Higher Dose of Merck's Cozaar (losartan potassium tablets) Significantly Reduced Deaths and Hospitalizations Due to Heart Failure In Investigational Study

Results from HEAAL Study Presented as Late-Breaker at American Heart Association Scientific Sessions 2009

 

ORLANDO, Fla.--(BUSINESS WIRE)--Nov 17, 2009 - In an investigational study, Merck's medicine COZAAR (losartan potassium tablets) 150 mg, administered once daily, significantly reduced the risk of all-cause death or hospitalization due to heart failure compared to a lower 50 mg once daily dose of COZAAR. The Merck-sponsored study compared the safety and efficacy of two doses of COZAAR® in patients with chronic heart failure and reduced cardiac function (left ventricular ejection fraction) who were intolerant of angiotensin-converting enzyme (ACE) inhibitors. The results of the study, called HEAAL -- Heart failure Endpoint evaluation of the A-II-Antagonist Losartan -- were presented by researchers during a late breaking clinical trial session at the American Heart Association (AHA) Scientific Sessions 2009.

COZAAR is not indicated in the U.S. for the treatment of patients with chronic heart failure and is not approved for use, for any indication, at the 150 mg dose used in the HEAAL study. COZAAR is an angiotensin II antagonist (AIIA), cardiovascular medicine approved for three indications:

 

  • for the treatment of hypertension and may be used alone or in combination with other antihypertensive agents, including diruetics.
  • to reduce the risk of stroke in patients with hypertension and left ventricular hypertrophy, although there is evidence that this benefit does not apply to black patients.
  • for the treatment of diabetic nephropathy with an elevated serum creatinine and proteinuria (urinary albumin to creatinine ratio ‰¥300 mg/g) in patients with type 2 diabetes and a history of hypertension. In this population, COZAAR reduces the rate of progression of nephropathy as measured by the occurrence of doubling of serum creatinine or end stage renal disease (need for dialysis or renal transplantation).

“HEAAL is the first study to examine and document the incremental benefit on clinical outcomes of prescribing a higher dose of an angiotensin II antagonist in patients with heart failure," said lead study investigator Marvin A. Konstam, M.D., Chief Physician Executive, the Cardiovascular Center, Tufts Medical Center, and Professor of Medicine, Tufts University School of Medicine.

"HEAAL is another important study in a long-line of large outcomes studies that Merck has sponsored and conducted to help the medical community to better understand the role of our cardiovascular medicines in improving cardiovascular outcomes," said Francis Plat, M.D., Vice President and clinical therapeutic area head for Atherosclerosis and Cardiovascular, Merck Research Laboratories. "Like SOLV-D, 4S, LIFE and RENAAL, this study, too, advances our understanding of the role that pharmaceutical innovations can have and answers an important outstanding question as only a clinical outcomes trial can."

About the HEAAL Study

Study results demonstrated COZAAR administered in a 150 mg once daily dose, when compared with COZAAR 50 mg per day, significantly reduced the risk of the primary composite endpoint (all cause death or hospitalization for heart failure) in patients with reduced left ventricular ejection fraction (LVEF); and reduced ACE inhibitor intolerance (p=0.027).

The multicenter, prospective, randomized, double-blind, event-driven clinical trial enrolled 3,834 patients with symptomatic congestive heart failure intolerant of ACE inhibitor treatment at 255 sites in 30 countries. Patients were randomized to two treatment arms: COZAAR 150 mg once daily (n=1,921) and COZAAR 50 mg once daily (n=1,913). Among these patients, 3,723 completed endpoint follow-up with a median follow-up time of 4.7 years. Prior to randomization, patients not already receiving an AIIA were titrated onto losartan from 12.5 mg daily to 25 mg daily over two weeks. For patients already receiving an AIIA, their prescription was discontinued, and investigators had the option of initiating open-label losartan 25 mg daily for one week or directly randomizing the patient.

The primary composite endpoint of the HEAAL study was all cause death or hospitalization for heart failure and the secondary composite endpoint was all cause death or cardiovascular hospitalization. Secondary symptom assessments, including an increase in LVEF and changes in New York Heart Association (NYHA) classification, were also completed.

Patients in the COZAAR 150 mg treatment group had a significantly lower risk of hospitalization due to heart failure or cardiovascular hospitalization compared to patients in the 50 mg treatment group. 450 patients in the COZAAR 150 mg treatment group (6.0 per 100 patient-years of follow-up) were hospitalized for heart failure during the course of the study compared to 503 patients in the 50 mg treatment group (7.0 per 100 patient-years of follow-up) (p=0.025).

Renal impairment, hyperkalameia (p<0.001), ,hypotension (p=0.002) and angioedema (p=0.03) as defined by the investigator were more common in the COZAAR 150 mg group than in the 50 mg treatment arm. Renal impairment was the adverse event which most commonly lead to drug discontinuation in the two groups (0.65 and 0.49 per 100 patient years respectively) but the number (and rate) of individual or total discontinuations were similar for the two treatment groups.

Additional important information about COZAAR

When used in pregnancy during the second or third trimesters, drugs that act directly on the renin-angiotensin system can cause injury and even death to the developing fetus. When pregnancy is detected, COZAAR should be discontinued as soon as possible.

COZAAR is contraindicated in patients who are hypersensitive to any component of these products. All patients receiving thiazides should be observed for clinical signs of fluid or electrolyte imbalance, including hypokalemia.

In patients who are volume-depleted, symptomatic hypotension may occur after initiation of therapy with COZAAR. This condition should be corrected prior to administration of COZAAR, or a dosage of COZAAR 25 mg should be used. As with other drugs that block angiotensin II or its effects, concomitant use of potassium-sparing diuretics, potassium supplements, or salt substitutes containing potassium may lead to increases in serum potassium.

In clinical trials with COZAAR for hypertension, the most common adverse events with an incidence greater or equal to two percent of patients treated with COZAAR (n=1,075) and occurring more commonly than placebo (n=334) included upper respiratory infection (8 percent for COZAAR vs. 7 percent for placebo), dizziness (3 percent for COZAAR vs. 2 percent for placebo), nasal congestion (2 percent for COZAAR vs. 1 percent for placebo), and back pain (2 percent for COZAAR vs. 1 percent for placebo).

Dosing and administration

In patients with hypertension, the usual starting dose is COZAAR 50 mg once daily. The maximum daily dose is 100 mg. If the antihypertensive effect measured at trough using once-a-day dosing is inadequate, a twice-a-day regimen at the same total daily dose or an increase in dose may give a more satisfactory response. In patients who are volume-depleted, symptomatic hypotension may occur after initiation of therapy with COZAAR. This condition should be corrected prior to administration of COZAAR, or a dosage of COZAAR 25 mg should be used. In patients with a history of hepatic impairment, a starting dose of COZAAR 25 mg should be used. In hypertensive patients with left ventricular hypertrophy, treatment should be initiated with COZAAR 50 mg once daily.

About Merck

Today's Merck is working to help the world be well. Through our medicines, vaccines, biologic therapies, and consumer and animal products, we work with customers and operate in more than 140 countries to deliver innovative health solutions. We also demonstrate our commitment to increasing access to healthcare through far-reaching programs that donate and deliver our products to the people who need them. Merck. Be Well. For more information, visit www.merck.com.

Forward Looking Statement

This news release includes “forward-looking statements” within the meaning of the safe harbor provisions of the United States Private Securities Litigation Reform Act of 1995. Such statements may include, but are not limited to, statements about the benefits of the proposed merger between Merck and Schering-Plough, including future financial and operating results, the combined company's plans, objectives, expectations and intentions and other statements that are not historical facts. Such statements are based upon the current beliefs and expectations of Merck's and Schering-Plough's management and are subject to significant risks and uncertainties. Actual results may differ from those set forth in the forward-looking statements.

The following factors, among others, could cause actual results to differ from those set forth in the forward-looking statements: the possibility that the expected synergies from the merger of Merck and Schering-Plough will not be realized, or will not be realized within the expected time period, due to, among other things, the impact of pharmaceutical industry regulation and pending legislation that could affect the pharmaceutical industry; the risk that the businesses will not be integrated successfully; disruption from the merger making it more difficult to maintain business and operational relationships; Merck's ability to accurately predict future market conditions; dependence on the effectiveness of Merck's patents and other protections for innovative products; the risk of new and changing regulation and health policies in the U.S. and internationally and the exposure to litigation and/or regulatory actions.

Merck undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in Merck's 2008 Annual Report on Form 10-K, Schering-Plough's Quarterly Report on Form 10-Q for the quarterly period ended Sept. 30, 2009, the proxy statement filed by Merck on June 25, 2009 and each company's other filings with the Securities and Exchange Commission (SEC) available at the SEC's Internet site (www.sec.gov).

Prescribing Information and Patient Product Information for COZAAR® are attached.

MERCK & CO, INC.

Whitehouse Station, NJ 08889, USA

9862833

COZAAR®

(LOSARTAN POTASSIUM TABLETS)

 
USE IN PREGNANCY

 

When used in pregnancy during the second and third trimesters, drugs that act directly on the renin-angiotensin system can cause injury and even death to the developing fetus. When pregnancy is detected, COZAAR should be discontinued as soon as possible. See WARNINGS, Fetal/Neonatal Morbidity and Mortality.

 

 

DESCRIPTION

COZAAR* (losartan potassium) is an angiotensin II receptor (type AT1) antagonist. Losartan potassium, a non-peptide molecule, is chemically described as 2-butyl-4-chloro-1-[p-(o-1H-tetrazol-5-ylphenyl)benzyl]imidazole-5-methanol monopotassium salt.

Its empirical formula is C22H22ClKN6O, and its structural formula is:

(Graphic Omitted)

Losartan potassium is a white to off-white free-flowing crystalline powder with a molecular weight of 461.01. It is freely soluble in water, soluble in alcohols, and slightly soluble in common organic solvents, such as acetonitrile and methyl ethyl ketone. Oxidation of the 5-hydroxymethyl group on the imidazole ring results in the active metabolite of losartan.

COZAAR is available as tablets for oral administration containing either 25 mg, 50 mg or 100 mg of losartan potassium and the following inactive ingredients: microcrystalline cellulose, lactose hydrous, pregelatinized starch, magnesium stearate, hydroxypropyl cellulose, hypromellose, titanium dioxide, D&C yellow No. 10 aluminum lake and FD&C blue No. 2 aluminum lake.

COZAAR 25 mg, 50 mg and 100 mg tablets contain potassium in the following amounts: 2.12 mg (0.054 mEq), 4.24 mg (0.108 mEq) and 8.48 mg (0.216 mEq), respectively. COZAAR 25 mg, COZAAR 50 mg, and COZAAR 100 mg may also contain carnauba wax.

CLINICAL PHARMACOLOGY

Mechanism of Action

Angiotensin II [formed from angiotensin I in a reaction catalyzed by angiotensin converting enzyme (ACE, kininase II)], is a potent vasoconstrictor, the primary vasoactive hormone of the renin-angiotensin system and an important component in the pathophysiology of hypertension. It also stimulates aldosterone secretion by the adrenal cortex. Losartan and its principal active metabolite block the vasoconstrictor and aldosterone-secreting effects of angiotensin II by selectively blocking the binding of angiotensin II to the AT1 receptor found in many tissues, (e.g., vascular smooth muscle, adrenal gland). There is also an AT2 receptor found in many tissues but it is not known to be associated with cardiovascular homeostasis. Both losartan and its principal active metabolite do not exhibit any partial agonist activity at the AT1 receptor and have much greater affinity (about 1000-fold) for the AT1 receptor than for the AT2 receptor. In vitro binding studies indicate that losartan is a reversible, competitive inhibitor of the AT1 receptor. The active metabolite is 10 to 40 times more potent by weight than losartan and appears to be a reversible, non-competitive inhibitor of the AT1 receptor.

Neither losartan nor its active metabolite inhibits ACE (kininase II, the enzyme that converts angiotensin I to angiotensin II and degrades bradykinin); nor do they bind to or block other hormone receptors or ion channels known to be important in cardiovascular regulation.

Pharmacokinetics

General

Losartan is an orally active agent that undergoes substantial first-pass metabolism by cytochrome P450 enzymes. It is converted, in part, to an active carboxylic acid metabolite that is responsible for most of the angiotensin II receptor antagonism that follows losartan treatment. Losartan metabolites have been identified in human plasma and urine. In addition to the active carboxylic acid metabolite, several inactive metabolites are formed. Following oral and intravenous administration of 14C-labeled losartan potassium, circulating plasma radioactivity is primarily attributed to losartan and its active metabolite. In vitro studies indicate that cytochrome P450 2C9 and 3A4 are involved in the biotransformation of losartan to its metabolites. Minimal conversion of losartan to the active metabolite (less than 1% of the dose compared to 14% of the dose in normal subjects) was seen in about one percent of individuals studied.

The terminal half-life of losartan is about 2 hours and of the metabolite is about 6-9 hours.

The pharmacokinetics of losartan and its active metabolite are linear with oral losartan doses up to 200 mg and do not change over time. Neither losartan nor its metabolite accumulate in plasma upon repeated once-daily dosing.

Following oral administration, losartan is well absorbed (based on absorption of radiolabeled losartan) and undergoes substantial first-pass metabolism; the systemic bioavailability of losartan is approximately 33%. About 14% of an orally-administered dose of losartan is converted to the active metabolite. Mean peak concentrations of losartan and its active metabolite are reached in 1 hour and in 3-4 hours, respectively. While maximum plasma concentrations of losartan and its active metabolite are approximately equal, the AUC of the metabolite is about 4 times as great as that of losartan. A meal slows absorption of losartan and decreases its Cmax but has only minor effects on losartan AUC or on the AUC of the metabolite (about 10% decreased).

The pharmacokinetics of losartan and its active metabolite were also determined after IV doses of each component separately in healthy volunteers. The volume of distribution of losartan and the active metabolite is about 34 liters and 12 liters, respectively. Total plasma clearance of losartan and the active metabolite is about 600 mL/min and 50 mL/min, respectively, with renal clearance of about 75 mL/min and 25 mL/min, respectively. After single doses of losartan administered orally, about 4% of the dose is excreted unchanged in the urine and about 6% is excreted in urine as active metabolite. Biliary excretion contributes to the elimination of losartan and its metabolites. Following oral 14C-labeled losartan, about 35% of radioactivity is recovered in the urine and about 60% in the feces. Following an intravenous dose of 14C-labeled losartan, about 45% of radioactivity is recovered in the urine and 50% in the feces.

Both losartan and its active metabolite are highly bound to plasma proteins, primarily albumin, with plasma free fractions of 1.3% and 0.2%, respectively. Plasma protein binding is constant over the concentration range achieved with recommended doses. Studies in rats indicate that losartan crosses the blood-brain barrier poorly, if at all.

Special Populations

Pediatric: Pharmacokinetic parameters after multiple doses of losartan (average dose 0.7 mg/kg, range 0.36 to 0.97 mg/kg) as a tablet to 25 hypertensive patients aged 6 to 16 years are shown in Table 1 below. Pharmacokinetics of losartan and its active metabolite were generally similar across the studied age groups and similar to historical pharmacokinetic data in adults. The principal pharmacokinetic parameters in adults and children are shown in the table below.

Table 1 Pharmacokinetic Parameters in Hypertensive Adults and Children Age 6-16 Following Multiple Dosing

 

 
    Adults given 50 mg once daily for 7 days N=12

 

  Age 6-16 given 0.7 mg/kg once daily for 7 days N=25

 

    Parent   Active Metabolite   Parent   Active Metabolite
AUC0-24a (ngh/mL)   442 ± 173   1685 ± 452   368 ± 169   1866 ± 1076
CMAX (ng/mL)a   224 ± 82   212 ± 73   141 ± 88   222 ± 127
T1/2 (h) b   2.1 ± 0.70   7.4 ± 2.4   2.3 ± 0.8   5.6 ± 1.2
TPEAK (h) c   0.9   3.5   2.0   4.1
CLREN (mL/min)a   56 ± 23   20 ± 3   53 ± 33   17 ± 8
 
a Mean ± standard deviation

 

b Harmonic mean and standard deviation

 

c Median

 

The bioavailability of the suspension formulation was compared with losartan tablets in healthy adults. The suspension and tablet are similar in their bioavailability with respect to both losartan and the active metabolite (see DOSAGE AND ADMINISTRATION, Preparation of Suspension).

Geriatric and Gender: Losartan pharmacokinetics have been investigated in the elderly (65-75 years) and in both genders. Plasma concentrations of losartan and its active metabolite are similar in elderly and young hypertensives. Plasma concentrations of losartan were about twice as high in female hypertensives as male hypertensives, but concentrations of the active metabolite were similar in males and females. No dosage adjustment is necessary (see DOSAGE AND ADMINISTRATION).

Race: Pharmacokinetic differences due to race have not been studied (see also PRECAUTIONS, Race and CLINICAL PHARMACOLOGY, Pharmacodynamics and Clinical Effects, Reduction in the Risk of Stroke, Race).

Renal Insufficiency: Following oral administration, plasma concentrations and AUCs of losartan and its active metabolite are increased by 50-90% in patients with mild (creatinine clearance of 50 to 74 mL/min) or moderate (creatinine clearance 30 to 49 mL/min) renal insufficiency. In this study, renal clearance was reduced by 55-85% for both losartan and its active metabolite in patients with mild or moderate renal insufficiency. Neither losartan nor its active metabolite can be removed by hemodialysis. No dosage adjustment is necessary for patients with renal impairment unless they are volume-depleted (see WARNINGS, Hypotension  Volume-Depleted Patients and DOSAGE AND ADMINISTRATION).

Hepatic Insufficiency: Following oral administration in patients with mild to moderate alcoholic cirrhosis of the liver, plasma concentrations of losartan and its active metabolite were, respectively, 5-times and about 1.7-times those in young male volunteers. Compared to normal subjects the total plasma clearance of losartan in patients with hepatic insufficiency was about 50% lower and the oral bioavailability was about 2-times higher. A lower starting dose is recommended for patients with a history of hepatic impairment (see DOSAGE AND ADMINISTRATION).

Drug Interactions

Losartan, administered for 12 days, did not affect the pharmacokinetics or pharmacodynamics of a single dose of warfarin. Losartan did not affect the pharmacokinetics of oral or intravenous digoxin. There is no pharmacokinetic interaction between losartan and hydrochlorothiazide. Coadministration of losartan and cimetidine led to an increase of about 18% in AUC of losartan but did not affect the pharmacokinetics of its active metabolite. Coadministration of losartan and phenobarbital led to a reduction of about 20% in the AUC of losartan and that of its active metabolite. A somewhat greater interaction (approximately 40% reduction in the AUC of active metabolite and approximately 30% reduction in the AUC of losartan) has been reported with rifampin. Fluconazole, an inhibitor of cytochrome P450 2C9, decreased the AUC of the active metabolite by approximately 40%, but increased the AUC of losartan by approximately 70% following multiple doses. Conversion of losartan to its active metabolite after intravenous administration is not affected by ketoconazole, an inhibitor of P450 3A4. The AUC of active metabolite following oral losartan was not affected by erythromycin, another inhibitor of P450 3A4, but the AUC of losartan was increased by 30%.

Pharmacodynamics and Clinical Effects

Adult Hypertension

Losartan inhibits the pressor effect of angiotensin II (as well as angiotensin I) infusions. A dose of 100 mg inhibits the pressor effect by about 85% at peak with 25-40% inhibition persisting for 24 hours. Removal of the negative feedback of angiotensin II causes a 2- to 3-fold rise in plasma renin activity and consequent rise in angiotensin II plasma concentration in hypertensive patients. Losartan does not affect the response to bradykinin, whereas ACE inhibitors increase the response to bradykinin. Aldosterone plasma concentrations fall following losartan administration. In spite of the effect of losartan on aldosterone secretion, very little effect on serum potassium was observed.

In a single-dose study in normal volunteers, losartan had no effects on glomerular filtration rate, renal plasma flow or filtration fraction. In multiple-dose studies in hypertensive patients, there were no notable effects on systemic or renal prostaglandin concentrations, fasting triglycerides, total cholesterol or HDL-cholesterol or fasting glucose concentrations. There was a small uricosuric effect leading to a minimal decrease in serum uric acid (mean decrease <0.4 mg/dL) during chronic oral administration.

The antihypertensive effects of COZAAR were demonstrated principally in 4 placebo-controlled, 6- to 12-week trials of dosages from 10 to 150 mg per day in patients with baseline diastolic blood pressures of 95-115. The studies allowed comparisons of two doses (50-100 mg/day) as once-daily or twice-daily regimens, comparisons of peak and trough effects, and comparisons of response by gender, age, and race. Three additional studies examined the antihypertensive effects of losartan and hydrochlorothiazide in combination.

The 4 studies of losartan monotherapy included a total of 1075 patients randomized to several doses of losartan and 334 to placebo. The 10- and 25-mg doses produced some effect at peak (6 hours after dosing) but small and inconsistent trough (24 hour) responses. Doses of 50, 100 and 150 mg once daily gave statistically significant systolic/diastolic mean decreases in blood pressure, compared to placebo in the range of 5.5-10.5/3.5-7.5 mmHg, with the 150-mg dose giving no greater effect than 50-100 mg. Twice-daily dosing at 50-100 mg/day gave consistently larger trough responses than once-daily dosing at the same total dose. Peak (6 hour) effects were uniformly, but moderately, larger than trough effects, with the trough-to-peak ratio for systolic and diastolic responses 50-95% and 60-90%, respectively.

Addition of a low dose of hydrochlorothiazide (12.5 mg) to losartan 50 mg once daily resulted in placebo-adjusted blood pressure reductions of 15.5/9.2 mmHg.

Analysis of age, gender, and race subgroups of patients showed that men and women, and patients over and under 65, had generally similar responses. COZAAR was effective in reducing blood pressure regardless of race, although the effect was somewhat less in Black patients (usually a low-renin population).

The effect of losartan is substantially present within one week but in some studies the maximal effect occurred in 3-6 weeks. In long-term follow-up studies (without placebo control) the effect of losartan appeared to be maintained for up to a year. There is no apparent rebound effect after abrupt withdrawal of losartan. There was essentially no change in average heart rate in losartan-treated patients in controlled trials.

Pediatric Hypertension

The antihypertensive effect of losartan was studied in one trial enrolling 177 hypertensive pediatric patients aged 6 to 16 years old. Children who weighed <50 kg received 2.5, 25 or 50 mg of losartan daily and patients who weighed ‰¥50 kg received 5, 50 or 100 mg of losartan daily. Children in the lowest dose group were given losartan in a suspension formulation (see DOSAGE AND ADMINISTRATION, Preparation of Suspension). The majority of the children had hypertension associated with renal and urogenital disease. The sitting diastolic blood pressure (SiDBP) on entry into the study was higher than the 95th percentile level for the patient's age, gender, and height. At the end of three weeks, losartan reduced systolic and diastolic blood pressure, measured at trough, in a dose-dependent manner. Overall, the two higher doses (25 to 50 mg in patients <50 kg; 50 to 100 mg in patients ‰¥50 kg) reduced diastolic blood pressure by 5 to 6 mmHg more than the lowest dose used (2.5 mg in patients <50 kg; 5 mg in patients ‰¥50 kg). The lowest dose, corresponding to an average daily dose of 0.07 mg/kg, did not appear to offer consistent antihypertensive efficacy. When patients were randomized to continue losartan at the two higher doses or to placebo after 3 weeks of therapy, trough diastolic blood pressure rose in patients on placebo between 5 and 7 mmHg more than patients randomized to continuing losartan. When the low dose of losartan was randomly withdrawn, the rise in trough diastolic blood pressure was the same in patients receiving placebo and in those continuing losartan, again suggesting that the lowest dose did not have significant antihypertensive efficacy. Overall, no significant differences in the overall antihypertensive effect of losartan were detected when the patients were analyzed according to age (<, ‰¥12 years old) or gender. While blood pressure was reduced in all racial subgroups examined, too few non-White patients were enrolled to compare the dose-response of losartan in the non-White subgroup.

Reduction in the Risk of Stroke: The Losartan Intervention For Endpoint reduction in hypertension (LIFE) study was a multinational, double-blind study comparing COZAAR and atenolol in 9193 hypertensive patients with ECG-documented left ventricular hypertrophy. Patients with myocardial infarction or stroke within six months prior to randomization were excluded. Patients were randomized to receive once daily COZAAR 50 mg or atenolol 50 mg. If goal blood pressure (<140>

Of the randomized patients, 4963 (54%) were female and 533 (6%) were Black. The mean age was 67 with 5704 (62%) age ‰¥65. At baseline, 1195 (13%) had diabetes, 1326 (14%) had isolated systolic hypertension, 1469 (16%) had coronary heart disease, and 728 (8%) had cerebrovascular disease. Baseline mean blood pressure was 174/98 mmHg in both treatment groups. The mean length of follow-up was 4.8 years. At the end of study or at the last visit before a primary endpoint, 77% of the group treated with COZAAR and 73% of the group treated with atenolol were still taking study medication. Of the patients still taking study medication, the mean doses of COZAAR and atenolol were both about 80 mg/day, and 15% were taking atenolol or losartan as monotherapy, while 77% were also receiving hydrochlorothiazide (at a mean dose of 20 mg/day in each group). Blood pressure reduction measured at trough was similar for both treatment groups but blood pressure was not measured at any other time of the day. At the end of study or at the last visit before a primary endpoint, the mean blood pressures were 144.1/81.3 mmHg for the group treated with COZAAR and 145.4/80.9 mmHg for the group treated with atenolol [the difference in systolic blood pressure (SBP) of 1.3 mmHg was significant (p<0.001), while the difference of 0.4 mmHg in diastolic blood pressure (DBP) was not significant (p=0.098)].

The primary endpoint was the first occurrence of cardiovascular death, nonfatal stroke, or nonfatal myocardial infarction. Patients with non-fatal events remained in the trial, so that there was also an examination of the first event of each type even if it was not the first event (e.g., a stroke following an initial myocardial infarction would be counted in the analysis of stroke). Treatment with COZAAR resulted in a 13% reduction (p=0.021) in risk of the primary endpoint compared to the atenolol group (see Figure 1 and Table 2); this difference was primarily the result of an effect on fatal and nonfatal stroke. Treatment with COZAAR reduced the risk of stroke by 25% relative to atenolol (p=0.001) (see Figure 2 and Table 2).

(Graphic Omitted)

Figure 1. Kaplan-Meier estimates of the primary endpoint of time to cardiovascular death, nonfatal stroke, or nonfatal myocardial infarction in the groups treated with COZAAR and atenolol. The Risk Reduction is adjusted for baseline Framingham risk score and level of electrocardiographic left ventricular hypertrophy.

(Graphic Omitted)

Figure 2. Kaplan-Meier estimates of the time to fatal/nonfatal stroke in the groups treated with COZAAR and atenolol. The Risk Reduction is adjusted for baseline Framingham risk score and level of electrocardiographic left ventricular hypertrophy.

Table 2 shows the results for the primary composite endpoint and the individual endpoints. The primary endpoint was the first occurrence of stroke, myocardial infarction or cardiovascular death, analyzed using an intention-to-treat (ITT) approach. The table shows the number of events for each component in two different ways. The Components of Primary Endpoint (as a first event) counts only the events that define the primary endpoint, while the Secondary Endpoints count all first events of a particular type, whether or not they were preceded by a different type of event.

Table 2 Incidence of Primary Endpoint Events

 

 
    COZAAR   Atenolol   Risk Reduction 

 

  95% CI

 

  p-Value
    N (%)   Rate*   N (%)   Rate*            
Primary Composite Endpoint

 

  508 (11)

 

  23.8

 

  588 (13)

 

  27.9

 

  13%

 

  2% to 23%

 

  0.021

 

Components of Primary Composite Endpoint (as a first event)

 

   
Stroke (nonfatal¡)   209 (5)       286 (6)                
Myocardial infarction (nonfatal¡)   174 (4)       168 (4)                
Cardiovascular mortality   125 (3)       134 (3)                
Secondary Endpoints (any time in study)

 

   
Stroke (fatal/nonfatal)   232 (5)   10.8   309 (7)   14.5   25%   11% to 37%   0.001
Myocardial infarction (fatal/nonfatal)   198 (4)   9.2   188 (4)   8.7   -7%   -13% to 12%   0.491
Cardiovascular mortality   204 (4)   9.2   234 (5)   10.6   11%   -7% to 27%   0.206
Due to CHD   125 (3)   5.6   124 (3)   5.6   -3%   -32% to 20%   0.839
Due to Stroke   40 (1)   1.8   62 (1)   2.8   35%   4% to 67%   0.032
Other§   39 (1)   1.8   48 (1)   2.2   16%   -28% to 45%   0.411
* Rate per 1000 patient-years of follow-up
  Adjusted for baseline Framingham risk score and level of electrocardiographic left ventricular hypertrophy
¡ First report of an event, in some cases the patient died subsequently to the event reported
§ Death due to heart failure, non-coronary vascular disease, pulmonary embolism, or a cardiovas

Posted: November 2009

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