Clinical Pharmacology for Entresto
Mechanism Of Action
ENTRESTO contains a neprilysin inhibitor, sacubitril, and an angiotensin receptor blocker, valsartan. ENTRESTO inhibits neprilysin (neutral endopeptidase; NEP) via LBQ657, the active metabolite of the prodrug sacubitril, and blocks the angiotensin II type-1 (AT1) receptor via valsartan. The cardiovascular and renal effects of ENTRESTO in heart failure patients are attributed to the increased levels of peptides that are degraded by neprilysin, such as natriuretic peptides, by LBQ657, and the simultaneous inhibition of the effects of angiotensin II by valsartan. Valsartan inhibits the effects of angiotensin II by selectively blocking the AT1 receptor, and also inhibits angiotensin II-dependent aldosterone release.
Pharmacodynamics
The pharmacodynamic effects of ENTRESTO 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 renin-angiotensin system blockade.
In a 7-day valsartan-controlled study in patients with reduced ejection fraction (HFrEF), administration of ENTRESTO resulted in a significant non-sustained increase in natriuresis, increased urine cGMP, and decreased plasma MR-proANP and NT-proBNP compared to valsartan.
In a 21-day study in HFrEF patients, ENTRESTO significantly increased urine ANP and cGMP and plasma cGMP, and decreased plasma NT-proBNP, aldosterone and endothelin-1. ENTRESTO also blocked the AT1-receptor as evidenced by increased plasma renin activity and plasma renin concentrations. In PARADIGM-HF, ENTRESTO decreased plasma NTÂproBNP (not a neprilysin substrate) and increased plasma BNP (a neprilysin substrate) and urine cGMP compared with enalapril.
In PARAMOUNT, a randomized, double-blind, 36-week study in patients with heart failure with LVEF greater than or equal to 45% comparing 97/103 mg of ENTRESTO (n=149) to 160 mg of valsartan (n =152) twice-daily, ENTRESTO decreased NT-proBNP by 17% while valsartan increased NT-proBNP by 8% at Week 12 (p = 0.005).
In PARAGON-HF, ENTRESTO decreased NT-proBNP by 24% (Week 16) and 19% (Week 48) compared to 6% and 3% reductions on valsartan, respectively.
In PANORAMA-HF, a reduction in NT-proBNP was observed at Weeks 4 and 12 for ENTRESTO (40% and 50%) compared to baseline. The NT-proBNP levels continued to decrease over the duration of the study with a reduction of 65% for ENTRESTO at Week 52 compared to baseline.
QT Prolongation: In a thorough QTc clinical study in healthy male subjects, single doses of ENTRESTO 194 mg sacubitril/206 mg valsartan and 583 mg sacubitril/617 mg valsartan had no effect on cardiac repolarization.
Amyloid-β: Neprilysin is one of multiple enzymes involved in the clearance of amyloid-β (Aβ) from the brain and cerebrospinal fluid (CSF). Administration of ENTRESTO 194 mg sacubitril/206 mg valsartan once-daily for 2 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 or CSF Aβ1-42. The clinical relevance of this finding is unknown [see Nonclinical Toxicology].
Blood Pressure: Addition of a 50 mg single dose of sildenafil to ENTRESTO at steady state (194 mg sacubitril/206 mg valsartan once daily for 5 days) in patients with hypertension was associated with additional blood pressure (BP) reduction (approximately 5/4 mmHg, systolic/diastolic BP) compared to administration of ENTRESTO alone.
Co-administration of ENTRESTO did not significantly alter the BP effect of intravenous nitroglycerin.
Pharmacokinetics
Absorption
Following oral administration, ENTRESTO dissociates into sacubitril and valsartan. Sacubitril is further metabolized to LBQ657. The peak plasma concentrations of sacubitril, LBQ657, and valsartan are reached in 0.5 hours, 2 hours, and 1.5 hours, respectively. The oral absolute bioavailability of sacubitril is estimated to be greater than or equal to 60%. The valsartan in ENTRESTO is more bioavailable than the valsartan in other marketed tablet formulations; 26 mg, 51 mg, and 103 mg of valsartan in ENTRESTO is equivalent to 40 mg, 80 mg, and 160 mg of valsartan in other marketed tablet formulations, respectively.
Following twice-daily dosing of ENTRESTO, steady-state levels of sacubitril, LBQ657, and valsartan are reached in 3 days. At steady state, sacubitril and valsartan do not accumulate significantly, whereas LBQ657 accumulates by 1.6-fold. ENTRESTO administration with food has no clinically significant effect on the systemic exposures of sacubitril, LBQ657, or valsartan. Although there is a decrease in exposure to valsartan when ENTRESTO is administered with food, this decrease is not accompanied by a clinically significant reduction in the therapeutic effect. ENTRESTO can therefore be administered with or without food.
Distribution
Sacubitril, LBQ657 and valsartan are highly bound to plasma proteins (94% to 97%). Based on the comparison of plasma and CSF exposures, LBQ657 crosses the blood brain barrier to a limited extent (0.28%). The average apparent volumes of distribution of valsartan and sacubitril are 75 and 103 L, respectively.
Metabolism
Sacubitril is readily converted to LBQ657 by esterases; LBQ657 is not further metabolized to a significant extent. Valsartan is minimally metabolized; only about 20% of the dose is recovered as metabolites. A hydroxyl metabolite has been identified in plasma at low concentrations (less than 10%).
Elimination
Following oral administration, 52% to 68% of sacubitril (primarily as LBQ657) and approximately 13% of valsartan and its metabolites are excreted in urine; 37% to 48% of sacubitril (primarily as LBQ657), and 86% of valsartan and its metabolites are excreted in feces. Sacubitril, LBQ657, and valsartan are eliminated from plasma with a mean elimination half-life (T½) of approximately 1.4 hours, 11.5 hours, and 9.9 hours, respectively.
Linearity/Nonlinearity
The pharmacokinetics of sacubitril, LBQ657, and valsartan were linear over an ENTRESTO dose range of 24 mg sacubitril/26 mg valsartan to 194 mg sacubitril/206 mg valsartan.
Drug Interactions
Effect Of Co-administered Drugs On ENTRESTO
Because CYP450 enzyme-mediated metabolism of sacubitril and valsartan is minimal, coadministration with drugs that impact CYP450 enzymes is not expected to affect the pharmacokinetics of ENTRESTO. Dedicated drug interaction studies demonstrated that coadministration of furosemide, warfarin, digoxin, carvedilol, a combination of levonorgestrel/ethinyl estradiol, amlodipine, omeprazole, hydrochlorothiazide (HCTZ), metformin, atorvastatin, and sildenafil, did not alter the systemic exposure to sacubitril, LBQ657 or valsartan.
Effect Of ENTRESTO On Co-administered Drugs
In vitro data indicate that sacubitril inhibits OATP1B1 and OATP1B3 transporters. The effects of ENTRESTO on the pharmacokinetics of coadministered drugs are summarized in Figure 1.
Figure 1: Effect of ENTRESTO on Pharmacokinetics of Coadministered Drugs
Specific Populations Effect of specific populations on the pharmacokinetics of LBQ657 and valsartan are shown in Figure 2.
Figure 2: Pharmacokinetics of ENTRESTO in Specific Populations
Note: Child-Pugh Classification was used for hepatic impairment.
Pediatric Patients: The pharmacokinetics of ENTRESTO were evaluated in pediatric heart failure patients 1 to less than 18 years old administered oral doses of 0.8 mg/kg and 3.1 mg/kg of ENTRESTO. Pharmacokinetic data indicated that exposure to ENTRESTO in pediatric and adult patients is similar.
Animal Toxicology And/Or Pharmacology
The effects of ENTRESTO on amyloid-β concentrations in CSF and brain tissue were assessed in young (2 to 4 years old) cynomolgus monkeys treated with ENTRESTO (24 mg sacubitril/26 mg valsartan/kg/day) for 2 weeks. In this study, ENTRESTO affected CSF Aβ clearance, increasing CSF Aβ 1-40, 1-42, and 1-38 levels in CSF; there was no corresponding increase in Aβ levels in the brain. In addition, in a toxicology study in cynomolgus monkeys treated with ENTRESTO at 146 mg sacubitril/154 mg valsartan/kg/day for 39-weeks, there was no amyloid-β accumulation in the brain.
Clinical Studies
Dosing in clinical trials was based on the total amount of both components of ENTRESTO, i.e., 24/26 mg, 49/51 mg, and 97/103 mg were referred to as 50 mg, 100 mg, and 200 mg, respectively.
Adult Heart Failure
PARADIGM-HF
PARADIGM-HF was a multinational, randomized, double-blind trial comparing ENTRESTO and enalapril in 8,442 adult patients with symptomatic chronic heart failure (NYHA class II–IV) and systolic dysfunction (left ventricular ejection fraction ≤ 40%). Patients had to have been on an ACE inhibitor or ARB for at least four weeks and on maximally tolerated doses of beta-blockers. Patients with a systolic blood pressure of less than 100 mmHg at screening were excluded.
The primary objective of PARADIGM-HF was to determine whether ENTRESTO, a combination of sacubitril and an RAS inhibitor (valsartan), was superior to an RAS inhibitor (enalapril) alone in reducing the risk of the combined endpoint of cardiovascular (CV) death or hospitalization for heart failure (HF).
After discontinuing their existing ACE inhibitor or ARB therapy, patients entered sequential single-blind run-in periods during which they received enalapril 10 mg twice-daily, followed by ENTRESTO 100 mg twice-daily, increasing to 200 mg twice-daily. Patients who successfully completed the sequential run-in periods were randomized to receive either ENTRESTO 200 mg (N = 4,209) twice-daily or enalapril 10 mg (N = 4,233) twice-daily. The primary endpoint was the first event in the composite of CV death or hospitalization for HF. The median follow-up duration was 27 months and patients were treated for up to 4.3 years.
The population was 66% Caucasian, 18% Asian, and 5% Black; the mean age was 64 years and 78% were male. At randomization, 70% of patients were NYHA Class II, 24% were NYHA Class III, and 0.7% were NYHA Class IV. The mean left ventricular ejection fraction was 29%. The underlying cause of heart failure was coronary artery disease in 60% of patients; 71% had a history of hypertension, 43% had a history of myocardial infarction, 37% had an eGFR less than 60 mL/min/1.73m², and 35% had diabetes mellitus. Most patients were taking beta-blockers (94%), mineralocorticoid antagonists (58%), and diuretics (82%). Few patients had an implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy-defibrillator (CRT-D) (15%).
PARADIGM-HF demonstrated that ENTRESTO, a combination of sacubitril and an RAS inhibitor (valsartan), was superior to a RAS inhibitor (enalapril), in reducing the risk of the combined endpoint of cardiovascular death or hospitalization for heart failure, based on a time-to-event analysis (hazard ratio [HR] 0.80; 95% confidence interval [CI], 0.73, 0.87, p < 0.0001). The treatment effect reflected a reduction in both cardiovascular death and heart failure hospitalization; see Table 4 and Figure 3. Sudden death accounted for 45% of cardiovascular deaths, followed by pump failure, which accounted for 26%.
ENTRESTO also improved overall survival (HR 0.84; 95% CI [0.76, 0.93], p = 0.0009) (Table 4). This finding was driven entirely by a lower incidence of cardiovascular mortality on ENTRESTO.
Table 4: Treatment Effect for the Primary Composite Endpoint, Its Components, and All-cause Mortality in PARADIGM-HF
|
ENTRESTO
N = 4,187 n (%) |
Enalapril
N = 4,212 n (%) |
Hazard Ratio (95% CI) |
p-value |
| Primary composite endpoint of cardiovascular death or heart failure hospitalization |
914 (21.8) |
1,117 (26.5) |
0.80
(0.73, 0.87) |
< 0.0001 |
| Cardiovascular death as first event |
377 (9.0) |
459 (10.9) |
|
|
| Heart failure hospitalization as first event |
537 (12.8) |
658 (15.6) |
|
|
| Number of patients with events:* |
| Cardiovascular death** |
558 (13.3) |
693 (16.5) |
0.80
(0.71, 0.89) |
|
| Heart failure hospitalizations |
537 (12.8) |
658 (15.6) |
0.79
(0.71, 0.89) |
|
| All-cause mortality |
711 (17.0) |
835 (19.8) |
0.84
(0.76, 0.93) |
0.0009 |
*Analyses of the components of the primary composite endpoint were not prospectively planned to be adjusted for multiplicity.
**Includes patients who had heart failure hospitalization prior to death. |
The Kaplan-Meier curves presented below (Figure 3) show time to first occurrence of the primary composite endpoint (3A), and time to occurrence of cardiovascular death at any time (3B) and first heart failure hospitalization (3C).
Figure 3: Kaplan-Meier Curves for the Primary Composite Endpoint (A), Cardiovascular Death (B), and Heart Failure Hospitalization (C)
A wide range of demographic characteristics, baseline disease characteristics, and baseline concomitant medications were examined for their influence on outcomes. The results of the primary composite endpoint were consistent across the subgroups examined (Figure 4).
Figure 4: Primary Composite Endpoint (CV Death or HF Hospitalization) -Subgroup Analysis (PARADIGM-HF)
Note: The figure above presents effects in various subgroups, all of which are baseline characteristics. The 95% confidence limits that are shown do not take into account the number of comparisons made, and may not reflect the effect of a particular factor after adjustment for all other factors. Apparent homogeneity or heterogeneity among groups should not be over-interpreted.
PARAGON-HF
PARAGON-HF, was a multicenter, randomized, double-blind trial comparing ENTRESTO and valsartan in 4,796 adult patients with symptomatic heart failure with left ventricular ejection fraction greater than or equal to 45%, and structural heart disease [either left atrial enlargement (LAE) or left ventricular hypertrophy (LVH)]. Patients with a systolic blood pressure of less than 110 mmHg and patients with any prior echocardiographic LVEF less than 40% at screening were excluded.
The primary objective of PARAGON-HF was to determine whether ENTRESTO reduced the rate of the composite endpoint of total (first and recurrent) heart failure (HF) hospitalizations and cardiovascular (CV) death.
After discontinuing their existing ACE inhibitor or ARB therapy, patients entered sequential single-blind run-in periods during which they received valsartan 80 mg twice-daily, followed by ENTRESTO 100 mg twice-daily. Patients on prior low doses of an ACEi or ARB began the run-in period receiving valsartan 40 mg twice-daily for 1 to 2 weeks. Patients who successfully completed the sequential run-in periods were randomized to receive either ENTRESTO 200 mg (N = 2,419) twice-daily or valsartan 160 mg (N = 2,403) twice-daily. The median follow-up duration was 35 months and patients were treated for up to 4.7 years.
The population was 81% Caucasian, 13% Asian, and 2% Black; the mean age was 73 years and 52% were female. At randomization, 77% of patients were NYHA Class II, 19% were NYHA Class III, and 0.4% were NYHA Class IV. The median left ventricular ejection fraction was 57%. The underlying cause of heart failure was of ischemic etiology in 36% of patients. Furthermore, 96% had a history of hypertension, 23% had a history of myocardial infarction, 46% had an eGFR less than 60 mL/min/1.73 m², and 43% had diabetes mellitus. Most patients were taking beta-blockers (80%) and diuretics (95%).
PARAGON-HF demonstrated that ENTRESTO had a numerical reduction in the rate of the composite endpoint of total (first and recurrent) HF hospitalizations and CV death, based on an analysis using a proportional rates model (rate ratio [RR] 0.87; 95% CI [0.75, 1.01], p = 0.06); see Table 5. The treatment effect was primarily driven by the reduction in total HF hospitalizations in patients randomized to ENTRESTO (RR 0.85; 95% CI [0.72, 1.00]).
Table 5: Treatment Effect for the Primary Composite Endpoint and Its Components in PARAGON-HF
| Efficacy Endpoints |
ENTRESTO
N = 2,407 |
Valsartan
N = 2,389 |
Effect Size (95% CI) |
| n |
Event Ratea |
n |
Event Ratea |
| Composite of total (first and recurrent) HF hospitalizations and CV death |
894 |
12.8 |
1,009 |
14.6 |
RR = 0.87 (0.75, 1.01) p-value 0.06 |
| Total HF Hospitalizations |
690 |
9.9 |
797 |
11.6 |
RR = 0.85 (0.72, 1.00) |
| CV Deathb |
204 |
2.9 |
212 |
3.1 |
HR = 0.95 (0.79, 1.16) |
Abbreviations: RR = rate ratio, HR = hazard ratio.
a Event rate per 100 patient-years.
b Includes patients who had CV death following HF hospitalization event. |
Figure 5 shows the mean number of composite endpoint events of total HF hospitalizations and CV death over time.
Figure 5: Mean Number of Events Over Time for the Primary Composite Endpoint of Total HF Hospitalizations and CV Death
A wide range of demographic characteristics, baseline disease characteristics, and baseline concomitant medications were examined for their influence on outcomes (Figure 6).
Figure 6: Primary Composite Endpoint of Total HF Hospitalizations and CV Death – Subgroup Analysis (PARAGON-HF)
Note: The figure above presents effects in various subgroups, all of which are baseline characteristics. The 95% confidence limits that are shown do not take into account the number of comparisons made, and may not reflect the effect of a particular factor after adjustment for all other factors.
In an analysis of the relationship between LVEF and outcome in PARADIGM-HF and PARAGON-HF, patients with LVEF below normal treated with ENTRESTO experienced greater risk reduction (Figure 7).
Figure 7: Treatment Effect for the Composite Endpoint of Time to First HF Hospitalization or CV Death by LVEF in PARADIGM-HF and PARAGON-HF
Pediatric Heart Failure
The efficacy of ENTRESTO was evaluated in a multinational, randomized, double-blind trial PANORAMA-HF comparing ENTRESTO (n = 187) and enalapril (n = 188) in pediatric patients aged 1 month to less than 18 years old due to systemic left ventricular systolic dysfunction (LVEF ≤ 45% or fractional shortening ≤ 22.5%). Patients with systemic right ventricle, single ventricle, restrictive cardiomyopathy or hypertrophic cardiomyopathy were excluded from the trial. Efficacy of ENTRESTO in patients less than 1 year old was not established. At Week 52, there were 144 ENTRESTO and 133 enalapril patients with a post-baseline assessment of NT-proBNP. The estimated least squares mean percent reduction from baseline in NT-proBNP was 65% and 62% in the ENTRESTO and enalapril groups, respectively. While the between-group difference was not nominally statistically significant, the reductions for ENTRESTO and enalapril were larger than what was seen in adults; these reductions did not appear to be attributable to post-baseline changes in background therapy.
Because ENTRESTO improved outcomes and reduced NT-proBNP in adults in PARADIGM-HF, the effect on NTÂproBNP was the basis to infer improved cardiovascular outcomes in pediatric patients.