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Abiraterone Acetate (Zytiga)

When prostate cancer spreads to another location in the body, it is considered to have metastasised, and surgery to remove the prostate and pelvic lymph nodes cannot eliminate the cancer. As a result, most men with metastatic prostate cancer (PCa) receive hormonal therapy which is also known as androgen ablation or androgen-deprivation therapy (ADT). ADT is used to reduce the levels of circulating androgens (male hormones) in the body (a process known as castration) or to keep them from reaching PCa cells. After sometime, however, the PCa no longer responds to hormone therapy, including LHRH analogues and anti-androgens, andis considered to be castration-resistant. At this stage, so-called metastatic castration-resistant PCa (mCRPC) becomes increasingly difficult to treat……………full article

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http://www.medicalgrapevineasia.com/mg/2013/07/09/drug-in-focus-abiraterone-acetate-zytiga/

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Dr Tan Yew Oo, Medical Oncologist and Hematologist in private practice at Gleneagles Hospital, to tell us more about AA.

Dr Tan Yew Oo is currently a Consultant Medical Oncologist and Hematologist in private practice at Gleneagles Hospital, Singapore. After graduating with MBBS from University of Singapore in 1971, he did his postgraduate training in Internal Medicine, Hematology and Medical Oncology in the United States and Canada. Upon his return to Singapore, he joined the Faculty of Medicine of the National University of Singapore in 1978 as Lecturer. He rapidly rose to be Chief of Medicine at National University Hospital (NUH) and Head, Division of Hematology-Oncology at NUH in 1988 and Professor of Medicine in 1991. He resigned and went into private practice since 1993. Dr Tan has been active in post-graduate education and has published many papers and has been an invited speaker for numerous meetings. He has participated in several international phase III clinical trials using novel drugs, and he has special interests in multiple myeloma, breast, thoracic and GI/GU oncology.

Chemical synthesis of Abiraterone acetate

The following synthetic route of Abiraterone acetate was  from J Med Chem. 1995 Jun 23;38(13):2463-71. Novel steroidal inhibitors of human cytochrome P45017 alpha (17 alpha-hydroxylase-C17,20-lyase): potential agents for the treatment of prostatic cancer. Potter GA, Barrie SE, Jarman M, Rowlands MG. Cancer Research Campaign Centre for Cancer Therapeutics, Institute of Cancer Research, Sutton, Surrey, U.K.

CAS#: 154229-18-2.

Synonym: CB 7630；CB-7630.

Chemical Formula: C26H33NO2
Exact Mass: 391.25113
Molecular Weight: 391.54
Elemental Analysis: C, 79.76; H, 8.50; N, 3.58; O, 8.17

IUPAC: [(3S,10R,13S)-10,13-dimethyl-17-pyridin-3-yl-2,3,4,7,8,9,11,12,14,15-decahydro-1H-cyclopenta[a]phenanthren-3-yl] acetate.

ZYTIGA™ (abiraterone acetate) received FDA Approval  in May 2011 for Treatment of Metastatic Prostate Cancer After Priority Review; First Once-Daily, Oral Treatment for Metastatic Prostate Cancer Inhibits Androgen Production. ZYTIGA^™ (abiraterone acetate) in combination with prednisone is indicated for the treatment of patients with metastatic castration-resistant prostate cancer (CRPC) who have received prior chemotherapy containing docetaxel.

According to Wikipedia, Abiraterone (tradename Zytiga) is a drug currently under investigation for use in castration-resistant prostate cancer (formerly hormone-resistant or hormone-refractory prostate cancer) (prostate cancer not responding to androgen deprivation or treatment with antiandrogens). After an expedited six-month review, the drug has been approved for use by the Food and Drug Administration (FDA). This drug was initially discovered in the Cancer Research UK Centre for Cancer Therapeutics at the Institute of Cancer Research in London. Rights for commercialization of the drug were assigned to BTG plc, a UK company that manages commercialization activity in pharmaceuticals. BTG then licensed the product to Cougar Biotechnology which began development of the commercial product.  In 2009, Cougar was acquired by Johnson & Johnson which is currently conducting clinical trials on abiraterone.   http://en.wikipedia.org/wiki/Abiraterone). 

Abiraterone acetate is an FDA approved drug, and is an orally active acetate ester of the steroidal compound abiraterone with antiandrogen activity. Abiraterone acetate was approved by the U.S. Food and Drug Administration (FDA) in April 2011. Abiraterone inhibits the enzymatic activity of steroid 17alpha-monooxygenase (17alpha-hydrolase/C17,20 lyase complex), a member of the cytochrome p450 family that catalyzes the 17alpha-hydroxylation of steroid intermediates involved in testosterone synthesis. Administration of this agent may suppress testosterone production by both the testes and the adrenals to castrate-range levels. Check for active clinical trials or closed clinical trials using this agent.

Current developer:  Cougar Biotechnology Inc, and Johnson & Johnson。