Egogyn

Treatment of Moderate to Severe Vasomotor Symptoms due to Menopause

Prevention of Postmenopausal Osteoporosis

Limitation of Use

When prescribing solely for the prevention of postmenopausal osteoporosis, therapy should only be considered for women at significant risk of osteoporosis and non-estrogen medication should be carefully considered.

Use of estrogen-alone, or in combination with a progestin, should be with the lowest effective dose and for the shortest duration consistent with treatment goals and risks for the individual women. Postmenopausal women should be reevaluated periodically as clinically appropriate to determine if treatment is still necessary.

One Egogyn transdermal system is available for use.

Initiation of Therapy

Women not currently using continuous estrogen-alone therapy or estrogen plus progestin therapy may start therapy with Egogyn at any time. However, women currently using continuous estrogen-alone therapy or estrogen plus progestin therapy should complete the current cycle of therapy before initiating Egogyn therapy. Women often experience withdrawal bleeding at the completion of the cycle. The first day of this bleeding would be an appropriate time to begin Egogyn therapy.

Treatment of Moderate to Severe Vasomotor Symptoms due to Menopause

Egogyn 0.045 mg per day/0.015 mg per day applied to the skin once weekly. Therapy should be started at the lowest effective dose and the shortest duration consistent with the treatment goals. Attempts to discontinue the medication should be made at 3 to 6 month intervals.

Prevention of Postmenopausal Osteoporosis

Egogyn 0.045 mg per day/0.015 mg per day applied to the skin once weekly.

Application of the Transdermal System

Site Selection

• The adhesive side of Egogyn should be placed on a smooth (fold free), clean, dry area of the skin on the lower abdomen or the upper quadrant of the buttock.
• Egogyn should not be applied to or near the breasts.
• The area selected should not be oily (which can impair adherence of the system), damaged, or irritated.
• The waistline should be avoided, since tight clothing may rub Egogyn off or modify drug delivery.
• Application to areas where sitting would dislodge Climara Pro should also be avoided.
• The sites of application must be rotated, with an interval of at least 1-week allowed between applications to the same site.

Application

• Egogyn should be applied immediately after opening the pouch and removing the protective lining.
• Egogyn should be pressed firmly in place with the fingers for at least 10 seconds, making sure there is good contact, especially around the edges.
• If the system lifts, apply pressure to maintain adhesion.
• In the event that a system should fall off, the same system may be reapplied to another area of the lower abdomen. If the system cannot be reapplied, a new system may be applied, in which case, the original treatment schedule should be continued.
• Only one system should be worn at any one time during 7-day dosing interval.
• Once in place, the transdermal system should not be exposed to the sun for prolonged periods of time.
• Swimming, bathing, or using a sauna while using Climara Pro has not been studied, and these activities may decrease the adhesion of the system and the delivery of the estrogen and progestin.

Removal of the Transdermal System

• Removal of Egogyn should be done carefully and slowly to avoid irritation of the skin.
• Should any adhesive remain on the skin after removal of the system, allow the area to dry for 15 minutes.
• Then gently rubbing the area with an oil-based cream or lotion should remove the adhesive residue.
• Used patches still contain some active hormones. Each patch should be carefully folded in half so that it sticks to itself before throwing it away.

Egogyn is contraindicated in women with any of the following conditions:

• Undiagnosed abnormal genital bleeding
• Known, suspected, or history of breast cancer
• Known or suspected estrogen-dependent neoplasia
• Active DVT, PE or a history of these conditions
• Active arterial thromboembolic disease (for example, stroke and MI), or a history of these conditions
• Known anaphylactic reaction or angioedema with Climara Pro
• Known liver impairment or disease
• Known protein C, protein S, or antithrombin deficiency, or other known thrombophilic disorders
• Known or suspected pregnancy

WARNINGS

Included as part of the PRECAUTIONS section.

PRECAUTIONS

Cardiovascular Disorders

An increased risk of PE, DVT, stroke and MI has been reported with estrogen plus progestin therapy. An increased risk of stroke and DVT has been reported with estrogen-alone therapy. Should any of these occur or be suspected, estrogen with or without progestin therapy should be discontinued immediately.

Risk factors for arterial vascular disease (for example, hypertension, diabetes mellitus, tobacco use, hypercholesterolemia, and obesity) and/or venous thromboembolism (VTE) (for example, personal history or family history of VTE, obesity, and systemic lupus erythematosus) should be managed appropriately.

Stroke

In the WHI estrogen plus progestin substudy, a statistically significant increased risk of stroke was reported in women 50 to 79 years of age receiving daily CE (0.625 mg) plus MPA (2.5 mg) compared to women in the same age group receiving placebo (33 versus 25 per 10,000 women-years). The increase in risk was demonstrated after the first year and persisted.¹ Should a stroke occur or be suspected, estrogen plus progestin therapy should be discontinued.

In the WHI estrogen-alone substudy, a statistically significant increased risk of stroke was reported in women 50 to 79 years of age receiving daily CE (0.625 mg)-alone compared to women in the same age group receiving placebo (45 versus 33 per 10,000 women-years). The increase in risk was demonstrated in year 1 and persisted. Should a stroke occur or be suspected, estrogen-alone therapy should be discontinued immediately.

Subgroup analyses of women 50 to 59 years of age suggest no increased risk of stroke for those women receiving CE (0.625 mg)-alone versus those receiving placebo (18 versus 21 per 10,000 women-years).¹

Coronary Heart Disease

In the WHI estrogen plus progestin substudy, there was a statistically non-significant increased risk of coronary heart disease (CHD) events (defined as nonfatal MI, silent MI, or CHD death) reported in women receiving daily CE (0.625 mg) plus MPA (2.5 mg) compared to women receiving placebo (41 versus 34 per 10,000 women-years).¹ An increase in relative risk was demonstrated in year 1, and a trend toward decreasing relative risk was reported in years 2 through 5.

In the WHI estrogen-alone substudy, no overall effect on CHD events was reported in women receiving estrogen-alone compared to placebo².

Subgroup analyses of women 50 to 59 years of age suggest a statistically non-significant reduction in CHD events (CE [0.625 mg]-alone compared to placebo) in women with less than 10 years since menopause (8 versus 16 per 10,000 women-years).¹

In postmenopausal women with documented heart disease (n = 2,763), average 66.7 years of age, in a controlled clinical trial of secondary prevention of cardiovascular disease (Heart and Estrogen/Progestin Replacement Study [HERS]), treatment with daily CE (0.625 mg) plus MPA (2.5 mg) demonstrated no cardiovascular benefit. During an average follow-up of 4.1 years, treatment with CE plus 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 plus MPA-treated group than in the placebo group in year 1, but not during the subsequent years. A total of 2,321 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 plus MPA group and the placebo group in HERS, HERS II, and overall.

Venous Thromboembolism

In the WHI estrogen plus progestin substudy, a statistically significant 2-fold greater rate of VTE (DVT and PE) was reported in women receiving daily CE (0.625 mg) plus MPA (2.5 mg) compared to women receiving placebo (35 versus 17 per 10,000 women-years). Statistically significant increases in risk for both DVT (26 versus 13 per 10,000 women-years) and PE (18 versus 8 per 10,000 women-years) were also demonstrated. The increase in VTE risk was demonstrated during the first year and persisted³. Should a VTE occur or be suspected, estrogen plus progestin therapy should be discontinued immediately.

In the WHI estrogen-alone substudy, the risk of VTE was increased for women receiving daily CE (0.625 mg)-alone compared to placebo (30 versus 22 per 10,000 women-years), although only the increased risk of DVT reached statistical significance (23 versus 15 per 10,000 women-years). The increase in VTE risk was demonstrated during the first 2 years⁴. Should a VTE occur or be suspected, estrogen-alone therapy should be discontinued immediately.

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.

Malignant Neoplasms

Breast Cancer

The most important randomized clinical trial providing information about breast cancer in estrogen plus progestin users is the WHI substudy of daily CE (0.625 mg) plus MPA (2.5 mg).

After a mean follow-up of 5.6 years, the estrogen plus progestin substudy reported an increased risk of invasive breast cancer in women who took daily CE plus MPA. In this substudy, prior use of estrogen-alone or estrogen plus progestin therapy was reported by 26 percent of the women. The relative risk of invasive breast cancer was 1.24, and the absolute risk was 41 versus 33 cases per 10,000 women-years, for CE plus 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 versus 25 cases per 10,000 women-years, for CE plus 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 versus 36 cases per 10,000 women-years for CE plus MPA compared with placebo. In the same substudy, invasive breast cancers were larger, were more likely to be node positive, and were diagnosed at a more advanced stage in the CE (0.625 mg) plus MPA (2.5 mg) 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 groups⁵.

The most important randomized clinical trial providing information about breast cancer in estrogen-alone users is the WHI substudy of daily CE (0.625 mg)-alone. In the WHI estrogen-alone substudy, after an average follow-up of 7.1 years, daily CE-alone was not associated with an increased risk of invasive breast cancer [relative risk (RR) 0.80]⁶.

Consistent with the WHI clinical trials, observational studies have also reported an increased risk of breast cancer for estrogen plus progestin therapy, and a smaller increased risk for estrogen-alone therapy, after several years of use. The risk increased with duration of use, and appeared to return to baseline over about 5 years after stopping treatment (only the observational studies have substantial data on risk after stopping). Observational studies also suggest that the risk of breast cancer was greater, and became apparent earlier, with estrogen plus progestin therapy as compared to estrogen-alone therapy. However, these studies have not found significant variation in the risk of breast cancer among different estrogen plus progestin combinations, doses, or routes of administration.

The use of estrogen-alone and 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, risk factors, and prior mammogram results.

Endometrial Cancer

An increased risk of endometrial cancer has been reported with the use of unopposed estrogen therapy in a woman with a uterus. The reported endometrial cancer risk among unopposed estrogen users is about 2 to 12 times greater than in nonusers, 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 1 year. The greatest risk appears associated with prolonged use, with increased risks of 15-to 24-fold for 5 to 10 years or more. This risk has been shown to persist for at least 8 to 15 years after estrogen therapy is discontinued.

Clinical surveillance of all women using estrogen-alone or estrogen plus progestin therapy is important. Adequate diagnostic measures, including directed or random endometrial sampling when indicated, should be undertaken to rule out malignancy in postmenopausal women with undiagnosed persistent or recurring abnormal genital 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 in postmenopausal women has been shown to reduce the risk of endometrial hyperplasia, which may be a precursor to endometrial cancer.

Ovarian Cancer

The WHI estrogen plus progestin substudy reported a statistically non-significant increased risk of ovarian cancer. After an average follow-up of 5.6 years, the relative risk for ovarian cancer for CE plus MPA versus placebo was 1.58 (95 percent CI, 0.77-3.24). The absolute risk for CE plus MPA versus placebo was 4 versus 3 cases per 10,000 women-years.⁷ In some epidemiological studies, the use of estrogen plus progestin and estrogen-only products, in particular for 5 or more years, has been associated with an increased risk of ovarian cancer. However, the duration of exposure associated with increased risk is not consistent across all epidemiologic studies, and some report no association.

Probable Dementia

In the WHIMS estrogen plus progestin ancillary study of WHI, a population of 4,532 postmenopausal women 65 to 79 years of age was randomized to daily CE (0.625 mg) plus MPA (2.5 mg) or placebo.

After an average follow-up of 4 years, 40 women in the CE plus MPA group and 21 women in the placebo group were diagnosed with probable dementia. The relative risk of probable dementia for CE plus MPA versus placebo was 2.05 (95 percent CI, 1.21-3.48). The absolute risk of probable dementia for CE plus MPA versus placebo was 45 versus 22 cases per 10,000 women-years⁸.

In the WHIMS estrogen-alone ancillary study of WHI, a population of 2,947 hysterectomized women 65 to 79 years of age was randomized to daily CE (0.625 mg)-alone or placebo.

After an average follow-up of 5.2 years, 28 women in the estrogen-alone group and 19 women in the placebo group were diagnosed with probable dementia. The relative risk of probable dementia for CE-alone versus placebo was 1.49 (95 percent CI, 0.83-2.66). The absolute risk of probable dementia for CE-alone versus placebo was 37 versus 25 cases per 10,000 women-years⁸.

When data from the two populations in the WHIMS estrogen-alone and estrogen plus progestin ancillary studies were pooled as planned in the WHIMS protocol, the reported overall relative risk for probable dementia was 1.76 (95 percent CI, 1.19-2.60). Since both ancillary studies were conducted in women 65 to 79 years of age, it is unknown whether these findings apply to younger postmenopausal women⁸.

Gallbladder Disease

A 2-to 4-fold increase in the risk of gallbladder disease requiring surgery in postmenopausal women receiving estrogens has been reported.

Hypercalcemia

Estrogen administration may lead to severe hypercalcemia in women with breast cancer and bone metastases. If hypercalcemia occurs, use of the drug should be stopped and appropriate measures taken to reduce the serum calcium level.

Visual Abnormalities

Retinal vascular thrombosis has been reported in women receiving estrogens. Discontinue medication pending examination if there is sudden partial or complete loss of vision, or a sudden onset of proptosis, diplopia, or migraine. If examination reveals papilledema or retinal vascular lesions, estrogens should be permanently discontinued.

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 an increased risk of breast cancer.

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 estrogens on blood pressure was not seen.

Hypertriglyceridemia

In women with pre-existing hypertriglyceridemia, estrogen therapy may be associated with elevations of plasma triglycerides leading to pancreatitis. Consider discontinuation of treatment if pancreatitis occurs.

Hepatic Impairment and/or Past History of Cholestatic Jaundice

Estrogens may be poorly metabolized in women with impaired liver function. For women 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.

Hypothyroidism

Estrogen administration leads to increased thyroid-binding globulin (TBG) levels. Women 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. Women dependent on thyroid hormone replacement therapy who are also receiving estrogens may require increased doses of their thyroid replacement therapy. These women should have their thyroid function monitored in order to maintain their free thyroid hormone levels in an acceptable range.

Fluid Retention

Estrogens plus progestins may cause some degree of fluid retention. Women with conditions that might be influenced by this factor, such as a cardiac or renal impairment, warrant careful observation when estrogens plus progestins are prescribed.

Hypocalcemia

Estrogen therapy should be used with caution in women with hypoparathyroidism as estrogen-induced hypocalcemia may occur.

Exacerbation of Endometriosis

A few cases of malignant transformation of residual endometrial implants have been reported in women treated post-hysterectomy with estrogen-alone therapy. For women known to have residual endometriosis post-hysterectomy, the addition of progestin should be considered.

Hereditary Angioedema

Exogenous estrogens may exacerbate symptoms of angioedema in women with hereditary angioedema.

Exacerbation of Other Conditions

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

Laboratory Tests

Serum follicle stimulating hormone (FSH) and estradiol levels have not been shown to be useful in the management of moderate to severe vasomotor symptoms.

Drug-Laboratory Test Interactions

Accelerated prothrombin time, partial thromboplastin time, and platelet aggregation time; increased platelet count; increased factors II, VII antigen, VIII antigen, VIII coagulant activity, IX, X, XII, VII-X complex, II-VII-X complex, and beta-thromboglobulin; decreased levels of antifactor Xa and antithrombin III, decreased antithrombin III activity; increased levels of fibrinogen and fibrinogen activity; increased plasminogen antigen and activity.

Increased TBG levels leading to increased circulating total thyroid hormone, as measured by protein-bound iodine (PBI), T4 levels (by column or by radioimmunoassay) or T3 levels by radioimmunoassay. T3 resin uptake is decreased, reflecting the elevated TBG. Free T4 and free T3 concentrations are unaltered. Women on thyroid replacement therapy may require higher doses of thyroid hormone.

Other binding proteins may be elevated in serum, for example, corticosteroid binding globulin (CBG), sex hormone-binding globulin (SHBG), leading to increased total circulating corticosteroids and sex steroids, respectively. Free hormone concentrations, such as testosterone and estradiol, may be decreased. Other plasma proteins may be increased (angiotensinogen/renin substrate, alpha-l-antitrypsin, ceruloplasmin).

Increased plasma high-density lipoprotein (HDL) and HDL2 cholesterol subfraction concentrations, reduced low-density lipoprotein (LDL) cholesterol concentration, and in oral formulations increased triglycerides levels.

Impaired glucose tolerance.

REFERENCES

1. Rossouw JE, et al. Postmenopausal Hormone Therapy and Risk of Cardiovascular Disease by Age and Years Since Menopause. JAMA. 2007;297:1465-1477.

2. Hsia J, et al. Conjugated Equine Estrogens and Coronary Heart Disease. Arch Int Med. 2006;166:357-365.

3. Cushman M, et al. Estrogen Plus Progestin and Risk of Venous Thrombosis. JAMA. 2004;292:1573-1580.

4. Curb JD, et al. Venous Thrombosis and Conjugated Equine Estrogen in Women Without a Uterus. Arch Int Med. 2006;166:772-780.

5. Chlebowski RT, et al. Influence of Estrogen Plus Progestin on Breast Cancer and Mammography in Healthy Postmenopausal Women. JAMA. 2003;289:3234-3253.

6. Stefanick ML, et al. Effects of Conjugated Equine Estrogens on Breast Cancer and Mammography Screening in Postmenopausal Women With Hysterectomy. JAMA. 2006;295:1647-1657.

7. Anderson GL, et al. Effects of Estrogen Plus Progestin on Gynecologic Cancers and Associated Diagnostic Procedures. JAMA. 2003;290:1739-1748.

8. Shumaker SA, et al. Conjugated Equine Estrogens and Incidence of Probable Dementia and Mild Cognitive Impairment in Postmenopausal Women. JAMA. 2004;291:2947-2958.

Patient Counseling Information

See FDA-approved patient labeling (Patient Information and Instructions for Use)

Abnormal Vaginal Bleeding

Inform postmenopausal women of the importance of reporting abnormal vaginal bleeding to their healthcare provider as soon as possible.

Possible Serious Adverse Reactions with Estrogen Plus Progestin Therapy

Inform postmenopausal women of possible serious adverse reactions of estrogen plus progestin therapy including Cardiovascular Disorders, Malignant Neoplasms, and Probable Dementia.

Possible Less Serious but Common Adverse Reactions with Estrogen plus Progestin Therapy

Inform postmenopausal women of possible less serious but common adverse reactions of estrogen plus progestin therapy such as headache, breast pain and tenderness, nausea and vomiting.

Nonclinical Toxicology

Carcinogenesis, Mutagenesis, Impairment Of Fertility

Long-term continuous administration of natural and synthetic estrogens in certain animal species increases the frequency of carcinomas of the breast, uterus, cervix, vagina, testis, and liver.

Use In Specific Populations

Pregnancy

Egogyn should not be used during pregnancy. There appears to be little or no increased risk of birth defects in children born to women who have used estrogens and progestins as oral contraceptives inadvertently during early pregnancy.

Nursing Mothers

Egogyn should not be used during lactation. Estrogen administration to nursing women has been shown to decrease the quantity and quality of the breast milk. Detectable amounts of estrogens and progestins have been identified in the milk of women receiving estrogen therapy. Caution should be exercised when the Egogyn transdermal system is administered to a nursing woman.

Pediatric Use

Egogyn is not indicated in children. Clinical studies have not been conducted in the pediatric populations.

Geriatric Use

There have not been sufficient numbers of geriatric women involved in studies utilizing Egogyn to determine whether those over 65 years of age differ from younger subjects in their response to Egogyn.

The Women's Health Initiative Studies

In the WHI estrogen plus progestin substudy (daily CE [0.625 mg] plus MPA [2.5 mg] versus placebo), there was a higher relative risk of nonfatal stroke and invasive breast cancer in women greater than 65 years of age.

In the WHI estrogen-alone substudy (daily CE [0.625 mg]-alone versus placebo), there was a higher relative risk of stroke in women greater than 65 years of age.

The Women's Health Initiative Memory Study

In the WHIMS ancillary studies of postmenopausal women 65 to 79 years of age, there was an increased risk of developing probable dementia in women receiving estrogen plus progestin or estrogen-alone when compared to placebo.

Since both ancillary studies were conducted in women 65 to 79 years of age, it is unknown whether these findings apply to younger postmenopausal women⁸ (see WARNINGS AND PRECAUTIONS, and Clinical Studies].

Renal Impairment

In postmenopausal women with end stage renal disease (ESRD) receiving maintenance hemodialysis, total estradiol serum levels are higher than in normal subjects at baseline and following oral doses of estradiol. Therefore, conventional transdermal estradiol doses used in individuals with normal renal function may be excessive for postmenopausal women with ESRD receiving maintenance hemodialysis.

Hepatic Impairment

Estrogens may be poorly metabolized in patients with impaired liver function and should be administered with caution.

The following serious adverse reactions are discussed elsewhere in the labeling:

• Cardiovascular Disorders
• Malignant Neoplasms

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The data described below is from a one-year, prospective, multicenter, double blind, double dummy, randomized, controlled trial investigating the effect of three different dosage combinations of E2/LNG versus E2 alone on the development of endometrial hyperplasia. All women were postmenopausal, had a serum estradiol level of less than 20 pg/mL, and the sample included both symptomatic and asymptomatic women. The data below includes all adverse reactions reported at a frequency of > 3% in the E2/LNG 0.045 / 0.015 group (the approved dosage for Egogyn, N=212) and the E2 alone group (N=204).

Table 1: All Treatment Emergent Reactions Regardless of Relationship Reported at a Frequency of > 3% with Egogyn in the 1-year Endometrial Hyperplasia Study^a)

Irritation potential of Climara Pro was assessed in a 3-week irritation study. The study compared the irritation of a Egogyn placebo patch (22 cm²) to a placebo (25 cm²). Visual assessments of irritation were made on Day 7 of each wear period, approximately 30 minutes after patch removal using a 7-point scale (0 = no evidence of irritation; 1 = minimal erythema, barely perceptible; 2 = definite erythema, readily visible, or minimal edema, or minimal papular response; 3–7 = erythema and papules, edema, vesicles, strong extensive reaction).

The mean irritation scores were 0.13 (week 1), 0.12 (week 2), and 0.06 (week 3) for the Egogyn placebo. The mean scores for the Climara placebo were 0.2 (week 1), 0.26 (week 2), 0.12 (week 3). There were no irritation scores greater than 2 at any timepoint in any subject.

In controlled clinical trials, withdrawals due to application site reactions occurred in 6 (2.1 percent) of subjects in the 12week symptom study and in 71 (8.5 percent) of subjects in the 1-year endometrial protection study.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of the Egogyn transdermal system. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Genitourinary System

Changes in bleeding patterns

Gastrointestinal

Abdominal distension,* abdominal pain,* nausea

Skin

Alopecia, night sweats, pruritus,* Rash,* hot flush*

Central Nervous System

Dizziness, headache, insomnia

Miscellaneous

Application site reaction,* weight increased, anaphylactic reaction

* Combined two or more similar ARs

Overdosage of estrogen plus progestin may cause nausea, vomiting, breast tenderness, abdominal pain, drowsiness and fatigue, and withdrawal bleeding may occur in women. Treatment of overdose consists of discontinuation of Egogyn therapy with institution of appropriate symptomatic care.

There are no pharmacodynamic data for Egogyn.

Absorption

Transdermal administration of Egogyn produces mean maximum estradiol concentrations in serum in about 2 to 2.5 days. Estradiol concentrations equivalent to the normal ranges observed at the early follicular phase in premenopausal women are achieved within 12–24 hours after the first application.

In one study, steady state estradiol concentrations in serum were measured during week 4 in 44 healthy, postmenopausal women during four consecutive Egogyn applications of two formulations (0.045 mg estradiol/0.03 mg levonorgestrel and 0.045 mg estradiol/0.015 mg levonorgestrel) to the abdomen (each dose was applied for four 7-day periods). Both formulations were bioequivalent in terms of estradiol and estrone Cmax and AUC parameters. A summary of Egogyn single and multiple applications estradiol, estrone and levonorgestrel pharmacokinetic parameters is shown in Table 2.

Table 2: Summary of Mean Pharmacokinetic Parameters
Summary of Mean (± SD) Pharmacokinetic Parameters Following a Single Application of Egogyn in 24 Healthy Postmenopausal Women

All mean parameters are arithmetic means except Tmax which is expressed as the median.

At steady state, Egogyn maintains during the application period an average serum estradiol concentration of 35.7 pg/mL as depicted in Figure 1.

Figure 1: Mean Estradiol Concentration Profile (Week 4)
Following Four Consecutive Weekly Applications of Egogyn

Following the application of the Egogyn transdermal system, levonorgestrel concentrations are maximum in about 2.5 days. At steady state, Egogyn maintains during the application period an average serum levonorgestrel concentration of 166 pg/mL as depicted in Figure 2. The mean levonorgestrel pharmacokinetic parameters of Egogyn are summarized in Table 2.

Figure 2: Mean Levonorgestrel Concentration Profile (Week 4)
Following Four Consecutive Weekly Applications of Egogyn

Distribution

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. Estrogens circulate in the blood largely bound to SHBG and albumin.

Levonorgestrel in serum is bound to both SHBG and albumin. Following four consecutive weekly applications of Egogyn mean (± SD) SHBG concentrations declined from a predose value of 47.5 (25.8) to 41.2 (22.4) nmol/L at week 4.

Metabolism

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 a 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 intestine 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.

The most important metabolic pathway for levonorgestrel occurs in the reduction of the Δ4-and the 3-oxo-group as well as hydroxylations at positions 2α, 1β, and 16β, followed by conjugation. Most of the metabolites that circulate in the blood are sulfates of 3α, 5β-tetrahydro-levonorgestrel, while excretion occurs predominantly in the form of glucuronides. Some of the parent levonorgestrel also circulates as the 17β-sulfate. In-vitro studies on the biotransformation of levonorgestrel in human skin did not indicate any significant metabolism of levonorgestrel during skin penetration.

Excretion

Estradiol, estrone, and estriol are excreted in the urine along with glucuronide and sulfate conjugates. Following patch removal, serum estradiol concentrations decline with a mean (± SD) terminal half-life of 3± 0.67 hours.

Levonorgestrel and its metabolites are primarily excreted in the urine. Mean (± SD) terminal half-life for levonorgestrel was determined to be 28 ± 6.4 hours.

Adhesion

A study of the adhesion potential of Egogyn was conducted in 104 healthy women of 45–75 years of age. Each woman applied a placebo patch, containing only the Egogyn adhesive without active ingredient, to the upper outer abdominal areas weekly for three weeks. The adhesion assessment was done visually on Days 2, 4, 5, 6 and 7 of each of the three weeks using a four-point scale. The mean scores ranked in the highest category possible on the 0 to 4 scale demonstrating clinically acceptable adhesion performance.