Elestrin

Description

ELESTRIN (estradiol gel) contains 0.06% of estradiol, an estrogen, in a colorless, non-staining hydroalcoholic gel base. One pump actuation delivers ELESTRIN in a unit dose of 0.52 mg of estradiol in 0.87 g of gel.

Estradiol is a white crystalline powder, chemically described as estra-1,3,5(10)-triene-3,17-diol, (17β)-. It has a molecular formula of C₁₈H₂₄O₂•½H₂O and molecular weight of 281.4.

The structural formula is:

 

 

The active component of ELESTRIN is estradiol. The remaining components of the gel (ethanol, propylene glycol, diethylene glycol monoethyl ether, carbomer 940, triethanolamine, edetate disodium, and purified water) are pharmacologically inactive.

Treatment Of Moderate To Severe Vasomotor Symptoms Due To Menopause

Dosage And Administration

Generally, when estrogen is prescribed for a postmenopausal woman with a uterus, consider addition of a progestin to reduce the risk of endometrial cancer.

Generally, a woman without a uterus does not need to take a progestin in addition to her estrogen therapy. In some cases, however, hysterectomized women who have a history of endometriosis may need a progestin [see WARNINGS AND PRECAUTIONS].

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

ELESTRIN is applied onto the skin in a thin layer. The recommended area of application is the upper arm to shoulder (approximately 320 cm²).

Treatment Of Moderate to Severe Vasomotor Symptoms due to Menopause

ELESTRIN is applied once daily to the upper arm for the treatment of moderate to severe vasomotor symptoms due to menopause using a metered-dose pump which delivers 0.87 grams of estradiol gel (0.52 mg estradiol) per actuation (1 pump).

Start therapy with one pump per day (0.87 grams per day, which contains 0.52 mg of estradiol).

Make dosage adjustments based on clinical response.

How Supplied

Dosage Forms And Strengths

ELESTRIN is available in a metered dose pump which delivers 0.52 mg of estradiol in 0.87 grams of gel per pump actuation.

Elestrin (estradiol gel) 0.06% in a colorless, non-staining hydroalcoholic gel supplied in a non-aerosol, metered-dose pump container constructed of polypropylene. The drug product is contained within a collapsible inner liner/bag consisting of an inner and outer layer of low density polyethylene with a resealable polypropylene cap. Each pump container holds 35 g of gel and is capable of delivering 26 g of gel as 30 metered doses. Each metered dose delivers 0.87 g of gel which contains 0.52 mg of estradiol.

NDC 0037-4801-35…..35 g pump container. This pump container is packaged individually or as two pump containers together in Cartons (0037-4801-35 and 0037- 4801-70).
NDC 0037-4801-35…..Carton containing one ELESTRIN 35 g pump container.
NDC 0037-4801-70…..Carton containing two ELESTRIN 35 g pump containers.

Storage And Handling

Store at 20° to 25°C (68° to 77°F); excursions permitted to 15° to 30°C (59° to 86°F). [See USP Controlled Room Temperature].

Distributed by: MEDA Pharmaceuticals Inc., Somerset, New Jersey 08873-4120. Revised: Oct 2020

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

• Cardiovascular Disorders [see BOXED WARNING, and WARNINGS AND PRECAUTIONS].
• Malignant Neoplasms [see BOXED WARNING, and WARNINGS AND PRECAUTIONS].

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.

ELESTRIN was studied in a placebo-controlled trial that included a total of 484 postmenopausal women. The adverse reactions that occurred at a rate greater than 5 percent in any of the treatment groups are summarized in Table 1.

TABLE 1 : Incidence of Treatment-Emergent Adverse Reactions Occurring in ≥ 5 Percent of Women

Body System / Signs and Symptoms	Placebo (n = 137)	Number (%) of Women ELESTRIN 0.87 g/day (n = 136)	ELESTRIN 1.7 g/day (n = 142)
Reproductive system & breast disorders
Breast tenderness	5 (3.6)	9 (6.6)	11 (7.7)
Metrorrhagia	3 (2.2)	6 (4.4)	13 (9.2)
Respiratory, thoracic & mediastinal disorders
Nasopharyngitis	10 (7.3)	14 (10.3)	12 (8.5)
Upper respiratory tract infection	5 (3.6)	8 (5.9)	5 (3.5)

 

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of ELESTRIN. 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 vaginal bleeding pattern and abnormal withdrawal bleeding or flow; breakthrough bleeding; spotting; dysmenorrhea; increase in size of uterine leiomyomata; vaginitis, including vaginal candidiasis; change in amount of cervical secretion; changes in cervical ectropion; ovarian cancer; endometrial hyperplasia; endometrial cancer.

Breasts

Tenderness; enlargement, pain, nipple discharge, galactorrhea; fibrocystic breast changes; breast cancer.

Cardiovascular

Deep and superficial venous thrombosis; pulmonary embolism; thrombophlebitis; myocardial infarction; stroke; increase in blood pressure.

Gastrointestinal

Nausea, vomiting; abdominal cramps, bloating; cholestatic jaundice; increased incidence of gallbladder disease; pancreatitis, enlargement of hepatic hemangiomas.

Skin

Chloasma or melasma that may persist when drug is discontinued; erythema multiforme; erythema nodosum; hemorrhagic eruption; loss of scalp hair; hirsutism; pruritus, rash.

Eyes

Retinal vascular thrombosis, intolerance to contact lenses.

Central Nervous System

Headache; migraine; dizziness; mental depression; chorea; nervousness; mood disturbances; irritability; exacerbation of epilepsy, dementia.

Miscellaneous

Increase or decrease in weight; reduced carbohydrate tolerance; aggravation of porphyria; edema; arthralgias; leg cramps; changes in libido; urticaria, angioedema, anaphylactoid/anaphylactic reactions; hypocalcemia; exacerbation of asthma; increased triglycerides.

Drug Interactions

In vitro and in vivo studies have shown that estrogens are metabolized partially by cytochrome P450 3A4 (CYP3A4). Therefore, inducers or inhibitors of CYP3A4 may affect estrogen drug metabolism. Inducers of CYP3A4, such as St. John’s wort (Hypericum perforatum) preparations, phenobarbital, carbamazepine, and rifampin, may reduce plasma concentrations of estrogens, possibly resulting in a decrease in therapeutic effects and/or changes in the uterine bleeding profile. Inhibitors of CYP3A4, such as erythromycin, clarithromycin, ketoconazole, itraconazole, ritonavir, and grapefruit juice, may increase plasma concentrations of estrogens and result in adverse reactions.

Included as part of the PRECAUTIONS section.

Precautions

Cardiovascular Disorders

Increased risk of stroke and DVT are reported with estrogen-alone therapy.

Increased risk of PE, DVT, stroke and MI are reported with estrogen plus progestin therapy. Immediately discontinue estrogen with or without progestin therapy if any of these occur or is suspected.

Manage appropriately any 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).

Stroke

The WHI estrogen-alone substudy reported a statistically significant increased risk of stroke 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 strokes per 10,000 women-years, respectively). The increase in risk was demonstrated in year 1 and persisted [see Clinical Studies]. Immediately discontinue estrogen-alone therapy if a stroke occurs or is suspected.

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

The WHI estrogen plus progestin substudy reported a statistically significant increased risk of stroke 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 strokes per 10,000 women-years) [see Clinical Studies]. The increase in risk was demonstrated after the first year and persisted.¹ Immediately discontinue estrogen plus progestin therapy if a stroke occurs or is suspected.

Coronary Heart Disease

The WHI estrogen-alone substudy reported no overall effect on coronary heart disease (CHD) events (defined as nonfatal MI, silent MI and CHD death) in women receiving estrogen-alone compared to placebo² [see Clinical Studies].

Subgroup analyses of women 50 to 59 years of age, who were less than 10 years since menopause, suggest a reduction (not statistically significant) in CHD events in those women receiving daily CE (0.625 mg)-alone compared to placebo (8 versus 16 per 10,000 women-years).¹

The WHI estrogen plus progestin substudy reported an increased risk of CHD events (not statistically significant) 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 [see Clinical Studies].

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. Two thousand, three hundred and twenty-one (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-alone substudy, the risk of VTE (DVT and PE) 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 years³ [see Clinical Studies]. Immediately discontinue estrogen-alone therapy if a VTE occurs or is suspected.

The WHI estrogen plus progestin substudy reported a statistically significant 2-fold greater rate of VTE 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 womenyears) 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 persisted⁴ [see Clinical Studies]. Immediately discontinue estrogen plus progestin therapy if a VTE occurs or is suspected.

If feasible, discontinue estrogens 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

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 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 1 year. The greatest risk appears associated with prolonged use, with an increased risk 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/progestin combinations is important. Perform adequate diagnostic measures, including directed or random endometrial sampling when indicated, to rule out malignancy in postmenopausal women with persistent or recurring abnormal vaginal bleeding with unknown etiology.

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.

In a 12-week clinical trial, one case of complex hyperplasia with atypia was reported in the ELESTRIN 1.7 g per day dose.

Breast Cancer

The WHI substudy of daily CE (0.625 mg)-alone provided information about breast cancer in estrogen-alone users. In the WHI estrogen-alone substudy, after an average of 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] compared to placebo⁵ [see Clinical Studies].

After a mean follow-up of 5.6 years, the WHI substudy of daily CE (0.625 mg) plus MPA (2.5 mg) reported an increased risk of invasive breast cancer in women who took daily CE plus MPA compared to placebo.

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 groups.⁶ [see Clinical Studies].

Consistent with the WHI clinical trial, observational studies have also reported an increased risk of breast cancer with estrogen plus progestin therapy, and a smaller increase in the risk for breast cancer with estrogen-alone therapy, after several years of use. The risk increased with duration of use and appeared to return to baseline in 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. These studies have not generally 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 self-examinations. In addition, mammography examinations should be scheduled based on patient age, risk factors, and prior mammogram results.

Ovarian Cancer

The CE plus 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 plus MPA versus placebo was 1.58 [95 percent CI, 0.77-3.24] but it was not statistically significant. The absolute risk for CE plus MPA versus placebo was 4 versus 3 cases per 10,000 women-years.⁷

A meta-analysis of 17 prospective and 35 retrospective epidemiology studies found that women who used hormonal therapy for menopausal symptoms had an increased risk for ovarian cancer. The primary analysis, using case-control comparisons, included 12,110 cancer cases from the 17 prospective studies. The relative risks associated with current use of hormonal therapy was 1.41 (95% confidence interval [CI] 1.32-1.50); there was no difference in the risk estimates by duration of the exposure (less than 5 years [median of 3 years] vs. greater than 5 years [median of 10 years] of use before the cancer diagnosis). The relative risk associated with combined current and recent use (discontinued use within 5 years before cancer diagnosis) was 1.37 (95% CI 1.27-1.48), and the elevated risk was significant for both estrogen-alone and estrogen plus progestin products. The exact duration of hormone therapy use associated with an increased risk of ovarian cancer, however, is unknown.

Probable Dementia

In the WHI Memory Study (WHIMS) estrogen-alone ancillary study, 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 [see Use In Specific Populations, and Clinical Studies].

In the WHIMS estrogen plus progestin ancillary study, 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% 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 [see Use In Specific Populations, and Clinical Studies].

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% 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 [see Use In Specific Populations, and Clinical Studies].

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. Discontinue estrogens, including ELESTRIN if hypercalcemia occurs, and take appropriate measures to reduce the serum calcium level.

Visual Abnormalities

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

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, placebocontrolled clinical trial, a generalized effect of estrogens on blood pressure was not seen.

Exacerbation Of Hypertriglyceridemia

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

Hepatic Impairment And/Or Past History Of Cholestatic Jaundice

Estrogens may be poorly metabolized in women with hepatic impairment. Exercise caution in any woman with a history of cholestatic jaundice associated with past estrogen use or with pregnancy. In the case of recurrence of cholestatic jaundice, discontinued ELESTRIN.

Exacerbation Of 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. Monitor thyroid function in these women during treatment with ELESTRIN to maintain their free thyroid hormone levels in an acceptable range.

Fluid Retention

Estrogens may cause some degree of fluid retention. Monitor any woman with a condition(s) that might predispose her to fluid retention, such as cardiac or renal impairment. Discontinue estrogen-alone therapy, including ELESTRIN, with evidence of medically concerning fluid retention.

Hypocalcemia

Estrogen-induced hypocalcemia may occur in women with hypoparathyroidism. Consider whether the benefits of estrogen therapy, including ELESTRIN, outweigh the risks in such women.

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. Consider the addition of a progestin for women known to have residual endometriosis post-hysterectomy.

Hereditary Angioedema

Exogenous estrogens may exacerbate symptoms of angioedema in women with hereditary angioedema. Consider whether the benefits of estrogen therapy outweigh the risks in such women.

Exacerbation Of Other Conditions

Estrogen therapy, including ELESTRIN, may cause an exacerbation of asthma, diabetes mellitus, epilepsy, migraine, porphyria, systemic lupus erythematosus, and hepatic hemangiomas. Consider whether the benefits of estrogen therapy outweigh the risks in such women.

Photosensitivity Or Photoallergy

Increased sensitivity to direct exposure to the sun on areas of ELESTRIN application has not been evaluated.

Sunscreen Application

Estradiol absorption was increased when sunscreen was applied 10 minutes before ELESTRIN application. Do not apply sunscreen to the application site of ELESTRIN until at least 25 minutes after the application of ELESTRIN.

Concomitant application of sunscreen and ELESTRIN to the same application site for 7 or more days may increase estradiol absorption. Avoid applying sunscreen to the area of ELESTRIN application for an extended period of 7 or more days [see CLINICAL PHARMACOLOGY, Pharmacokinetics].

Miscellaneous

Alcohol based gels, including ELESTRIN, are potentially flammable. Avoid fire, flame, or smoking until ELESTRIN has dried.

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 anti-factor Xa and antithrombin III, decreased antithrombin III activity; increased levels of fibrinogen and fibrinogen activity; increased plasminogen antigen and activity.
• Increased thyroid binding globulin (TBG) levels leading to increased circulating total thyroid hormone levels 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 T and free T4 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-1-antitrypsin, ceruloplasmin).
• Increased plasma high-density lipoprotein (HDL) and HDL2 cholesterol subfraction concentrations, reduced low-density lipoprotein (LDL) cholesterol concentration, and increased triglycerides levels.
• Impaired glucose tolerance.

Patient Counseling Information

Advise women to read the FDA-approved patient labeling (PATIENT INFORMATION and Instructions for Use).

Vaginal Bleeding

Inform postmenopausal women to report any vaginal bleeding to their healthcare provider as soon as possible [see WARNINGS AND PRECAUTIONS].

Possible Serious Adverse Reactions With Estrogen-Alone Therapy

Inform postmenopausal women of possible serious adverse reactions of estrogen-alone therapy including Cardiovascular Disorders, Malignant Neoplasms, and Probable Dementia [see WARNINGS AND PRECAUTIONS].

Possible Common Adverse Reactions With Estrogen-Alone Therapy

Inform postmenopausal women of possible less serious but common adverse reactions of estrogen-alone 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

Risk Summary

ELESTRIN is not indicated for use in pregnancy. There are no data with the use of ELESTRIN in pregnant women; however, epidemiologic studies and meta-analyses have not found an increased risk of genital or nongenital birth defects (including cardiac anomalies or limb-reduction defects) following exposure to combined hormonal contraceptives (estrogen and progestins) before conception or during early pregnancy. Animal studies to evaluate embryo/fetal toxicity were not conducted with ELESTRIN.

Lactation

Risk Summary

Estrogens are present in human milk and can reduce milk production in breast-feeding women. This reduction can occur at any time but is less likely to occur once breast-feeding is well-established. The developmental and health benefits of breast-feeding should be considered along with the mother’s clinical need for ELESTRIN and any potential adverse effects on the breast-fed child from ELESTRIN or from the underlying maternal condition.

Pediatric Use

ELESTRIN is not indicated in pediatric patients. Clinical studies have not been conducted in the pediatric population.

Geriatric Use

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

The Women’s Health Initiative Study

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 [see Clinical 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 [see Clinical Studies].

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-alone or estrogen plus progestin when compared to placebo [see WARNINGS AND PRECAUTIONS, and Clinical Studies].

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].

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

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

5. 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.

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

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.

Overdosage of estrogen 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 ELESTRIN therapy with institution of appropriate symptomatic care.

Contraindications

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

• Undiagnosed abnormal genital bleeding [see WARNINGS AND PRECAUTIONS].
• Breast cancer or a history of breast cancer [see WARNINGS AND PRECAUTIONS].
• Estrogen-dependent neoplasia [see WARNINGS AND PRECAUTIONS].
• Active DVT, PE, or history of these conditions [see WARNINGS AND PRECAUTIONS].
• Active arterial thromboembolic disease (for example, stroke and MI) or a history of these conditions [see WARNINGS AND PRECAUTIONS].
• Known anaphylactic reaction, or angioedema, or hypersensitivity to ELESTRIN.
• Hepatic impairment or disease.
• Protein C, protein S, or antithrombin deficiency, or other known thrombophilic disorders.

Mechanism Of Action

Endogenous estrogens are largely responsible for the development and maintenance of the female reproductive system and secondary sexual characteristics. Although circulating estrogens exist in a dynamic equilibrium of metabolic interconversions, estradiol is the principal intracellular human estrogen and is substantially more potent than its metabolites, estrone and estriol, at the receptor level.

The primary source of estrogen in normally cycling adult women is the ovarian follicle, which secretes 70 to 500 mcg of estradiol daily, depending on the phase of the menstrual cycle. After menopause, most endogenous estrogen is produced by conversion of androstenedione, secreted by the adrenal cortex, to estrone in the peripheral tissues. Thus, estrone and the sulfate-conjugated form, estrone sulfate, are the most abundant circulating estrogens in postmenopausal women.

Estrogens act through binding to nuclear receptors in estrogen-responsive tissues. To date, two estrogen receptors have been identified. These vary in proportion from tissue to tissue.

Circulating estrogens modulate the pituitary secretion of the gonadotropins, luteinizing hormone (LH) and FSH through a negative feedback mechanism. Estrogens act to reduce the elevated levels of these hormones seen in postmenopausal women.

Pharmacodynamics

Generally, a serum estrogen concentration does not predict an individual woman’s therapeutic response to ELESTRIN nor her risk for adverse outcomes. Likewise, exposure comparisons across different estrogen products to infer efficacy or safety for the individual woman may not be valid.

Pharmacokinetics

Absorption

Steady-state serum concentrations of estradiol are achieved in approximately 3 days following daily application of ELESTRIN to the upper arm.

Pharmacokinetic parameters for estradiol on Day 14 following daily application of 0.87 g or 1.7 g of ELESTRIN are summarized in Table 2. Dose dependent PK parameters for ELESTRIN 0.87 g and 1.7 g indicated the dose and serum estradiol (E2) concentrations to be linearly related but not dose-proportional (i.e., doubling in dose led to a 2.5- to 3.0-fold increase in PK parameters). The nominal mean delivery rates of estradiol using the baseline-adjusted average serum concentrations from pharmacokinetic studies using 0.87 g per day and 1.7 g per day are 0.0125 mg per day and 0.0375 mg per day, respectively.

TABLE 2 :  Summary of Unadjusted PK Parameters for Estradiol after 14 Days of Dosing

Pharmacokinetic Parameter	0.87 g ELESTRIN (0.52 mg/d Estradiol) Mean	1.7 g ELESTRIN (1.04 mg/d Estradiol) Mean
AUCq.24 (pg’hr/mL)	335.2	940.2
Cmax (pg/mL)	21.6	66.7
Cave (pg/mL)	15.4	39.2
Cmin (pg/mL)	9.4	21.1
Tmax (h)*	18 (1 – 20)	4 (1 – 20)
Fluctuation Index	0.80	1.16
E2:E1† ratio	0.53	0.98
* Tmax shown max as median (range) † E2:E1 (estradiol:estrone) ratio

 

Mean concentrations of estradiol over a 24-hour period on Day 14 are shown in Figure 1.

 

Based on the Cave values at steady state, the E2:E1 ratio was 0.53 for the 0.87 g and 0.98 for the 1.7 g doses. The significance of this finding is that the 1.7 g dose produced an E2:E1 ratio of a premenopausal woman. The 1.7 g dose of ELESTRIN reached the goal of restoring the E2:E1 ratio (~1.0) to that observed in premenopausal women in the early follicular phase of the menstrual cycle.

Application of sunscreen 10 minutes before application of ELESTRIN increased the exposure to estradiol by approximately 55 percent. No significant change in estradiol exposure was observed when sunscreen was applied 25 minutes after application of ELESTRIN. In the same study, prolonged (7 days) concomitant application of sunscreen to the site of ELESTRIN application increased exposure to estradiol by about 2-fold, regardless of whether it was applied before or after application of ELESTRIN.

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 blood largely bound to SHBG and albumin.

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.

Excretion

Estradiol, estrone and estriol are excreted in the urine along with glucuronide and sulfate conjugates.

Potential For Estradiol Transfer

The potential for estradiol transfer between treated postmenopausal female subjects and their untreated male partners was evaluated. Two and 8 hours after women applied 2.6 g ELESTRIN to one arm (12 women per time point), they engaged in direct arm-to-arm contact with a male partner for 5 minutes. No significant changes in estradiol pharmacokinetic parameters were observed in the male partners after contact.

Less than 10 percent of the estradiol dose was measured on the skin at 2 and 8 hours after application. After washing the application site with soap and water at 8 hours after application, about 1 percent of the dose of estradiol was measurable.

Clinical Studies

Effects On Vasomotor Symptoms In Postmenopausal Women

A randomized, double-blind, placebo-controlled clinical trial evaluated the efficacy of 12-week treatment with three different daily doses of ELESTRIN for the treatment of vasomotor symptoms in 484 postmenopausal women between 28 and 74 years of age (mean 54 years; 83-88 percent Caucasian per group) who had at least 60 moderate-to-severe hot flushes per week at baseline. At baseline, mean hot flushes is 13 per day, mean serum estradiol is 11.2-13.2 pg/mL, and prior hormone/estrogen therapy is 75.7-84.5 percent. Participants applied placebo, 1.7 g (1.04 mg estradiol), or 2.6 g (1.56 mg estradiol) once daily to the upper arm. The study was amended to identify the lowest effective dose of ELESTRIN and limit the number of women exposed to the 2.6 g dose. After the study amendment, ELESTRIN 0.87 g (0.52 mg estradiol) was added and the 2.6 g was discontinued from further enrollment. Reduction in both the frequency and severity of moderate to severe hot flushes was statistically significant for the ELESTRIN 1.7 g per day dose compared to placebo at week 4. Statistically significant reductions in both the frequency and severity of moderate to severe hot flushes when compared to placebo were delayed for the ELESTRIN 0.87 g per day dose to week 5. Both the 0.87 g per day and 1.7 g per day doses were statistically significant compared to placebo at week 12. Statistically significant reductions in the frequency and severity of daily moderate-to-severe hot flush rate compared to placebo were noted beginning at week 3 for the 1.7 g per day ELESTRIN treatment (data on file). The reductions in frequency and severity are shown in Table 3.

TABLE 3 : Mean Change from Baseline* in the Number and Severity of Hot Flushes after ELESTRIN Treatment

Evaluation	Placebo (N=137)	ELESTRIN 0.87 g/day (N=136)	ELESTRIN 1.7 g/day (N=142)
Number of Daily Hot Flushes
Baseline (Mean ± SD)†	13.5 ± 4.5	13.3 ± 4.6	13.1 ± 6.5
Mean Change:Week 4	-5.1	-6.5‡	-8.0§
Week 5	-5.1	-7.5¶	-8.8§
Week 12	-5.4	-8.5§	-10.0§
Daily Hot Flush Severity#
Baseline (Mean ± SD)†	2.4 ± 0.3	2.4 ± 0.3	2.4 ± 0.3
Mean Change:Week 4	-0.2	-0.5‡	-0.7§
Week 5	-0.2	-0.5¶	-0.8§
Week 12	-0.3	-0.8§	-1.2§
*Differences from baseline based on LS means derived from the ANCOVA model with factors for baseline, treatment, site, and treatment-by-baseline interaction. †Unadjusted means and standard deviations, based on the first 14 days of the Screening Period. ‡P=ns §P<0.0001 for treatment comparison with placebo (Dunnett’s test). ¶P<0.01, P<0.001 #Severity score: 1=mild, 2=moderate, 3=severe.

 

Women’s Health Initiative Studies

The WHI enrolled approximately 27,000 predominantly healthy postmenopausal women in two substudies to assess the risks and benefits of daily oral CE (0.625 mg)- alone or in combination with MPA (2.5 mg) compared to placebo in the prevention of certain chronic diseases. The primary endpoint was the incidence of CHD (defined as nonfatal MI, silent MI and CHD death), with invasive breast cancer as the primary adverse outcome. A “global index” included the earliest occurrence of CHD, invasive breast cancer, stroke, PE, endometrial cancer (only in the CE plus MPA substudy), colorectal cancer, hip fracture, or death due to other cause. These substudies did not evaluate the effects of CE-alone or CE plus MPA on menopausal symptoms.

WHI Estrogen-Alone Substudy

The WHI estrogen-alone substudy was stopped early because an increased risk of stroke was observed, and it was deemed that no further information would be obtained regarding the risk and benefits of estrogen-alone in predetermined endpoints.

Results of the estrogen-alone substudy, which included 10,739 women (average 63 years of age, range 50 to 79; 75.3 percent White, 15.1 percent Black, 6.1 percent Hispanic, 3.6 percent Other), after an average follow-up of 7.1 years are presented in Table 4.

TABLE 4 : Relative and Absolute Risk Seen in the Estrogen-Alone substudy of WHI*

Event	Relative Risk CE vs. Placebo(95% nCl†)	CE n = 5,310	Placebo n = 5,429
		Absolute Risk per 10,000 Women-Years
CHD events‡	0.95 (0.78-1.16)	54	57
Non-fatal MI‡	0.91 (0.73-1.14)	40	43
CHD death‡	1.01 (0.71-1.43)	16	16
All Stroke‡	1.33 (1.15-1.68)	45	33
Ischemic stroke‡	1.55 (1.19-2.01)	38	25
Deep vein thrombosis‡§	1.47 (1.06-2.06)	23	15
Pulmonary embolism‡	1.37 (0.90-2.07)	14	10
Invasive breast cancer‡	0.80 (0.62-1.04)	28	34
Colorectal cancer‡	1.08 (0.75-1.55)	17	16
Hip fracture‡	0.65 (0.45-0.94)	12	19
Vertebral fractures‡§	0.64 (0.44-0.93)	11	18
Lower arm/wrist fractures‡§	0.58 (0.47-0.72)	35	59
Total fractures‡§	0.71 (0.64-0.80)	144	197
Death due to other causes¶#	1.08 (0.88-1.32)	53	50
Overall mortality ‡,§	1.04 (0.88-1.22)	79	75
Global indexÞ	1.02 (0.92-1.13)	206	201
*Adapted from numerous WHI publications. WHI publications can be viewed at www.nhlbi.nih.gov/whi. †Nominal confidence intervals unadjusted for multiple looks and multiple comparisons. ‡Results are based on centrally adjudicated data for an average follow-up of 7.1 years. §Not included in “global index”. ¶Results are based on an average follow-up of 6.8 years. #All deaths, except from breast or colorectal cancer, definite or probable CHD, PE or cerebrovascular disease. ÞA subset of the events was combined in a “global index”, defined as the earliest occurrence of CHD events, invasive breast cancer, stroke, pulmonary embolism, endometrial cancer, colorectal cancer, hip fracture, or death due to other causes.

 

For those outcomes included in the WHI “global index,” that reached statistical significance, the absolute excess risks per 10,000 women-years in the group treated with CE-alone were 12 more strokes, while the absolute risk reduction per 10,000 women-years was 7 fewer hip fractures.⁹ The absolute excess risk of events included in the “global index” was a non-significant 5 events per 10,000 women-years. There was no difference between the groups in terms of all-cause mortality.

No overall difference for primary CHD events (nonfatal MI, silent MI and CHD death) and invasive breast cancer incidence in women receiving CE-alone compared with placebo was reported in final centrally adjudicated results from the estrogen-alone substudy, after an average follow-up of 7.1 years.

Centrally adjudicated results for stroke events from the estrogen-alone substudy, after an average follow-up of 7.1 years, reported no significant difference in the distribution of stroke subtype and severity, including fatal strokes, in women receiving estrogen-alone compared to placebo. Estrogen-alone therapy increased the risk of ischemic stroke, and this excess risk was present in all subgroups of women examined.¹⁰

Timing of initiation of estrogen-alone therapy relative to the start of menopause may affect the overall risk benefit profile. The WHI estrogen-alone substudy stratified by age showed in women 50 to 59 years of age a non-significant trend toward reduced risk for CHD [hazard ratio (HR) 0.63 (95 percent CI, 0.36-1.09)] and overall mortality [HR 0.71 (95 percent CI, 0.46–1.11)].

WHI Estrogen Plus Progestin Substudy

The WHI estrogen plus progestin substudy was stopped early. According to the predefined stopping rule, after an average follow-up of 5.6 years of treatment, the increased risk of invasive breast cancer and cardiovascular events exceeded the specified benefits included in the “global index.” The absolute excess risk of events included in the “global index” was 19 per 10,000 women-years.

For those outcomes included in the WHI “global index” that reached statistical significance after 5.6 years of follow-up, the absolute excess risks per 10,000 womenyears in the group treated with CE plus MPA were 7 more CHD events, 8 more strokes, 10 more PEs, and 8 more invasive breast cancers, while the absolute risk reduction per 10,000 women-years were 6 fewer colorectal cancers and 5 fewer hip fractures.

Results of the CE plus MPA substudy, which included 16,608 women (average 63 years of age, range 50 to 79; 83.9 percent White, 6.8 percent Black, 5.4 percent Hispanic, 3.9 percent Other) are presented in Table 5. These results reflect centrally adjudicated data after an average follow-up of 5.6 years.

TABLE 5 : Relative and Absolute Risk Seen in the Estrogen Plus Progestin Substudy of WHI at an Average of 5.6 Years

Event	Relative Risk CE/MPA vs. Placebo (95%nCl‡)	CE/MPA n = 8,506	Placebo n = 8,102
		Absolute Risk per 10,000 Women-Years
CHD events	1.23 (0.99-1.53)	41	34
Non-fatal MI	1.28 (1.00-1.63)	31	25
CHD death	1.10 (0.70-1.75)	8	8
All Stroke	1.31 (1.03-1.68)	33	25
Ischemic stroke	1.44 (1.09-1.90)	26	18
Deep vein thrombosis§	1.95 (1.43-2.67)	26	13
Pulmonary embolism	2.13 (1.45-3.11)	18	8
Invasive breast cancer‡¶	1.24 (1.01-1.54)	41	33
Colorectal cancer	0.61 (0.42-0.87)	10	16
Endometrial cancer§	0.81 (0.48-1.36)	6	7
Cervical cancer§	1.44 (0.47-4.42)	2	1
Hip fracture	0.67 (0.47-0.96)	11	16
Vertebral fractures§	0.65 (0.46-0.92)	11	17
Lower arm/wrist fractures§	0.71 (0.59-0.85)	44	62
Total fractures	0.76 (0.69-0.83)	152	199
Overall mortality#	1.00 (0.83-1.19)	52	52
Global IndexÞ	1.13 (1.02-1.25)	184	165
* Adapted from numerous WHI publications. WHI publications can be viewed at www.nhlbi.nih.gov/whi. † Results are based on centrally adjudicated. ‡ Nominal confidence intervals unadjusted for multiple looks and multiple comparisons. § Not included in “global index”. ¶ Includes metastatic and non-metastatic breast cancer with the exception of in situ breast cancer. # All deaths, except from breast or colorectal cancer, definite or probable CHD, PE or cerebrovascular disease. ÞA subset of the events was combined in a “global index”, defined as the earliest occurrence of CHD events, invasive breast cancer, stroke, pulmonary embolism, endometrial cancer, colorectal cancer, hip fracture, or death due to other causes.

 

Timing of initiation of estrogen plus progestin therapy relative to the start of menopause may affect the overall risk benefit profile. The WHI estrogen plus progestin substudy stratified by age showed in women 50 to 59 years of age a non-significant trend toward reduced risk for overall mortality [HR 0.69 (95 percent CI, 0.44-1.07)].

Women’s Health Initiative Memory Study

The WHIMS estrogen-alone ancillary study of WHI enrolled 2,947 predominantly healthy hysterectomized postmenopausal women 65 to 79 years of age (45 percent were 65 to 69 years of age, 36 percent were 70 to 74 years of age, and 19 percent were 75 years of age and older) to evaluate the effects of daily CE (0.625 mg)-alone on the incidence of probable dementia (primary outcome) compared to placebo.

After an average follow-up of 5.2 years, 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-years. Probable dementia as defined in the study included Alzheimer’s disease (AD), vascular dementia (VaD) and mixed type (having features of both AD and VaD). The most common classification of probable dementia in the treatment group and the placebo group was AD. Since the ancillary study was conducted in women 65 to 79 years of age, it is unknown whether these findings apply to younger postmenopausal women [see WARNINGS AND PRECAUTIONS and Use In Specific Populations].

The WHIMS estrogen plus progestin ancillary study enrolled 4,532 predominantly healthy postmenopausal women 65 years of age and older (47 percent were 65 to 69 years of age, 35 percent were 70 to 74 years of age, and 18 percent were 75 years of age and older) to evaluate the effects of daily CE (0.625 mg) plus MPA (2.5 mg) on the incidence of probable dementia (primary outcome) compared to placebo.

After an average follow-up of 4 years, 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-years. Probable dementia as defined in the study included AD, VaD and mixed types (having features of both AD and VaD). The most common classification of probable dementia in the treatment group and the placebo group was AD. Since the ancillary study was conducted in women 65 to 79 years of age, it is unknown whether these findings apply to younger postmenopausal women [see WARNINGS AND PRECAUTIONS and Use In Specific Populations].

When data from the two populations 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). Differences between groups became apparent in the first year of treatment. It is unknown whether these findings apply to younger postmenopausal women [see WARNINGS AND PRECAUTIONS, and Use In Specific Populations].

REFERENCES

9. Jackson RD, et al. Effects of Conjugated Equine Estrogen on Risk of Fractures and BMD in Postmenopausal Women With Hysterectomy: Results From the Women’s Health Initiative Randomized Trial. J Bone Miner Res. 2006;21:817-828.

10. Hendrix SL, et al. Effects of Conjugated Equine Estrogen on Stroke in the Women’s Health Initiative. Circulation. 2006;113:2425-2434.