73 m2 at Screening are also required. Subject eligibility will be reassessed at the initiation of the 2-week single-blind Placebo Run-in Period and at the Randomization Visit (see Study Schematic), and only those subjects who continue to meet inclusion/exclusion criteria at these visits will be randomized into the study. In particular, SBP and DBP measured at the Placebo Run-in Visit and at the Randomization Visit must be within 20 mmHg and 10 mmHg, respectively, of the values recorded at Screening in order for the subject to be eligible for randomization. NOTE: Subjects who fail to meet entry criteria after entering the placebo run-in phase will not be allowed to re-screen for the study.
All potential subjects will be classified with regard to diabetes and CKD as part of the Screening process. Diabetic subjects must have a documented diagnosis of Type 2 diabetes prior to Screening, and all screened subjects will be evaluated for the presence of CKD according to the following definition: (i) reduced excretory function with an eGFR <60 mL/min/1.73 m2 and/or (ii) the presence of albuminuria in a spot urine sample (>200 mg/g [22.60 mg/mmol] creatinine).
Antihypertensive therapy must include:
A diuretic, preferably a thiazide; and
Two or more drugs from at least two of the following classes of antihypertensive agents:

    
    
        ACEIs, ARBs, and/or renin inhibitors
        CCBs
        beta-blockers
        central alpha-2 agonists
        peripheral alpha-1 antagonists
        direct vasodilators
        other centrally-acting drugs
    
    


The combination of antihypertensive drugs administered should be consistent with current treatment guidelines [1,2]. For example, common multi-drug therapy may include a thiazide diuretic, an ACEI or an ARB, and a CCB. Subjects may be on more than 3 antihypertensive drugs at entry as long as the minimum requirements described above are met.
The minimum allowable dose of hydrochlorothiazide (HCTZ) will be 25 mg. For other thiazide-type diuretics, an equivalent dose to 25 mg HCTZ is also required. A loop diuretic may be substituted for the thiazide diuretic in subjects with CKD or a documented contraindication/intolerance to treatment with a thiazide. A potassium-sparing diuretic alone (e.g., triamterene) will not qualify as adequate diuretic therapy. The dose of each antihypertensive medication that the subject is receiving will be documented at Screening, and monitored throughout study participation. In addition, the dose of each concomitant antihypertensive medication will be classified at study entry according to the following criteria:

    
    
        Highest labeled dose according to the product's package insert/labeling information for the applicable country/region
        Highest usual dose per clinical guidelines [1]
        Highest tolerated dose
        Highest appropriate dose for the subject per the Principal Investigator's best clinical judgment
    
    


It is expected that subjects will have been optimized on their antihypertensive drug regimens well in advance of Screening for this study. Subjects must be stable on all antihypertensive drugs for at least 4 weeks prior to the Screening Visit. Adjustments to the number or dosage of concomitant antihypertensive medications will not be permitted at any time during the study, with the exception of protocol-allowed changes to diuretic therapy implemented to specifically address fluid retention-related events (see Study Design section below).
Subjects who meet any one of the following criteria will be deemed ineligible for participation in the study:

    1. Subjects with an average sitting SBP of 180 mmHg or DBP of 110 mmHg.
    2. Subjects with left ventricular (LV) systolic dysfunction as evidenced by a LV ejection fraction <40% and/or a LV internal diastolic diameter (LVIDD) >3.2 cm/m2 or >6.0 cm, measured by echocardiogram at Screening (Visit 1) or within 3 months prior to Screening.
    3. Subjects with a HbA1c>10% at Screening (Visit 1).
    4. Subjects who have:
    
        a. A hemoglobin concentration <11.5 g/dL at Screening (Visit 1) or
        b. A hematocrit <34% at Screening (Visit 1)
    
    
    5. Subjects with hypo- or hyperthyroidism, as evidenced by a serum thyroid stimulating hormone (TSH) concentration >1.5×ULN or <1.5× the lower limit of normal (LLN) at Screening (Visit 1).
    6. Subjects with a serum ALT or AST >2×ULN at Screening (Visit 1).
    7. Subjects with other identifiable secondary causes of resistant hypertension (e.g., parathyroid disease, pheochromocytoma, aortic coarctation, Cushing's disease, hyperaldosteronism).
    8. Subjects who have experienced a myocardial infarction, unstable angina pectoris, or a cerebrovascular accident within 6 months of the Screening Visit (Visit 1).
    9. Subjects with sick sinus syndrome or second or third degree atrioventricular (AV) block, chronic atrial fibrillation or recurrent atrial tachyarrhythmia (including paroxysmal atrial tachycardia), a history of recurrent ventricular tachycardia, or symptomatic bradycardia.
    10. Subjects with implanted pacemakers or an implanted cardioverter defibrillator (ICD).
    11. Subjects with a historical or current diagnosis of symptomatic or asymptomatic CHF, treated or untreated.
    12. Subjects with hemodynamically significant valvular heart disease.
    13. Subjects with Type 1 diabetes mellitus.
    14. Subjects on hemodialysis or peritoneal dialysis at the time of Screening (Visit 1) and subjects with a history of solid organ transplant (e.g., kidney, heart).
    15. Subjects who have had a diagnosis or recurrence of malignancy within the past 3 years, with the exception of basal cell carcinoma of the skin or in situ carcinoma of the cervix.
    16. Subjects with sleep apnea are excluded, unless a post-treatment sleep study has confirmed treatment efficacy and there are no recordings of blood oxygen saturation (SpO2)<90% at any time during the testing period.
    17. Subjects who perform alternating shift or night work.
    18. Women of childbearing potential or women who are pregnant or nursing.
    19. Subjects not on stable doses of all concomitant medications for a minimum of 4 weeks prior to Screening, and subjects treated with any of the following prohibited medications:
    
        a. Oral or injected corticosteroids within 3 months of Screening (Visit 1). Systemic treatment with oral or injected steroids is also prohibited during study participation. NOTE: The use of inhaled steroids is allowed.
        b. Aspirin in excess of 325 mg per day.
        c. Chronic stable or unstable use of non-steroidal anti-inflammatory drugs (NSAIDS) other than aspirin is prohibited. Chronic use is defined as consecutive or nonconsecutive days of treatment per week. (Note: In addition, the intermittent use of NSAIDs is strongly discouraged throughout the duration of this study. If intermittent treatment is required, NSAIDs must not be used for more than a total of 2 days during the single-blind Placebo Run-in Period or the 2 weeks prior to the Week 14 Visit [Visit 10a]. For all subjects requiring analgesic or anti-pyretic agents, the use of acetaminophen is recommended during study participation).
        d. Selective serotonin reuptake inhibitors (SSRIs), if a subject is not compliant with the medication and/or has not been receiving a stable dose for at least 3 months prior to Screening. In addition, SSRIs or similar drugs for the treatment of anxiety or depression may not be initiated at any time during the study.
        e. Tricyclic antidepressants (TCAs), if a subject is not compliant with the medication and/or has not been receiving a stable dose for at least 3 months prior to Screening. In addition, TCAs or similar drugs for the treatment of anxiety or depression may not be initiated at any time during the study.
        f. Another ERA (e.g., bosentan, sitaxsentan, atrasentan, TBC3711) at or within 6 months of Screening (Visit 1). In addition, subjects may not initiate treatment with another ERA at any time during the study.
        g. The use of short-acting oral nitrates (e.g., sublingual nitroglycerin) is permitted; however, subjects should not take short-acting oral nitrates within 4 hours of Screening (Visit 1) or any subsequent study visit.
        h. The use of long-acting oral nitrates (e.g., Isordil) is permitted; however, the dose must be stable for at least 2 weeks prior to Screening (Visit 1) and Randomization (Visit 3a).
        i. The use of oral sympathomimetic decongestants or β-agonists is permitted; however, not within 1 week prior to Screening (Visit 1), initiation of the Placebo Run-in (Visit 2), or Randomization (Visit 3a). In addition, use of these medications will be prohibited within 1 day prior to any clinic visit during study participation. NOTE: The stable chronic use of inhaled β-agonists is permitted. These drugs may be used as prescribed without the visit-based prohibitions described above.
        j. The use of theophylline is permitted; however, the dose must be stable for at least 4 weeks prior to Screening (Visit 1) and throughout study participation.
        k. The use of phosphodiesterase (PDE) type V inhibitors is permitted; however, subjects must refrain from taking these medications within three (3) days of Screening (Visit 1) or any subsequent study visit.
        l. Use of thiazolidinedione (i.e., glitazone) class of anti-diabetic medications (e.g., rosiglitazone, pioglitazone; alone or in combination pills) at or within 4 weeks of Screening (Visit 1). Subjects should not initiate treatment with thiazolidinediones at any time during the study.
        Note: Subjects receiving exclusionary medications at Screening must undergo a minimum of 4 weeks washout prior to being re-screened for the study.
    
    
    20. Subjects who have demonstrated non-compliance with previous medical regimens.
    21. Subjects with a contraindication to treatment with an ERA. Contraindications include, but are not limited to, a history of elevated liver function tests (e.g., aminotransferases >2×ULN) or an event defined as a serious adverse event (SAE) attributed to previous treatment with an ERA.
    22. Subjects who participated in a prior clinical study of darusentan and were randomized to, and received, active treatment.
    23. Subjects who have participated in a clinical study involving another investigational drug or device within 4 weeks of the Screening Visit (Visit 1).
    24. Subjects who have failed screening for this study two times.
    25. Subjects who have any concomitant condition that, in the opinion of the investigator, may adversely affect the safety and/or efficacy of the study drug or severely limit the subject's lifespan or ability to complete the study (e.g., alcohol or drug abuse, disabling or terminal illness, mental disorders, institutionalization by judicial order).

Objectives



The primary objective of this study is to determine if darusentan is effective in reducing SBP and DBP in subjects with RHTN, despite treatment with full doses of three or more antihypertensive drugs, including a diuretic.
Secondary objectives of this study are to examine the effect of darusentan on mean 24-hour ambulatory blood pressure, percent of subjects meeting SBP goal, and eGFR. The safety and tolerability of darusentan in the subject population will also be evaluated.
Several measures of interest will also be examined.
Study Design
This is a Phase 3 randomized, double-blind, placebo-controlled, multi-center, parallel group study in subjects with RHTN, despite treatment with full doses of three or more antihypertensive drugs, including a diuretic.
The study will consist of three periods: Screening, Placebo Run-in, and Treatment. Screening assessments and evaluations may be conducted over a period of not more than 2 weeks. Following Screening, all eligible subjects will undergo a single-blind, Placebo Run-in of 2 weeks duration to ensure that blood pressure remains stable and continues to meet eligibility criteria for randomization. Subjects who continue to meet eligibility criteria following the 2-week Placebo Run-in Period will be randomized to one of four treatment groups (50, 100, or 300 mg of darusentan or placebo po qd), stratified by co-morbidity status (i.e., presence of diabetes and/or CKD versus the absence of these conditions) and race (i.e., Black versus non-Black). Subjects randomized to placebo or 50 mg darusentan will receive their randomized dose of study drug throughout the 14-week Treatment Period. Subjects randomized to 100 or 300 mg darusentan will be initiated on 50 mg for 2 weeks and will subsequently undergo up-titration to the next higher dose of darusentan every 2 weeks until the randomized dose is achieved (see FIG. 1). If a subject experiences a severe study drug-related AE during the Treatment Period, the subject's study drug dose may be reduced, according to investigator discretion. The choice to reduce the study drug dose may be made only once during the Treatment Period, and the change must be implemented prior to or at the Week 6 Visit. Once a subject's study drug dose has been down-titrated, it may not be subsequently increased. Subjects requiring down-titration of study drug after study Week 6 must discontinue treatment with study drug; however, the subject should remain in study through the end of the Treatment Period (i.e., Week 14). Study drug assignments will remain double-blinded throughout the Treatment Period. All subjects will receive a fixed dose of study drug for a minimum of 8 weeks prior to the evaluation of study endpoints at the Week 14 Visit.
Adjustments to the number or dosage of concomitant antihypertensive medications will not be permitted at any time during the study. However, if a subject develops signs or symptoms of fluid retention during the Treatment Period, manifested as peripheral edema and/or clinically significant weight gain between study visits that in the opinion of the investigator requires immediate treatment, the subject's diuretic therapy may be adjusted according to investigator discretion. It is recommended that a loop diuretic be added, or the dose increased for subjects already receiving a loop diuretic, prior to adjusting concomitant thiazide diuretic therapy. All changes will be documented in detail in the subject's case report form (CRF). Adjustment of diuretics will not be allowed within 2 weeks of the primary endpoint assessment.
Subjects who complete participation in the study through the Week 14 Visit, on or off study drug, will have the option to participate in a long-term safety extension study, with the exception of subjects who discontinue study drug due to a study drug-related AE. Subjects who discontinue treatment with study drug prior to the end of the Treatment Period due to a study drug-related AE will not be eligible to participate in the long-term safety extension study. Subjects who do not participate in the long-term safety extension study will discontinue treatment with study drug at the Week 14 Visit, and will return to the clinic for two safety visits prior to concluding study participation. Maximum placebo exposure in this study will be 16 weeks.
Women of childbearing potential will be excluded from study participation. Women who are surgically sterile or documented post-menopausal for at least 2 years are not considered to be of childbearing potential. Post-menopausal female subjects who are not surgically sterile will be required to use a double-barrier method of birth control throughout study participation. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase, gamma glutamyl aminotransferase (GGT), and total bilirubin will be monitored in all subjects throughout the study. All men will be required to provide blood samples for hormone analyses, and men who are able will be required to undergo semen analyses prior to and during treatment with study drug in order to evaluate the potential effects of darusentan on male fertility. Men who have had a vasectomy or who are unable to provide semen samples will be excused from this requirement.
Schedule of Assessments













STUDY VISIT




















1
2
3a
3b
4
5
6
7
8
9
10a
10b










Study Week













Random.

14






















−4
−2
D 1
D 2
2
4
6
8
10
12
D 1
D 2
UV1
























Assessments















Informed consent
X


Review
X
X
X


Inclusion/Exclusion


criteria


Medical
X


history/demographics


ConMed assessment
X
X
X

X
X
X
X
X
X

X
X


Adverse Event

X
X

X
X
X
X
X
X

X
X


assessment


Trough sitting/standing
X
X
X

X
X
X
X
X
X
X

X


BP and HR


Full physical examination
X









X


Abbreviated physical

X
X

X
X
X
X
X
X


X


examination


Measure body weight
X
X
X

X
X
X
X
X
X
X

X


12-lead ECG
X

X


X

X


X


Echocardiogram
X2


Ambulatory BP


on
off






on
off


Monitoring


Health Economics
X3


Questionnaire


Obtain vital status4


Laboratory Tests


Chemistry
X5

X

X

X

X

X

X


Hematology
X

X

X

X

X

X

X


Urine sample
X

X
X6
X6
X6
X6



X
X6


Fasting Blood Collection7

X, S







S


Trough PK plasma


X





X
X
X


sample


Biomarker plasma


X







X


sample


Women only:


Serum pregnancy test
X









X


β-hCG urine pregnancy


X


test


Men only:


Hormone analysis


X







X


















Semen analysis

S8 ▪ ▪ ▪ (X)






S8 ▪ ▪ ▪ (X)






















Warfarin-treated















subjects only:


Coagulation9


X







x


Study Drug


Collect study drug/assess


X

X
X
X
X
X
X
X

X10


compliance


Register study visit
X
X
X
X
X
X
X
X
X
X
X
X
X


Randomization



X


Dispense study drug

X11

X12
X
X
X
X
X
X


X10





1UV = Unscheduled Visit;


2An echocardiogram must be obtained during the Screening Period or within 3 months prior to Screening. However, historical echocardiograms must report predefined criteria necessary to determine subject eligibility.


3A Health Economics Questionnaire will be completed by all screened subjects.


4All randomized subjects must be contacted to assess vital status at or shortly after the time of the last subject visit and again for the purposes of Global Data Collection.


5The chemistry panel performed at Screening will include measurements of immunoglobulin M (IgM), thyroid stimulation hormone (TSH) and glycosylated hemoglobin (HbA1c). TSH and HbA1c will be used to evaluate subject eligibility.


6Spot urine collection for subjects with clinically significant albuminuria (≧30 mg/g [3.39 mg/mmol] creatinine) at Screening.


7S = Schedule. Fasting Blood Collection-Baseline may occur at Placebo Run-in (Visit 2) or within 2 weeks after that visit, but not at the Randomization Visit (Visit 3). Fasting Blood Collection-End of Study (EOS) for all subjects may occur within the 2 weeks following the Week 12 Visit (Visit 9), but not during the Week 14 Visit (Visit 10).


8Schedule a semen sample collection within 2 weeks prior to or during Randomization (Visit 3a). Schedule a post-baseline semen sample collection within 2 weeks prior to or during the Week 14 Visit (Visit 10a).


9Coagulation labs will be completed for subjects receiving warfarin (Coumadin) or warfarin-like anticoagulants.


10If down-titration of study drug occurs at an unscheduled visit, collection of study drug, assessment of compliance, and dispensation of study drug should also be performed.


11Single-blind, placebo study drug will be dispensed to all eligible subjects at this visit.


12Randomized, double-blind treatment begins for all eligible subjects.






Primary Efficacy Endpoints

The co-primary endpoints are the change from baseline to Week 14 in trough sitting SBP and trough sitting DBP, as measured by sphygmomanometry.
Secondary Endpoints
The following secondary endpoints will be assessed during this study:

    
    
        Change from baseline to final measurement in mean 24-hour SBP measured by ABPM
        Change from baseline to final measurement in mean 24-hour DBP measured by ABPM
        The percent of subjects who reach SBP goal after 14 weeks of treatment, defined as follows:
        
            Subjects with diabetes and/or CKD must reach a SBP goal of <130 mmHg
        
        
        All other subjects must reach a SBP goal of <140 mmHg
        Change from baseline to Week 14 in eGFR

Measures of Interest

    
    


The following measures of interest will be examined:

    
    
        Change from baseline in the following ABPM measures:
        
            Mean hourly ambulatory SBP and DBP over a 24-hour monitoring period
            Mean trough ambulatory SBP and DBP
            Mean peak ambulatory SBP and DBP
            Mean trough/peak ratio
            Mean daytime ambulatory SBP and DBP
            Mean nighttime ambulatory SBP and DBP
            Mean daytime/nighttime ratio;
        
        
        Change from baseline to Week 14 in pulse pressure measured by sphygmomanometry;
        Change from baseline in selected biomarker concentrations;
        Change from baseline in glycosylated hemoglobin (HbA1c), fasting plasma glucose, serum lipid profile, serum insulin, serum C-peptide, serum C-reactive protein, and waist circumference;
        Change from baseline in urinary albumin-to-creatinine ratio (UACR) in a subset of subjects with clinically significant albuminuria (i.e., ≧30 mg/g [3.39 mg/mmol] creatinine in a spot urine sample);
        Trough plasma concentrations of darusentan and its metabolites;

Statistical Methods

    
    


Change in SBP and DBP from baseline to Week 14 will be tested with analysis of covariance, using stratification factors (comorbidity status and race) and baseline blood pressure as covariates. Proportion at goal blood pressure will be tested with logistic regression, using the same covariates. The last observation during double blind therapy will be used for analyses.
Adjustment for multiple comparisons for the primary endpoints of change in SBP and DBP will use the fallback method. First, SBP will be compared between the 300 mg dose and placebo at the nominal alpha level of 0.04. If this is significant, DBP will be compared between the 300 mg dose and placebo at the nominal level of 0.04. From this point, the fixed sequence procedure will be followed, requiring significance on an endpoint before allowing testing of the following endpoint, and testing all comparisons at the same level. If the 300 mg dose was significant at the 0.04 level for both SBP and DBP, the tests will be reported at the 0.05 level; otherwise the tests will be reported at the 0.01 level. These comparisons will be, in order, the 100 mg dose compared to placebo for SBP then DBP, and the 50 mg dose compared to placebo for SBP and then DBP. Continuous secondary endpoints will be handled analogously.
Assuming a difference in placebo-adjusted change from baseline of 8 mmHg in trough SBP for each darusentan dose and a standard deviation of 15 mmHg, 121 subjects randomized to placebo and 77 subjects randomized to each dose of darusentan will provide 85-90% power to detect a difference between placebo and any individual darusentan dose, and 95% power to find at least one dose of darusentan that is different from placebo.
It is expected that treatment of a human subject, for example a human subject having diabetic nephropathy and/or metabolic syndrome, in accordance with the foregoing protocol will produce an enhancement in glycemic control and/or insulin sensitivity.
REFERENCES


    [1] Chobanian A V, Bakris G L, Black H R, Cushman W C, Green L A, Izzo J L, Jr. et al. Seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Hypertension 2003; 42(6):1206-1252.
    [2] 2003 European Society of Hypertension-European Society of Cardiology Guidelines for the Management of Arterial Hypertension. J Hypertens 2003; 21(6):1011-1053.


All patents and publications cited herein are incorporated by reference into this application in their entirety.
The words “comprise”, “comprises”, and “comprising” are to be interpreted inclusively rather than exclusively.

## Claims

1. A method for treating diabetic nephropathy in a human subject in need of such treatment, said method comprising:
administering to the subject atrasentan or a salt thereof, and a dose of at least one angiotensin converting enzyme inhibitor or an angiotensin II receptor blocker.

2. The method of claim 1, comprising administering the dose of the angiotensin converting enzyme inhibitor or angiotensin II receptor blocker at an adequate dose labeled for a hypertension indication.

3. The method of claim 1, comprising administering the dose of the angiotensin converting enzyme inhibitor or angiotensin II receptor blocker at a highest dose labeled for a hypertension indication.

4. The method of claim 1, comprising administering the dose of the angiotensin converting enzyme inhibitor or angiotensin II receptor blocker at a highest usual dose prescribed according to Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC7), British Hypertensive Society (BHD-IV), European Society of Hypertension/European Society of Cardiology (ESH/ESC) or World Health Organization/International Society of Hypertension (WHO/ISH) guidelines.

5. The method of claim 1, comprising administering the dose of the angiotensin converting enzyme inhibitor or angiotensin II receptor blocker at a highest tolerated dose in the human subject.

6. The method of claim 1, wherein the angiotensin converting enzyme inhibitor is selected from the group consisting of alacepril, benzapril, captopril, ceronapril, cilazapril, delapril, enalapril, enalaprilat, eosinopril, fosinopril, imidapril, lisinopril, moexipril, moveltipril, omapatrilat, perindopril, quinapril, ramipril, sampatrilat, spirapril, temocapril, trandolapril, and combinations thereof.

7. The method of claim 1, wherein the angiotensin II receptor blocker is selected from the group consisting of candesartan, eprosartan, irbesartan, losartan, olmesartan, tasosartan, telmisartan, valsartan and combinations thereof.

8. The method of claim 1, wherein the method further comprises administering a thiazide diuretic selected from the group consisting of althiazide, bendroflumethiazide, benzthiazide, benzyl hydrochlorothiazide, buthiazide, chlorothiazide, chlorthalidone, cyclopenth iazide, ethiazide, fenquizone, hydrochlorothiazide, hydroflumethiazide, indapamide, methyclothiazide, metolazone, paraflutizide, polythiazide, quinethazone, teclothiazide, trichlormethiazide, and combinations thereof.

9. The method of claim 1, wherein the method further comprises administering a loop diuretic selected from the group consisting of bumetanide, furosemide, torsemide and combinations thereof.

10. The method of claim 1, wherein the diabetic nephropathy is overt diabetic nephropathy.

11. The method of claim 1, wherein the diabetic nephropathy is caused by Type II diabetes.

12. The method of claim 1, wherein the human subject is diagnosed with Type II diabetes.

13. The method of claim 1, comprising administering atrasentan or salt thereof for a period of at least 3 months.

14. The method of claim 1, comprising administering the atrasentan or a salt thereof for as long as a therapeutic benefit is provided thereby and any adverse side effect thereof remains commensurate with the therapeutic benefit.

15. The method of claim 1, wherein the atrasentan or salt thereof is administered concomitantly with the angiotensin converting enzyme inhibitor or angiotensin II receptor blocker.

16. A method of treating diabetic nephropathy in a human subject in need of treatment comprising:
administering to the subject atrasentan or a salt thereof, and a dose of at least one of an angiotensin converting enzyme inhibitor or an angiotensin II receptor blocker, and
wherein the method results in a beneficial effect on one or more morphological markers of diabetic nephropathy.

17. The method of claim 16, wherein the morphologic marker of diabetic nephropathy is glomerulosclerosis.

18. A method of treating diabetic nephropathy in a human subject in need of treatment comprising:
administering to the subject atrasentan or a salt thereof, and a dose of at least one of an angiotensin converting enzyme inhibitor or an angiotensin II receptor blocker, and
wherein the method results in a beneficial effect on one or more indicators of renal function.

19. The method of claim 18, wherein the indicator of renal function is albuminuria.

20. The method of claim 19, wherein the beneficial effect on albuminuria is a reduction in albuminuria.

21. The method of claim 18, wherein the indicator of renal function is urinary albumin-to-creatinine ratio (UACR).

22. The method of claim 21, wherein the beneficial effect on urinary albumin-to-creatinine ratio (UACR) is a reduction in urinary albumin-to-creatinine ratio (UACR).

23. The method of claim 18, wherein the indicator of renal function is glomerular filtration rate.

24. The method of claim 23, wherein the beneficial effect on glomerular filtration rate is an increase in glomerular filtration rate.

25. The method of claim 18, wherein the indicator of renal function is creatinine clearance.

26. The method of claim 25, wherein the beneficial effect on creatinine clearance is an increase in creatinine clearance.

27. The method of claim 25, wherein the beneficial effect on creatinine clearance is a reduction in serum creatinine.

28. The method of claim 19, wherein the beneficial effect on albuminuria is a reduction in the rate of increase of albuminuria compared to a baseline albuminuria.

29. The method of claim 21, wherein the beneficial effect on urinary albumin-to-creatinine ratio (UACR) is a reduction in the rate of increase of urinary albumin-to-creatinine ratio (UACR) compared to a baseline urinary albumin-to-creatinine ratio (UACR).

30. The method of claim 23, wherein the beneficial effect on glomerular filtration rate is a reduction in the rate of decrease of glomerular filtration rate compared to a baseline glomerular filtration rate.

31. The method of claim 25, wherein the beneficial effect on creatinine clearance is a reduction in the rate of decrease of creatinine clearance compared to a baseline creatinine clearance.

32. The method of claim 25, wherein the beneficial effect on creatinine clearance is a reduction in the rate of increase of serum creatinine.