Introduction

Abiraxen 250 mg, formulated with Abiraterone Acetate, is a targeted oral treatment designed for patients with advanced prostate cancer. Specifically, it is used in combination with corticosteroids for the treatment of metastatic castration-resistant prostate cancer (mCRPC) and metastatic high-risk castration-sensitive prostate cancer (mCSPC). Manufactured under stringent pharmaceutical standards by Everest Pharmaceuticals Ltd, Abiraxen is reliably sourced and globally supplied by Orio Pharma, a specialist in oncology medicines.

Abiraterone Acetate belongs to the class of androgen biosynthesis inhibitors. By blocking the enzyme CYP17A1, it reduces androgen production not only in the testes but also in the adrenal glands and within the tumor itself—providing a systemic anti-androgenic effect.

Key Indications

Abiraxen 250 mg is indicated for the treatment of:

1. Metastatic Castration-Resistant Prostate Cancer (mCRPC)

For use in adult men whose disease has progressed despite androgen deprivation therapy, including those previously treated with chemotherapy or who are chemotherapy-naïve.

2. Metastatic High-Risk Castration-Sensitive Prostate Cancer (mCSPC)

Recommended in combination with prednisone and androgen deprivation therapy (ADT) for patients newly diagnosed with high-volume or symptomatic metastatic disease.

Mechanism of Action

Abiraterone Acetate is a prodrug that converts in vivo to abiraterone, a selective and irreversible inhibitor of 17α-hydroxylase/C17,20-lyase (CYP17A1). This enzyme plays a pivotal role in androgen biosynthesis. Inhibition of CYP17A1 blocks the synthesis of testosterone and other androgens from cholesterol precursors.

This systemic suppression of androgens starves androgen-dependent tumor cells, leading to cell death and inhibition of tumor progression. Unlike traditional anti-androgens that block androgen receptors, Abiraterone acts upstream in the biosynthesis cascade, offering a more comprehensive anti-androgenic effect

Dosage and Administration

Standard Regimen:

• Abiraxen: 1,000 mg (four 250 mg tablets) taken orally once daily
  
• Prednisone: 5 mg taken orally twice daily
  

Key Administration Notes:

• Take on an empty stomach (no food 2 hours before and 1 hour after)
  
• Swallow tablets whole with water
  
• Continue treatment until disease progression or unacceptable toxicity
  

Dose adjustments may be required in hepatic impairment or when co-administered with strong CYP3A4 inhibitors or inducers.

Pharmacokinetics

• Absorption: Rapid oral absorption with peak plasma levels in 2 hours
  
• Bioavailability: Increases with food intake; hence, should be taken fasting
  
• Metabolism: Primarily hepatic (CYP3A4 and SULT2A1)
  
• Elimination: Mostly fecal, with minor renal clearance
  
• Half-life: Approximately 12 ± 5 hours
  

Contraindications

• Hypersensitivity to Abiraterone or excipients
  
• Severe hepatic impairment (Child-Pugh Class C)
  
• Women who are or may become pregnant
  
• Patients with uncontrolled hypertension, hypokalemia, or heart failure (prior to correction)
  

Warnings and Precautions

1. Adrenal Insufficiency

Use with corticosteroids minimizes the risk; monitor cortisol levels if symptoms arise.

2. Hepatotoxicity

Monitor liver enzymes regularly. Temporary or permanent discontinuation may be necessary.

3. Hypertension, Hypokalemia, Fluid Retention

Resulting from increased mineralocorticoid levels. Monitor blood pressure, serum potassium, and fluid status.

4. Cardiac Disorders

Caution in patients with a history of cardiovascular disease or QT prolongation.

Adverse Effects

Common:

• Fatigue
  
• Hypertension
  
• Hypokalemia
  
• Fluid retention
  
• Elevated liver enzymes
  
• Joint swelling or discomfort
  
• Hot flushes
  

Serious:

• Hepatotoxicity
  
• Adrenal insufficiency
  
• Cardiac arrhythmias
  
• Severe hypertension
  

Clinical monitoring should include liver function tests, serum potassium, blood pressure, and cardiac evaluations.

Drug Interactions

• CYP3A4 inducers/inhibitors: May affect abiraterone plasma levels.
  
• CYP2D6 substrates: Enhanced effects due to CYP2D6 inhibition by abiraterone.
  
• Mineralocorticoid-sparing agents: Use caution when combining with spironolactone or eplerenone.
  

Avoid grapefruit and grapefruit juice due to potential CYP3A4 interaction.

Use in Special Populations

Pregnancy and Lactation

Not indicated for use in women. Contraindicated in pregnancy due to teratogenic effects.

Pediatric Use

Safety and efficacy in children have not been established.

Geriatric Use

No dose adjustment required; monitor comorbidities closely.

Hepatic Impairment

Not recommended in severe hepatic impairment. Use with caution in mild-to-moderate hepatic dysfunction.

Renal Impairment

No dosage adjustment required for mild to moderate impairment.

Clinical Efficacy

COU-AA-301 and COU-AA-302 Trials

Abiraterone significantly improved overall survival and radiographic progression-free survival in both chemotherapy-naïve and post-chemotherapy patients with mCRPC. It also demonstrated quality-of-life benefits including pain reduction and improved physical functioning.

Storage and Handling

• Store below 30°C in a dry environment
  
• Protect from moisture and direct sunlight
  
• Keep out of reach of children
  
• Do not crush or split the tablets
  

Packaging Information

Each blister pack contains 10 tablets of Abiraxen 250 mg. The packaging is designed to ensure product stability and patient convenience, labeled with dosage, batch number, and expiration date for easy identification.

Advantages of Abiraxen 250 mg

• Oral formulation – convenient and non-invasive
  
• Potent and selective CYP17A1 inhibition
  
• Demonstrated survival benefit in large-scale clinical trials
  
• Can be combined safely with corticosteroids
  
• Manufactured in compliance with international GMP standards
  

Conclusion

Abiraxen 250 mg (Abiraterone Acetate) is a clinically validated, life-extending therapy for advanced stages of prostate cancer. With its ability to target androgen biosynthesis at multiple sites, Abiraxen offers comprehensive suppression of the hormonal drivers of prostate tumor growth. Manufactured by Everest Pharmaceuticals Ltd and globally offered by Orio Pharma, Abiraxen is a trusted option for oncologists and patients worldwide seeking effective, accessible, and advanced oral anti-cancer therapy.