What Is Abiraterone Acetate (Zytiga)? FDA Approval, Licensing and Reimbursement in Turkey

• FDA Approved: Yes (Initial approval: April 28, 2011)
• Brand Name: Zytiga (Original Molecule)
• Active Ingredient: Abiraterone Acetate
• Administration: Oral (By Mouth)
• Class: Steroid Inhibitor / CYP17 Inhibitor
• Category: Hormonal Medicine
• Manufacturer: Johnson & Johnson
• Distribution in Turkey: Johnson & Johnson and other generic manufacturers
• Generic Medicines: Ebatyl, Abiratex, Abitiga, Abyga, Arvila, Byretu, Dipon, Ratebir, Zateron
• Approved Cancer Indications: Prostate Cancer

Abiraterone acetate is a new-generation hormonal medicine used for prostate cancer. It slows tumor growth by blocking testosterone production in the body. It is generally used alongside conventional hormonal treatment for prostate cancer and helps prevent the cancer from spreading.

1. Abiraterone acetate is a prodrug of abiraterone and is rapidly converted in the body into the active metabolite abiraterone.
2. Abiraterone inhibits enzymes needed to produce hormones called androgens: 17α-hydroxylase and C17,20-lyase (CYP17). These enzymes are found in the testes, adrenal glands and prostate tumor tissues.
3. CYP17 inhibition blocks the conversion of pregnenolone and progesterone into their 17α-hydroxy derivatives, stopping androgen production.
4. This process stops the formation of DHEA and androstenedione.
5. Abiraterone may increase mineralocorticoids produced by the adrenal glands. This is a side effect that requires attention during treatment and is managed with steroid medicines (prednisone/prednisolone).

FDA approval dates and indications for medicines containing abiraterone are as follows:

• April 28, 2011: For patients with metastatic castration-resistant prostate cancer who had previously received docetaxel.
• December 10, 2012: For patients receiving treatment for metastatic castration-resistant prostate cancer before docetaxel.
• February 2018: In combination with prednisone for patients with metastatic high-risk hormone-sensitive prostate cancer.
• May 2023: In combination with olaparib and prednisone or prednisolone, for patients carrying a BRCA mutation who have metastatic castration-resistant prostate cancer.

• August 11, 2023: Niraparib and abiraterone acetate as a fixed-dose combination with prednisone, for adults carrying a BRCA mutation who have metastatic castration-resistant prostate cancer.

Medicines containing abiraterone are licensed by the Turkish Ministry of Health for the following indications:

1. In combination with androgen deprivation therapy (ADT) for adult men with newly diagnosed metastatic hormone-sensitive prostate cancer (mHSPC) and at least 2 of the defined high-risk factors, until progression or unacceptable side effects occur.
2. For metastatic castration-resistant prostate cancer in adult men without visceral metastases who are asymptomatic or mildly symptomatic after failure of androgen deprivation therapy and for whom chemotherapy is not yet clinically indicated, until progression or unacceptable side effects occur.
3. For mCRPC in adult men whose disease progresses during or after docetaxel-based chemotherapy.

Turkey's Social Security Institution (SGK) reimburses abiraterone in the following clinical situations:

• Patients With Castration-Resistant Progression: Covered when progression is demonstrated by PSA and imaging, and testosterone is at castration levels (<50 ng/dl).
• Patients With Resistance to Hormonal Therapy and Docetaxel: Reimbursed when used with prednisolone in patients with metastatic prostate cancer, documented progression and an ECOG performance score of 0-1.
• Patients With Hormone-Sensitive Metastatic Disease (New Diagnosis / ADT Combination): Reimbursed for newly diagnosed patients with at least two of the following risk factors, when used with prednisolone:
  • A Gleason score of 8 or higher,
  • At least 3 bone metastases,
  • Visceral (organ) metastases.
• Patients Ineligible for Chemotherapy: Patients with an ECOG performance score >1, severely reduced bone marrow reserve (neutrophils <1500/mm³, platelets <100000/mm³), or reduced creatinine clearance or liver reserve.

💵 Current Price Information (June 2026): The approximate retail price for a pack of Zytiga 500 mg, 60 tablets / 250 mg, 120 tablets, is 31299.70 TL. *(Prices may vary with exchange rates and updates to the Medicine Pricing Decree).*

• CYP17 Enzyme Overexpression: When tumor cells begin producing more CYP17 enzyme, abiraterone's blockade can be bypassed.
• AR Splice Variants (e.g., AR-V7): Some cancer cells produce splice variants that allow the androgen receptor (AR) to become active without androgen hormones, resulting in ligand-independent transactivation.
• Truncated Receptors: Cancer cells increase the production of truncated androgen receptors, allowing them to remain active and continue growing independently of hormones.

Absorption: After oral administration, the time to maximum plasma concentration (Tmax) is usually between 1.5 and 4 hours. Abiraterone must be taken on an empty stomach. Taking it with food causes an uncontrolled, several-fold increase in absorption and raises the risk of toxicity. No food should therefore be consumed for at least 2 hours before and at least 1 hour after taking the medicine.

Distribution: Abiraterone is highly bound to human plasma proteins, at a rate of 99.8%.

Metabolism and Excretion: After oral administration, abiraterone acetate is rapidly hydrolyzed into its active metabolite, abiraterone. Its two main circulating metabolites, abiraterone sulfate and N-oxide abiraterone sulfate, are inactive. Approximately 90% of the dose is excreted in feces and only 5% in urine. Its terminal half-life ranges from 5-14 hours, averaging 12 hours.

• Recommended Dose: Once daily, 1000 mg taken orally as a single dose.
• Steroid Combination: To counter mineralocorticoid side effects (hypertension, edema and hypokalemia), it must be combined with a daily dose of 5 mg prednisone or prednisolone.
• How to Take It: Tablets should be swallowed whole with water and must not be chewed or broken.

Critical Interaction Parameters:

• Abiraterone is a strong CYP2D6 inhibitor. Dosage should therefore be monitored when it is used with medicines activated or metabolized by CYP2D6.
• Strong CYP3A4 inducers (e.g., rifampicin, phenytoin, carbamazepine and St. John's Wort) may reduce plasma abiraterone levels, so concomitant use of these agents should be avoided.

Clinical Precautions and Liver Monitoring:

• Hepatic Impairment: No dose adjustment is required in mild hepatic impairment. In patients with moderate hepatic impairment (Child-Pugh class B), the starting dose should be reduced to 250 mg once daily. It must not be used in severe hepatic impairment.
• Renal Impairment: No dose adjustment is needed in patients with impaired renal function.
• Risk of Adrenal Insufficiency: Particular vigilance for symptoms of adrenal insufficiency is required when accompanying prednisone/prednisolone is stopped or reduced, or when the patient experiences additional stress or infection.

The clinical side-effect profile, from most to less common, is as follows: