Absorption

Serum concentrations of DRSP reach peak levels approximately 1 hour after administration of ANGELIQ and mean absolute bioavailability of DRSP ranges from 76–85%. Following oral administration, peak serum estradiol concentrations are typically reached 6–8 hours after dosing with ANGELIQ. The oral relative bioavailability of estradiol and DRSP following administration of ANGELIQ is 107% and 102%, respectively when compared to a combination oral suspension.

The pharmacokinetics of DRSP are dose proportional within the dose range of 0.5–4 mg. Following daily dosing of ANGELIQ, steady state DRSP concentrations were observed after 10 days. Mean accumulation ratios for estradiol and DRSP were 1.9 and 2.4, respectively. Mean concentrations at 2 hours for DRSP ranged between 5.9 and 6.7 ng/mL after treatment with ANGELIQ for 365 days. Mean steady state serum DRSP and E2 concentrations are shown in Figure 1, and a summary of primary pharmacokinetic parameters following the administration of 1mg E2/1mg DRSP for 28 days is presented in Table 1.

Figure 1: Mean steady state serum drospirenone and estradiol concentrations following daily oral administration of 1 mg E2/0.5 mg DRSP11DRSP levels are simulated based on data obtained after oral administration of 1 mg DRSP/1 mg Estradiol

Effect of Food:

The effect of food on the absorption and bioavailability of DRSP and E2 have not been investigated following the administration of ANGELIQ. However, clinical studies with different formulations containing DRSP or E2 have shown that the bioavailability of both drugs is not affected by concomitant food intake.

Distribution

The mean volume of distribution of DRSP is 4.2 L/kg. DRSP does not bind to sex hormone binding globulin (SHBG) or corticosteroid binding globulin (CBG) but binds about 97% to other serum proteins. The distribution of exogenous estrogens is similar to that of endogenous estrogens. Estrogens are widely distributed in the body and are generally found in higher concentrations in the sex hormone target organs. Estradiol circulates in the blood bound to SHBG (37%) and to albumin (61%), while only approximately 1%–2% is unbound.

Metabolism

Mean clearance of DRSP is 1.2 mL/min/kg. DRSP is extensively metabolized after oral administration. The 2 main metabolites of DRSP found in human plasma were identified to be the acid form of DRSP generated by opening of the lactone ring and the 4,5-dihydrodrospirenone-3-sulfate, both of which are formed without the involvement of the cytochrome P450 system. These metabolites were shown not to be pharmacologically active. In in vitro studies with human liver microsomes, DRSP was metabolized only to a minor extent mainly by Cytochrome P450 3A4 (CYP3A4).

Exogenous estrogens are metabolized in the same manner as endogenous estrogens. Circulating estrogens exist in a dynamic equilibrium of metabolic interconversions. These transformations take place mainly in the liver. Estradiol is converted reversibly to estrone, and both can be converted to estriol, which is the major urinary metabolite. Estrogens also undergo enterohepatic recirculation via sulfate and glucuronide conjugation in the liver, biliary secretion of conjugates into the intestine, and hydrolysis in the gut followed by reabsorption. In postmenopausal women, a significant proportion of the circulating estrogens exist as sulfate conjugates, especially estrone sulfate, which serves as a circulating reservoir for the formation of more active estrogens.

Excretion

DRSP serum levels are characterized by a terminal elimination half-life of approximately 36–42 hours. Excretion of DRSP was nearly complete after 10 days and amounts excreted were slightly higher in feces compared to urine. DRSP was extensively metabolized and only trace amounts of unchanged DRSP were excreted in urine and feces. At least 20 different metabolites were observed in urine and feces. About 38% to 47% of the metabolites in urine were glucuronide and sulfate conjugates. In feces, about 17% to 20% of the metabolites were excreted as glucuronides and sulfates. Estradiol, estrone, and estriol are excreted in the urine along with glucuronide and sulfate conjugates.

Special Populations

Geriatric: No pharmacokinetic studies were conducted in the geriatric population.

Pediatric: No pharmacokinetic study for ANGELIQ has been conducted in a pediatric population.

Gender: ANGELIQ is indicated for use in women only.

Race: No studies were done to determine the effect of race on the pharmacokinetics of ANGELIQ.

Patients with Hepatic Impairment: ANGELIQ is contraindicated in patients with hepatic dysfunction (also see BOLDED Warnings). The mean exposure to DRSP in women with moderate liver impairment is approximately three times the exposure in women with normal liver function.

Patients with Renal Impairment: ANGELIQ is contraindicated in patients with renal insufficiency (also see BOLDED Warnings).

The effect of renal insufficiency on the pharmacokinetics of DRSP (3 mg daily for 14 days) and the effects of DRSP on serum potassium levels were investigated in female subjects (n = 28, age 30–65) with normal renal function (11 patients), and mild (10 patients) and moderate (7 patients) renal impairment. All subjects were on a low potassium diet. During the study 7 subjects continued the use of potassium-sparing drugs for the treatment of the underlying illness. On the 14th day (steady-state) of DRSP treatment, the serum DRSP levels were on average 37% higher in the group with moderate renal impairment (CLcr 30–50 mL/min) compared to those in the group with normal renal function. Serum DRSP levels in the group with mild renal impairment (creatinine clearance CLcr, 50–80 mL/min) were comparable to those in the group with normal renal function (CLcr, >80 mL/min). DRSP treatment was well tolerated by all groups. DRSP treatment did not show any clinically significant effect on serum potassium concentration. Although hyperkalemia was not observed in the study, in 5 of the 7 subjects who continued use of potassium sparing drugs during the study, individual mean serum potassium levels increased by up to 0.33 mEq/L. Therefore, potential exists for hyperkalemia to occur in subjects with renal impairment whose serum potassium is in the upper reference range, and who are concomitantly using potassium sparing drugs.

Effects of Drospirenone on Other Drugs

Co-Administration with Drugs that Have the Potential to Increase Serum Potassium

There is a potential for an increase in serum potassium in women taking drospirenone with other drugs that may affect electrolytes, such as angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers, or non-steroidal anti-inflammatory drugs (NSAIDs).

Electrolytes were studied in 230 postmenopausal women with hypertension and/or diabetes mellitus requiring an ACE inhibitor or angiotensin receptor blocker (ARB). Of these, 26 patients had a creatinine clearance >50 mL/min to <80 mL/min. Patients were given 1 mg estradiol (E2) and 3 mg drospirenone (DRSP) (n=112) or placebo (n=118) over 28 days. Non-diabetic patients also received ibuprofen 1200 mg/day for 5 days during the study. There was a single case of serum potassium >6.0 mEq/L and a single case of serum sodium <130 mEq/L on treatment, both occurring following five days of ibuprofen therapy in two women taking E2/DRSP. Serum potassium levels ≥5.5 mEq/L were observed in 8 (7.3%) E2/DRSP-treated subjects (3 diabetic and 5 non-diabetic) and in 3 (2.6%) placebo-treated subjects (2 diabetic and 1 non-diabetic). After 28 days of exposure, the mean change from baseline in serum potassium was 0.11 mEq/L for the E2/DRSP group and 0.08 mEq/L for the placebo group. None of the subjects with serum potassium levels ≥5.5 mEq/L had cardiovascular adverse events. A drug-drug interaction study of DRSP 3 mg/estradiol (E2) 1 mg versus placebo was performed in 24 mildly hypertensive postmenopausal women taking enalapril maleate 10 mg twice daily. Potassium levels were obtained every other day for a total of 2 weeks in all subjects. Mean serum potassium levels in the DRSP/E2 treatment group relative to baseline were 0.22 mEq/L higher than those in the placebo group. Serum potassium concentrations also were measured at multiple timepoints over 24 hours at baseline and on Day 14. On Day 14, the ratios for serum potassium Cmax and AUC in the DRSP/E2 group to those in the placebo group were 0.955 (90% CI: 0.914, 0.999) and 1.010 (90% CI: 0.944, 1.080), respectively. No patient in either treatment group developed hyperkalemia (serum potassium concentrations >5.5 mEq/L).

Of note, occasional or chronic use of NSAID medication was not restricted in any of the ANGELIQ clinical trials.

Support for the indications

Support for treatment of vasomotor symptoms and vaginal and vulvar atrophy was shown through bioequivalence of the E2 component of the combination product with a currently marketed E2 product (Estrace®). The multiple-dose bioequivalence study evaluated the bioequivalence of E2 from a tablet containing DRSP (2 mg) and E2 (1 mg) relative to Estrace (1 mg) tablet. DRSP/E2 tablets met the criteria for bioequivalence to Estrace.

Effects on Endometrium

In a one year clinical trial of 1,142 postmenopausal subjects treated with E2 alone or E2 + 0.5, 1, 2, or 3 mg DRSP, endometrial biopsies were performed on 966 (84.6%) subjects during the treatment period. Eight subjects in the E2 monotherapy group developed endometrial hyperplasia (4 simple hyperplasia with no cytological atypia, 3 complex hyperplasia with no cytological atypia, and 1 complex hyperplasia with cytological atypia), and one subject in the 1 mg E2 + 2 mg DRSP group developed simple hyperplasia with no cytological atypia. Table 2 shows that there were no diagnoses of endometrial hyperplasia in the ANGELIQ group.

Effects on Uterine Bleeding or Spotting

In a cumulative analysis performed over 12 months in a double blind trial, the proportions of women with amenorrhea increased and at one year, 73.5% of subjects on ANGELIQ had amenorrhea. Results are shown in Figure 2.

Figure 2: Cumulative proportion of subjects with amenorrhea at a given cycle through cycle 13, LOCF

Women's Health Initiative Studies

The Women's Health Initiative (WHI) enrolled a total of 27,000 predominantly healthy postmenopausal women to assess the risks and benefits of either the use of 0.625 mg conjugated equine estrogens (CE) per day alone or the use of 0.625 mg conjugated equine estrogens plus 2.5 mg medroxyprogesterone acetate (MPA) per day compared to placebo in the prevention of certain chronic diseases. The primary endpoint was the incidence of coronary heart disease (CHD) (nonfatal myocardial infarction and CHD death), with invasive breast cancer as the primary adverse outcome studied. A "global index" included the earliest occurrence of CHD, invasive breast cancer, stroke, pulmonary embolism (PE), endometrial cancer, colorectal cancer, hip fracture, or death due to other cause. The study did not evaluate the effects of CE or CE/MPA on menopausal symptoms.

The CE/MPA sub-study was stopped early because, according to the predefined stopping rule, the increased risk of breast cancer and cardiovascular events exceeded the specified benefits included in the "global index". Results of the CE/MPA sub-study, which included 16,608 women (average age of 63 years, range 50 to 79; 83.9% White, 6.5% Black, 5.5% Hispanic), after an average follow-up of 5.2 years are presented in Table 3 below:

For those outcomes included in the "global index," absolute excess risks per 10,000 person-years in the group treated with CE/MPA were 7 more CHD events, 8 more strokes, 8 more PEs, and 8 more invasive breast cancers, while absolute risk reductions per 10,000 person-years were 6 fewer colorectal cancers and 5 fewer hip fractures.

The absolute excess risk of events included in the "global index" was 19 per 10,000 person-years. There was no difference between the groups in terms of all-cause mortality. (See Boxed Warnings , Warnings, and Precautions.)

Women's Health Initiative Memory Study

The Women's Health Initiative Memory Study (WHIMS), a substudy of WHI, enrolled 4,532 predominantly healthy postmenopausal women 65 years of age and older (47% were age 65 to 69 years, 35% were 70 to 74 years, and 18% were 75 years of age and older) to evaluate the effects of CE/MPA (0.625 mg conjugated estrogens plus 2.5 mg medroxyprogesterone acetate) on the incidence of probable dementia (primary outcome) compared with placebo.

After an average follow-up of 4 years, 40 women in the estrogen/progestin (45 per 10,000 women-years) and 21 in the placebo group (22 per 10,000 women-years) were diagnosed with probable dementia. The relative risk of probable dementia in the hormone therapy group was 2.05 (95% CI, 1.21 to 3.48) compared to placebo. Differences between groups became apparent in the first year of treatment. It is unknown whether these findings apply to younger postmenopausal women. (See Boxed Warnings and Warnings, 3. Dementia.)

a. Coronary heart disease and stroke

In the Women's Health Initiative study (WHI), an increase in the number of myocardial infarctions and strokes has been observed in women receiving oral CE compared to placebo. (See Clinical Pharmacology, Clinical Studies sections.)

In the CE/MPA substudy of WHI an increased risk of coronary heart disease (CHD) events (defined as non-fatal myocardial infarction and CHD death) was observed in women receiving CE/MPA compared to women receiving placebo (37 vs 30 per 10,000 person years). The increase in risk was observed in year one and persisted.

In the same substudy of WHI, an increased risk of stroke was observed in women receiving CE/MPA compared to women receiving placebo (29 vs 21 per 10,000 person-years). The increase in risk was observed after the first year and persisted.

In postmenopausal women with documented heart disease (n = 2,763, average age 66.7 years) a controlled clinical trial of secondary prevention of cardiovascular disease (Heart and Estrogen/Progestin Replacement Study; HERS) treatment with CE/MPA-0.625mg/2.5mg per day demonstrated no cardiovascular benefit. During an average follow-up of 4.1 years, treatment with CE/MPA did not reduce the overall rate of CHD events in postmenopausal women with established coronary heart disease. There were more CHD events in the CE/MPA-treated group than in the placebo group in year 1, but not during the subsequent years.

Two thousand three hundred and twenty one women from the original HERS trial agreed to participate in an open label extension of HERS, HERS II. Average follow-up in HERS II was an additional 2.7 years, for a total of 6.8 years overall. Rates of CHD events were comparable among women in the CE/MPA group and the placebo group in HERS, HERS II, and overall.

Large doses of estrogen (5 mg conjugated estrogens per day), comparable to those used to treat cancer of the prostate and breast, have been shown in a large prospective clinical trial in men to increase the risks of nonfatal myocardial infarction, pulmonary embolism, and thrombophlebitis.

b. Venous thromboembolism (VTE)

In the Women's Health Initiative study (WHI), an increase in VTE has been observed in women receiving CE compared to placebo. (See Clinical Pharmacology and Clinical Studies sections.)

In the CE/MPA substudy of WHI, a 2-fold greater rate of VTE, including deep venous thrombosis and pulmonary embolism, was observed in women receiving CE/MPA compared to women receiving placebo. The rate of VTE was 34 per 10,000 woman-years in the CE/MPA group compared to 16 per 10,000 woman-years in the placebo group. The increase in VTE risk was observed during the first year and persisted.

If feasible, estrogens should be discontinued at least 4 to 6 weeks before surgery of the type associated with an increased risk of thromboembolism, or during periods of prolonged immobilization.

a. Endometrial cancer

The use of unopposed estrogens in women with intact uteri has been associated with an increased risk of endometrial cancer. The reported endometrial cancer risk among unopposed estrogen users is about 2- to 12-fold greater than in non-users, and appears dependent on duration of treatment and on estrogen dose. Most studies show no significant increased risk associated with use of estrogens for less than one year. The greatest risk appears associated with prolonged use, with increased risks of 15- to 24-fold for five to ten years or more and this risk has been shown to persist for at least 8 to 15 years after estrogen therapy is discontinued.

Clinical surveillance of all women taking estrogen/progestin combinations is important. Adequate diagnostic measures, including endometrial sampling when indicated, should be undertaken to rule out malignancy in all cases of undiagnosed persistent or recurring abnormal vaginal bleeding. There is no evidence that the use of natural estrogens results in a different endometrial risk profile than synthetic estrogens of equivalent estrogen dose. Adding a progestin to estrogen therapy has been shown to reduce the risk of endometrial hyperplasia, which may be a precursor to endometrial cancer.

b. Breast cancer

The use of estrogens and progestins by postmenopausal women has been reported to increase the risk of breast cancer. The most important randomized clinical trial providing information about this issue is the Women's Health Initiative (WHI) substudy of CE/MPA (see Clinical Pharmacology,Clinical Studies). The results from observational studies are generally consistent with those of the WHI clinical trial and report no significant variation in the risk of breast cancer among different estrogens or progestins, doses, or routes of administration.

The CE/MPA substudy of WHI reported an increased risk of breast cancer in women who took CE/MPA for a mean follow-up of 5.6 years. Observational studies have also reported an increased risk for estrogen/progestin combination therapy, and a smaller increased risk for estrogen alone therapy, after several years of use. In the WHI trial and from observational studies, the excess risk increased with duration of use. From observational studies, the risk appeared to return to baseline in about five years after stopping treatment. In addition, observational studies suggest that the risk of breast cancer was greater, and became apparent earlier, with estrogen/progestin combination therapy as compared to estrogen alone therapy.

In the CE/MPA substudy, 26% of the women reported prior use of estrogen alone and/or estrogen/progestin combination hormone therapy. After a mean follow-up of 5.6 years during the clinical trial, the overall relative risk of invasive breast cancer was 1.24 (95% confidence interval 1.01–1.54), and the overall absolute risk was 41 vs. 33 cases per 10,000 women-years, for CE/MPA compared with placebo. Among women who reported prior use of hormone therapy, the relative risk of invasive breast cancer was 1.86, and the absolute risk was 46 vs. 25 cases per 10,000 women-years, for CE/MPA compared with placebo. Among women who reported no prior use of hormone therapy, the relative risk of invasive breast cancer was 1.09, and the absolute risk was 40 vs. 36 cases per 10,000 women-years for CE/MPA compared with placebo. In the same substudy, invasive breast cancers were larger and diagnosed at a more advanced stage in the CE/MPA group compared with the placebo group. Metastatic disease was rare with no apparent difference between the two groups. Other prognostic factors such as histologic subtype, grade and hormone receptor status did not differ between the groups.

The use of estrogen plus progestin has been reported to result in an increase in abnormal mammograms requiring further evaluation. All women should receive yearly breast examinations by a healthcare provider and perform monthly breast self-examinations. In addition, mammography examinations should be scheduled based on patient age, and risk factors, and prior mammogram results.

1. Addition of a progestin when a woman has not had a hysterectomy

Studies of the addition of a progestin for 10 or more days of a cycle of estrogen administration or daily with estrogen in a continuous regimen, have reported a lowered incidence of endometrial hyperplasia than would be induced by estrogen treatment alone. Endometrial hyperplasia may be a precursor to endometrial cancer.

There are, however, possible risks that may be associated with the use of progestins with estrogens compared to estrogen-alone regimens. These include a possible increased risk of breast cancer.

2. Elevated blood pressure

In a small number of case reports, substantial increases in blood pressure have been attributed to idiosyncratic reactions to estrogens. In a large, randomized, placebo-controlled clinical trial, a generalized effect of estrogen therapy on blood pressure was not seen. Blood pressure should be monitored at regular intervals with estrogen use.

3. Hypertriglyceridemia

In patients with pre-existing hypertriglyceridemia, estrogen therapy may be associated with elevations of plasma triglycerides leading to pancreatitis and other complications.

4. Impaired liver function and past history of cholestatic jaundice

Estrogens may be poorly metabolized in patients with impaired liver function. For patients with a history of cholestatic jaundice associated with past estrogen use or with pregnancy, caution should be exercised and in the case of recurrence, medication should be discontinued.

The clearance of drospirenone was decreased in patients with moderate hepatic impairment.

5. Hypothyroidism

Estrogen administration leads to increased thyroid-binding globulin (TBG) levels. Patients with normal thyroid function can compensate for the increased TBG by making more thyroid hormone, thus maintaining free T4 and T3 serum concentrations in the normal range. Patients dependent on thyroid hormone replacement therapy who are also receiving estrogens may require increased doses of their thyroid replacement therapy. These patients should have their thyroid function monitored in order to maintain their free thyroid hormone levels in an acceptable range.

6. Fluid retention

Because estrogen and estrogen/progestin therapy may cause some degree of fluid retention, patients with conditions that might be influenced by this factor, such as a cardiac or renal dysfunction, warrant careful observation when estrogens are prescribed.

7. Hypocalcemia

Estrogens should be used with caution in individuals with severe hypocalcemia.

8. Hyponatremia

As an aldosterone antagonist, drospirenone may increase the possibility of hyponatremia in high-risk patients.

9. Ovarian cancer

The CE/MPA substudy of WHI reported that estrogen plus progestin increased the risk of ovarian cancer. After an average follow-up of 5.6 years, the relative risk for ovarian cancer for CE/MPA versus placebo was 1.58 (95% confidence interval 0.77–3.24) but was not statistically significant. The absolute risk for CE/MPA versus placebo was 4.2 versus 2.7 cases per 10,000 women-years. In some epidemiologic studies, the use of estrogen alone, in particular for ten or more years, has been associated with an increased risk of ovarian cancer. Other epidemiologic studies have not found these associations.

10. Exacerbation of endometriosis

Endometriosis may be exacerbated with administration of estrogens.

11. Exacerbation of other conditions

Estrogens may cause an exacerbation of asthma, diabetes mellitus, epilepsy, migraine, porphyria, systemic lupus erythematosus, and hepatic hemangiomas, and should be used with caution in women with these conditions.