Amlodipine and Olmesartan Medoxomil (Page 6 of 7)
13 NONCLINICAL TOXICOLOGY
13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility
Amlodipine. Rats and mice treated with amlodipine maleate in the diet for up to two years, at concentrations calculated to provide daily dosage levels of amlodipine 0.5, 1.25, and 2.5 mg/kg/day showed no evidence of a carcinogenic effect of the drug. For the mouse, the highest dose was, on a mg/m2 basis, similar to the maximum recommended human dose (MRHD) of amlodipine 10 mg/day. For the rat, the highest dose was, on a mg/m2 basis, about two and a half times the MRHD. (Calculations based on a 60 kg patient.)
Mutagenicity studies conducted with amlodipine maleate revealed no drug related effects at either the gene or chromosome level.
There was no effect on the fertility of rats treated orally with amlodipine maleate (males for 64 days and females for 14 days prior to mating) at doses of amlodipine up to 10 mg/kg/day (about 10 times the MRHD of 10 mg/day on a mg/m2 basis).
Olmesartan medoxomil. Olmesartan was not carcinogenic when administered by dietary administration to rats for up to 2 years. The highest dose tested (2000 mg/kg/day) was, on a mg/m2 basis, about 480 times the maximum recommended human dose (MRHD) of 40 mg/day. Two carcinogenicity studies conducted in mice, a 6-month gavage study in the p53 knockout mouse and a 6-month dietary administration study in the Hras2 transgenic mouse, at doses of up to 1000 mg/kg/day (about 120 times the MRHD), revealed no evidence of a carcinogenic effect of olmesartan.
Both olmesartan medoxomil and olmesartan tested negative in the in vitro Syrian hamster embryo cell transformation assay and showed no evidence of genetic toxicity in the Ames (bacterial mutagenicity) test. However, both were shown to induce chromosomal aberrations in cultured cells in vitro (Chinese hamster lung) and tested positive for thymidine kinase mutations in the in vitro mouse lymphoma assay. Olmesartan medoxomil tested negative in vivo for mutations in the MutaMouse intestine and kidney and for clastogenicity in mouse bone marrow (micronucleus test) at oral doses of up to 2000 mg/kg (olmesartan not tested).
Fertility of rats was unaffected by administration of olmesartan at dose levels as high as 1000 mg/kg/day (240 times the MRHD) in a study in which dosing was begun 2 (female) or 9 (male) weeks prior to mating.
14 CLINICAL STUDIES
14.1 Amlodipine and olmesartan medoxomil tablets
An 8-week multicenter, randomized, double-blind, placebo controlled, parallel group factorial study in patients with mild to severe hypertension was conducted to determine if treatment with amlodipine and olmesartan medoxomil tablets was associated with clinically significant reduction in blood pressure compared to the respective monotherapies. The study randomized 1940 patients equally to one of the following 12 treatment arms: placebo, monotherapy treatment with amlodipine 5 mg or 10 mg, monotherapy treatment with olmesartan medoxomil 10 mg, 20 mg, or 40 mg, or combination therapy with amlodipine/ olmesartan medoxomil at doses of 5/10 mg, 5/20 mg, 5/40 mg, 10/10 mg, 10/20 mg, and 10/40 mg. Patients discontinued their prior antihypertensive treatment. The mean baseline blood pressure of the study population was 164/102 mmHg. Of the total cohort, 970 patients were treated with the combination as initial therapy. Treatment with amlodipine and olmesartan medoxomil tablets resulted in statistically significant greater reductions in diastolic and systolic blood pressure compared to the respective monotherapy components. Maximum antihypertensive effects were attained within 2 weeks after a change in dose.
The following table presents the results for mean reduction in seated systolic and diastolic blood pressure following 8 weeks of treatment with amlodipine and olmesartan medoxomil tablets. Placebo-adjusted reductions from baseline in blood pressure were progressively greater with increases in dose of both amlodipine and olmesartan medoxomil components of amlodipine and olmesartan medoxomil tablets.
|(mmHg)||Placebo||10 mg||20 mg||40 mg|
|Amlodipine||Placebo||Mean ChangePlacebo-Adjusted Mean Change||-5/-3–||-12/-8-8/-5||-14/-9-10/-6||-16/-10-13/-7|
|5 mg||Mean ChangePlacebo-Adjusted Mean Change||-15/-9-12/-7||-24/-14-20/-11||-24/-14-20/-11||-25/-16-22/-13|
|10 mg||Mean ChangePlacebo-Adjusted Mean Change||-20/-13-16/-10||-25/-16-22/-13||-29/-17-25/-14||-30/-19-26/-16|
The antihypertensive effect of amlodipine and olmesartan medoxomil tablets was similar in patients with and without prior antihypertensive medication use, in patients with and without diabetes, in patients ≥ 65 years of age and < 65 years of age, and in women and men. Limited data exist in patients ≥ 75 years of age.
Amlodipine and olmesartan medoxomil tablets were effective in treating black patients (usually a low-renin population), and the magnitude of blood pressure reduction in black patients approached that observed for non-Black patients. This effect in black patients has been seen with ACE inhibitors, angiotensin receptor blockers, and beta-blockers.
The blood pressure lowering effect was maintained throughout the 24-hour period with amlodipine and olmesartan medoxomil tablets once daily, with trough-to-peak ratios for systolic and diastolic response between 71% and 82%.
Upon completing the 8-week, double-blind, placebo-controlled study, 1684 patients entered a 44-week open-label extension and received combination therapy with amlodipine 5 mg plus olmesartan medoxomil 40 mg. During the open-label extension, patients whose blood pressure was not adequately controlled (i.e., did not achieve a blood pressure goal of < 140/90 mmHg, or < 130/80 mmHg for those patients with diabetes) on amlodipine/olmesartan medoxomil 5/40 mg were titrated to amlodipine /olmesartan medoxomil 10/40 mg. Patients whose blood pressure was still not adequately controlled were offered additional hydrochlorothiazide 12.5 mg and subsequently 25 mg as required to achieve adequate blood pressure goal.
There are no trials of amlodipine and olmesartan medoxomil demonstrating reductions in cardiovascular risk in patients with hypertension, but at least one pharmacologically similar drug has demonstrated such benefits.
The antihypertensive efficacy of amlodipine has been demonstrated in a total of 15 double-blind, placebo-controlled, randomized studies involving 800 patients on amlodipine and 538 on placebo. Once daily administration produced statistically significant placebo-corrected reductions in supine and standing blood pressures at 24 hours post-dose, averaging about 12/6 mmHg in the standing position and 13/7 mmHg in the supine position in patients with mild to moderate hypertension. Maintenance of the blood pressure effect over the 24-hour dosing interval was observed, with little difference in peak and trough effect.
14.3 Olmesartan Medoxomil
The antihypertensive effects of olmesartan medoxomil have been demonstrated in seven placebo-controlled studies at doses ranging from 2.5 mg to 80 mg for 6 to 12 weeks, each showing statistically significant reductions in peak and trough blood pressure. A total of 2693 patients (2145 olmesartan medoxomil; 548 placebo) with essential hypertension were studied. The blood pressure lowering effect was maintained throughout the 24-hour period with olmesartan medoxomil once daily, with trough-to-peak ratios for systolic and diastolic response between 60% and 80%.
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