Aliskiren monotherapy does not cause paradoxical blood pressure rises: meta-analysis of data from 8 clinical trials

Clinical efficacy, safety and tolerability of Aliskiren Monotherapy (AM): an umbrella review of systematic reviews

Background

Aliskiren is a newly developed drug. Its role in lowering BP has been recognized. However, the role of aliskiren in treating heart and renal diseases are still controversial.

Objective

To evaluate the existing evidence about clinical efficacy, safety and tolerability of aliskiren monotherapy (AM).

Methods

An umbrella review of systematic reviews of interventional studies. We searched Pubmed, Embase and Cochrane Library up to June 2019. Two reviewers applied inclusion criteria to the select potential articles independently. The extract and analyze of accessible data were did by two reviewers independently too. Discrepancies were resolved with discussion or the arbitration of the third author.

Results

Eventually, our review identified 14 eligible studies. Results showed that for essential hypertension patients, aliskiren showed a great superiority over placebo in BP reduction, BP response rate and BP control rate. Aliskiren and placebo, ARBs or ACEIs showed no difference in the number or extent of adverse events. For heart failure patients, AM did not reduce BNP levels (SMD -0.08, − 0.31 to 0.15) or mortality rate (RR 0.76, 0.32 to 1.80), but it decreased NT-proBNP (SMD -0.12, − 0.21 to − 0.03) and PRA levels (SMD 0.52, 0.30 to 0.75), increased PRC levels (SMD -0.66, − 0.8 to − 0.44). For patients who are suffered from hypertension and diabetes and/or nephropathy or albuminuria at the same time, aliskiren produced no significant effects (RR 0.97, 0.81 to 1.16).

Conclusion

We found solid evidence to support the benefits of aliskiren in the treatment of essential hypertension, aliskiren can produce significant effects in lowering BP and reliable safety. However, the effects of aliskiren in cardiovascular and renal outcomes were insignificant.

Trial registration

Study has been registered in PROSPERO (CRD42019142141).

Renin Inhibition with Aliskiren: A Decade of Clinical Experience

The renin-angiotensin-aldosterone system (RAAS) plays a key role in the pathophysiology of arterial hypertension as well as in more complex mechanisms of cardiovascular and renal diseases. RAAS-blocking agents like angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers, have long been key components in the treatment of essential hypertension, heart failure, diabetic nephropathy, and chronic kidney disease, showing benefits well beyond blood pressure reduction. Renin blockade as the first step of the RAAS cascade finally became possible in 2007 with the approval of aliskiren, the first orally active direct renin inhibitor available for clinical use and the newest antihypertensive agent on the market. In the last decade, many clinical trials and meta-analyses have been conducted concerning the efficacy and safety of aliskiren in comparison to other antihypertensive agents, as well as the efficacy and potential clinical use of various combinations. Large trials with cardiovascular and renal endpoints attempted to show potential benefits of aliskiren beyond blood pressure lowering, as well as morbidity and mortality outcomes in specific populations such as diabetics, heart failure patients, and post-myocardial infarction individuals. The purpose of this review is to present the currently available data regarding established and future potential clinical uses of aliskiren.

Aliskiren - an alternative to angiotensin-converting enzyme inhibitors or angiotensin receptor blockers in the therapy of arterial hypertension

There has been enormous progress in antihypertensive therapy over the last few decades. However, the management of arterial hypertension is still insufficient and more efforts are needed to improve both non-pharmacological and pharmacological treatment of this widely prevalent disease. Renin-angiotensin-aldosterone system (RAAS) inhibition is crucial both for blood pressure (BP) control and for prevention of organ damage or its development in patients with hypertension. Angiotensin-converting enzyme inhibitors and/or sartans block RAAS incompletely. Aliskiren is one of the novel drugs that has been introduced to antihypertensive therapy recently. Up to now no trial has confirmed that aliskiren is efficacious in reducing cardiovascular events. Double RAAS blockade with aliskiren was not always safe. This review article presents the current view on the place of aliskiren in the therapy of arterial hypertension.

Effectiveness of the direct renin inhibitor, aliskiren, in patients with resistant hypertension

Currently there is no consensus regarding which add-on therapy to use in resistant hypertension. We have conducted an open observational study of the use of aliskiren in resistant hypertensive patients. Forty-three patients with resistant hypertension were included in the study. The inclusion criteria were as follows: 1) office blood pressure (BP) > 140/90 mmHg despite treatment with at least three or more antihypertensive drugs; 2) no prior therapy with aliskiren; and 3) no renal insufficiency. Follow-up BP was determined at 1 and 3 months. Baseline BP was 153 ± 12/79 ± 12 mmHg. After 3 months, systolic BP (SBP) and diastolic BP (DBP) dropped significantly: 140 ± 19/73 ± 13 mmHg (P < 0.0001). Twenty-one patients (49%) had an office BP < 140/90 mmHg, and these patients were assigned to the good BP control group. Another 22 were placed into the poor BP control group. BP reductions from baseline in the good BP control group (SBP/ DBP: 19 ± 11/8 ± 7 mmHg) were larger than those in the poor BP control group (5 ± 15/3 ± 9 mmHg, P < 0.05). Mean BP (MBP) values at baseline, 1, and 3 months were higher in the poor BP control group. There was no significant difference in pulse pressure at baseline between the 2 groups. In multivariate analysis, only MBP at baseline correlated with lack of BP control. Aliskiren administration to resistant hypertensive patients was effective in reducing BP. The present findings suggest aliskiren may be useful as a fourth-line or fifth-line treatment added to other drugs in the treatment of resistant hypertension.

Direct renin inhibition: extricating facts from façades

The renin–angiotensin system (RAS) affects vascular tone, cardiac output and kidney function. By these means the RAS plays a key role in the pathogenesis of arterial hypertension. As a result, RAS inhibition is highly effective not only in lowering blood pressure but also in reducing kidney disease progression (particularly when associated with proteinuria) and cardiovascular events.

Among RAS blocking agents, direct renin inhibitors have shown not only excellent efficacy in hypertension control but also pharmacologic tolerance that is comparable with other renin–angiotensin suppressors. Indeed, aliskiren, the only direct renin inhibitor available is effective in controlling blood pressure as monotherapy or in combination with other antihypertensive drugs, irrespective of patient’s age, ethnicity or sex. It is also effective in patients with metabolic syndrome, obesity and diabetes. Long-term studies comparing ‘hard endpoints’ of aliskiren therapy versus treatment with other RAS inhibitors, including cardiac and kidney protection, are currently ongoing. Combined with other antihypertensive agents, aliskiren not only improves their hypotensive response but may also lessen the adverse effects of other drugs. In high-risk patients, however, precautions should be taken when combining two or more renin–angiotensin inhibiting agents, as tissue perfusion may be highly renin-dependent in these patients and serious adverse side effects could take place.

The role of renin inhibition in treating the hypertensive patient with diabetes: a summary of preclinical and clinical evidence

Comorbid hypertension and diabetes is common and associated with substantially greater cardiovascular and renal risk relative to hypertension alone. Tissue renin-angiotensin system (RAS) overactivity is a hallmark of diabetes and contributes to target organ damage. Treatment guidelines recommend angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) for reducing cardiorenal risk in patients with hypertension plus diabetes. However, these agents only partially prevent cardiovascular and renal morbidity/mortality. Further attempts to improve clinical outcomes have focused on the use of an ACE inhibitor plus an ARB, but this combination has not demonstrated a favorable risk-benefit profile. Direct renin inhibitors provide a more comprehensive blockade of the RAS compared with ACE inhibitors or ARBs, and may be of particular benefit in counteracting tissue RAS overactivity. In this article, the role of the RAS in diabetic hypertension and the preclinical and clinical effects of direct renin inhibitor therapy on target organs are reviewed.

Aliskiren, amlodipine and hydrochlorothiazide triple combination for hypertension

Cardiovascular-related morbidity and mortality is linked to hypertension with proportional gains in cardiovascular risk factor reduction with the lowering of blood pressure. Clinical trial data has shown that attaining goal blood pressure requires, for most patients, at least two antihypertensive medications, with a significant proportion requiring regimens of three or more medications. Single-pill triple combinations have returned to the market following results of increased efficacy and adherence over dual- and mono-therapy. The combination of aliskiren, amlodipine and hydrochlorothiazide is a rational choice for combination therapy and recent studies suggest that it is safe and effective in lowering blood pressure in patients who fail dual combination therapy.

Efficacy and safety of aliskiren-based dual and triple combination therapies in US minority patients with stage 2 hypertension

Minority patients with hypertension generally require combination therapy to reach blood pressure (BP) goals. We examined the BP-lowering efficacy and safety of combination aliskiren/amlodipine therapy in self-identified minority patients in the United States with stage 2 hypertension and the impact of adding hydrochlorothiazide (HCTZ) to this combination. In this 8-week double-blind study, 412 patients were randomized to receive aliskiren/amlodipine (150/5 mg) or amlodipine (5 mg) with forced titration up to aliskiren/amlodipine/HCTZ (300/10/25 mg) or aliskiren/amlodipine (300/10 mg), respectively. Overall, mean age was 55.2 years, mean body mass index was 32 kg/m(2), 62.3% were black, 28.2% were Hispanic/Latino, and 69.1% had metabolic syndrome. Mean sitting systolic blood pressure (MSSBP), the primary efficacy outcome, was reduced from 167.1 mm Hg at baseline to 130.7 mm Hg at week 8 with aliskiren/amlodipine/HCTZ and from 167.4 mm Hg to 137.9 mm Hg with aliskiren/amlodipine (P < .0001 between groups). At week 8, BP goal (<140/90 mm Hg) was achieved in 72.6% and 53.2% of patients in the two treatment groups, respectively (P < .0001). Adverse events were experienced by 34.2% and 40.2%, respectively. Combination aliskiren/amlodipine therapy was effective in treating these high-risk patients but inclusion of HCTZ provided greater antihypertensive efficacy. Both treatments were similarly well tolerated.

Aliskiren-based stepped-care treatment algorithm provides effective blood pressure control

AIMS

Recent guidelines for the management of hypertension recommend an individualised stepped-care treatment approach in mild-to-moderate hypertensive patients, to achieve blood pressure (BP) goals. This study evaluated the probability of patients achieving BP targets with an aliskiren-based stepped-care treatment regimen.

METHODS

This was a 24-week, open-label, non-comparator study design that included six sequential 4-week treatment periods in patients with mild-to-moderate hypertension. Over the potential 24 weeks of active treatment, incremental therapy included the following add-on therapies at 4-week intervals: aliskiren 150-300 mg once daily, hydrochlorothiazide (HCTZ) 12.5-25 mg once daily, and finally amlodipine 5-10 mg once daily, as needed to achieve target BP. Subjects achieving BP targets following any given 4 weeks of therapy were considered study completers, while subjects not achieving their clinical BP target entered into the next step of incremental therapy. The primary efficacy end-point was the estimated cumulative probability of patients achieving BP target.

RESULTS

Of 256 patients treated, 232 (90.6%) completed the study. Baseline mean sitting BP was 155.7/91.7 mmHg. At study end-point, the estimated cumulative probability of reaching BP target was 86.12%. The stepped-care treatment regimen was well tolerated at the maximal recommended doses of all the individual complimentary therapies.

CONCLUSION

An aliskiren-based stepped-care treatment regimen that subsequently included both HCTZ and amlodipine is effective in achieving BP goals in approximately 90% of patients with mild-to-moderate hypertension.

Renin and cardiovascular disease: Worn-out path, or new direction

Inhibition of the renin angiotensin system has beneficial effects in cardiovascular prevention and treatment. The advent of orally active direct renin inhibitors adds a novel approach to antagonism of the renin-angiotensin system. Inhibition of the first and rate-limiting step of the renin angiotensin cascade offers theoretical advantages over downstream blockade. However, the recent discovery of the (pro)renin receptor which binds both renin and prorenin, and which can not only augment catalytic activity of both renin and prorenin in converting angiotensinogen to angiotensin I, but also signal intracellularly via various pathways to modulate gene expression, adds a significant level of complexity to the field. In this review, we will examine the basic and clinical data on renin and its inhibition in the context of cardiovascular pathophysiology.

First-line treatment of hypertension: critical appraisal of potential role of aliskiren and hydrochlorothiazide in a fixed combination

Arterial hypertension is one of the major diseases in the Western world. It is an independent cardiovascular risk factor and is associated with increased morbidity and mortality. Several drug classes have been shown to be effective in the treatment of hypertension. Aliskiren is a direct renin inhibitor and belongs to the class of renin-angiotensin-aldosterone system inhibitors. Several large studies have shown that aliskiren is effective in lowering blood pressure, and equivalent in this respect to the angiotensin-converting enzyme (ACE) inhibitors and the angiotensin receptor-1 blockers (ARBs). Furthermore, aliskiren has a safety and tolerability profile comparable with that of the ARBs and slightly better than that of the ACE inhibitors. From a pathophysiologic perspective, it can be combined with hydrochlorothiazide successfully, because it can block the diuretic-induced increase in plasma renin activity. Its combination with hydrochlorothiazide in a single pill has been investigated and shown to be superior to monotherapy with respect to blood pressure control and improvement in patient compliance with therapy. Further studies are needed to show whether aliskiren and its combination with hydrochlorothiazide is effective in preventing cardiovascular events and mortality when end organ damage is present.

An angiotensin II- and NF-kappaB-dependent mechanism increases connexin 43 in murine arteries targeted by renin-dependent hypertension

AIMS

Connexins (Cxs) play a role in the contractility of the aorta wall. We investigated how connexins of the endothelial cells (ECs; Cx37, Cx40) and smooth muscle cells (SMCs; Cx43, Cx45) of the aorta change during renin-dependent and -independent hypertension.

METHODS AND RESULTS

We subjected both wild-type (WT) mice and mice lacking Cx40 (Cx40(-/-)), to either a two-kidney, one-clip procedure or to N-nitro-l-arginine-methyl-ester treatment, which induce renin-dependent and -independent hypertension, respectively. All hypertensive mice featured a thickened aortic wall, increased levels of Cx37 and Cx45 in SMC, and of Cx40 in EC (except in Cx40(-/-) mice). Cx43 was up-regulated, with no effect on its S368 phosphorylation, only in the SMCs of renin-dependent models of hypertension. Blockade of the renin-angiotensin system of Cx40(-/-) mice normalized blood pressure and prevented both aortic thickening and Cx alterations. Ex vivo exposure of WT aortas, carotids, and mesenteric arteries to physiologically relevant levels of angiotensin II (AngII) increased the levels of Cx43, but not of other Cx. In the aortic SMC line of A7r5 cells, AngII activated kinase-dependent pathways and induced binding of the nuclear factor-kappa B (NF-kappaB) to the Cx43 gene promoter, increasing Cx43 expression.

CONCLUSION

In both large and small arteries, hypertension differently regulates Cx expression in SMC and EC layers. Cx43 is selectively increased in renin-dependent hypertension via an AngII activation of the extracellular signal-regulated kinase and NF-kappaB pathways.

Novel therapeutic targets for hypertension

Despite the existence of established, effective therapies for hypertension, new methods of blood pressure and cardiovascular risk reduction are still needed. Novel approaches are targeted towards treating resistant hypertension, improving blood-pressure control, and achieving further risk reduction beyond blood-pressure lowering. Modulation of the renin-angiotensin-aldosterone system (RAAS) provides the rationale for current antihypertensive therapies, including the relatively new agents eplerenone and aliskiren. Novel targets for antihypertensive therapy are also likely to be RAAS-related. The stimulation of angiotensin II type 2 receptors, or supplementation with renalase, could counteract the effects of angiotensin II type 1 receptor stimulation or catecholamine release. Combined angiotensin-converting-enzyme and neutral endopeptidase blockade decreases blood pressure, but is associated with a high incidence of angioedema. Aldosterone synthase inhibitors might improve tolerability in aldosterone antagonism. A (pro)renin-receptor blocker could prevent the deleterious angiotensin-independent actions of renin that are not inhibited by aliskiren. Finally, new minimally invasive surgical procedures have revived the concept of renal denervation, and could be a therapeutic option for patients with resistant hypertension. All of these strategies are exciting prospects, but which of them will prove valuable in clinical setting remains to be discovered.

Unmet needs in managing hypertension: potential role of direct renin inhibition

Hypertension is the most prevalent and important risk factor for cardiovascular and renal disease worldwide. Despite the large armamentarium of available blood pressure-lowering agents, the need remains for safer and more effective antihypertensive treatment. Based on current target levels of < 140/90 mm Hg, only one-third of hypertensive Americans have achieved goal blood pressure. Several strategies can help address these challenges, including increasing public awareness, and improving physician awareness of evidence-based therapeutic guidelines. There also remains a need for new therapeutic options. This review examines new developments among those agents having inhibitory activity on the renin-angiotensin-aldosterone system (RAAS). All currently available RAAS blockers cause a reactive increase in plasma renin concentration. However, the direct renin inhibitors are the only class that diminishes plasma renin activity, an effect that may provide additional cardiovascular and/or renoprotective benefit. Aliskiren is the first clinically available direct renin inhibitor that has been shown to be effective and well tolerated both as monotherapy and in combination with other established agents in hypertensive patients. Randomized clinical trials are underway to explore the extent to which direct renin inhibition provides additive protection against cardiovascular and renal disease events.