Iris Rajman

The effect of LCZ696 (sacubitril/valsartan) on amyloid-β concentrations in cerebrospinal fluid in healthy subjects

Aims LCZ696 (angiotensin receptor neprilysin inhibitor) is a novel drug developed for the treatment of heart failure with reduced ejection fraction. Neprilysin is one of multiple enzymes degrading amyloid‐β (Aβ). Its inhibition may increase Aβ levels. The potential exists that treatment of LCZ696, through the inhibition of neprilysin by LBQ657 (an LCZ696 metabolite), may result in accumulation of Aβ. The aim of this study was to assess the blood–brain‐barrier penetration of LBQ657 and the potential effects of LCZ696 on cerebrospinal fluid (CSF) concentrations of Aβ isoforms in healthy human volunteers. Methods In a double‐blind, randomized, parallel group, placebo‐controlled study, healthy subjects received once daily LCZ696 (400 mg, n = 21) or placebo (n = 22) for 14 days. Results LCZ696 had no significant effect on CSF AUEC(0,36 h) of the aggregable Aβ species 1–42 or 1–40 compared with placebo (estimated treatment ratios 0.98 [95% CI 0.73, 1.34; P = 0.919] and 1.05 [95% CI 0.82, 1.34; P = 0.702], respectively). A 42% increase in CSF AUEC(0,36 h) of soluble Aβ 1–38 was observed (estimated treatment ratio 1.42 [95% CI 1.05, 1.91; P = 0.023]). CSF levels of LBQ657 and CSF Aβ 1–42, 1–40, and 1–38 concentrations were not related (r 2 values 0.022, 0.010, and 0.008, respectively). Conclusions LCZ696 did not cause changes in CSF levels of aggregable Aβ isoforms (1–42 and 1–40) compared with placebo, despite achieving CSF concentrations of LBQ657 sufficient to inhibit neprilysin. The clinical relevance of the increase in soluble CSF Aβ 1–38 is currently unknown.

The effect of LCZ696 on amyloid‐β concentrations in cerebrospinal fluid in healthy subjects

Aims LCZ696 (angiotensin receptor neprilysin inhibitor) is a novel drug developed for the treatment of heart failure with reduced ejection fraction. Neprilysin is one of multiple enzymes degrading amyloid‐β (Aβ). Its inhibition may increase Aβ levels. The potential exists that treatment of LCZ696, through the inhibition of neprilysin by LBQ657 (an LCZ696 metabolite), may result in accumulation of Aβ. The aim of this study was to assess the blood–brain‐barrier penetration of LBQ657 and the potential effects of LCZ696 on cerebrospinal fluid (CSF) concentrations of Aβ isoforms in healthy human volunteers. Methods In a double‐blind, randomized, parallel group, placebo‐controlled study, healthy subjects received once daily LCZ696 (400 mg, n = 21) or placebo (n = 22) for 14 days. Results LCZ696 had no significant effect on CSF AUEC(0,36 h) of the aggregable Aβ species 1–42 or 1–40 compared with placebo (estimated treatment ratios 0.98 [95% CI 0.73, 1.34; P = 0.919] and 1.05 [95% CI 0.82, 1.34; P = 0.702], respectively). A 42% increase in CSF AUEC(0,36 h) of soluble Aβ 1–38 was observed (estimated treatment ratio 1.42 [95% CI 1.05, 1.91; P = 0.023]). CSF levels of LBQ657 and CSF Aβ 1–42, 1–40, and 1–38 concentrations were not related (r 2 values 0.022, 0.010, and 0.008, respectively). Conclusions LCZ696 did not cause changes in CSF levels of aggregable Aβ isoforms (1–42 and 1–40) compared with placebo, despite achieving CSF concentrations of LBQ657 sufficient to inhibit neprilysin. The clinical relevance of the increase in soluble CSF Aβ 1–38 is currently unknown.

Pharmacodynamic and Pharmacokinetic Profiles of Sacubitril/Valsartan (LCZ696) in Patients with Heart Failure and Reduced Ejection Fraction

Summary Aims Concomitant renin–angiotensin–aldosterone system blockade and natriuretic peptide system enhancement may provide unique therapeutic benefits to patients with heart failure and reduced ejection fraction (HFrEF). This study assessed the pharmacodynamics and pharmacokinetics of LCZ696 in patients with HFrEF. Methods This was an open‐label, noncontrolled single‐sequence study. After a 24‐h run‐in period, patients (n = 30) with HFrEF (EF ≤ 40%; NYHA class II–IV) received LCZ696 100 mg twice daily (bid) for 7 days and 200 mg bid for 14 days, along with standard treatment for heart failure (HF) (except angiotensin‐converting enzyme inhibitors [ACEIs] or angiotensin receptor blockers [ARBs]). Results On Day 21, significant increases were observed in the plasma biomarkers indicative of neprilysin and RAAS inhibition (ratio‐to‐baseline: cyclic guanosine monophosphate [cGMP], 1.38; renin concentration and activity, 3.50 and 2.27, respectively; all, P < 0.05). Plasma NT‐proBNP levels significantly decreased at all the time points on Days 7 and 21; plasma aldosterone and endothelin‐1 levels significantly decreased on Day 21 (all, P < 0.05). Following administration of LCZ696, the Cmax of sacubitril (neprilysin inhibitor prodrug), LBQ657 (active neprilysin inhibitor), and valsartan were reached within 0.5, 2.5, and 2 h. Between 100‐ and 200‐mg doses, the Cmax and AUC 0–12 h for sacubitril and LBQ657 were approximately dose‐proportional while that of valsartan was less than dose‐proportional. Conclusions Treatment with LCZ696 for 21 days was well tolerated and resulted in plasma biomarker changes indicative of neprilysin and RAAS inhibition in patients with HF. The pharmacokinetic exposure of the LCZ696 analytes in patients with HF observed in this study is comparable to that observed in the pivotal Phase III study.

Safety and tolerability of serelaxin, a recombinant human relaxin-2 in development for the treatment of acute heart failure, in healthy Japanese volunteers and a comparison of pharmacokinetics and pharmacodynamics in healthy Japanese and Caucasian populations

Serelaxin, a recombinant form of the human relaxin‐2 hormone, is currently under clinical investigation for treatment of acute heart failure. This double‐blind, placebo‐controlled, dose‐ranging study investigated the effect of Japanese ethnicity on the pharmacokinetics (PK), pharmacodynamics (PD), and safety and tolerability of serelaxin. Japanese healthy subjects (n = 32) received 10, 30, or 100 µg/kg/day of serelaxin, or placebo, administered as a 48‐hour intravenous infusion. A Caucasian cohort (n = 8) receiving 30 µg/kg/day open‐label serelaxin was included for comparison. In all subjects, serum serelaxin concentrations increased rapidly after the start of infusion, approached steady state as early as 4 hours, and declined rapidly upon treatment cessation. Serum exposure to serelaxin increased with increasing doses. Statistical dose proportionality was shown for AUCinf over the entire dose range. A significant increase in estimated glomerular filtration rate from baseline to Day 2 (30 and 100 µg/kg/day) and to Day 3 (10 and 100 µg/kg/day) was observed compared with placebo. Serelaxin was well tolerated by all subjects. In conclusion, PK, PD, and safety profiles of serelaxin were generally comparable between Japanese and Caucasian subjects, suggesting that no dose adjustment will be required in Japanese subjects during routine clinical use of this agent.

Pharmacokinetics of serelaxin in patients with hepatic impairment: a single-dose, open-label, parallel group study.

AIMS Serelaxin is a recombinant form of human relaxin-2 in development for treatment of acute heart failure. This study aimed to evaluate the pharmacokinetics (PK) of serelaxin in patients with hepatic impairment. Secondary objectives included evaluation of immunogenicity, safety and tolerability of serelaxin. METHODS This was an open-label, parallel group study (NCT01433458) comparing the PK of serelaxin following a single 24 h intravenous (i.v.) infusion (30 μg kg(-1)  day(-1) ) between patients with mild, moderate or severe hepatic impairment (Child-Pugh class A, B, C) and healthy matched controls. Blood sampling and standard safety assessments were conducted. Primary non-compartmental PK parameters [including area under the serum concentration-time curve AUC(0-48 h) and AUC(0-∞) and serum concentration at 24 h post-dose (C24h )] were compared between each hepatic impairment group and healthy controls. RESULTS A total of 49 subjects (including 25 patients with hepatic impairment) were enrolled, of which 48 subjects completed the study. In all groups, the serum concentration of serelaxin increased over the first few hours of infusion, reached steady-state at 12-24 h and then declined following completion of infusion, with a mean terminal half-life of 7-8 h. All PK parameter estimates were comparable between each group of patients with hepatic impairment and healthy controls. No serious adverse events, discontinuations due to adverse events or deaths were reported. No serelaxin treatment-related antibodies developed during this study. CONCLUSIONS The PK and safety profile of serelaxin were not affected by hepatic impairment. No dose adjustment is needed for serelaxin treatment of 48 h i.v. infusion in patients with hepatic impairment.

Pharmacokinetic drug-drug interaction assessment of LCZ696 (an angiotensin receptor neprilysin inhibitor) with omeprazole, metformin or levonorgestrel-ethinyl estradiol in healthy subjects.

LCZ696 is a novel angiotensin receptor neprilysin inhibitor in development for the treatment of cardiovascular diseases. Here, we assessed the potential for pharmacokinetic drug‐drug interaction of LCZ696 (400 mg, single dose or once daily [q.d.]) when co‐administered with omeprazole 40 mg q.d. (n = 28) or metformin 1000 mg q.d. (n = 27) or levonorgestrel‐ethinyl estradiol 150/30 μg single dose (n = 24) in three separate open‐label, single‐sequence studies in healthy subjects. Pharmacokinetic parameters of LCZ696 analytes (sacubitril, LBQ657, and valsartan), metformin, and levonorgestrel‐ethinyl estradiol were assessed. Omeprazole did not alter the AUCinf of sacubitril and pharmacokinetics of LBQ657; however, 7% decrease in the Cmax of sacubitril, and 11% and 13% decreases in AUCinf and Cmax of valsartan were observed. Co‐administration of LCZ696 with metformin had no significant effect on the pharmacokinetics of LBQ657 and valsartan; however, AUCtau,ss and Cmax,ss of metformin were decreased by 23%. Co‐administration of LCZ696 with levonorgestrel‐ethinyl estradiol had no effect on the pharmacokinetics of ethinyl estradiol and LBQ657 or AUCinf of levonorgestrel. The Cmax of levonorgestrel decreased by 15%, and AUCtau,ss and Cmax,ss of valsartan decreased by 14% and 16%, respectively. Co‐administration of LCZ696 with omeprazole, metformin, or levonorgestrel‐ethinyl estradiol was not associated with any clinically relevant pharmacokinetic drug interactions.

Pharmacokinetic drug–drug interaction assessment between LCZ696, an angiotensin receptor neprilysin inhibitor, and hydrochlorothiazide, amlodipine, or carvedilol

LCZ696 is a first‐in‐class angiotensin receptor neprilysin inhibitor in development for treatments of hypertension and heart failure indications. In 3 separate studies, pharmacokinetic drug–drug interactions (DDIs) potential was assessed when LCZ696 was coadministered with hydrochlorothiazide (HCTZ), amlodipine, or carvedilol. The studies used a open‐label, single‐sequence, 3‐period, crossover design in healthy subjects. Blood samples were collected to determine the pharmacokinetic parameters of LCZ696 analytes (AHU377, LBQ657, and valsartan), HCTZ, amlodipine, or carvedilol (R[+]‐ and S[−]‐carvedilol) for statistical analysis. When coadministered LCZ696 with HCTZ, the 90% CIs of the geometric mean ratios of AUCtau,ss of HCTZ and that of LBQ657 were within a 0.80–1.25 interval, whereas HCTZ Cmax,ss decreased by 26%, LBQ657 Cmax,ss increased by 19%, and the AUCtau,ss and Cmax,ss of valsartan increased by 14% and 16%, respectively. Pharmacokinetics of amlodipine, R(+)‐ and S(−)‐carvedilol, or LBQ657 were not altered after coadministration of LCZ696 with amlodipine or carvedilol. Coadministration of LCZ696 400 mg once daily (qd) with HCTZ 25 mg qd, amlodipine 10 mg qd, or carvedilol 25 mg twice a day (bid) had no clinically relevant pharmacokinetic drug–drug interactions. LCZ696, HCTZ, amlodipine, and carvedilol were safe and well tolerated when given alone or concomitantly in the investigated studies.

Effects of age and sex on the pharmacokinetics of LCZ696, an angiotensin receptor neprilysin inhibitor

LCZ696, a novel angiotensin receptor neprilysin inhibitor, is in development for the treatment of heart failure. Administration of LCZ696 results in systemic exposure to sacubitril (inactive prodrug of LBQ657), LBQ657 (neprilysin inhibitor), and valsartan (angiotensin II receptor blocker). We investigated the potential effects of age and sex on the pharmacokinetics of LCZ696 analytes (LBQ657 and valsartan) in an open‐label, single oral dose (400 mg), parallel‐group study in healthy subjects. Among 36 enrolled subjects, there were 19 male and 17 female subjects; 18 subjects were 18–45 years old (young), and 18 subjects were 65 years of age or older (elderly). Compared with young subjects, the AUCinf and T1/2 for LBQ657 were 42% and 30% greater, respectively, in elderly subjects. The Cmax for LBQ657 was similar between age groups. The AUCinf, Cmax, and T1/2 for valsartan were 30%, 24% greater, and 3.35 hours longer, respectively, in the elderly when compared with young subjects. All pharmacokinetic parameters of LCZ696 analytes (LBQ657 and valsartan) were similar between male and female subjects, indicating no effect on the pharmacokinetics of LCZ696 analytes based on sex. Considering the magnitude of change and its clinical significance, dose adjustment based on age or sex is not considered necessary.

Assessment of Drug Interaction Potential between LCZ696, an Angiotensin Receptor Neprilysin Inhibitor, and Digoxin or Warfa rin

LCZ696 (sacubitril/valsartan) is a first-in-class angiotensin receptor neprilysin inhibitor that simultaneously inhibits neprilysin and blocks the angiotensin II receptor. LCZ696 has been recently approved for treatment of HF and likely be co-administered with digoxin or warfarin. The drug interaction potential between LCZ696 and digoxin or warfarin was evaluated because of their potentially shared metabolic/elimination pathways. Two separate drug-drug interaction studies were conducted in healthy subjects: LCZ696 200 mg twice daily was co-administered with digoxin 0.25 mg once daily (n=24) and warfarin 25 mg single dose (n=26), respectively. The pharmacokinetic profiles of the LCZ696 analytes (sacubitril, LBQ657 and valsartan), digoxin and R- and S-warfarin, the pharmacodynamic effects of warfarin and the safety and tolerability of the investigational drugs were assessed. The geometric mean ratio (GMR) and 90%confidence interval (90% CI) for Cmax and AUCs of R- and S-warfarin, digoxin, and pharmacologically active LCZ696 analytes were within the bioequivalence range of 0.8-1.25 when co-administered. The GMR and 90% CI of warfarin pharmacodynamics effects were also within 0.8-1.25 range when co-administered with LCZ696. LCZ696 was generally safe and welltolerated when administered alone or in combination with digoxin/warfarin. No drug-drug interaction was observed upon co-administration of LCZ696 with digoxin/warfarin in healthy subjects.

African Genetic Diversity: Implications for Cytochrome P450-mediated Drug Metabolism and Drug Development

Genetic diversity is greater in Africa than in other continental populations. Genetic variability in genes encoding drug metabolizing enzymes may contribute to the high numbers of adverse drug reactions reported in Africa. We reviewed publications (1995–April 2016) reporting frequencies of known cytochrome P450 (CYP) variants in African populations. Using principal components analysis (PCA) we identified CYP alleles of potential clinical relevance with a marked difference in distribution in Africa, compared with Asian and Caucasian populations. These were CYP2B6*6, CYP2C8*2, CYP2D6*3, CYP2D6*17, CYP2D6*29, CYP3A5*6, and CYP3A5*7. We show clearly that there is greater diversity in CYP distribution in Africa than in other continental populations and identify a need for optimization of drug therapy and drug development there. Further pharmacogenetic studies are required to confirm the CYP distributions we identified using PCA, to discover uniquely African alleles and to identify populations at a potentially increased risk of drug-induced adverse events or drug inefficacy.