European Heart Journal Supplements (2004) 6 (Supplement H), H55–H60 Importance of CHARM in relation to other heart failure trials with ARBs Christopher B. Granger* Duke University Medical Center, Durham, NC 27705, USA KEYWORDS AT1 -receptor blockers; Candesartan; Clinical trials; Drug therapy; Heart failure; Valsartan The clinical need for improved heart-failure therapies In spite of use of proven therapies, chronic heart failure continues to be one of the most important causes of death and disability worldwide. Large randomized clinical trials have established life-saving benefits of angiotensin-converting-enzyme (ACE) inhibitors 1,2 , b-blockers 3–5 , and spironolactone (for patients with * Correspondence: Christopher B Granger MD FACC. Duke University Medical Center, 2400 Pratt Street, Durham, NC 27705, USA. Tel.: +1-919668-8736 fax: +1-919-668-7056. E-mail address: [email protected] 0169-5002/$ – see front matter severe heart failure) 6 . ACE inhibitors are especially impressive in the breadth of evidence of benefit, with demonstration of survival benefits for patients following acute myocardial infarction 7 , for secondary prevention of vascular disease events 8 , and in all stages of chronic heart failure 1,2,9 . Their particular benefits in patients with diabetes, including protection against renal dysfunction 10 , are important since diabetes and heart failure commonly occur together and their combination can be a lethal one. B-blockers have shown impressive additional benefit when added to ACE inhibitors, with 34–35% relative risk reductions in death with bisoprolol 3 , extended-release metoprolol 4 , and carvedilol 5 . Other b-blockers, however, do not © 2004 The European Society of Cardiology. Published by Elsevier Ltd. All rights reserved. Downloaded from by guest on November 12, 2014 Angiotensin-converting-enzyme (ACE) inhibitors, b-blockers, and spironolactone (for patients with severe heart failure) have substantially improved survival in chronic heart failure. Because angiotensin-receptor blockers (ARBs) provide specific and potent inhibition of the angiotensin type-1 receptor, there has been hope that they might extend the benefits of ACE inhibitors. ELITE-II found no benefit with losartan 50 mg a day compared with captopril. In retrospect, losartan may have been less effective than other ARBs or under-dosed. In Val-HeFT, valsartan 160 mg twice daily was beneficial in a population where 93% were on an ACE inhibitor, although subgroup analysis led to speculation that this benefit was largely restricted to patients not on ACE inhibitors and that addition of valsartan may have been harmful in patients treated with both ACE inhibitors and b-blockers. However, no such safety concern with valsartan plus b-blockers was found in the subsequent VALIANT trial. CHARM directly addressed the major questions raised by Val-HeFT. In CHARM, candesartan titrated to 32 mg a day reduced mortality and morbidity both in patients who were receiving ACE inhibitors and in those intolerant to ACE inhibitors. There was also substantial benefit in adding candesartan to the combination of ACE inhibitors and b-blockers. Among patients with low ejection fraction, candesartan resulted in highly significant reductions in cardiovascular death and heart-failure hospitalization, and in all-cause mortality. Thus, in patients with low ejection fraction, candesartan improves survival, regardless of background therapy. Candesartan should now be considered as another important treatment to further improve outcome in patients with chronic heart failure. © 2004 The European Society of Cardiology. Published by Elsevier Ltd. All rights reserved. H56 C.B. Granger Fig. 1. Morbidity and mortality in the Val-HeFT trial. Reproduced with permission from Cohn et al. 2001 16 ; copyright © 2001 Massachusetts Medical Society. All rights reserved. Previous trials of ARBs How do ARBs compare to ACE inhibitors? The promise of ARBs in chronic heart failure was fuelled by the Evaluation of Losartan in the Elderly (ELITE) trial 13 , which randomized 722 patients who were >65 years old to losartan 50 mg a day or captopril 50– mg three times a day. The primary objective was to assess effects on renal function, and the drugs resulted in similar rates of renal dysfunction. However, there was a 46% relative risk reduction in death at 48 weeks with losartan, which reached statistical significance. Given the known unreliability of small trials to estimate effects on mortality, it should not have been surprising that this represented an extreme finding. The first large trial of an ARB in heart failure was the ELITE-II trial 14 , which was designed to replicate the first ELITE trial but powered to assess effect on mortality. The trial enrolled 3152 elderly patients with chronic heart failure, and there was no impact on mortality – in fact, the mortality was slightly higher with losartan (odds ratio (OR) 1.13, 95.7% confidence interval (CI) 0.95–1.35, p = 0.16). In retrospect, whether the results were because losartan was underdosed or because captopril is in fact at least as good as losartan remains unknown. Do ARBs add to ACE inhibitors and other proven treatments? Because ACE inhibitors may have important benefits beyond the effects on angiotensin II, including enhancing bradykinin effects, there is a rationale for combining ACE inhibitors and ARBs. The RESOLVD trial showed that the combination of candesartan and enalapril had a greater impact on limiting remodelling over 43 weeks, as assessed by change in left-ventricular end-diastolic volume 15 . The combination caused greater reductions in both aldosterone and B-type natriuretic peptide than did monotherapy. The Val-HeFT trial was designed to address whether valsartan 160 mg twice daily would improve outcome when added to contemporary treatments for heart failure including ACE inhibitors 16 . 93% of patients were on an ACE inhibitor, and 35% were on a b-blocker. Valsartan caused a significant ( p = 0.009) 13% relative risk reduction in mortality and morbidity, a co-primary endpoint of the trial (Fig. 1). The absolute reduction was 3.3%, and hospitalization for heart failure was reduced from 18.2% to 13.8%, a highly significant (p < 0.001) reduction. Quality of life measures were also improved with valsartan. All-cause mortality, a co-primary endpoint, was not affected (OR: 1.02, 95% CI: 0.88–1.18). Subgroup analysis led to speculation that the benefit of valsartan was largely restricted to patients not on ACE inhibitors, where the benefit was large. Only 366 patients were in this group, however. Of concern, post-hoc subgroup analyses showed a 42% increase in odds of death by adding valsartan among patients treated with both b-blockers and ACE inhibitors. This led to the hypothesis that “triple neurohormonal blockade” should be avoided. Alternatively, it was recognized that this may have been yet another example of subgroup analyses providing misleading results due to the play of chance. CHARM provides answers to questions raised by Val-HeFT The CHARM trial was able to address questions raised by prior trials about the role of ARBs in heart failure. Downloaded from by guest on November 12, 2014 appear to have the same degree of benefit 11,12 , emphasizing the importance of using proven drugs in proven doses rather than assuming “class effects”. Because angiotensin-receptor blockers (ARBs) have the theoretic advantage over ACE inhibitors of specific, potent and sustained inhibition of the angiotensin II type-1 receptor, there has been hope that they might extend the clinical benefits observed with ACE inhibitors. Moreover, a substantial portion of patients have ACE inhibitors discontinued because of intolerance, and many of those patients might tolerate an angiotensinreceptor blocker. Importance of CHARM in relation to other heart failure trials with ARBs H57 Fig. 2. Cardiovascular death or hospitalization for heart failure in CHARM-Alternative. Reproduced from Granger et al. 2003 18 with permission from Elsevier. CHARM was designed to assess the role of candesartan in the broad population of patients with symptomatic heart failure, including patients with low left-ventricular ejection fraction (LVEF 40%) not on an ACE inhibitor due to intolerance (CHARM-Alternative), patients with low LVEF on ACE-inhibitor therapy (CHARM-Added), and patients with preserved LV function (CHARMPreserved) 17 . CHARM was different from prior trials in that the majority of patients were on b-blockers, and thus the trial was well powered to address whether there would be risk in using triple therapy. A substantial proportion – 20% of patients with low LVEF – were also on spironolactone. CHARM-Alternative: Does candesartan improve outcome in chronic heart failure? In CHARM-Alternative 18 , candesartan titrated to 32 mg a day significantly reduced cardiovascular mortality and heart-failure hospitalization among patients intolerant to ACE inhibitors by 23% (Fig. 2), an effect in the same order of magnitude as that seen with ACE inhibitors in the SOLVD trial. In the first year, the 37% mortality reduction in CHARM 19 was of at least the same order of magnitude as the 1-year mortality reduction in the SOLVD treatment trial (23%; Fig. 3). Importantly, the effect in CHARM was in a population in which the majority were also on a b-blocker. Thus, CHARM has shown that ARBs, and specifically candesartan, are highly effective at improving outcome in heart failure among patients who do not tolerate ACE inhibitors. CHARM-Added: does candesartan provide added benefit on top of ACE inhibitors and b-blockers? In CHARM-Added 20 , candesartan was added to doses of background ACE inhibitors that were similar to those shown to be effective in clinical trials; for example, the average dose of enalapril in CHARM was 17 mg a day, similar to the 16 mg a day average in the SOLVD trial. Most patients (55% at baseline, 66% at trial completion) were also on b-blockers. In this well-treated population with chronic heart failure, candesartan provided additional benefit, with a 15% relative risk reduction ( p = 0.011) in cardiovascular death and heart-failure hospitalization over the three years of the trial (Fig. 4). The effect at 1 year was even more significant, showing a 28% relative reduction in all-cause mortality. There was no safety concern – on the contrary, there was substantial benefit – in adding candesartan to ACE inhibitors and b-blockers. Among patients on ACE inhibitors, the benefit of candesartan appeared to be at least as great in patients on baseline b-blockers as in those not on b-blockers. Downloaded from by guest on November 12, 2014 Fig. 3. 1-year mortality in CHARM-Alternative 18 and the SOLVD Treatment trial 2 . H58 C.B. Granger Fig. 4. Cardiovascular death or hospitalization for heart failure in CHARM-Added. Reproduced from McMurray et al. 2003 20 with permission from Elsevier. Effect of candesartan in patients with low LV ejection fraction In CHARM, candesartan resulted in highly significant reductions in cardiovascular death and heart-failure hospitalization, and also significantly ( p = 0.018) reduced (12% relative risk reduction) all-cause mortality among all patients with low LV ejection fraction 22 . Other benefits of candesartan As with valsartan in Val-HeFT, candesartan was found to improve functional status in CHARM, with significant improvements in NYHA class overall and in each of the three component trials 23 . Candesartan was also found to prevent the onset of diabetes, with an odds ratio of 0.78 ( p = 0.02). How to view VALIANT results in context of CHARM The VALIANT trial studied a different patient population than CHARM, namely patients with left-ventricular dysfunction and/or heart failure in the days following acute myocardial infarction 24 . The results are generally consistent with CHARM: valsartan 160 mg twice a day provided a similar survival benefit to captopril 50 mg three times a day, and there was no safety concern with the combination of valsartan and a b-blocker. In VALIANT, however, the combination of valsartan and captopril, with titration of valsartan to half the dose combined with full-dose captopril, was not better than either monotherapy, and resulted in more adverse effects. Whether this was due to differences in the patient populations or the dosing regimens is unclear. The postacute myocardial infarction population is quite different, with a minority of these patients developing chronic heart failure. Thus, the direct comparability of CHARM and VALIANT is limited. The large trials of ARBs suggest that there is heterogeneity in the clinical effects of different ARBs at different doses, such that losartan at 50 mg a day tended to be worse than captopril in both ELITE-II 14 and OPTIMAAL 25 . Thus, clinicians should generally use the drug and the dose proven to be effective in large clinical trials, in order to have the most confidence of achieving clinical benefit. How to manage chronic heart failure patients in light of recent trials The incremental benefit of adding effective treatments for chronic heart failure can make a large impact on heart-failure morbidity and mortality. To make major improvements in patient outcome demands systematic approaches to use a “cocktail” of drugs that when combined can reduce mortality by over 50%, as well as improving quality of life. The challenge is that these treatments can be costly and complex to titrate and monitor. In patients with low ejection fraction, the foundation of therapy to improve morbidity and mortality remains ACE inhibitors (and ARB for ACE-inhibitor intolerance) and b-blockers, with ARBs being added for patients with continued symptoms and low ejection fraction, with attempts to achieve target dose and monitoring of electrolytes (Fig. 5). For patients with more severe heart failure, spironolactone should be added, and digoxin can provide important improvements in quality of life 26 . Conclusion In summary, a series of clinical trials, culminating in CHARM, have established that ARBs can provide Downloaded from by guest on November 12, 2014 As would be expected for any inhibitor of the renin–angiotensin–aldosterone system, candesartan did result in excess renal insufficiency and hyperkalaemia. Therefore, monitoring of electrolytes during initiation and titration of candesartan is important. In CHARM, investigators were asked to monitor electrolytes with each dose titration, which is a prudent approach. The excess of clinically relevant hyperkalaemia that has occurred with the adoption of spironolactone for heart failure in practice 21 reinforces the need to monitor patients when using any renin–angiotensin–aldosterone antagonist. Importance of CHARM in relation to other heart failure trials with ARBs H59 Fig. 5. Approaches to the patient with heart failure: implications from recent trials. References 1. The CONSENSUS Trial Study Group. 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