What is the administration method for Abiraterone (Zytiga) in prostate cancer treatment?

From the Guidelines

Abiraterone should be administered at a dose of 250 mg/day following a low-fat breakfast, or 1,000 mg/day after an overnight fast, in combination with concurrent steroid therapy, such as oral prednisone 5 mg twice daily or oral methylprednisolone 4 mg twice daily, to prevent mineralocorticoid excess side effects. This recommendation is based on the most recent study from 2023 1, which found that the low-dose arm (250 mg/day) was non-inferior to the standard dose (1,000 mg/day) in terms of log change in PSA and PSA response rate. The study also suggested that the low-dose arm may be associated with reduced financial toxicity and improved adherence.

Administration Guidelines

• Abiraterone should be taken orally once daily, either on an empty stomach or with a low-fat breakfast
• The medication should be administered with concurrent steroid therapy to prevent mineralocorticoid excess side effects
• Patients should swallow the tablets whole with water and should not crush or chew them
• Regular monitoring of liver function, potassium levels, and blood pressure is necessary during treatment

Monitoring and Side Effects

• Monitoring of liver function, potassium and phosphate levels, and blood pressure readings on a monthly basis is warranted during abiraterone therapy 1
• Symptom-directed assessment for cardiac disease is also warranted, particularly in patients with pre-existing cardiovascular disease
• Common adverse reactions with abiraterone/prednisone include fatigue, back or joint discomfort, peripheral edema, diarrhea, nausea, and hypokalemia 1

Special Considerations

• Food impacts absorption unpredictably, and side effects should be monitored closely when administering abiraterone with food
• The fine-particle formulation of abiraterone can be used instead of the original formulation in the treatment of men with metastatic CRPC, but switching from one formulation to the other on disease progression should not be undertaken 1

From the FDA Drug Label

2.1 Recommended Dose for Metastatic CRPC The recommended dose of abiraterone acetate tablets is 1,000 mg (two 500 mg tablets or four 250 mg tablets) orally once daily with prednisone 5 mg orally twice daily. 2.3 Important Administration Instructions Abiraterone acetate tablets must be taken on an empty stomach, at least one hour before or at least two hours after a meal [see Clinical Pharmacology (12.3)] . The tablets should be swallowed whole with water. Do not crush or chew tablets.

The administration of abiraterone for prostate cancer is as follows:

• Dose: 1,000 mg (two 500 mg tablets or four 250 mg tablets) orally once daily
• Administration: on an empty stomach, at least one hour before or at least two hours after a meal
• Co-administration: with prednisone 5 mg orally twice daily
• Tablet handling: swallow whole with water, do not crush or chew tablets 2

From the Research

Administration of Abiraterone for Prostate Cancer

• Abiraterone acetate is an orally administered small molecule that irreversibly inhibits a rate-limiting enzyme in androgen biosynthesis, CYP17, and blocks the synthesis of androgens in the testes, adrenal glands, and prostate without causing adrenal insufficiency 3.
• The recommended Phase II dose of abiraterone acetate is 1000 mg orally daily in combination with prednisone 5 mg twice daily 3.
• In clinical studies, abiraterone acetate is well tolerated and shows promising clinical activity in castration-resistant prostate cancer 3.
• Abiraterone acetate plus prednisone is indicated for metastatic castration-resistant prostate cancer, and the recommended dose is 1000 mg daily, given once daily as four 250-mg tablets, plus prednisone 5 mg daily 4.

Combination Therapy

• The addition of abiraterone acetate and prednisone to androgen-deprivation therapy significantly increased overall survival and radiographic progression-free survival in men with newly diagnosed, metastatic, castration-sensitive prostate cancer 4.
• Apalutamide plus abiraterone acetate and prednisone versus placebo plus abiraterone and prednisone in metastatic, castration-resistant prostate cancer showed that apalutamide plus abiraterone-prednisone improved radiographic progression-free survival 5.
• Abiraterone acetate plus prednisolone with or without enzalutamide for patients with metastatic prostate cancer starting androgen deprivation therapy showed that combining enzalutamide with abiraterone and androgen deprivation therapy did not improve survival 6.

Efficacy and Toxicity

• A systematic review and meta-analysis of abiraterone for treatment of metastatic castration-resistant prostate cancer showed that abiraterone significantly prolonged overall survival, radiographic progression-free survival, and time to PSA progression, and increased PSA response rate and objective response rate 7.
• The adverse events caused by abiraterone are acceptable and can be controlled, with the most common grade 3-4 treatment-emergent adverse events being hypertension, hypokalemia, and edema 3, 4, 5, 6.