1. DRUGS ACTING ON RAAS
DR SHREETAL RAJAN NAIR

2. The Renin Angiotensin Aldosterone System (RAAS)
Most important neurohormonal system that maintains vascular tone and fluid-electrolyte balance in our body
Is involved in the pathophysiology of most cardiovascular diseases and hence its importance
Works through a negative feedback loop in our body

3. Pathophysiology of RAS

5. Factors stimulating renin release
Low arterial blood pressure
Decreased sodium concentration in the distal tubule
Decreased blood volume
Increased beta -1 sympathetic activity

7. Drugs influencing PRA Increasing PRA ACEI ARBs Vasodilators Diuretics
Decreasing PRA
Adrenergic blockers
Renin inhibitors

10. DRUGS ACTING ON RAAS ACE Inhibitors Angiotensin receptor blockers
Aldosterone antagonists
Renin inhibitors
New therapeutic pathways

11. ACE Inhibitors

12. Historical aspects
ACE was initially discovered from the venom of pit viper and named bradykinin potentiating factor and later it was found that this kininase and ACE were the same.
Teprotide was the first ACEI to be synthezised
But it had limitations
Later , captopril was developed as the first ACEI in 1977

13. ACEI ACE inhibitors differ
in the chemical structure of their active moieties,
in potency,
in bioavailability,
in plasma half-life,
in route of elimination,
in their distribution and affinity for tissue-bound ACE, and
in whether they are administered as prodrugs.

14. ACE Inhibitors CLASSIFICATION Class I : Containing a sulfhydryl group
- Captopril ( proline derivative)
Class II : Prodrugs
Class III : Water soluble
- Lisinopril ( Lysine derivative )

15. ACEI
Captopril is the prototype of the sulfhydryl-containing ACE inhibitors; others are fentiapril, pivalopril, zofenopril, and alacepril.
In vitro studies suggest that the presence of the sulfhydryl group may confer properties other than ACE inhibition to these drugs, such as free-radical scavenging and effects on prostaglandins
In vivo no much benefit has been found

16. ACEI – salient features
Captopril by itself is active and its metabolites are also active
Prodrugs by itself are not active and need to be converted to the active diacids in the liver and prodrugs have better bioavailability
Lisinopril is active and is not metabolised and excreted unchanged
All ACEI are excreted exclusively via renal system except fosinopril,spirapril and trandolapril which are excreted via the biliiary system and feces.

18. ACEI – salient features
Bioavailability : highest – captopril; least – perindopril
Most prodrugs are carboxyl derivatives except fosinopril
Time to peak action – fastest captopril ( 1 hr)
Elimination t ½ - longest with ramipril (8-48 hrs)
ACEI with duration of action > 24 hrs : enalapril,lisinopril,ramipril and perindopril
Captopril is the only ACEI to cross BBB but its clinical significance is unknown

19. ACEI – pharmacokinetics in a nut shell
Nancy J. Brown, MD; Douglas E. Vaughan, MD Circulation. 1998;97:

21. ACEI- hemodynamic effects
ACEI are beneficial in many ways
Prevents generation of angiotensin II
Useful in conditions in which the renin angiotensin system is dysregulated like essential hypertension and renovascular hypertension
Decreases the peripheral vascular resistance
Fall in systolic and diastolic BP
No effect on cardiac output

22. INDICATIONS OF ACEI 1. Heart failure
Chronic heart failure due to any cause
2. AMI
Early phase
AMI with HF
3. Hypertension
4. Chronic Renal Disease
5. Diabetic nephropathy
6. Risk prevention

23. ACEI – other indications
Non – cardiovascular
Diabetic and non- diabetic nephropathy
Scleroderma crisis ( captopril test to diagnose renovascular hypertension )

25. Adverse effects

26. Adverse effects
First dose hypotension more in diuretic treated patients
Hyperkalemia more in patients with impaired renal function and those taking potassium sparing diuretics and NSAIDs
Cough : occurs in patients within 1-8 weeks ; subsides in 7-21 days after discontinuation ;not dose related- earlier it was believed to be due to inhibition of bradykinin degradation; now it is believed to be mediated by substance P as kininase II is also believed to be degrade substance P. More in women

27. Adverse effects
Angioedema: the pathogenesis is found to be similar to the cough;
cough and angioedema found in higher incidence in those concomitantly using DPP IV inhibitors as DPP is also responsible for substance P breakdown.
Rashes,urticaria: do not need drug stoppage
Dysguesia is a reversible alteration in the taste sensation – found in captopril treated patients and believed to be due to the sulfhydryl moiety

28. ADAPTED from www./spo.escardio.org/eslides

29. Adverse effects
Granulocytopenia and proteinuria very rare but warrant withdrawal
Headache,dizziness ,nausea and bowel upset- in 1-4 %
ARF in bilateral RAS due to dilatation of efferent arterioles and fall in GFR and hence contraindicated
Fetopathic effects- 1st trimester produces cardiovascular malformations ( PDA ) and 2nd and 3rd trimester responsible for oligohydramnios, fetal calvarial hypoplasia, fetal pulmonary hypoplasia, fetal growth retardation, fetal death, neonatal anuria, and neonatal death and hence contraindicated in pregnancy.

30. Interactions NSAIDs especially in elderly, taking diuretics and ACEI
Potassium sparing diuretics/ on K+ supplements
Antacids decrease absorption
Reduce Lithium clearance and predispose to toxicity in those taking lithium
Caution in
Impaired renal function, hypovolemia or dehydration

31. Contraindications Bilateral RAS Pregnancy Hyperkalemia
Known allergy or hypersensitivity
Serum creatinine (>2.5 – 3.0 mg/dl ) arbitrary cut off in patients with heart failure

32. Pharmacogenomics
Found to be less effective in young and elderly blacks
because are found to have less PRA.
Adding drugs which increase PRA like diuretics have found to increase response to therapy
An insertion (I)/deletion (D) polymorphism in the ACE gene that correlates with ACE activity such that ACE levels are highest in patients who are homozygous for the ACE D allele, lowest in patients homozygous for the ACE I allele, and intermediate in those who are heterozygous . Persons with the D/D phenotype had subdued response to the ACEI
Angioedema more in whites.

33. Some new concepts in ACE inhibition
ACE inhibitors have also been shown to cause a central enhancement of parasympathetic nervous system activity in healthy volunteers and patients with heart failure. This action may reduce the prevalence of malignant cardiac arrhythmias, and the reduction in sudden death .
The ACE inhibitor enalapril has also been shown to reduce cardiac cachexia in patients with chronic heart failure. Cachexia is a poor prognostic sign in patients with chronic heart failure

34. Some new concepts in ACE inhibition
ACE inhibitors are under early investigation for the treatment of frailty and muscle wasting (sarcopenia) in elderly patients without heart failure
The lactotripeptides Val-Pro-Pro and Ile-Pro-Pro produced by the probiotic Lactobacillus helveticus or derived from casein have been shown to have ACE-inhibiting and antihypertensive functions ( discovered in Japan IN 1991)

36. ACEI in heart failure
Panel A- ACEI in HF with depressed EF in a post AMI metaanalysis
Panel B – ACEI in HF with depressed EF including postinfarction trials (metaanalysis)
Benefit from therapy is seen very early and persisted long term

37. Omapatrilat
Omapatrilat was a novel antihypertensive agent that inhibits both neutral endopeptidase (NEP) and angiotensin converting enzyme (ACE).
NEP inhibition results in elevated natriureticpeptide levels, promoting natriuresis, diuresis, vasodilation, and reductions in preload and ventricular remodeling.
This was being promoted for CHF but was not approved by the FDA due to angioedema safety concerns

38. Omapatrilat - trials
The OVERTURE (Omapatrilat Versus Enalapril Randomized Trial of Utility in Reducing Events) study:
Omapatrilat was as good as enalapril but not better
In the OCTAVE (Omapatrilat Cardiovascular Treatment Assessment Versus Enalapril) study 25,267 hypertensives were randomised to Omapatrilat or enalapril and a difference of approximately 3 mmHg in favour of Omapatrilat was seen.
Significantly more cases of angioedema were seen with Omapatrilat in both trials.

39. IMPRESS randomised trial
Comparison of vasopeptidase inhibitor, omapatrilat, and lisinopril on exercise tolerance and morbidity in patients with heart failure
Showed a trend in favour of omapatrilat

40. Angiotensin receptor blockers (ARBs)

41. ARBs
The ARBs act on the next step in RAAS and they block the angiotensin II receptor through which angiotensin II exerts its effects
Why the need of ARBs arose after ACEI ?
Clinical and experimental studies showed the initial suppression of angiotensin II after the administration of angiotensin-converting enzyme (ACE) inhibitors is later reversed and returns almost to pretreatment levels.
The ESCAPE phenomenon was hypothesized which was strengthened by the discovery that angiotensin II can also be generated through non-ACEs
Increased incidence of adverse effects with ACEI therapy

42. Advantages of ARBs over ACEI
Do not interfere with degradation of bradykinin and other ACE substrates
More complete inhibition of AT1 receptor activation
Indirect activation of AT2 receptor
Other molecular effects apart from the receptor action

43. Losartan was the first ARB to be synthezised and it was a imidazole derivative
All ARBs expect for losartan are highly selective for the AT1 receptor. In fact, ARBs show 10,000–30,000 times greater affinity for the AT1 receptor than for the AT2 receptor
The majority of ARBs produce insurmountable antagonism ( non competitive inhibition )

44. What is the advantage of AT1 receptor specificity ?
AT2 receptor may be exposed to a higher concentration of Ang II
It increases the Ang II-induced AT2 receptor stimulation which may cause anti-cell proliferation and vasodilation

45. Other effects of ARBs Inverse agonism of AT1 receptor
Anti platelet effects
Anti – inflammatory effects
Reduction in serum uric acid levels

47. Benefits of Inverse agonism
1. Sometimes AT1 receptors are mutated and have constitutive activity which means the receptors can get activated in the absence of its ligand
Constitutive has also been found in wild type receptors
Losartan,valsartan,olmesartan and candesartan have significant inverse agonism

48. Benefits of inverse agonism
2. AT1 receptor mRNA levels are upregulated by myocyte stretching over time
Studies have demonstrated that the AT1 receptor is activated by the mechanical stretching of cultured rat myocytes and constriction of the transverse aorta in angiotensinogen knockout mice without the involvement of Ang II, and these adverse effects were suppressed by an inverse agonist

49. Anti platelet effects
Losartan has some degree of antagonistic action on the thromboxane A2 receptor which is responsible for the platelet antiaggregatory effects

50. Anti inflammatory effects
Ang II induces inflammation in vasculature and vascular remodeling, and subsequently promotes atherosclerosis. Ang II stimulates monocyte chemoattractant protein-1 (MCP-1), interleukin (IL)-8, tumor necrosis factor-a and IL-6 production
Decrease in MCP-1 levels seen with irbesartan and losartan
Increase in adiponectin expression seen with irbesartan,losartan,candesartan and telmisartan

51. Anti inflammatory effects
PPAR gamma activation with eprosartan – may be one reason of preventing New Onset Diabetes(NOD), the other being increased adiponectin levels
Irbesartan and olmesartan act as antagonists of chemokine receptors
Actions are independent of actions on the AT1 and AT2 receptors and suggest a molecular level of action for the ARBs

52. Decrease in uric acid levels
Compared with other ARBs, losartan, telmisartan and irbesartan have been shown to reduce serum uric acid.
These effects are believed to be mediated at the molecular levels independent of action on the AT1 receptor

53. In a nut shell
Angiotensin II type 1 receptor blockers: class effects versus molecular effects
Shin-ichiro Miura, Sadashiva S. Karnik and Keijiro Saku -Journal ofthe Renin-Angiotensin-Aldosterone System (Including other Peptidergic systems)
March 2011 Volume 12 Number 1

54. ARB in hypertension

56. ACC/AHA recommendations (2005)

58. The concept of dual RAAS blockade with ACEI and ARB
Arose because of the phenomenon of escape phenomenon with ACEI
To achieve complete and more effective blockade of Angotensin action
It was combining ACEI and ARB would be of benefit but studies did not give promising results
Now dual ACEI and ARB therapy not recommended except in non- diabetic renal disease -(COOPERATE,2003 trial showed progression of non diabetic renal disease retarded to a greater extent than with monotherapy.

59. Some salient features of ARBs
Highest affinity for AT1 receptor – candesartan
Longest duration of action - telmisartan
All ARBs need dose reduction in liver diseases

60. Adverse effects Similar to ACEI except
Less incidence of first dose hypotension
Cough , angioedema , dysguesia incidence less

61. Interactions
Similar to that with ACEI

62. T cells and angiotensin II induced hypertension
T cells, which express AT1 receptors and NADPH oxidase, may play an important role in the genesis of A II–dependent hypertension, particularly obesity-related hypertension, as the activated T cells are selectively sequestered in adipose tissue.
Homing of activated T cells to perivascular fat promotes vasoconstriction and vascular remodeling.
Homing of activated T cells to perinephric fat promotes renal dysfunction and sodium retention

63. The ARB- MI paradox – a controversy unresolved
The major ARB trials in high-risk patients have thus far demonstrated almost a complete lack of reduction in MI and mortality despite significant reductions in blood pressure.
Paradoxically, rates of MI in some trials have actually increased with ARBs, which suggests that ARBs and ACEIs may exert distinctive effects on both the coronary circulation and atherosclerotic plaque stability
This unexpected relationship of ARBs with MI may be aptly described as the “ARB-MI paradox.”
Martin H. Strauss and Alistair S. Hall: Angiotensin Receptor Blockers May Increase Risk of Myocardial Infarction : Unraveling the ARB-MI paradox ; Circulation. 2006;114: ;
LIONEL H. OPIE and BERNARD J GERSH : DRUGS FOR THE HEART ; 7 Edition 2009

64. Aldosterone antagonists

65. Role of aldosterone in CV disease
Direct correlation of aldosterone levels and mortality in heart failure
Increase in myocardial fibrosis
Inhibition of the release of NO
Increased incidence of arrhythmias
Increased response to vasoconstrictor doses of angiotensin I
Critical mediator of early angiotensin II induced experimental myocardial injury

66. Deleterious effects of aldosterone

67. Aldosterone antagonists
Spironolactone
Eplerenone
Canrenone ( available only in europe)

68. What do they do? Decrease extracellular markers of fibrosis
Decreases the release of cardiac norepinephrine
Vasodilator effects

69. Spironolactone- mechanism of action
It is a steroid chemically related to aldosterone
Competitive inhibition of the mineralocorticoid receptor from the interstitial side of the tubular cell
Inhibits formation of (Aldosterone induced proteins) AIPs

71. Spironolactone
Spironolactone acts as an antagonist and/or agonist at the following sites:
Antagonism
Mineralocorticoid receptor
Androgen receptor
Agonism
Progesterone receptor
Glucocorticoid receptor

72. Spironolactone bodies
Long-term administration of spironolactone gives the histologic characteristic of spironolactone bodies in the adrenal cortex. Spironolactone bodies are eosinophilic, round, concentrically laminated cytoplasmic inclusions surrounded by clear halos in preparations stained with hematoxylin and eosin

73. Contraindications Hyperkalemic states
Pregnancy - high risk of feminisation of female fetuses

74. Pharmacokinetics 75% oral bioavailability
Highly bound to plasma proteins
Completely metabolised in the liver
Active metabolite canrenone ( ½ - 2/3rd of action in vivo is due to this metabolite)
Half life of spironolactone is 1-2 hours; canrenone is 18 hours

75. Indications Hypertension
To improve survival of stable patients with LV systolic dysfunction ( EF </= 40% )
Clinical evidence of CHF after AMI
Refractory edema in cirrhosis and renal disease – helps to breakdown resistance to thiazide diuretics due to secondary hyperaldosteronism
To counteract K+ loss due to thiazide and loop diuretics

76. Interactions
Dangerous hyperkalemia can occur if given with K+ supplements or drugs causing hyperkalemia ( ACEI or ARBs)
Aspirin blocks action of spironolactone by inhibiting tubular secretion of canrenone
Spironolactone increases plasma digoxin concentration

77. Adverse effects Drowsiness , confusion and abdominal discomfort
Hirsutism,gynecomastia,impotence and menstrual irregularities
Hyperkalemia especially in renal disease
Risk of acidosis in cirrhotics

78. Eplerenone More selective aldosterone antagonist
Less likely to cause hormonal disturbances like gynecomastia,impotence and menstrual irregularities

79. EPLERENONE
Starting dose 25 mg daily increased to 50 mg daily if serum potassium < 5.0 mEq/L
If serum K+ is > 5.5 mEq/L then the dose must be decreased or discontinued
Specific warning in T2DM with hypertension and microalbuminuria because of the risk of hyperkalemia
Dose for hypertension ; mg once daily
Equally effective in white and black patients.

81. Trial data – aldosterone antagonists
Aldosterone antagonists (or mineralocorticoid receptor antagonists [MRAs]) are guideline-recommended therapy for patients with moderate to severe heart failure (HF) symptoms and reduced left ventricular ejection fraction (LVEF), and in postmyocardial infarction patients with HF.

82. Trial data RALES,TOPCAT ( spironolactone)
EPHESUS ; EMPHASIS-HF ; 4E ( eplerenone)
AREA IN CHF ( canrenone )

83. The Eplerenone in Mild Patients Hospitalization and Survival Study in Heart Failure (EMPHASIS-HF) 
Eplerenone reduced the risk of the primary endpoint of cardiovascular death or HF hospitalization (hazard ratio [HR] 0.63, 95% confidence interval [CI] , P < .001) and all-cause mortality (adjusted HR 0.76, 95% CI , P < .008) after a median of 21 months

84. The Randomized Aldactone Evaluation Study(RALES)
Eplerenone Post-Acute Myocardial Infarction Heart Failure Efficacy and Survival Study (EPHESUS) established that spironolactone and eplerenone, respectively, increased survival in patients with severe CHF symptoms from LV systolic dysfunction occurring with minimal exertion or at rest (New York Heart Association [NYHA] class III or IV) or CHF after an acute myocardial infarction

85. THE 4E STUDY
The 4E Study (Eplerenone,Enalapril, and Eplerenone/Enalapril Combination Therapy in Patients with Left Ventricular Hypertrophy) compared the effects of 9-month treatment with eplerenone 200 mg/d (n=64), enalapril 40 mg/d (n=71), or eplerenone 200 mg/d plus enalapril 10 mg/d (n= 67) on LV mass, systolic and diastolic blood pressures, and urinary albumin-creatinine ratio (UACR) in patients with mild-to-moderate hypertension and echocardiographic evidence of LVH.
Combination therapy with eplerenone and enalapril significantly reduced LV mass

86. Ongoing trial TOPCAT study (Treatment of Preserved Cardiac
Function Heart Failure With an Aldosterone
Antagonist)- is ongoing
At this time, however, there are insufficient clinical data to recommend the use of aldosterone antagonist therapy for the treatment of diastolic dysfunction.

87. Anti-remodelling effect of canrenone in patients with mild chronic heart failure (AREA IN-CHF study):
To test whether canrenone, an aldosterone receptor antagonist, improves left ventricular (LV) remodelling in NYHA class II heart failure (HF). Aldosterone receptor antagonists improve outcome in severe HF, but no information is available in NYHA class II.
Canrenone on top of optimal treatment for HF did not have additional effects on LVEDV, but it increased EF, and reduced left atrial size and circulating BNP, with potential beneficial effects on outcome

88. Direct renin inhibitors

89. DRI- Historical aspects
The concept of blocking the RAAS at its origin by inhibiting renin has existed for at least 50 years.
The first synthetic renin inhibitor was pepstatin, which was followed by first-generation agents that were active but required parenteral administration
Oral agents that were subsequently developed, such as enalkiren,remikiren, and zankiren, had limited clinical use because they demonstrated poor bioavailability (< 2%), short half-lives, and weak antihypertensive activity

90. Aliskiren
Aliskiren is the first synthetic non peptide direct renin inhibitor (DRI) to be approved by the U.S. Food and Drug Administration and the European Medicines Agency for treating hypertension in 2007.
Aliskiren binds to the active site (S1/S3 hydrophobic binding pocket) of renin, preventing the conversion of angiotensinogen to angiotensin I

91. Aliskiren Binding to Renin
Aliskiren bound to
Active site
Wood et al. BBRC 2003.

92. ALISKIREN named after ALICE HUXLEY

93. Aliskiren - pharmacokinetics
Direct renin inhibitor
50 – 80 % decrease plasma renin activity
Pharmacokinetics
Accumulation Half-life of ~ 24 hours
Oral bioavailability of 2.6%
7 – 8 days to achieve steady state levels
Elimination Half-life of ~ 48 hours
25 % excreted by kidneys
Metabolized by CYP 450-3A4
Does not induce or suppress CYP 450
No effect on QT interval

94. Aliskiren – pharmacokinetics
Pathway of elimination for aliskiren is via biliary excretion as unmetabolized drug.
Less than 1% of an orally administered dose is excreted in urine.
Not metabolized by, and does not induce or inhibit, cytochrome P450 enzymes and shows no clinically relevant pharmacokinetic interactions with warfarin, lovastatin, atenolol,celecoxib,cimetidine,amlodipine,valsartan,hydrochlorothiazide (HCTZ), or ramipril.
The pharmacokinetics of aliskiren remain unaffected by ethnicity, age, gender, hepatic impairment, renal impairment, and diabetes.

95. Drug interactions It reduces furosemide blood concentration.
Atorvastatin may increase blood concentration, but no dose adjustment is needed.
Due to possible interaction with ciclosporin, the concomitant use of ciclosporin and aliskiren is contraindicated.
Aliskiren is a minor substrate of CYP3A4 and, more important, P-glycoprotein
Caution should be exercised when aliskiren is administered with ketoconazole or other moderate P-gp inhibitors (itraconazole, clarithromycin, telithromycin, erythromycin, or amiodarone).
Doctors should stop prescribing aliskiren-containing medicines to patients with diabetes (type 1 or type 2) or with moderate to severe kidney impairment who are also taking an ACE inhibitor or ARB, and should consider alternative antihypertensive treatment as necessary

96. Adverse effects Angioedema
Hyperkalemia (particularly when used with ACE inhibitors in diabetic patients)
Hypotension (particularly in volume-depleted patients)
Diarrhea and other GI symptoms
Headache, Dizziness
Cough
Rash
Elevated uric acid, gout, and renal stones

97. Potential therapeutic roles of aliskiren
Monotherapy for hypertension
Component of combination therapy for hypertension, with a diuretic, a CCB, an ACEI, and/or an ARB
Alternative to ACEIs or ARBs in the management of hypertension and the prevention of organ damage
Alternative to ACEIs in patients with diabetic nephropathy or cardiovascular disease
Use in patients with diabetic nephropathy or in African American hypertensive patients, in whom intrarenal angiotensin II formation occurs via ACE or non–ACE-dependent pathways

98. ali

99. ATMOSPHERE (Efficacy and Safety of Aliskiren and Aliskiren/Enalapril Combination on Morbi-mortality in Patients With Chronic Heart Failure) study
Aliskiren is currently being evaluated in a phase III study that will evaluate the efficacy and safety of both aliskiren monotherapy and aliskiren-enalapril combination therapy as compared with enalapril monotherapy in regard to cardiovascular death and heart failure hospitalizations in NYHA Classes II to IV HF patients

101. Aldosterone antagonists

102. Role of aldosterone in CV disease
Direct correlation of aldosterone levels and mortality in heart failure
Increase in myocardial fibrosis
Inhibition of the release of NO
Increased incidence of arrhythmias
Increased response to vasoconstrictor doses of angiotensin I
Critical mediator of early angiotensin II induced experimental myocardial injury

103. Deleterious effects of aldosterone

104. Major outcome trials of RAAS inhibitors with favourable evidence
Trials in post MI HF
ACEI – SAVE (Captopril), AIRE (Ramipril ), TRACE (Trandolapril)
ARB – VALIANT (Valsartan )
Aldosterone antagonists ( EPHESUS)

105. Major outcome trials of RAAS inhibitors with favourable evidence
Trial in AMI – Early phase
GISSI – lisinopril.
Trials in cardiovascular risk prevention
ACEI : EUROPA (perindopril), HOPE( ramipril),
PEACE( trandolapril)
ARBs : ONTARGET ( Telmisartan)

106. New therapeutic pathways in ACE inhibition

107. Biased AT1 receptor blockade
A very novel development in the field of ARBs is the concept of “biased” AT1-receptor blockade.
Biased ARBs block AT1-receptor-coupled G-protein signalling in the “traditional” way, while simultaneously stimulating β-arrestin-coupled signalling which, for example, results in improved cardiac function.
TRV is the first biased ARB in clinical development and is currently being evaluated in a phase II clinical study for the treatment of heart failure.

108. AT1-receptor blockade combined with neutral endopeptidase inhibition
NEP is responsible for the degradation of atrial and brain natriuretic factor, which both have cardioprotective properties. Consequently, inhibition of NEP increases plasma levels of these protective molecules.
LCZ696, which may become the first in class ARNI (AT1-receptor and NEP inhibitor) lowered blood-pressure more effectively than valsartan monotherapy in a phase II clinical trial.
Phase III clinical trials are currently ongoing to test LCZ696 for the treatment of heart failure.
Outcomes of these studies and data about long-term safety (potential risks for obesity, Alzheimer’s disease and angioedema have been discussed) have to be awaited

109. Novel therapies
AT1-receptor blockade combined with endothelin A receptor blockade
RE-021 is a dual AT1-receptor and endothelin-A receptor (ETA) antagonist which was successfully taken through a phase IIb study in patients in hypertension . It has potential for use in FSGS
AT1-receptor blockade combined with nitric oxide (NO) release is in the pipeline

110. Novel therapies AT2 RECEPTOR AGONISTS
potential use in post-myocardial infarction (MI) cardiac function,hypertension-induced vascular remodelling, pulmonary hypertension), neurological (e.g. stroke, spinal cord injury, Alzheimer’s disease) and immunological (e.g. multiple sclerosis, rheumatoid arthritis) diseases
AT2 RECEPTOR ANTAGONISTS in post herpetic pain
ANGIOTENSIN 1-7 analogues and special formulations in hypertension, post-MI cardiac failure, metabolic syndrome, diabetes, renal disease and RA
Recombinant ACE2 and ACE2 formulations