Megestrol Acetate

Megestrol acetate oral suspension is indicated for the treatment of anorexia, cachexia, or an unexplained significant weight loss in patients with a diagnosis of acquired immunodeficiency syndrome (AIDS). Limitations of Use Therapy with megestrol acetate oral suspension for weight loss should only be insti­tuted after treatable causes of weight loss are sought and addressed. These treatable causes include possible malignancies, systemic infections, gastrointestinal disorders affecting absorption, endocrine disease, renal disease or psychiatric diseases. Megestrol acetate oral suspension is not intended for prophylactic use to avoid weight loss. Megestrol acetate oral suspension is a progestin indicated for the treatment of anorexia, cachexia, or an unexplained significant weight loss in patients with a diagnosis of acquired immunodeficiency syndrome (AIDS) (1) .

Megestrol acetate oral suspension is milky white, lemon flavored, and contains 125 mg per mL. Oral suspension containing 125 mg of megestrol acetate per mL (3) .

History of hypersensitivity to megestrol acetate or any component of the formulation. Pregnancy [see Warnings and Precautions ( 5.2 ), Use in Specific Populations ( 8.1 , 8.3 )]. History of hypersensitivity to megestrol acetate or any component of the formulation ( 4 ). Pregnancy ( 4 )( 8.1 ).

Use with caution in patients with a history of thromboembolic disease (5.1) . Fetal Effects: May cause fetal harm. Females of reproductive potential should be advised to avoid becoming pregnant ( 5.2 ). Clinical cases of overt Cushing's Syndrome have been reported in association with the chronic use of megestrol acetate. In addition, clinical cases of adrenal insufficiency have been observed in patients receiving or being withdrawn from chronic megestrol acetate in the stressed and non-stressed state (5.3) . New onset and exacerbation of pre-existing diabetes have been reported (5.4) .

5.1 General Effects on HIV viral replication have not been determined. Use with caution in patients with a history of thromboembolic disease.

5.2 Fetal Toxicity Based on animal studies, megestrol acetate may cause fetal harm when administered to a pregnant woman. Pregnant rats treated with low doses of megestrol acetate resulted in a reduction in fetal weight and number of live births, and feminization of male fetuses. There are no available human data to assess for any drug associated risks of miscarriage, birth defects, or adverse maternal or fetal outcomes. If this drug is used during pregnancy, or if the patient becomes pregnant while taking (receiving) this drug, advise the patient of the poten­tial hazard to the fetus [see Use in Specific Populations ( 8.1 ), Nonclinical Toxicology ( 13.1 )]. Obtain a pregnancy test in females of reproductive potential prior to initiating treatment with megestrol acetate oral suspension [see Dosage and Administration ( 2.1 )]. Advise females of reproductive potential to use effective contraception while taking megestrol acetate oral suspension [see Use in Specific Populations ( 8.3 )].

5.3 Adrenal Insufficiency The glucocorticoid activity of megestrol acetate oral suspension has not been fully evaluated. Clinical cases of overt Cushing's Syndrome have been reported in association with the chronic use of megestrol acetate. In addition, clinical cases of adrenal insufficiency have been observed in patients receiving or being withdrawn from chronic megestrol acetate therapy in the stressed and non-stressed state. Furthermore, adrenocorticotropin (ACTH) stimulation testing has revealed the frequent occurrence of asymptomatic pituitary-adrenal suppression in patients treated with chronic megestrol acetate therapy. Therefore, the possibility of adrenal insufficiency should be considered in any patient receiving or being withdrawn from chronic megestrol acetate oral suspension therapy who presents with symptoms and/or signs suggestive of hypoadrenalism (e.g., hypotension, nausea, vomiting, dizziness, or weakness) in either the stressed or non-stressed state. Laboratory evaluation for adrenal insufficiency and consideration of replacement or stress doses of a rapidly acting glucocorticoid are strongly recommended in such patients. Failure to recognize inhibition of the hypothalamic-pituitary adrenal axis may result in death. Finally, in patients who are receiving or being withdrawn from chronic megestrol acetate oral suspension therapy, consideration should be given to the use of empiric therapy with stress doses of a rapidly acting glucocorticoid during stress or serious intercurrent illness (e.g., surgery, infection).

5.4 Diabetes Clinical cases of new onset diabetes mellitus and exacerbation of pre-existing diabetes mellitus have been reported in association with the chronic use of megestrol acetate.

The most common adverse events occurring in > 5% of all patients receiving 800mg/20mL of megestrol acetate oral suspension in the two clinical efficacy trials were nausea, diarrhea, impotence, rash, flatulence, hypertension, and asthenia (6.2) . To report SUSPECTED ADVERSE REACTIONS, contact TWi Pharmaceuticals, Inc. at 1-844-518-2989 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

6.1 Serious and Otherwise Important Adverse Reactions The following serious reactions and otherwise important adverse drug reactions are discussed in greater detail in other sections of the labeling: Hypersensitivity [see Contraindications ( 4 )] Thromboembolic Disease [see Warnings and Precautions ( 5.1 )] Adrenal Insufficiency [see Warnings and Precautions ( 5.3 )] Diabetes [see Warnings and Precautions ( 5.4 )]

6.2 Clinical Trial Experience Because clinical trials are conducted under widely varying conditions, adverse reactions 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 safety of megestrol acetate oral suspension, 125 mg/mL was based on three studies of megestrol acetate oral suspension (40 mg/mL). The adverse reaction profile of these 3 studies are presented below. Adverse events which occurred in at least 5% of patients in any arm of the two clinical efficacy trials and the open trial for megestrol acetate oral suspension are listed below by treatment group. All patients listed had at least one post baseline visit during the 12 study weeks. Table 1: Adverse Events Percentage of Patients Reporting Adverse Events Trial 1 (N=236) Trial 2 (N=87) Open Label Trial Placebo Placebo Megestrol Acetate mg/day 0 100 400 800 0 800 1200 No. of Patients N=34 N=68 N=69 N=65 N=38 N=49 N=176 Diarrhea 15 13 8 15 8 6 10 Impotence 3 4 6 14 0 4 7 Rash 9 9 4 12 3 2 6 Flatulence 9 0 1 9 3 10 6 Hypertension 0 0 0 8 0 0 4 Asthenia 3 2 3 6 8 4 5 Insomnia 0 3 4 6 0 0 1 Nausea 9 4 0 5 3 4 5 Anemia 6 3 3 5 0 0 0 Fever 3 6 4 5 3 2 1 Libido Decreased 3 4 0 5 0 2 1 Dyspepsia 0 0 3 3 5 4 2 Hyperglycemia 3 0 6 3 0 0 3 Headache 6 10 1 3 3 0 3 Pain 6 0 0 2 5 6 4 Vomiting 9 3 0 2 3 6 4 Pneumonia 6 2 0 2 3 0 1 Urinary Frequency 0 0 1 2 5 2 1 Adverse events which occurred in 1% to 3% of all patients enrolled in the two clinical efficacy trials with at least one follow-up visit during the first 12 weeks of the study are listed below by body system. Adverse events occurring less than 1% are not included. There were no significant differences between incidence of these events in patients treated with megestrol acetate and patients treated with placebo. Body as a Whole – abdominal pain, chest pain, infection, moniliasis and sarcoma Cardiovascular System – cardiomyopathy and palpitation Digestive System – constipation, dry mouth, hepatomegaly, increased salivation and oral moniliasis Hemic and Lymphatic System – leukopenia Metabolic and Nutritional – LDH increased, edema and peripheral edema Nervous System – paresthesia, confusion, convulsion, depression, neuropathy, hypesthesia and abnormal thinking Respiratory System – dyspnea, cough, pharyngitis and lung disorder Skin and Appendages – alopecia, herpes, pruritus, vesiculobullous rash, sweating and skin disorder Special Senses – amblyopia Urogenital System – albuminuria, urinary incontinence, urinary tract infection and gynecomastia.

6.3 Postmarketing Experience Postmarketing reports associated with megestrol acetate oral suspension include thromboembolic phenomena including thrombophlebitis, deep vein thrombosis, and pulmonary embolism; and glucose intolerance.

Due to a significant decrease in indinavir exposure, administration of a higher dose of indinavir should be considered when coadministering with megestrol acetate ( 7.1 , 12.3 ).

7.1 Indinavir Due to the significant decrease in the exposure of indinavir by megestrol acetate, administration of a higher dose of indinavir should be considered when coadministering with megestrol acetate [See Clinical Pharmacology ( 12.3 )] .

7.2 Zidovudine and Rifabutin No dosage adjustment for zidovudine and rifabutin is needed when megestrol acetate is coadministered with these drugs [See Clinical Pharmacology ( 12.3 )] .

Lactation : Women infected with HIV-1 should be instructed not to breastfeed due to the potential for HIV transmission ( 8.2 ). Geriatrics : In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal or cardiac function, and of concomitant disease or other therapy ( 8.5 ).

8.1 Pregnancy Risk Summary Based on animal data, megestrol acetate may cause fetal harm when administered to a pregnant woman and is contraindicated during pregnancy [see Contraindications ( 4 )] . There are no available human data to assess for any drug-associated risks of miscarriage, birth defects, or adverse maternal or fetal outcomes. There are no adequate animal developmental toxicity data at clinically relevant doses. Pregnant rats treated with low doses of megestrol acetate resulted in a reduction in fetal weight and number of live births, and feminization of male fetuses at doses below maximum recommended clinical dosing based on body surface area ( see Data ). Advise a pregnant women of the potential risk to the fetus. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and of miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. Data Reproduction studies were performed in pregnant rats at oral doses ranging from 0.05 to 12.5 mg/kg/day, which are below the maximum recommended clinical dose based on body surface area. Reduction in fetal weight and number of live births were observed at 12.5 mg/kg/day (5 times lower than the maximum clinical dose) when dams were dosed on days 12 through 18 of pregnancy. Feminization of male fetuses also occurred when dams were dosed on days 13 through 20 of pregnancy at 3 mg/kg/day, approximately 22 times below the maximum clinical dose.

8.2 Lactation Risk Summary The Centers for Disease Control and Prevention recommend that HIV-1 infected mothers not breastfeed their infants to avoid risking postnatal transmission of HIV-1. Megestrol acetate is present in human milk. There are no data on the effects of megesterol acetate on the breastfed infant or the effects on milk production. Because of the potential for HIV transmission and adverse effects on a breastfed infant, instruct mothers not to breastfeed if they are taking megestrol acetate oral suspension.

8.3 Females and Males of Reproductive Potential Pregnancy testing Pregnancy testing is recommended prior to treatment with megestrol acetate oral suspension [see Dosage and Administration ( 2.1 ), Use in Specific Populations ( 8.1 )]. Contraception Megestrol acetate oral suspension may cause fetal harm when administered during pregnancy [see Use in Specific Populations ( 8.1 )]. Advise females of reproductive potential to use effective contraception during treatment with megestrol acetate oral suspension.

8.4 Pediatric Use Safety and effectiveness in pediatric patients have not been established.

8.5 Geriatric Use Clinical studies of megestrol acetate oral suspension in the treatment of anorexia, cachexia, or an unexplained significant weight loss in patients with AIDS did not include sufficient numbers of patients aged 65 years and older to determine whether they respond differently than younger patients. Other reported clinical experience has not identified differences in responses between elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy. Megestrol acetate is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

8.6 Use in Women Megestrol acetate has had limited use in HIV infected women. All 10 women in the clinical trials reported breakthrough bleeding. Megestrol acetate oral suspension is a progesterone derivative, which may induce vaginal bleeding in women.

Several investigators have reported on the appetite enhancing property of megestrol acetate and its possible use in cachexia. The precise mechanism by which megestrol acetate produces effects in anorexia and cachexia is unknown at the present time.