Abiraterone acetate, trade name Zytiga, is a white to off-white oval tablet, 250 mg/tablet, 120 tablets/bottle.
- In April 2011, the U.S. Food and Drug Administration (FDA) approved abiraterone for patients with prostate cancer that has worsened despite chemotherapy such as docetaxel;
- In May 2015, the Chinese Drug Administration (FDA) approved abiraterone acetate for marketing in China.
Abiraterone acetate is a highly selective, irreversible inhibitor of CYP17, a key rate-limiting enzyme for androgen synthesis, and thus the drug efficiently inhibits androgen synthesis from various pathway sources. These pathways include intra-testicular, intra-adrenal, and intra-prostate cancer cells, allowing androgen inhibition at minimal levels, thereby inhibiting prostate cancer progression and metastasis
Abiraterone is usually used in combination with prednisone to treat patients with metastatic castration-resistant prostate cancer (mCRPC) who have not responded to prior chemotherapy.
In layman’s terms, abiraterone is a second-line drug for advanced prostate cancer that significantly reduces the production of the male hormone testosterone for “depot” purposes.
The recommended regimen for abiraterone is as follows:
The recommended regimen for abiraterone is as follows
- Take 1000 mg (4 tablets) once daily by mouth on an empty stomach (at least 2 hours of fasting before and 1 hour of fasting after taking the drug);
- A combination of oral prednisone tablets at 5 mg (1 tablet) twice daily is also required.
Abiraterone helps prolong survival in patients with advanced disease
Multiple clinical trials in China and abroad have shown that abiraterone in combination with prednisone significantly prolongs radiographic progression free survival (rPFS) and overall survival (OS) in patients with mCRPC.
The results of the pivotal clinical trial on abiraterone (COU-AA-302 phase III clinical trial), published in 2014 in the prestigious European Urology journal, confirmed the significant efficacy of abiraterone [6].
- Compared with treatment with prednisone alone, this drug combined with prednisone for chemotherapy-free CRPC resulted in longer rPFS (16.5 months vs 8.2 months) and OS (35.3 months vs 30.1 months).
- There was also a significant improvement in PSA progression, pain medication application, and time to deterioration of patient physical status.
In China, Xu Yuxia et al retrospectively analyzed the effect of treatment with abiraterone in 58 patients with CRPC after chemotherapy. Of the 53 patients with evaluable efficacy, 19%, 62% achieved disease control with a median OS of 15 months, and 28 patients had a decrease in PSA >50%; adverse effects were mostly mild.
In addition, several studies suggest that abiraterone in combination with other treatments, such as ADT (androgen deprivation therapy), chemotherapy, and radiation therapy, may have better clinical outcomes, but this requires specific analysis and individualized treatment plans.
Safety of abiraterone
The main adverse effects of abiraterone are hepatic and cardiotoxicity, but they are usually mild. Hypokalemia, hypertension, and sodium retention may occur in a subset of patients, but are also usually mild and do not interfere with continued use of the drug.
These adverse effects are well tolerated by most patients with early intervention, so there is no need to be overly concerned.
Cautions with abiraterone
- Abiraterone is contraindicated in patients with severe liver injury (Child-Pugh class C).
- Abiraterone is contraindicated in patients with previous adrenal gland disease, pituitary gland disease.
- Used with caution in patients with a history of cardiovascular disease.
- Patients with moderate hepatic impairment at baseline (Child-Pugh class B) must reduce the daily dose to 250 mg (1 tablet). and begin weekly monitoring of liver function parameters, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and bilirubin, if ALT and AST values are elevated greater than 5 times the upper limits of normal (ULN) or total bilirubin. normal (ULN) or total bilirubin greater than 3 times the ULN, discontinue abiraterone and do not attempt it again in the future.
- Abiraterone should be swallowed whole with water and not crushed or chewed.
- Keep the medicine at 15-30°C and away from children.
- Pregnant women or women at risk of pregnancy should avoid any form of direct contact with the medicine; if you need to touch the medicine, use protection (eg, gloves).
How much does abiraterone treatment cost? Can Medicare pay for it?
In May 2015, the Chinese Drug Administration approved the marketing of abiraterone acetate tablets (trade name: Zecor) in China for the treatment of metastatic debulking-resistant prostate cancer (mCRPC), which provides another highly effective treatment option for patients with advanced prostate cancer in China.
When it was first introduced into the domestic market, the market price was approximately RMB 17,000 per vial. After coordination with relevant government departments, nearly 20 provinces and municipalities nationwide have included abiraterone in their health insurance coverage, and more mCRPC patients are now enjoying health insurance benefits.
It is understood that the current price of a box is around 6,800 yuan after reimbursement by Medicare, which greatly reduces the burden of medical costs, but there may be some regional differences in reimbursement rates due to differences in local Medicare policies.