Pharmacotherapeutic group: Agents acting on the renin-angiotensin system; angiotensin II receptor blockers (ARBs), other combinations, ATC code: C09DX04
Mechanism of action
Sacubitril/valsartan exhibits the mechanism of action of an angiotensin receptor neprilysin inhibitor by simultaneously inhibiting neprilysin (neutral endopeptidase; NEP) via LBQ657, the active metabolite of the prodrug sacubitril, and by blocking the angiotensin II type‑1 (AT1) receptor via valsartan. The complementary cardiovascular benefits of sacubitril/valsartan in heart failure patients are attributed to the enhancement of peptides that are degraded by neprilysin, such as natriuretic peptides (NP), by LBQ657 and the simultaneous inhibition of the effects of angiotensin II by valsartan. NPs exert their effects by activating membrane‑bound guanylyl cyclase‑coupled receptors, resulting in increased concentrations of the second messenger cyclic guanosine monophosphate (cGMP), which could result in vasodilation, natriuresis and diuresis, increased glomerular filtration rate and renal blood flow, inhibition of renin and aldosterone release, reduction of sympathetic activity, and anti‑hypertrophic and anti‑fibrotic effects.
Valsartan inhibits detrimental cardiovascular and renal effects of angiotensin II by selectively blocking the AT1 receptor, and also inhibits angiotensin II‑dependent aldosterone release. This prevents sustained activation of the renin‑angiotensin‑aldosterone system that would result in vasoconstriction, renal sodium and fluid retention, activation of cellular growth and proliferation, and subsequent maladaptive cardiovascular remodelling.
Pharmacodynamic effects
The pharmacodynamic effects of sacubitril/valsartan were evaluated after single and multiple dose administrations in healthy subjects and in patients with heart failure, and are consistent with simultaneous neprilysin inhibition and RAAS blockade. In a 7‑day valsartan‑controlled study in patients with reduced ejection fraction (HFrEF), administration of sacubitril/valsartan resulted in an initial increase in natriuresis, increased urine cGMP, and decreased plasma levels of mid‑regional pro-atrial natriuretic peptide (MR‑proANP) and N‑terminal prohormone brain natriuretic peptide (NT‑proBNP) compared to valsartan. In a 21‑day study in HFrEF patients, sacubitril/valsartan significantly increased urine ANP and cGMP and plasma cGMP, and decreased plasma NT‑proBNP, aldosterone and endothelin‑1 compared to baseline. The AT1‑receptor was also blocked as evidenced by increased plasma renin activity and plasma renin concentrations. In the PARADIGM‑HF study, sacubitril/valsartan decreased plasma NT‑proBNP and increased plasma BNP and urine cGMP compared with enalapril. In the PANORAMA-HF study, a reduction in NT-proBNP was observed at weeks 4 and 12 for sacubitril/valsartan (40.2% and 49.8%) and enalapril (18.0% and 44.9%) compared to baseline. The NT-proBNP levels continued to decrease over the duration of the study with a reduction of 65.1% for sacubitril/valsartan and 61.6% for enalapril at week 52 compared to baseline. BNP is not a suitable biomarker of heart failure in patients treated with sacubitril/valsartan because BNP is a neprilysin substrate (see section 4.4). NT‑proBNP is not a neprilysin substrate and is therefore a more suitable biomarker.
In a thorough QTc clinical study in healthy male subjects, single doses of sacubitril/valsartan 194 mg sacubitril/206 mg valsartan and 583 mg sacubitril/617 mg valsartan had no effect on cardiac repolarisation.
Neprilysin is one of multiple enzymes involved in the clearance of amyloid‑β (Aβ) from the brain and cerebrospinal fluid (CSF). Administration of sacubitril/valsartan 194 mg sacubitril/206 mg valsartan once daily for two weeks to healthy subjects was associated with an increase in CSF Aβ1‑38 compared to placebo; there were no changes in concentrations of CSF Aβ1‑40 and 1‑42. The clinical relevance of this finding is not known (see section 5.3).
Clinical efficacy and safety
The 24 mg/26 mg, 49 mg/51 mg and 97 mg/103 mg strengths are in some publications referred to as 50, 100 or 200 mg.
PARADIGM‑HF
PARADIGM‑HF, the pivotal phase 3 study, was a multinational, randomised, double‑blind study of 8 442 patients comparing sacubitril/valsartan to enalapril, both given to adult patients with chronic heart failure, NYHA class II‑IV and reduced ejection fraction (left ventricular ejection fraction [LVEF] ≤40%, amended later to ≤35%) in addition to other heart failure therapy. The primary endpoint was the composite of cardiovascular (CV) death or hospitalisation for heart failure (HF). Patients with SBP <100 mmHg, severe renal impairment (eGFR <30 ml/min/1.73 m2) and severe hepatic impairment were excluded at screening and therefore not prospectively studied.
Prior to study participation, patients were well treated with standard of care therapy which included ACE inhibitors/ARBs (>99%), beta blockers (94%), mineralocorticoid antagonists (58%) and diuretics (82%). The median follow‑up duration was 27 months and patients were treated for up to 4.3 years.
Patients were required to discontinue their existing ACE inhibitor or ARB therapy and enter a sequential single‑blind run‑in period during which they received treatment with enalapril 10 mg twice daily, followed by single‑blind treatment with sacubitril/valsartan 100 mg twice daily, increasing to 200 mg twice daily (see section 4.8 for discontinuations during this period). They were then randomised to the double‑blind period of the study, during which they received either sacubitril/valsartan 200 mg or enalapril 10 mg twice daily [sacubitril/valsartan (n=4 209); enalapril (n=4 233)].
The mean age of the population studied was 64 years of age and 19% were 75 years of age or older. At randomisation, 70% of patients were NYHA class II, 24% were class III and 0.7% were class IV. The mean LVEF was 29% and there were 963 (11.4%) patients with a baseline LVEF >35% and ≤40%.
In the sacubitril/valsartan group, 76% of patients remained on the target dose of 200 mg twice daily at the end of the study (mean daily dose of 375 mg). In the enalapril group, 75% of patients remained on the target dose of 10 mg twice daily at the end of the study (mean daily dose of 18.9 mg).
Sacubitril/valsartan was superior to enalapril, reducing the risk of cardiovascular death or heart failure hospitalisations to 21.8% compared to 26.5% for enalapril treated patients. The absolute risk reductions were 4.7% for the composite of the CV death or HF hospitalisation, 3.1% for CV death alone, and 2.8% for first HF hospitalisation alone. The relative risk reduction was 20% versus enalapril (see Table 3). This effect was observed early and was sustained throughout the duration of the study (see Figure 1). Both components contributed to the risk reduction. Sudden death accounted for 45% of cardiovascular deaths and was reduced by 20% in sacubitril/valsartan‑treated patients compared to enalapril‑treated patients (hazard ratio [HR] 0.80, p=0.0082). Pump failure accounted for 26% of cardiovascular deaths and was reduced by 21% in sacubitril/valsartan‑treated patients compared to enalapril‑treated patients (HR 0.79, p=0.0338).
This risk reduction was consistently observed across subgroups including: gender, age, race, geography, NYHA class (II/III), ejection fraction, renal function, history of diabetes or hypertension, prior heart failure therapy, and atrial fibrillation.
Sacubitril/valsartan improved survival with a significant reduction in all‑cause mortality of 2.8% (sacubitril/valsartan, 17%, enalapril, 19.8%). The relative risk reduction was 16% compared with enalapril (see Table 3).
Table 3 Treatment effect for the primary composite endpoint, its components and all‑cause mortality over a median follow-up of 27 months
| | Sacubitril/ valsartan N=4 187♯ n (%) | Enalapril N=4 212♯ n (%) | Hazard ratio (95% CI) | Relative risk reduction | p‑value *** |
| Primary composite endpoint of CV death and heart failure hospitalisations* | 914 (21.83) | 1 117 (26.52) | 0.80 (0.73, 0.87) | 20% | 0.0000002 |
| Individual components of the primary composite endpoint |
| CV death** | 558 (13.33) | 693 (16.45) | 0.80 (0.71, 0.89) | 20% | 0.00004 |
| First heart failure hospitalisation | 537 (12.83) | 658 (15.62) | 0.79 (0.71, 0.89) | 21% | 0.00004 |
| Secondary endpoint |
| All‑cause mortality | 711 (16.98) | 835 (19.82) | 0.84 (0.76, 0.93) | 16% | 0.0005 |
*The primary endpoint was defined as the time to first event of CV death or hospitalisation for HF.
**CV death includes all patients who died up to the cut‑off date irrespective of previous hospitalisation.
***One‑sided p‑value
♯ Full analysis set
Figure 1 Kaplan‑Meier curves for the primary composite endpoint and the CV death component

TITRATION
TITRATION was a 12‑week safety and tolerability study in 538 patients with chronic heart failure (NYHA class II–IV) and systolic dysfunction (left ventricular ejection fraction ≤35%) naïve to ACE inhibitor or ARB therapy or on varying doses of ACE inhibitors or ARBs prior to study entry. Patients received a starting dose of sacubitril/valsartan of 50 mg twice daily and were up‑titrated to 100 mg twice daily, then to the target dose of 200 mg twice daily, with either a 3‑week or a 6‑week regimen.
More patients who were naïve to previous ACE inhibitor or ARB therapy or on low‑dose therapy (equivalent to <10 mg enalapril/day) were able to achieve and maintain sacubitril/valsartan 200 mg when up‑titrated over 6 weeks (84.8%) versus 3 weeks (73.6%). Overall, 76% of patients achieved and maintained the target dose of sacubitril/valsartan 200 mg twice daily without any dose interruption or down‑titration over 12 weeks.
Paediatric population
PANORAMA-HF
PANORAMA-HF, a phase 3 study, was a multinational, randomised, double‑blind study comparing sacubitril/valsartan and enalapril in 375 paediatric patients aged 1 month to <18 years with heart failure due to systemic left ventricular systolic dysfunction (LVEF ≤45% or fractional shortening ≤22.5%). The primary objective was to determine whether sacubitril/valsartan was superior to enalapril in paediatric HF patients over a 52‑week treatment duration based on a global rank endpoint. The global rank primary endpoint was derived by ranking patients (worst‑to‑best outcome) based on clinical events such as death, initiation of mechanical life support, listing for urgent heart transplant, worsening HF, measures of functional capacity (NYHA/ROSS scores), and patient‑reported HF symptoms (Patient Global Impression Scale [PGIS]). Patients with systemic right ventricles or single ventricles and patients with restrictive or hypertrophic cardiomyopathy were excluded from the study. The target maintenance dose of sacubitril/valsartan was 2.3 mg/kg twice daily in paediatric patients aged 1 month to <1 year and 3.1 mg/kg twice daily in patients aged 1 to <18 years with a maximum dose of 200 mg twice daily. The target maintenance dose of enalapril was 0.15 mg/kg twice daily in paediatric patients aged 1 month to <1 year and 0.2 mg/kg twice daily in patients aged 1 to <18 years with a maximum dose of 10 mg twice daily.
In the study, 9 patients were aged 1 month to <1 year, 61 patients were aged 1 year to <2 years, 85 patients were aged 2 to <6 years and 220 patients were aged 6 to <18 years. At baseline, 15.7% of patients were NYHA/ROSS class I, 69.3% were class II, 14.4% were class III and 0.5% were class IV. The mean LVEF was 32%. The most common underlying causes of heart failure were cardiomyopathy related (63.5%). Prior to study participation, patients were treated most commonly with ACE inhibitors/ARBs (93%), beta-blockers (70%), aldosterone antagonists (70%), and diuretics (84%).
The Mann-Whitney Odds of the global rank primary endpoint was 0.907 (95% CI 0.72, 1.14), numerically in favour of sacubitril/valsartan (see Table 4). Sacubitril/valsartan and enalapril showed comparable clinically relevant improvements in the secondary endpoints of NYHA/ROSS class and PGIS score change compared to baseline. At week 52, the NYHA/ROSS functional class changes from baseline were: improved in 37.7% and 34.0%; unchanged in 50.6% and 56.6%; worsened in 11.7% and 9.4% of patients for sacubitril/valsartan and enalapril respectively. Similarly, the PGIS score changes from baseline were: improved in 35.5% and 34.8%; unchanged in 48.0% and 47.5%; worsened in 16.5% and 17.7% of patients for sacubitril/valsartan and enalapril respectively. NT‑proBNP was substantially reduced from baseline in both treatment groups. The magnitude of NT‑proBNP reduction with Entresto was similar to that observed in adult heart failure patients in PARADIGM-HF. Because sacubitril/valsartan improved outcomes and reduced NT-proBNP in PARADIGM-HF, the reductions in NT-proBNP coupled with the symptomatic and functional improvements from baseline seen in PANORAMA-HF were considered a reasonable basis to infer clinical benefits in paediatric heart failure patients. There were too few patients aged below 1 year to evaluate the efficacy of sacubitril/valsartan in this age group.
Table 4 Treatment effect for the primary global rank endpoint in PANORAMA-HF
| | Sacubitril/valsartan N=187 | Enalapril N=188 | Treatment effect |
| Global rank primary endpoint | Probability of favourable outcome (%)* | Probability of favourable outcome (%)* | Odds** (95% CI) |
| 52.4 | 47.6 | 0.907 (0.72, 1.14) |
*The probability of favourable outcome or Mann-Whitney probability (MWP) for the given treatment was estimated based on percentage of wins in pairwise comparisons of global rank score between sacubitril/valsartan‑treated patients versus enalapril‑treated patients (each higher score counts as one win and each equal score counts as half a win).
**Mann‑Whitney Odds was calculated as the estimated MWP for enalapril divided by the estimated MWP for sacubitril/valsartan, with odds <1 in favour of sacubitril/valsartan and >1 in favour of enalapril.