Combination Angiotensin-Converting Enzyme Inhibitor and Angiotensin Receptor Blocker Therapy: Its Role in Clinical Practice

Fixed-dose Combination of Metoprolol, Telmisartan, and Chlorthalidone for Essential Hypertension in Adults with Stable Coronary Artery Disease: Phase III Study

INTRODUCTION

The aim of the study was to evaluate the efficacy and safety of fixed-dose combination (FDC) of metoprolol, telmisartan, and chlorthalidone in patients with essential hypertension and stable coronary artery disease (CAD) who showed inadequate response to dual therapy.

METHODS

In this phase III, open-label, multicenter study, 254 adults with stable CAD having uncontrolled hypertension despite being treated with FDC of metoprolol (25/50 mg) and telmisartan (40 mg) were included. Patients received either of the following FDC for 24 weeks: metoprolol (25 mg), telmisartan (40 mg), and chlorthalidone (12.5 mg) (FDC1; n = 139) or metoprolol (50 mg), telmisartan (40 mg), and chlorthalidone (12.5 mg) (FDC2; n = 115) tablets once daily. The FDCs were developed using the novel Wrap Matrix™ platform technology. Primary endpoint assessed the mean change in seated diastolic blood pressure (SeDBP) and seated systolic blood pressure (SeSBP) from baseline to 24 weeks. Secondary efficacy endpoints included proportion of patients achieving < 90 mmHg SeDBP (SeDBP responder) and < 140 mmHg SeSBP (SeSBP responder) at weeks 12, 16, 20, and 24. Safety was assessed throughout the study.

RESULTS

A total of 243 (95.70%) patients completed study. The mean change in BP from baseline (FDC1, 155/96 mmHg; FDC2, 165/98 mmHg) to week 24 (FDC1, 128/82 mmHg; FDC2, 131/83 mmHg) was statistically significant (both groups p < 0.0001). Within FDC1 and FDC2, the mean change from baseline to week 24 in SeDBP (82.60 mmHg and 83.09 mmHg) and SeSBP (128.07 mmHg and 131.29 mmHg) was statistically significant (both groups p < 0.0001). At week 24, in FDC1, 80.15% and 84.73% were SeDBP and SeSBP responders, respectively; in FDC2, 79.46% and 74.11% were SeDBP and SeSBP responders, respectively. No serious adverse events or deaths were reported.

CONCLUSION

Triple FDCs of metoprolol, telmisartan, and chlorthalidone were considered effective and well tolerated in patients with hypertension who respond inadequately to dual therapy.

CLINICAL TRIAL REGISTRATION

CTRI/2016/11/007491.

Intrarenal Renin–Angiotensin System Involvement in the Pathogenesis of Chronic Progressive Nephropathy—Bridging the Informational Gap Between Disciplines

Chronic progressive nephropathy (CPN) is the most commonly encountered spontaneous background finding in laboratory rodents. Various theories on its pathogenesis have been proposed, but there is a paucity of data regarding specific mechanisms or physiologic pathways involved in early CPN development. The current CPN mechanism of action for tumorigenesis is largely based on its associated increase in tubular cell proliferation without regard to preceding subcellular degenerative changes. Combing through the published literature from multiple biology disciplines provided insight into the preceding cellular events. Mechanistic pathways involved in the progressive age-related decline in rodent kidney function and several key inflexion points have been identified. These critical pathway factors were then connected using data from renal models from multiple rodent strains, other species, and mechanistic work in humans to form a cohesive picture of pathways and protein interactions. Abundant data linked similar renal pathologies to local events involving hypoxia (hypoxia-inducible factor 1α), altered intrarenal renin–angiotensin system (RAS), oxidative stress (nitric oxide), and pro-inflammatory pathways (transforming growth factor β), with positive feedback loops and downstream effectors amplifying the injury and promoting scarring. Intrarenal RAS alterations seem to be central to all these events and may be critical to CPN development and progression.

Overview of endocrine systems in primary hypertension

Multiple hormonal factors play a major role in the functional and structural abnormalities of hypertension (HT). At present, the kidneys and, in particular, renal Na(+) retention are thought to constitute a primary and sustaining mechanism in the development of HT. However, the precise renal and hormonal mechanisms leading to increased Na(+) reabsorption and HT remain unknown. Because the vast majority of HT is primary, this article focuses on the major endocrine systems, the RAS, aldosterone, and the SNS, that play a prominent role in the pathogenesis of HT.

Reduction of proteinuria with angiotensin receptor blockers

Renal pathophysiology is elicited by activation of angiotensin II type 1 (AT(1)) receptors at all stages of renovascular disease. Angiotensin receptor blockers (ARBs) that specifically block the AT(1) receptor offer the potential to prevent or delay progression to end-stage renal disease independently of reductions in blood pressure. Proteinuria--an early and sensitive marker for progressive renal dysfunction--is reduced by ARB use in patients with type 2 diabetic nephropathy and microalbuminuria or macroalbuminuria. Retrospective analysis of data available from early trials has confirmed this finding and has shown that albuminuria reduction is associated with lessening of cardiovascular risk. The ARB telmisartan is equivalent to enalapril in preventing glomerular filtration rate decline, and equivalent to valsartan in reducing proteinuria. Telmisartan is more effective than conventional therapy in lowering the risk of transition to overt nephropathy in hypertensive and normotensive patients. An additive effect has been seen in smaller studies when telmisartan has been added to lisinopril therapy, and high-dose telmisartan reduces albuminuria better than low-dose telmisartan. Similar data were obtained with other ARBs such as candesartan, losartan, valsartan, or irbesartan. These data support the proposition that blockade of the renin-angiotensin system beyond that required for maximum blood pressure reduction provides optimum renal protection.

The need for combination antihypertensive therapy to reach target blood pressures: what has been learned from clinical practice and morbidity-mortality trials?

Pharmacological treatment of hypertension represents a cost-effective way for preventing cardiovascular and renal complications. To benefit maximally from antihypertensive treatment blood pressure (BP) should be brought to below 140/90 mmHg in every hypertensive patient, and even lower (< 130/80 mmHg) if diabetes or renal disease co-exists. Most of the time such targets cannot be reached using monotherapies. This is especially true in patients who exhibit a high cardiovascular risk. The co-administration of two agents acting by different mechanisms considerably increases BP control. Such preparations are not only efficacious, but also well tolerated, and some fixed low-dose combinations have a tolerability profile similar to placebo. This is for instance the case for the preparation containing the angiotensin-converting enzyme inhibitor perindopril (2 mg) and the diuretic indapamide (0.625 mg), a fixed low-dose combination that has recently been shown in controlled interventional trials to be more effective than monotherapies in reducing albuminuria, regressing cardiac hypertrophy and improving macrovascular stiffness. Fixed-dose combinations are becoming more and more popular and are even proposed by current hypertension guidelines as a first-line option to treat hypertensive patients.

Reduction of dopaminergic degeneration and oxidative stress by inhibition of angiotensin converting enzyme in a MPTP model of parkinsonism

There is growing evidence indicating that oxidative stress is a key contributor to the pathogenesis and progression of Parkinson's disease. The brain, and particularly the basal ganglia, possesses a local rennin-angiotensin system. Angiotensin activates NAD(P)H-dependent oxidases, which are a major intracellular source of superoxide, and angiotensin converting enzyme inhibitors (ACEIs) have shown antioxidant properties. We treated mice with MPTP and the ACEI captopril to study the possible neuroprotective and antioxidant effects of the latter on the dopaminergic system. Pre-treatment with captopril induced a significant reduction in the MPTP-induced loss of dopaminergic neurons in the substantia nigra and a significant reduction in the loss of dopaminergic terminals in the striatum. Furthermore, captopril reduced the MPTP-induced increase in the levels of major oxidative stress indicators (i.e. lipid peroxidation and protein oxidation) in the ventral midbrain and the striatum. Captopril did not reduce striatal MPP(+) levels, MAO-B activity or dopamine transporter activity, which may reduce MPTP neurotoxicity. Our results suggest that angiotensin-converting enzyme inhibitors may be useful for treatment of Parkinson's disease, and that further investigation should focus on the neuroprotective capacity of these compounds.

Angiotensin-converting enzyme inhibition reduces oxidative stress and protects dopaminergic neurons in a 6-hydroxydopamine rat model of Parkinsonism

It is now established that the brain possesses a local renin-angiotensin system and that angiotensin II exerts multiple actions in the nervous system, including regulation of striatal dopamine release. Furthermore, angiotensin activates NADPH-dependent oxidases, which are a major source of superoxide, and angiotensin-converting enzyme inhibitors, commonly used in the treatment of hypertension and chronic heart failure, have shown antioxidant properties in several tissues. Oxidative stress is a key contributor to the pathogenesis and progression of Parkinson's disease. In the present study, we treated rats with intraventricular injections of the dopaminergic neurotoxin 6-hydroxydopamine and subcutaneous injections of the angiotensin-converting enzyme inhibitor Captopril to study the possible neuroprotective effect of the latter on the dopaminergic system and on 6-hydroxydopamine-induced oxidative stress. Rats treated with Captopril and 6-hydroxydopamine showed significantly less reduction in the number of dopaminergic neurons (i.e., immunoreactive to tyrosine hydroxylase) in the substantia nigra and in the density of striatal dopaminergic terminals than 6-hydroxydopamine-lesioned rats not treated with Captopril. In addition, Captopril reduced the levels of major oxidative stress indicators (i.e., lipid peroxidation and protein oxidation) in the ventral midbrain and the striatum of 6-hydroxydopamine-lesioned rats. Our results suggest that angiotensin-converting enzyme inhibitors may be useful for treatment of Parkinson's disease and that further investigation should focus on the neuroprotective capacity of these compounds.

Effects of oral fixed-dose combinations of telmisartan plus ramipril and losartan plus ramipril in hypertension: A multicenter, prospective, randomized, double-blind, phase iii trial in adult indian patients

BACKGROUND

A new oral fixed-dose combination (FDC) of telmisartan plus ramipril is being introduced in India for the treatment of patients with stage 2 hypertension.

OBJECTIVE

The aim of this study was to compare the effectiveness and tolerability of an oral FDC of telmisartan plus ramipril with those of an oral FDC of losartan plus ramipril in adult Indian patients with stage 2 hypertension.

METHODS

This multicenter, prospective, randomized, double-blind, Phase III study was conducted at 5 centers in India. Indian patients aged 18 to 65 years with uncomplicated stage 2 essential hypertension (systolic/diastolic blood pressure [SBP/DBP], >160/>100 mm Hg) were enrolled. After a 2-week placebo run-in period, patients were randomly assigned to receive telmisartan 40 mg plus ramipril 5 mg (T + R) or losartan 50 mg plus ramipril 5 mg (L + R), PO (tablet) QD (before the morning meal) for 8 weeks. Supine blood pressure (BP) was measured at 0 (baseline) and 8 weeks of treatment. The primary end point was the mean reduction from baseline in BP. Responders were classified as patients who had a DBP <90 mm Hg at the end of 8 weeks of therapy. Tolerability was assessed using spontaneous reports of adverse events (AEs) during the follow-up visits and laboratory analyses performed at week 8.

RESULTS

A total of 289 patients were enrolled (155 men, 134 women; mean age, 50.74 years). Of these, 8 patients in the T + R group and 7 in the L + R group were lost to follow-up and considered withdrawals. At the end of week 8, the mean percentage reduction in SBP was significantly greater in the T + R group compared with that in the L + R group (24.1% vs 19.4%; P < 0.05). The mean percentage reduction in DBP was also significantly greater in the T + R group compared with that in the L + R group (17.3% vs 12.5%; P < 0.05). The response rates in the T + R and L + R groups were statistically similar (79.1% vs 68.7%). The most common AEs in the T + R and L + R groups were cough (9 [6.1%] and 11 [7.8%] patients, respectively) and headache (7 [4.7%] and 8 [5.7%] patients, respectively).

CONCLUSIONS

The results in this study in Indian patients with stage 2 essential hypertension suggest that the FDC of T + R controlled BP more effectively compared with the FDC of L + R over 8 weeks. The response rates were similar between the 2 groups. Both treatments were well tolerated.

The cardiovascular continuum and renin-angiotensin-aldosterone system blockade

A progressive chain of pathophysiological events links cardiovascular risk factors to clinical manifestations of disease and life-threatening cardiovascular events. This chain--the cardiovascular continuum--underlies cardiovascular disease and holds the key to its prevention and treatment. Progressive tissue damage can result in morbidity from congestive heart failure, end-stage heart disease, nephrotic proteinuria and dementia and, eventually, death from cardio- or cerebrovascular causes. The renin-angiotensin-aldosterone system (RAAS) is involved at all stages of the cardiovascular continuum, because the effector molecules of the RAAS, angiotensin II in particular, have direct pathobiological effects on a variety of tissues, including the endothelium, vascular smooth muscle and the renal mesangium. Clinical trials of angiotensin II receptor blockers (ARBs) and angiotensin-converting enzyme (ACE) inhibitors have demonstrated the essential validity of this hypothesis. Interruption of the RAAS has been shown to reduce cardiovascular morbidity and mortality in patients with left ventricular hypertrophy, heart failure and post-myocardial infarction, as well as renal disease in patients with type 2 diabetes. Key questions remain, however. What are the clinical effects of combination ARB and ACE inhibitor treatment? How will combinations of RAAS blockade with other agents, such as statins, affect the cardiovascular continuum? Answers to these questions will require well-planned, adequately powered clinical trials, such as the Programme of Research tO evaluate Telmisartan End-organ proteCTION (PROTECTION) and the ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial (ONTARGET) programmes. However, it is already clear that RAAS blockade is an essential part of blocking progression along the cardiovascular continuum.

Addition of an angiotensin receptor blocker to full-dose ACE-inhibition: controversial or common sense?

Both angiotensin-converting enzyme (ACE)-inhibitors and angiotensin receptor blockers (ARBs) interfere with the activity of the renin-angiotensin system (RAS) in a different way. Theoretically, one might expect beneficial effects when they are used in combination, as a more complete suppression of the RAS can be achieved. But can this additional effect still be seen in patients on full-dose ACE-inhibition? Several controlled trials demonstrated that combination therapy can have additional benefits in hypertensive patients, in chronic heart failure patients, and in both diabetic and non-diabetic nephropathy patients. However, the clinical benefit was not always as pronounced as expected and not every patient will benefit from dual blockade of the RAS. There is some evidence of a less pronounced effect of combination therapy when a full dose of the ACE-inhibitor is given. However, it is well known that ACE-inhibitors cannot completely suppress the formation of angiotensin II, in particular, when the RAS is activated. Indeed, clinical trials indicated that add-on therapy with an ARB was especially of use when the RAS remained activated despite full-dose ACE-inhibitor treatment. In summary, combination of a full-dose ACE-inhibitor and an ARB can be a rational choice in selected patients.

Pharmacotherapy review: angiotensin-converting enzyme inhibitors

On inspection of most treatment algorithms for hypertension, it is apparent that multiple drug classes are available. In choosing a medication class for hypertension therapy, nuances of the selection process often go unappreciated. This article is the first in a series describing important pharmacotherapeutic considerations of the individual drug classes used in the treatment of hypertension.