Aliskiren as a novel therapeutic agent for hypertension and cardio-renal diseases

Interaction of the renin inhibitor aliskiren with the SARS-CoV-2 main protease: a molecular docking study

The renin protein is an upstream enzymatic regulator of the renin-aldosterone-angiotensin system (RAAS) essential for the maintenance of blood pressure. The angiotensin-converting enzyme-2 (ACE2) is a major component of the RAAS and a cell surface receptor exploited by the SARS-CoV-2 virus to enter host cells. A recent molecular modeling study has revealed that the direct renin peptide inhibitor remikiren can bind to the catalytic site of SARS-CoV-2 main protease (M^pro). By analogy, we postulated that the non-peptidic drug aliskiren, a more potent renin inhibitor than remikiren and a drug routinely used to treat hypertension, may also be able to interact with M^pro. An in silico comparison of the binding of the two compounds to M^pro indicates that aliskiren (ΔE = -75.9 kcal/mol) can form stable complexes with the main viral protease, binding to the active site, as remikiren (ΔE = -83.2 kcal/mol). The comparison with a panoply of 30 references compounds (mainly antiviral drugs) indicated that remikiren is a potent M^pro binder comparable to drugs like glecaprevir and pibrentasvir (ΔE = -96.5 kcal/mol). The energy of interaction (ΔE) of aliskiren with M^pro is about 10% lower than with remikiren, comparable to that calculated with drugs like velpatasvir and sofosbuvir. A model is proposed to define the drug binding site, with the best binders (including remikiren) penetrating deeply into the site, whereas the less potent binders (including aliskiren) interact more superficially with the protein.Communicated by Ramaswamy H. Sarma.

Single-dose pharmacokinetics of the renin inhibitor ACT-077825 in elderly and young subjects of both sexes

BACKGROUND/AIMS

The study objective was to investigate and compare the pharmacokinetics of a single oral dose of ACT-077825, a novel direct renin inhibitor, in young and elderly, male and female healthy subjects and to evaluate the safety and tolerability of ACT-077825 in these population groups.

METHODS

A total of 32 healthy subjects were included in this single-center, open-label study. The subjects were divided into 4 groups, including 8 young male, 8 young female, 8 elderly male and 8 elderly female subjects. Each participant received a single 200-mg dose of ACT-077825. Blood samples were taken over 5 days (120 h) to determine the plasma levels of ACT-077825. Safety and tolerability were monitored using standard assessments before drug administration, on the administration day and at the end of the blood sampling period.

RESULTS

Upon pooling male and female subjects, exposure was higher in elderly compared to young subjects, showing an increase of 65% for AUC0-∞, 40% for Cmax and 38% for t1/2. While young male and female subjects showed similar plasma profiles and exposure, a significant increase in exposure occurred with age in both sexes compared to younger subjects. The difference was largest between young and elderly females. Furthermore, the exposure to ACT-077825 was around 30% higher in elderly female compared to elderly male subjects. ACT-077825 was well tolerated by all groups, including the elderly females who showed the highest exposure.

CONCLUSIONS

ACT-077825 exposure is moderately increased in elderly subjects. The clinical relevance of this observation should be explored in the context of further studies.

A comparison of the antihypertensive and anti-inflammatory effects of aliskiren and ramipril add-on therapy in peritoneal dialysis patients--a pilot open label study

Most hypertensive dialysis patients are currently treated with angiotensin converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB). Aliskiren, the direct renin inhibitor, has not been specifically studied in peritoneal dialysis patients. The aim of the study was to compare hypotensive effects of aliskiren and ramipril and their influence on serum potassium and inflammatory parameters in hypertensive peritoneal dialysis patients. Eighteen hypertensive patients on chronic peritoneal dialysis were enrolled in an open-label comparative fixed-order study. The patients had been off RAAS blocking drugs for ≥4 weeks prior to an inclusion. At each of 3 study visits (baseline and after each of the treatment periods) blood pressure, serum lipids, potassium, renin, aldosterone, C-reactive protein (CRP) and monocyte chemotactic protein-1 (MCP-1) were measured. After the baseline visit aliskiren was started (150 mg/d) and after 12 weeks replaced with ramipril (5 mg/d) for the next 12 weeks. Blood pressure was 142/88±15/11 mmHg at baseline, 137/84±10/8 mmHg after aliskiren (ns) and 126/81±11/7 mmHg after ramipril (p<0.05 vs baseline and aliskiren). No incidents of hyperkalemia were observed. Plasma renin concentration increased significantly during aliskiren treatment compared to ramipril (227,6±844 vs. 58,3±765 pg/mL). CRP was similar after both therapies (8,8±34 vs. 8,4±32 µg/mL) but MCP-1 concentration was significantly lower after aliskiren than after ramipril (294,0±172,6 vs. 358,9±183,3 pg/mL). Aliskiren 150 mg/day decreases blood pressure less effectively than ramipril 5 mg/day in peritoneal dialysis patients. It does not influence serum potassium. The decrease of MCP-1 concentration after aliskiren treatment may provide an indirect evidence for its blood pressure independent cardioprotective and anti-inflammatory effects.