Contraindications
ZYTIGA™ may cause fetal harm (Pregnancy Category X) and is contraindicated in women who are or may become pregnant.


Warnings and Precautions

Hypertension, Hypokalemia and Fluid Retention Due to Mineralocorticoid Excess
Mineralocorticoid Excess - Use with caution in patients with a history of cardiovascular disease or with medical conditions that might be compromised by increases in hypertension, hypokalemia and fluid retention. Safety has not been established in patients with LVEF < 50% or NYHA Class III or IV heart failure. Control hypertension and correct hypokalemia before and during treatment. Monitor blood pressure, serum potassium, and symptoms of fluid retention at least monthly.

Adrenocortical Insufficiency
Adrenocortical Insufficiency (AI) has been reported in clinical trials after an interruption of daily steroids and/or with concurrent infection or stress. Use caution and monitor for symptoms and signs of AI if prednisone is stopped or withdrawn or if the patient experiences unusual stress. Perform appropriate tests, if indicated, to confirm AI. Increased dosages of corticosteroids may be used before, during and after stressful situations.

Hepatotoxicity
Hepatotoxicity - Increases in liver enzymes have led to drug interruption, dose modification and/or discontinuation. Monitor liver function and modify, withhold or discontinue ZYTIGA™ dosing as recommended (See Prescribing Information for more information).

Food Effect
Food Effect - ZYTIGA™ must be taken on an empty stomach. Exposure of abiraterone increases up to 10-fold when abiraterone acetate is taken with meals. No food should be eaten for at least two hours before the dose of ZYTIGA™ is taken and for at least one hour after the dose of ZYTIGA™ is taken.

Adverse Reactions

The most common adverse reactions (≥5%) reported in clinical trials were joint swelling or discomfort, hypokalemia, edema, muscle discomfort, hot flush, diarrhea, urinary tract infection, cough, hypertension, arrhythmia, urinary frequency, nocturia, dyspepsia and upper respiratory tract infection.

Drug Interactions

ZYTIGA™ is an inhibitor of the hepatic drug-metabolizing enzyme CYP2D6. Avoid co-administration with CYP2D6 substrates that have a narrow therapeutic index. If an alternative cannot be used, exercise caution and consider a dose reduction of the CYP2D6 substrate. Additionally, abiraterone is a substrate of CYP3A4 in vitro. Strong inhibitors and inducers of CYP3A4 should be avoided or used with caution.

FDA批准Zytiga用于晚期前列腺癌
2011年4月28日，美国食品药品监督管理局(FDA)批准Zytiga(醋酸阿比特龙酯abiraterone acetate)与强的松(甾体化合物)联用可治疗晚期(转移型)已经接受多西他赛(化疗)治疗的阉割难治性前列腺癌。

前列腺癌患者的男性荷尔蒙睾丸素会刺激前列腺肿瘤增长，药物或手术可减少睾丸素产生或阻断睾丸素影响。但某些情况下即使睾丸素水平很低时前列腺癌也会继续发展，这样即为阉割难治性前列腺癌。

Zytiga为药丸，其靶目标是名为细胞色素P450 17A1(CYP17A1)的蛋白质，该蛋白质对于睾丸素的产生有重要作用。Zytiga会降低睾丸素的产生进而防止癌细胞继续生长。该药物是通过FDA优先审查程序(6个月)获得批准的，由于其治疗优势，或为现有治疗方案提供了补足。FDA在预定审查期2011年6月20日之前完成了对其审查。

FDA药品评价中心肿瘤药物办公室负责人Richard Pazdur表示：Zytiga可延长晚期前列腺癌患者的生命，他们通常都已经接受了其他的治疗且可选的治疗方案非常有限。

通过1195名已经接受过多西他赛化疗的晚期阉割难治性前列腺癌患者对Zytiga的安全性和有效性进行研究。患者分别使用Zytiga和强的松或安慰剂和强的松。

设计该试验研究患者的存活率，时间自开始接受治疗到患者死亡。使用Zytiga的患者平均存活率为14.8个月，而是用安慰剂为10.9个月。

常见的不良反应有关节肿胀或不适、低血钾、水肿、肌肉不适，热潮红、腹泻、尿路感染、咳嗽、高血压、心律失常、尿频、夜间尿频、肚子疼或消化不良、上呼吸道感染等。

Zytiga由Biotech的Horsham生产上市。