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exemestane 25 mg tablet generic aromasin

Out of Stock Manufacturer GREENSTONE LLC. 59762285801
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Uses

Breast Cancer

Initial or Sequential Adjuvant Therapy for Early-stage Breast Cancer

Exemestane is used as sequential adjuvant therapy in postmenopausal women with early-stage estrogen receptor-positive breast cancer who have received 2-3 years of adjuvant tamoxifen therapy and are switched to exemestane to complete a total of 5 consecutive years of adjuvant hormonal therapy. Exemestane also has been used alone as initial adjuvant therapy in postmenopausal women with early-stage hormone receptor-positive breast cancer. Aromatase inhibitors, including exemestane, currently are considered a treatment of choice for adjuvant hormonal therapy to lower the risk of breast cancer recurrence in postmenopausal women with early-stage hormone receptor-positive breast cancer. Although tamoxifen historically has been the drug of choice for adjuvant hormonal therapy in such patients, results of large, randomized clinical studies indicate that an aromatase inhibitor-containing regimen is modestly more effective than tamoxifen alone. Longer-term follow-up of these studies is needed to further clarify lasting clinical efficacy, effects on survival, and late adverse effects of aromatase inhibitor therapy.

Clinical Trials of Exemestane as Sequential Adjuvant Therapy

In Intergroup Exemestane Study 031, a randomized double-blind trial, 4724 postmenopausal women who previously had been diagnosed with early-stage breast cancer and who remained free of disease after 2-3 years of adjuvant tamoxifen therapy were randomized to switch to exemestane therapy or to continue receiving tamoxifen to complete a total of 5 years of adjuvant hormonal therapy. The median duration of tamoxifen therapy prior to randomization was approximately 28 months. Exemestane was administered at a dosage of 25 mg daily, and tamoxifen was administered at a dosage of 20 or 30 mg daily (about 3% of patients received the 30-mg dosage). About 86% of patients enrolled in the study had estrogen receptor-positive disease. The primary end point of the trial was disease-free survival.

Analysis of the data at a median follow-up of 34.5 months, when patients had received study treatment for a median of 27 months, showed that disease-free survival was prolonged in patients who were switched from tamoxifen to exemestane compared with those who continued receiving tamoxifen (hazard ratio of 0.69). Distant recurrence-free survival and time to contralateral breast cancer also were prolonged in patients receiving exemestane. Breast cancer-related events in patients receiving exemestane versus tamoxifen included locoregional recurrence (1.4 versus 1.9%), distant recurrence (5.4 versus 7.7%), primary cancer in the contralateral breast (0.3 versus 1%), breast cancer-related death (0.04 versus 0.25%), and ipsilateral breast cancer (0.04 versus 0%). No difference in overall survival was observed between the 2 treatment groups overall or within the subset of patients with hormone receptor-positive disease.

Subsequent analyses showed that the disease-free survival benefit associated with switching to exemestane was maintained at a median follow-up of about 4.6 years (hazard ratio of 0.76, which corresponded to an absolute improvement in disease-free survival of 3.3 or 3.4% at 2.5 or 5 years, respectively, after randomization) and at a median follow-up of about 7.6 years (hazard ratio of 0.84, which corresponded to an absolute difference in disease-free survival of 2.8 or 4.1% at 5 or 8 years, respectively, after randomization). No difference in overall survival was observed between the 2 treatment groups. However, among patients with estrogen receptor-positive or estrogen receptor-unknown disease, use of exemestane as sequential adjuvant therapy was associated with a modest overall survival benefit at 7.6 years of follow-up (hazard ratio of 0.86, which corresponded to an absolute difference in disease-free survival of 1.4 or 2.4% at 5 or 8 years, respectively, after randomization).

Hypertension, other cardiovascular events (e.g., cardiac ischemia), musculoskeletal pain, arthralgia, arthritis, osteoporosis, fracture, carpal tunnel syndrome, paresthesia, diarrhea, and gastric ulcer occurred more frequently during treatment or posttreatment follow-up in patients receiving exemestane, whereas venous thromboembolism, muscle cramp, serious gynecologic event (e.g., vaginal bleeding, uterine dilatation and curettage), endometrial hyperplasia, and uterine polyp/fibroid occurred more frequently in patients receiving tamoxifen.

Clinical Trials of Exemestane as Initial Adjuvant Therapy

Data from two phase 3 randomized open-label clinical trials indicate that initial therapy with exemestane is at least as effective as initial therapy with anastrozole or sequential therapy with tamoxifen followed by exemestane in postmenopausal women with early-stage hormone receptor-positive breast cancer.

In the first study (Tamoxifen Exemestane Adjuvant Multinational [TEAM]), 9779 postmenopausal women with early-stage hormone receptor-positive breast cancer were randomized to receive exemestane 25 mg daily for 5 years or sequential therapy with tamoxifen 20 mg daily for 2-3 years followed by exemestane 25 mg daily for a total treatment duration of 5 years. Most (98%) of the patients enrolled in the study had estrogen receptor-positive tumors. The primary end point of the study was disease-free survival. At a median follow-up of 5.1 years, no significant difference in estimated 5-year disease-free survival was observed between patients receiving sequential therapy and those receiving initial exemestane therapy (85 and 86%, respectively; hazard ratio of 0.97 with a 95% confidence interval of 0.88-1.08); in addition, no difference in 5-year overall survival was observed between the groups. Disease relapse or breast cancer-related death occurred in similar proportions of patients receiving sequential therapy (11%) or initial exemestane therapy (10%). In this study, fractures, osteoporosis, hyperlipidemia, hypertension, and cardiac failure occurred more frequently in patients receiving initial exemestane therapy, whereas venous thrombosis, vaginal bleeding, and endometrial disorders occurred more frequently in those receiving sequential therapy.

In the second study (MA.27), 7576 postmenopausal women with hormone receptor-positive primary invasive breast cancer were randomized to receive exemestane 25 mg daily or anastrozole 1 mg daily for 5 years, with or without celecoxib; however, random assignment to celecoxib was halted when data from another study suggested that celecoxib may increase cardiovascular risk. Patients were stratified according to lymph node status, receipt of prior adjuvant chemotherapy, use of concomitant trastuzumab therapy, and previous random assignment to celecoxib and concomitant prophylactic aspirin therapy. Most (99%) of the patients enrolled in the study had estrogen receptor-positive tumors. The primary end point of the study was event-free survival. At a median follow-up of 4.1 years, no significant difference in estimated 4-year event-free survival was observed between patients receiving exemestane and those receiving anastrozole (91 and 91.2%, respectively; hazard ratio of 1.02 with a 95% confidence interval of 0.87-1.18). In addition, no difference in overall survival was observed between the groups. Elevations in aminotransferase (ALT or AST) concentrations (3 versus 1%), elevations in serum bilirubin concentrations (2 versus 1%), and atrial fibrillation (2 versus 1%) occurred more frequently in patients receiving exemestane, whereas hyperlipidemia (18 versus 15%), hypertriglyceridemia (3 versus 2%), and osteoporosis (35 versus 31%) occurred more frequently in patients receiving anastrozole.

Clinical Role

Based on data from randomized controlled trials demonstrating prolonged disease-free survival in patients receiving aromatase inhibitor-based adjuvant regimens, use of exemestane may be considered a reasonable choice (accepted, with possible conditions) for initial adjuvant therapy in postmenopausal women with early-stage hormone receptor-positive breast cancer; factors that should be considered when selecting an appropriate aromatase inhibitor include tolerability, patient preference, and preexisting conditions.

The American Society of Clinical Oncology (ASCO) states that most postmenopausal women with early-stage hormone receptor-positive breast cancer should consider receiving an aromatase inhibitor (e.g., exemestane) during the course of adjuvant therapy, either as primary (initial) therapy or following 2-3 years of tamoxifen therapy (sequential therapy), to complete a total of 5 years of adjuvant endocrine therapy. Clinically meaningful differences among the currently available aromatase inhibitors (i.e., anastrozole, exemestane, letrozole) have not been demonstrated to date. Data also support switching to an aromatase inhibitor following 5 years of adjuvant tamoxifen therapy (extended therapy) (see Extended Adjuvant Therapy for Early-stage Breast Cancer under Uses: Breast Cancer). The optimal time for switching from tamoxifen to an aromatase inhibitor is not known. The duration of aromatase inhibitor therapy should not exceed 5 years, since toxicity of long-term (e.g., beyond 5 years) use of aromatase inhibitors, including exemestane, has not been determined. The optimal duration of adjuvant exemestane therapy is not known. ASCO states that clinicians should consider adverse effects, patient preference, and preexisting conditions when selecting an adjuvant regimen; during the course of adjuvant therapy, patients who are intolerant of one aromatase inhibitor may be switched to a different aromatase inhibitor or to tamoxifen.

The use of a luteinizing hormone-releasing hormone (LHRH) agonist (e.g., triptorelin) in combination with exemestane as adjuvant therapy in premenopausal women with hormone receptor-positive breast cancer† is being investigated in a large randomized trial. The use of an aromatase inhibitor as a single agent for adjuvant therapy is not appropriate in premenopausal women with breast cancer because these agents alone are not likely to provide sufficient suppression of ovarian function to be of clinical benefit. Similarly, the use of an aromatase inhibitor as monotherapy for adjuvant therapy for hormone receptor-positive breast cancer in premenopausal women experiencing a chemotherapy-induced disruption in ovarian function is not advised; a substantial number of such patients can expect resumption of ovarian function, and this would likely render therapy with an aromatase inhibitor ineffective.

Extended Adjuvant Therapy for Early-stage Breast Cancer

Exemestane has been used as extended adjuvant therapy in postmenopausal women with early-stage breast cancer who have received 5 years of adjuvant tamoxifen therapy.

Clinical Trials

Efficacy of exemestane as extended adjuvant therapy in postmenopausal women with early-stage breast cancer who have received 5 years of adjuvant tamoxifen therapy has been evaluated in a double-blind, placebo-controlled, randomized phase 3 trial (National Surgical Adjuvant Breast and Bowel Project [NSABP] B-33) in postmenopausal women mostly with hormone receptor-positive breast cancer (97% hormone receptor-positive, 3% hormone receptor-unknown). In this trial, 1598 patients who had received adjuvant therapy with tamoxifen for approximately 5 years (range: approximately 4.75-5.6 years) were randomized to receive exemestane 25 mg daily or placebo for 5 years. Based on interim results from a similarly designed trial demonstrating benefit from extended adjuvant therapy with letrozole, recruitment of patients for the NSABP B-33 trial was halted early, the study was unblinded, and exemestane therapy was offered to all women who had been receiving placebo. After the study was unblinded, 44% of patients randomized to receive placebo crossed over to receive exemestane therapy and 72% of patients randomized to receive exemestane continued their assigned therapy.

At a median follow-up of 30 months, the estimated 4-year disease-free survival did not differ significantly between patients receiving exemestane and those receiving placebo (91 versus 89%, respectively, based on intent-to-treat analysis); in addition, no difference in overall survival was observed between the groups. A significant difference in estimated 4-year relapse-free survival was observed between patients randomized to receive exemestane and those randomized to receive placebo (96 versus 94%, respectively). Exemestane treatment was associated with numerically, but not significantly, fewer local or metastatic recurrences and with a significant reduction in the incidence of new contralateral breast cancer, as compared with placebo. An exploratory subset analysis suggested that the effect of exemestane on disease-free survival was greater in patients with tumors larger than 2 cm or with node-positive disease. Although grade 3 adverse effects occurred more commonly in patients receiving exemestane, the incidence of grade 4 adverse effects was similar for patients receiving exemestane or placebo.

Clinical Role

Based on data from randomized controlled trials demonstrating prolonged disease-free survival in patients receiving aromatase inhibitors as extended adjuvant therapy, use of exemestane may be considered a reasonable choice (accepted, with possible conditions) for extended adjuvant therapy in postmenopausal women with early-stage hormone receptor-positive breast cancer who have received 5 years of adjuvant tamoxifen therapy; factors that should be considered when selecting an appropriate aromatase inhibitor include tolerability, patient preference, and preexisting conditions.

ASCO recommends extended therapy with an aromatase inhibitor (e.g., exemestane) in postmenopausal women with early-stage hormone receptor-positive breast cancer who complete 5 years of adjuvant tamoxifen therapy. Clinically meaningful differences among the currently available aromatase inhibitors (i.e., anastrozole, exemestane, letrozole) have not been demonstrated to date. Clinicians should consider adverse effects, patient preference, and preexisting conditions when selecting an adjuvant regimen. ASCO states that women who receive extended adjuvant therapy should receive a total of 8-10 years of adjuvant endocrine therapy, including 5 years of tamoxifen therapy followed by 3-5 years of aromatase inhibitor therapy. The optimal duration of exemestane as extended adjuvant therapy is not known, and the toxicity of long-term (e.g., beyond 5 years) use of aromatase inhibitors, including exemestane, in this setting has not been determined. Ongoing clinical trials are evaluating whether longer durations of aromatase inhibitor therapy are more effective.

Second-line Therapy for Advanced Breast Cancer

Exemestane is used in the treatment of advanced breast cancer in postmenopausal women whose disease has progressed following tamoxifen therapy. Efficacy was evaluated in one comparative study (versus megestrol acetate) and 2 single-arm studies in postmenopausal women with advanced breast cancer that progressed after tamoxifen therapy for metastatic disease or as adjuvant therapy; some patients also received prior chemotherapy either for metastasis or as adjuvant therapy. The studies evaluated objective response rates (complete and partial response); time to tumor progression (TTP) and overall survival also were assessed in the comparative study. In the comparative study, objective response rates for exemestane and megestrol were comparable at 15 and 12.4%, respectively. Response rates for exemestane in the 2 single-arm studies were 23.4 and 28.1%. In the comparative study, the median duration of response was 76.1 and 71 weeks for exemestane and megestrol, respectively, and the median TTP was 20.3 and 16.6 weeks, respectively. No conclusions could be drawn related to overall survival differences with the limited study data available.

Dosage and Administration

General

Exemestane is administered orally after a meal (to enhance GI absorption).

Breast Cancer

Dosage adjustments are recommended when exemestane is used in conjunction with potent inducers of cytochrome P-450 (CYP) isoenzyme 3A4.(See Cytochrome P-450 Isoenzyme 3A4 Inducers under Drug Interactions: Drugs Affecting or Metabolized by Hepatic Microsomal Enzymes.)

Initial or Sequential Adjuvant Therapy for Early-stage Breast Cancer

For sequential adjuvant treatment in postmenopausal women with early-stage estrogen receptor-positive breast cancer, the recommended dosage of exemestane is 25 mg once daily. Exemestane is used in patients who have received 2-3 years of adjuvant tamoxifen therapy and are being switched to exemestane to complete a total of 5 consecutive years of adjuvant hormonal therapy.

When used for initial adjuvant treatment in postmenopausal women with early-stage hormone receptor-positive breast cancer, exemestane has been administered at a dosage of 25 mg once daily for 5 years.

The American Society of Clinical Oncology (ASCO) states that an aromatase inhibitor (e.g., exemestane) may be administered to postmenopausal women with early-stage hormone receptor-positive breast cancer as initial adjuvant therapy and continued for a total of 5 years or may be administered following initial tamoxifen therapy as part of a sequential adjuvant regimen. The optimal time to switch from tamoxifen to aromatase inhibitor therapy is not known; however, based on clinical trials conducted to date, ASCO recommends that patients who are disease-free may be switched to an aromatase inhibitor after 2-3 years of tamoxifen therapy to complete a 5-year sequential adjuvant regimen. In patients who initially receive an aromatase inhibitor but discontinue therapy prior to 5 years, ASCO states that consideration should be given to administering tamoxifen to complete the 5-year adjuvant regimen.

Extended Adjuvant Therapy for Early-stage Breast Cancer

When used for extended adjuvant treatment in postmenopausal women with early-stage breast cancer who have received 5 years of adjuvant tamoxifen therapy, exemestane has been administered at a dosage of 25 mg once daily. ASCO recommends that patients who receive an extended adjuvant regimen receive an aromatase inhibitor (e.g., exemestane) for 3-5 years beyond the initial 5 years of tamoxifen therapy, to complete a total of 8-10 years of adjuvant endocrine therapy.

Second-line Therapy for Advanced Breast Cancer

For the second-line treatment of advanced breast cancer in postmenopausal women whose disease has progressed following tamoxifen therapy, the recommended dosage of exemestane is 25 mg once daily. Higher dosages have not been shown to provide substantially greater suppression of plasma estrogens but may be associated with increased adverse effects. In clinical trials, treatment generally was continued until tumor progression or unacceptable toxicity occurred.

Special Populations

The safety of chronic dosing in patients with moderate to severe renal or hepatic impairment has not been studied. Although exemestane AUCs are increased (e.g., threefold) in patients with renal or hepatic insufficiency, the manufacturer states that experience with exemestane at repeated doses up to 200 mg daily in patients without such insufficiency (which demonstrated a moderate increase in non-life-threatening adverse effects) indicates that dosage adjustment does not appear to be necessary.

Cautions

Contraindications

Known hypersensitivity to exemestane or any ingredient in the formulation.

Pregnancy and premenopausal women. (See Fetal/Neonatal Morbidity and Mortality and also Premenopausal Women under Cautions: Warnings/Precautions.)

Warnings/Precautions

Fetal/Neonatal Morbidity and Mortality

Exemestane may cause fetal harm; the drug has been shown to be embryotoxic, fetotoxic, and abortifacient in animals. There are no adequate and well-controlled studies in pregnant women. Exemestane is contraindicated in women who are or may become pregnant (i.e., premenopausal women). If exemestane is used during pregnancy or if the patient becomes pregnant while receiving the drug, the patient should be apprised of the potential hazard to the fetus and the potential risk for pregnancy loss.

Estrogenic Agents

Estrogenic agents should not be administered concomitantly with exemestane.(See Drug Interactions: Estrogenic Agents.)

Effects on Bone

Exemestane may cause a reduction in bone mineral density (BMD). Postmenopausal women receiving an aromatase inhibitor as adjuvant therapy are at high risk for osteoporosis. Following 2 years of adjuvant treatment with exemestane or tamoxifen, the reductions from baseline in lumbar spine and femoral neck BMD were 3.1 and 4.2%, respectively, in patients receiving exemestane and 0.2 and 0.3%, respectively, in those receiving tamoxifen. In a placebo-controlled trial, lumbar spine and femoral neck BMD were decreased by 3.5 and 4.6%, respectively, in patients receiving exemestane for 2 years, compared with 2.4 and 2.6%, respectively, in those receiving placebo. Concomitant bisphosphonate therapy and supplementation of vitamin D and calcium were not allowed in these clinical trials. In Intergroup Exemestane Study 031 (which was initiated after patients had completed 2-3 years of adjuvant tamoxifen therapy), patients switched to exemestane to complete 5 years of adjuvant therapy had a higher incidence of fracture during study treatment or posttreatment follow-up than did those who continued receiving tamoxifen (11 versus 8%).

All postmenopausal women initiating adjuvant therapy with an aromatase inhibitor should be evaluated for risk of osteoporotic fractures. Screening with dual energy radiographic absorptiometry (DXA) to determine the BMD of the hip and spine should be performed in conjunction with assessment of other risk factors for fracture (e.g., age, low body mass index, family history of hip fracture, prior fragility fracture, history of cigarette smoking, excess alcohol consumption, current or prior corticosteroid use). Patients should be monitored closely for changes in risk status during therapy, and BMD should be assessed at regular intervals (e.g., every 1-2 years in those with osteopenia or osteoporosis). Other potential causes of osteoporosis (e.g., vitamin D deficiency, hyperthyroidism, hyperparathyroidism, hypercalciuria) should be considered. The manufacturer states that concentrations of 25-hydroxyvitamin D should be measured routinely prior to initiation of exemestane therapy, and women with vitamin D deficiency should receive supplemental vitamin D. Appropriate therapy to prevent further bone loss should be initiated as clinically indicated. The decision to initiate therapy with an antiresorptive agent (e.g., a bisphosphonate, denosumab) should be based on overall risk of fracture and rate of bone loss. All women receiving adjuvant therapy with an aromatase inhibitor should be advised to adopt lifestyle changes (e.g., weight-bearing exercise, abstinence from smoking, moderation in alcohol consumption) and dietary supplementation with calcium and vitamin D to reduce the risk of osteoporosis.

Hematologic Effects

Grade 3 or 4 lymphocytopenia was reported in 20% of patients with advanced breast cancer receiving exemestane therapy; however, 89% of these patients had preexisting lower-grade lymphocytopenia, and 40% either recovered or improved to a lesser severity lymphopenia during exemestane therapy. Patients did not experience a substantial increase in viral infections, and no opportunistic infections were observed.

In patients with early-stage breast cancer, hematologic abnormalities were reported less frequently in those receiving exemestane compared with those receiving tamoxifen; grade 3 or 4 abnormalities occurred rarely (about 0.1% of patients).

Hepatic Effects

Serum aminotransferase (AST, ALT), alkaline phosphatase, and γ-glutamyltransferase (γ-glutamyltranspeptidase, GGT, GGTP) concentrations exceeding 5 times the upper limit of normal (i.e., grade 3 or worse) have been rarely reported in patients receiving exemestane for treatment of advanced breast cancer, but generally appear to be attributable to bone or liver metastasis. In one study, grade 3 or 4 elevations in GGT concentrations occurred in patients without evidence of liver metastasis in 3 or 2% of those receiving exemestane or megestrol acetate, respectively.

In patients with early-stage breast cancer, elevated serum concentrations of bilirubin and alkaline phosphatase were reported more frequently in patients receiving exemestane (5-7 and 14-15%, respectively) compared with those receiving tamoxifen (0.8 and 3%, respectively) or placebo (0 and 7%, respectively). Grade 3-4 elevations in bilirubin concentrations occurred rarely in patients receiving exemestane (0.9%) or tamoxifen (0.1%).

Renal Effects

In clinical studies in patients with early-stage breast cancer, elevated serum creatinine concentrations were reported in 6% of patients receiving exemestane compared with 4% of those receiving tamoxifen and 0% of those receiving placebo.

Specific Populations

Pregnancy

Category X.(See Fetal/Neonatal Morbidity and Mortality under Cautions: Warnings/Precautions.)

Lactation

Exemestane is distributed into milk in rats; because of the potential for serious adverse effects in nursing infants, a decision should be made whether to discontinue the drug, taking into account the importance of the drug to the woman.

Pediatric Use

Exemestane is not indicated in pediatric patients; safety and efficacy have not been established.

Geriatric Use

Use of exemestane in geriatric patients requires no special precautions.

Premenopausal Women

Because of the lack of safety and efficacy data and because of concerns about possible incomplete estrogen suppression and reflex increases in gonadotrophin levels (ovarian hyperstimulation syndrome) in this population, the manufacturer states that exemestane is contraindicated in premenopausal women.

Hepatic or Renal Impairment

Although safety of chronic dosing in patients with moderate or severe hepatic or renal impairment has not been established, dosage adjustment does not appear to be necessary.(See Dosage and Administration: Special Populations.)

Common Adverse Effects

Adverse events reported in 10% or more of patients with early-stage breast cancer receiving exemestane include hot flushes (flashes), fatigue, arthralgia, headache, insomnia, increased sweating, alopecia, hypertension, nausea, and abdominal pain. Adverse events resulting in drug discontinuance occurred in similar proportions of exemestane- and tamoxifen-treated patients.

Adverse events reported in 10% or more of patients with advanced breast cancer receiving exemestane include fatigue, nausea, hot flushes, pain, depression, insomnia, anxiety, and dyspnea.

Drug Interactions

Drugs Affecting or Metabolized by Hepatic Microsomal Enzymes

Exemestane is metabolized by cytochrome P-450 isoenzyme 3A4 (CYP3A4). Exemestane does not inhibit CYP isoenzymes 1A2, 2C9, 2D6, 2E1, or 3A4.

Cytochrome P-450 Isoenzyme 3A4 Inhibitors

Concomitant administration of ketoconazole, a potent CYP3A4 inhibitor, and exemestane did not substantially alter the pharmacokinetics of exemestane. Therefore, clinically important pharmacokinetic interactions between exemestane and CYP3A4 inhibitors appear to be unlikely.

Cytochrome P-450 Isoenzyme 3A4 Inducers

Administration of the potent CYP3A4 inducer rifampin (600 mg daily for 14 days) followed by exemestane (single 25-mg dose) resulted in a 41% decrease in peak plasma concentrations and a 54% decrease in systemic exposure of exemestane. Concomitant use of other CYP3A4 inducers (e.g., carbamazepine, phenobarbital, phenytoin, St. John's wort [Hypericum perforatum]) also may result in decreased exposure to exemestane. An increase in exemestane dosage to 50 mg once daily is recommended in patients receiving concomitant therapy with a potent CYP3A4 inducer.

Estrogenic Agents

Because estrogens may diminish the pharmacologic action of exemestane, the drugs should not be used concomitantly.

Pharmacokinetics

Absorption

Bioavailability

Rapidly absorbed following oral administration, with peak concentrations in women with breast cancer or healthy women attained within about 1.2 or 2.9 hours, respectively.

Steady-state plasma concentrations achieved in approximately 7 days.

Food

High-fat meal increases plasma exemestane concentrations by approximately 40%.

Distribution

Extent

Extensively distributed into tissues.

Crosses placenta.

Distributed into milk in animals; not studied in pregnant or nursing women.

Plasma Protein Binding

90% (mainly α1-acid glycoprotein and albumin).

Elimination

Metabolism

Extensively metabolized via CYP3A4 and aldoketoreductases; metabolites are inactive or inhibit aromatase with decreased potency compared with parent drug. One metabolite, 17-hydroexemestane, may have androgenic activity.

Elimination Route

Excreted similarly (42%) in both urine and feces; <1% excreted as unchanged drug in urine.

Half-life

Approximately 24 hours.

Special Populations

In patients with moderate or severe hepatic or renal impairment, AUC is approximately 3 times higher than in healthy individuals.

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