Efficacy and safety of a fixed low-dose perindopril/indapamide combination in essential hypertension. A randomised controlled study

Angiotensin-converting enzyme inhibitor associated cough: deceptive information from the Physicians' Desk Reference

BACKGROUND

Dry cough is a common, annoying adverse effect of all angiotensin-converting enzyme (ACE) inhibitors. The present study was designed to compare the rate of coughs reported in the literature with reported rates in the Physicians' Desk Reference (PDR)/drug label.

METHODS

We searched MEDLINE/EMBASE/CENTRAL for articles published from 1990 to the present about randomized clinical trials (RCTs) of ACE inhibitors with a sample size of at least 100 patients in the ACE inhibitors arm with follow-up for at least 3 months and reporting the incidence or withdrawal rates due to cough. Baseline characteristics, cohort enrolled, metrics used to assess cough, incidence, and withdrawal rates due to cough were abstracted.

RESULTS

One hundred twenty-five studies that satisfied our inclusion criteria enrolled 198,130 patients. The pooled weighted incidence of cough for enalapril was 11.48% (95% confidence interval [CI], 9.54% to 13.41%), which was ninefold greater compared to the reported rate in the PDR/drug label (1.3%). The pooled weighted withdrawal rate due to cough for enalapril was 2.57% (95% CI, 2.40-2.74), which was 31-fold greater compared to the reported rate in the PDR/drug label (0.1%). The incidence of cough has increased progressively over the last 2 decades with accumulating data, but it has been reported consistently several-fold less in the PDR compared to the RCTs. The results were similar for most other ACE inhibitors.

CONCLUSION

The incidence of ACE inhibitor-associated cough and the withdrawal rate (the more objective metric) due to cough is significantly greater in the literature than reported in the PDR/drug label and is likely to be even greater in the real world when compared with the data from RCTs. There exists a gap between the data available from the literature and that which is presented to the consumers (prescribing physicians and patients).

Efficacy and safety profiles of a new S(-)-amlodipine nicotinate formulation versus racemic amlodipine besylate in adult Korean patients with mild to moderate hypertension: an 8-week, multicenter, randomized, double-blind, double-dummy, parallel-group, phase III, noninferiority clinical trial

BACKGROUND

"Chiral switching" from an existing racemate to a pure enantiomeric compound is a popular theme in drug development, especially when the enantiomer is found to have better efficacy and safety profiles. Amlodipine is a racemic mixture, composed of the S(-)-enantiomer, which is the pharmacologically active isomer, and the R(+)-enantiomer, which is 1000-fold less active. S(-)-amlodipine nicotinate, a chirally switched form of amlodipine nicotinate, has been developed and found to be bioequivalent to amlodipine besylate in Phase I clinical trials in Korea.

OBJECTIVE

The aim of this study was to compare the efficacy and safety profiles of S(-)-amlodipine nicotinate with those of amlodipine besylate in adult Korean patients with mild to moderate hypertension (diastolic blood pressure [DBP] >or=90 mm Hg and <or=109 mm Hg).

METHODS

This was an 8-week, multicenter, randomized, double-blind, double-dummy, parallel-group, Phase III, noninferiority clinical trial. After an initial 2-week placebo run-in period, patients aged 18 to 75 years with sitting DBP (SiDBP) >or=90 and <or=109 mm Hg at day 0 (baseline) were randomly allocated to receive S(-)-amlodipine nicotinate 2.5 mg QD or amlodipine besylate 5 mg QD for 8 weeks. The dose of study medication was doubled after 4 weeks in patients who had not responded to treatment (SiDBP >or=90 mm Hg). The primary end point was noninferiority of the difference in mean SiDBP from baseline to week 8 for S(-)-amlodipine nicotinate compared with amlodipine besylate. Secondary end points were as follows: (1) noninferiority of the difference in mean sitting systolic blood pressure (SiSBP) from baseline to week 8 between the study groups; and (2) SiDBP response rate (defined as the proportion of patients whose SiDBP was <90 mm Hg or whose SiDBP reduction was >or=10 mm Hg from baseline) after the 8-week treatment. Also, the incidence and severity of adverse events (AEs) and adverse drug reactions (ADRs) were reported. Severe AEs/ADRs were defined as those associated with any of the following: death; an event associated with a high risk of mortality; an event requiring hospitalization; or development of a permanent disability or congenital malformation.

RESULTS

One hundred fifty-seven patients were assessed for inclusion in the study. Of these, 124 patients were randomly allocated to receive S(-)-amlodipine nicotinate (42 men, 21 women; mean [SD] age, 52.4 [10.3] years [range, 23-70 years]; weight, 67.7 [10.8] kg [range, 44-92 kg]) or amlodipine besylate (45 men, 16 women; mean [SD] age, 54.5 [10.0] years [range, 30-73]; weight, 68.9 [9.8] kg [range, 49-95 kg]). One hundred sixteen patients completed the study, but 11 patients (8.9%) were dropped from the per-protocol analysis due to violations; therefore, 105 patients were included in the modified intent-to-treat population analysis (S[-]-amlodipine nicotinate, 55 patients; amlodipine besylate, 50 patients). There were no significant between-group differences in the baseline characteristics. Baseline mean (SD) SiSBP and SiDBP were 142.6 (11.3) and 94.9 (4.8) mm Hg in the S(-)-amlodipine nicotinate group, and 141.8 (8.3) and 96.1 (4.9) mm Hg in the amlodipine besylate group. Mean (SD) changes in SiSBP were 17.6 (11.2) mm Hg in the S(-)-amlodipine nicotinate group and 18.6 (12.3) mm Hg in the amlodipine besylate group. The SiDBP response rates were 92.7% in the S(-)-amlodipine nicotinate group and 88.0% in the amlodipine besylate group. There were no significant between-group differences in the prevalence of AEs and ADRs. In the S(-)-amlodipine nicotinate group, 15 patients (23.8%) reported a total of 28 AEs, and 19 patients (31.1%) reported a total of 27 AEs in the amlodipine besylate group. Six patients (9.5%) in the S(-)-amlodipine nicotinate group and 7 patients (11.4%) in the amlodipine besylate group experienced a total of 19 ADRs (11 and 8, respectively). The most common ADRs were liver enzyme elevation (3/63 [4.8%]) in the S(-)-amlodipine nicotinate group and facial flushing (3/61 [4.9%]) in the amlodipine besylate group. No cases of severe AEs or ADRs were reported in either group.

CONCLUSIONS

The reduction of SiDBP after 8 weeks of treatment with S(-)-amlodipine nicotinate was noninferior compared with that of racemic amlodipine besylate in these adult Korean patients with mild to moderate hypertension. The SiDBP response rate and the reduction of SiSBP after 8 weeks of treatment with S(-)-amlodipine nicotinate were not significantly different from those with racemic amlodipine besylate. Both treatments were generally well tolerated.

ADVANCE: lessons from the run-in phase of a large study in type 2 diabetes

BACKGROUND

ADVANCE is a major international trial assessing the effects of routine compared with more intensive blood pressure lowering and intensive glucose control on macrovascular and microvascular outcomes, among high-risk individuals with type 2 diabetes. We describe the experience of participants receiving active blood pressure lowering therapy during the run-in phase of the study, and the characteristics of participants who withdrew during this phase.

METHODS

All participants potentially eligible for inclusion in ADVANCE underwent 6 weeks of therapy with fixed low-dose perindopril 2 mg and indapamide 0.625 mg combination daily, as part of an active run-in phase of the study. This treatment was provided in addition to the participants' existing therapeutic regimen, including other blood pressure lowering drugs.

RESULTS

Of the 12 878 registered participants who entered the run-in phase, 11140 participants were randomized. Only 459 participants (3.6%) withdrew due to suspected intolerance of perindopril-indapamide. The mean blood pressure fell by an average of 8/3 mmHg from 145/81 mmHg (standard deviation 22/11 mmHg) to 137/78 (20/10). Participants who proceeded to randomization were broadly similar to those who withdrew during the run-in phase; however, some features suggest that those randomized were a higher risk group overall.

CONCLUSIONS

A substantial fall in blood pressure was observed following 6 weeks of treatment with a fixed low-dose combination of perindopril-indapamide in a broad range of high-risk individuals with type 2 diabetes. Good tolerability and safety of the study drug was confirmed during the active run-in phase of the ADVANCE study.

Choice of delta: requirements and reality--results of a systematic review

An essential problem in planning clinical non-inferiority or equivalence studies is the specification of the 'irrelevant difference' (irrelevance margin; delta). This quantifies the amount of non-inferiority or difference, respectively, between a new test therapy and an established standard treatment which is to be considered as tolerable. In the past, most recommendations and guidelines for clinical non-inferiority and equivalence studies contained only general statements and formulations concerning the specification of delta. The current unsatisfactory situation was the reason for performing a systematic review of published clinical non-inferiority and equivalence studies. It was the aim to gain an overview on the irrelevance margins used in such studies, and on reasons for choosing the particular margins. For the sake of comparability, the irrelevance margins were converted into standardized differences and odds ratios. Overall, there were 332 non-inferiority or equivalence trials obtained by means of an extensive literature search. The results of the systematic review show that current requirements on the choice of delta and the reality of recent clinical non-inferiority and equivalence trials differ substantially. In about one half of the trials a difference of 0.5 standard deviations or more was regarded as 'irrelevant' explicitly or implicitly. Estimates of standard-placebo differences formed the basis of the irrelevance margin in less than every tenth trial. Reasons for this very low proportion might be (1) the possibly resulting very small irrelevance margins, and (2) unsolved problems of the requirements themselves. Overall, it seems that a more global definition of 'irrelevance' might be warranted.

Diuretics in the therapy of hypertension

Antihypertensive monopharmacotherapy with diuretics renders blood pressure (BP) values under control in a large percentage of patients suffering from essential hypertension, and it reduces cardiovascular morbidity and mortality. Diuretics are effective in adult and elderly hypertensive subjects, independently of their race. Treatments with classic (high) doses of antihypertensive diuretics, such as 25 mg hydrochlorothiazide once daily, raise the activity of the RAA system, decrease plasma potassium and magnesium concentrations, and cause untoward changes in carbohydrate metabolism and in the plasma lipid profile. These changes appear to limit the positive response of cardiovascular prognosis to antihypertensive therapy with classic doses of diuretics. Lower doses of diuretics reduce high BP to the sought extent in many patients, and they do not elicit or cause only mild unfavourable neuroendocrine and metabolic changes. When a low dose of an antihypertensive diuretic substance is used as monopharmacotherapy, it may take 12-14 weeks after the initiation of treatment for BP to attain final stable values. The following low-dose oral formulations of diuretics constitute effective once-daily monopharmacotherapies for mild-to-moderate uncomplicated essential hypertension: bendrofluazide 1.25 mg, chlorthalidone 12.5 and 15 mg, cicletanine 50 mg, cyclopenthiazide 0.125 mg, HCTZ 12.5 mg, and torasemide 2.5 and 5 mg. These formulations are safer than classically used high-dose formulations such as hydrochlorothiazide 25 and 50 mg.

Dosage considerations with perindopril for systemic hypertension

Perindopril erbumine is a once-daily angiotensin-converting enzyme (ACE) inhibitor that effectively lowers systolic and diastolic blood pressure (BP) in patients with mild-to-moderate hypertension. Converted from the prodrug ester perindopril, the active diacid perindoprilat is distributed rapidly and extensively, primarily to tissues with high ACE activity. Its ability to lower BP is comparable to or better than that of other antihypertensive agents, both of its own class and other classes, and its trough-peak ratio is consistently between 75% and 100%, translating into 24 hours of true efficacy per dose. First-dose hypotension caused by an initial acute BP depression occurs less frequently with perindopril than with other ACE inhibitors, an advantage in volume-contracted patients and those whose BP is angiotensin II dependent, such as patients with congestive heart failure. A missed-dose study showed that most of the antihypertensive effect of perindopril remains for 24 to 48 hours after dosing, a characteristic that confers protection to patients who miss a dose. Perindopril improves the distensibility and compliance of large and small arteries, which are compromised in hypertension, and can effect vascular remodeling by a mechanism independent of BP lowering. The clinical implications of these effects are being investigated in large trials. Perindopril is well tolerated in the elderly, and combination therapy with a diuretic was shown to yield significant additional BP reduction. Perindoprilat is cleared renally; dosage should be adjusted in patients with renal impairment.