abiraterone acetate

abiraterone acetate

Zytiga

Pharmacologic class: CYP17 inhibitor

Therapeutic class: Antineoplastic

Pregnancy risk category X

Action

Converts from abiraterone acetate in vivo to abiraterone, an androgen biosynthesis inhibitor that inhibits 17α-hydroxylase/C17,20-lyase (CYP17), an enzyme that's expressed in testicular, adrenal, and prostatic tumor tissues and is required for androgen biosynthesis, thereby causing androgen-sensitive prostatic carcinoma to respond to such treatment that decreases androgen levels

Availability

Tablets: 250 mg

Indications and dosages

Metastatic castration-resistant prostate cancer in combination with prednisone in patients who have received prior chemotherapy containing docetaxel

Adults: 1,000 mg P.O. daily in combination with prednisone 5 mg P.O. b.i.d.

Dosage adjustment

• Baseline moderate hepatic impairment (Child-Pugh Class B)

Contraindications

• Pregnancy
• Women of childbearing age

Precautions

Use cautiously in:
• mild to moderate hepatic disease, mineralocorticoid excess, adrenocortical insufficiency, CV disease
• co-administration of CYP2D6 substrates with a narrow therapeutic index (avoid use or if alternative treatments can't be used, consider a dosage reduction of the concomitant CYP2D6 substrate)
• co-administration of strong inhibitors and inducers of CYP3A4 (avoid or use with caution)
• breastfeeding women
• children (safety and efficacy not established).

Administration

Be aware that pregnant women and women of childbearing age shouldn't handle drug without wearing gloves.
• Control hypertension and correct hypokalemia before starting drug.
• Give tablets whole and be aware that patient shouldn't eat for at least 2 hours before drug is administered and for at least 1 hour after drug is administered.

Don't use in patients with baseline severe hepatic impairment (Child-Pugh Class C).
• Withhold drug in patients who develop hepatotoxicity during treatment until recovery. May restart drug at a reduced dosage.

Discontinue drug if patient develops severe hepatotoxicity.
• Be aware that safety isn't established in patients with left ventricular ejection fraction less than 50% or New York Heart Association Class III or IV heart failure.

Adverse reactions

CV: hypertension, arrhythmia, heart failure

GI: diarrhea, dyspepsia

GU: urinary tract infection, urinary frequency, nocturia

Hepatic: hepatotoxicity

Metabolic: hypokalemia, mineralocorticoid excess with fluid retention, adrenocortical insufficiency,

hyperosmolar coma or death Musculoskeletal: joint swelling or discomfort, muscle discomfort, fractures, musculoskeletal and connective tissue disorders

Respiratory: cough, upper respiratory tract infection

Other: fluid retention, edema, hot flushes, chest pain or discomfort

Interactions

Drug-drug.CYP2D6 substrates with a narrow therapeutic index (such as thioridazine): increased CYP2D6 substrate Cmax and area under the curve (AUC) CYP3A4 inducers (such as carbamazepine, phenobarbital, phenytoin, rifabutin, rifapentine, rifampin): unknown effects Strong CYP3A4 inhibitors (such as atazanavir, clarithromycin, indinavir, itraconazole, ketoconazole, nefazodone, nelfinavir, ritonavir, saquinavir, telithromycin, voriconazole): unknown effects

Drug-diagnostic tests.ALT, AST, triglycerides, total bilirubin): increased levels

Potassium: reduced level

Drug-food.Any food: increased abiraterone AUC

Patient monitoring

• Monitor hepatic function tests closely and modify, interrupt, or discontinue dosing as prescribed.
• Monitor blood pressure, serum potassium level, and signs and symptoms of fluid retention at least monthly.
• Monitor patient for signs and symptoms of adrenocortical insufficiency (such as hypoglycemia, hypotension, orthostatic hypotension, dehydration, weight loss, and nausea and vomiting); be aware that increased dosage of corticosteroids may be indicated before, during, and after stressful situations.

Patient teaching

• Tell patient to swallow tablets whole with water on an empty stomach (don't eat for at least 2 hours before taking drug and for at least 1 hour after taking drug).
• Instruct patient to take drug with prednisone as prescribed and not to interrupt or stop either drug without consulting prescriber.
• Instruct patient to report joint or muscle discomfort, urinary or respiratory tract infection, urinating more frequently or during the night, dizziness on standing, extreme thirst, or weight loss.

Advise pregnant women and women of childbearing age not to handle drug without wearing gloves.
• Advise male patient of child-producing age to use a condom and another effective contraceptive during therapy if having sex with a woman of childbearing potential.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and food mentioned above.

Lockerbie Bomber's cancer drug

A popular term for an anti-androgenic agent which results in a 36% increase in average survival and reduced pain in men with advanced castration-resistant metastatic prostate cancer.

Adverse effects
Joint swelling and discomfort, hypokalaemia, oedema, muscle discomfort, hypophosphataemia, hot flushing, diarrhoea, urinary tract infection, cough.
References in periodicals archive ?
Food and Drug Administration (FDA) for Abiraterone Acetate Tablets, 250 mg.
The Phase III Randomized, Double-blind, Placebo-controlled Trial of Radium-223 Dichloride in Combination With Abiraterone Acetate and Prednisone/Prednisolone in the Treatment of Asymptomatic or Mildly Symptomatic Chemotherapy-naive Subjects With Bone Predominant Metastatic Castration-resistant Prostate Cancer (ERA223), investigating radium-223 in combination with abiraterone acetate and prednisone among chemotherapy-naive men with CRPC and bone metastases, is currently recruiting patients.
Effects of Abiraterone Acetate on Androgen Signaling in Castrate-Resistant Prostate Cancer in Bone, J.
Differential response to abiraterone acetate and di-n- butyl phthalate in an androgensensitive human fetal testis xenograft bioassay.
These drugs are Degarelix, Abiraterone acetate, Plerixafor, Eribulin mesylate, Mucotrol, Crizotinib, Etravirine, Nelarabine, Fingolimod, Tolvaptan, Rilpivirine, Vemurafenib, Lipiodol UF, Cabazitaxel and Panitumumab.
This trend continued in 2011 and 2012, when 3 therapies, the CYP17 inhibitor abiraterone acetate (Zytiga; Janssen Biotech) (7), the bone-targeting agent [sup.
The medication, abiraterone acetate -- marketed as Zytiga -- also delayed the development of pain and deterioration of the patients' overall condition.
The All-Wales Medicines Strategy Group (AWMSG) has approved the use of the drug abiraterone acetate for men with cancer, which has spread beyond the prostate and is resistant to conventional hormone treatment (metastatic castration-resistant prostate cancer).
The new treatments are folfirinox for advanced pancreatic cancer, degarelix for advanced prostate cancer, abiraterone acetate with prednisone or prednisolone for advanced prostate cancer, ipilimumab for malignant melanoma, imatinib for patients who have been treated for stomach cancer to reduce the risk of the disease recurring and bevacizumab (avastin) and capecitabine for breast cancer.
The study demonstrated that abiraterone acetate, in combination with prednisone or prednisolone, improved overall survival (OS) in patients with metastatic castration resistant prostate cancer whose disease had progressed following chemotherapy.
European regulators have been asked to approve the pill, abiraterone acetate, which is already licensed in the US.
Abiraterone acetate (AA) plus low dose prednisone (P) improves overall survival (OS) in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC) who have progressed after docetaxel-based chemotherapy (chemo): Results of COU-AA-301, a randomized double-blind placebo-controlled phase III study.