What is the recommended regimen, dosing, and monitoring for androgen deprivation therapy (ADT) combined with abiraterone acetate and prednisone in prostate cancer?

ADT Plus Abiraterone-Prednisone Regimen

For metastatic castration-sensitive prostate cancer, administer abiraterone acetate 1,000 mg orally once daily with prednisone 5 mg orally once daily, combined with continuous ADT (LHRH agonist, LHRH antagonist, or bilateral orchiectomy), and continue treatment until disease progression to castration-resistant state. 1, 2

Dosing Specifications

Standard Regimen

• Abiraterone acetate: 1,000 mg (four 250 mg tablets or two 500 mg tablets) orally once daily 3, 4, 3, 2
• Prednisone: 5 mg orally once daily for metastatic castration-sensitive disease 1, 4, 2
• ADT backbone: LHRH agonist, LHRH antagonist, or surgical castration must be continued concurrently 5, 2

Administration Requirements

• Fasting requirement: Take on an empty stomach—no food for 2 hours before and 1 hour after administration 2
• Tablet integrity: Swallow whole with water; do not crush or chew 2

Alternative Dosing Options

• Low-fat breakfast dosing: 250 mg daily administered after a low-fat breakfast as an alternative to 1,000 mg fasting dose to reduce financial toxicity and improve adherence 1, 6
• Fine-particle formulation: 500 mg with 4 mg methylprednisolone orally twice daily (Category 2B alternative) 1

Patient Selection Criteria

Strong Recommendation (Category 1)

High-risk metastatic castration-sensitive disease defined by LATITUDE criteria—at least 2 of the following 3, 5, 3:

• Gleason score ≥8
• ≥3 bone lesions
• Visceral metastases

Moderate Recommendation

Lower-risk or all metastatic castration-sensitive disease per STAMPEDE, including heterogeneous populations with M1, N1, or high-risk M0 disease 1, 3, 1, 4

Age Considerations

• Patients <70 years: Derive greater survival benefit (HR 0.51) compared to those ≥70 years (HR 0.94) 1, 6
• Patients ≥70 years: Experience higher grade 3-5 adverse events (47% vs 33%) and increased treatment-related deaths (9 vs 3), requiring careful risk-benefit assessment 1, 6

Duration of Treatment

Metastatic Disease (M1)

Continue abiraterone plus prednisone until progression to castration-resistant prostate cancer 3, 5, 4, 3

Node-Positive or High-Risk M0 Disease

2 years of abiraterone plus prednisone when combined with curative-intent external beam radiotherapy 1

Monitoring Requirements

Baseline Assessment

• Hepatic function: ALT, AST, total bilirubin 1, 2
• Blood pressure: Establish baseline 1, 6
• Serum potassium: Check for hypokalemia 1, 6
• Renal function: Baseline assessment 1

Ongoing Monitoring

• Monthly minimum: Blood pressure, serum potassium, symptoms of fluid retention 1, 6
• Hepatic monitoring: Regular ALT, AST, bilirubin checks given 7% incidence of grade 3-5 liver toxicity 1, 6
• Cardiovascular surveillance: Monitor for hypertension (10% severe) and cardiac disorders including atrial fibrillation 1, 5, 1, 6
• Testosterone levels: Document castrate levels (<50 ng/dL) if clinically indicated 1

Patients with Diabetes

Critical monitoring: Assess blood glucose and antidiabetic medication adjustments when combining with thiazolidinediones or repaglinide due to severe hypoglycemia risk 2

Dose Modifications

Moderate Hepatic Impairment (Child-Pugh Class B)

• Starting dose: Reduce to 250 mg once daily 2
• Enhanced monitoring: Weekly ALT/AST/bilirubin for first month, every 2 weeks for next 2 months, then monthly 2
• Discontinuation criteria: ALT/AST >5× ULN or total bilirubin >3× ULN—discontinue permanently 2

Severe Hepatic Impairment (Child-Pugh Class C)

Contraindicated: Do not use abiraterone 2

Treatment-Emergent Hepatotoxicity

• Interrupt treatment: If ALT/AST >5× ULN or total bilirubin >3× ULN 2
• Restart at 750 mg daily: After recovery to baseline or ALT/AST ≤2.5× ULN and bilirubin ≤1.5× ULN 2
• Further reduction to 500 mg: If hepatotoxicity recurs at 750 mg dose 2
• Monitoring after restart: Every 2 weeks for 3 months, then monthly 2

Common Adverse Events

Mineralocorticoid Excess (Most Common)

• Hypertension: 22% overall, 4% severe; requires blood pressure control before treatment initiation 5
• Hypokalemia: 17% incidence; correct before starting therapy 5
• Peripheral edema: 28% incidence 5

Other Frequent Events (>10%)

• Fatigue (39%), arthralgia, nausea, hot flushes (22%), diarrhea, upper respiratory infection, cough 5, 2
• Cardiac events including atrial fibrillation (4%) 5

Laboratory Abnormalities (>20%)

Anemia, elevated alkaline phosphatase, hypertriglyceridemia, lymphopenia, hypercholesterolemia, hyperglycemia 2

Critical Contraindications and Warnings

Combination with Radium-223

Not recommended: Increased fractures and mortality when abiraterone plus prednisone combined with radium-223 dichloride 2

Adrenocortical Insufficiency

Monitor for symptoms during stressful situations; increased corticosteroid dosing may be required before, during, and after stress 2

Reproductive Considerations

Embryo-fetal toxicity: Males with female partners of reproductive potential must use effective contraception 2

Efficacy Outcomes

Overall Survival

• LATITUDE (high-risk): Median OS 53.3 months vs 36.5 months (HR 0.62; P<0.0001) 7, 8
• STAMPEDE (all-comers): HR 0.63 (95% CI 0.50-0.76; P<0.0001) 1

Radiographic Progression-Free Survival

• LATITUDE: 33.0 months vs 14.8 months (HR 0.47; P<0.001) 7
• STAMPEDE: HR 0.29 overall for failure-free survival 1, 6

Quality of Life Benefits

Significant improvements in pain intensity progression, fatigue, functional decline, prostate cancer-related symptoms, and overall health-related quality of life 5, 9

Common Pitfalls to Avoid

LHRH agonist flare: In patients with weight-bearing bone metastases at risk for flare symptoms, coadminister first-generation antiandrogen for at least 7 days when using LHRH agonist (not required with LHRH antagonists) 5

Inadequate monitoring: Failure to monitor blood pressure and potassium monthly leads to preventable cardiovascular complications given 10% severe hypertension rate 1, 6

Age-related toxicity: Patients ≥70 years require heightened surveillance due to 47% grade 3-5 adverse event rate versus 33% in younger patients 1, 6

Food interaction: Taking with food significantly increases absorption and toxicity risk—strict fasting requirement must be emphasized 2

Premature discontinuation of ADT: Continue ADT backbone throughout treatment; discontinuing castration negates abiraterone efficacy 5, 2