|References on Abiraterone:
1 . Li R, Evaul K, Sharma KK, Chang KH, Yoshimoto J, Liu J, Auchus RJ, Sharifi N.Abiraterone inhibits 3β-hydroxysteroid dehydrogenase: a rationale for increasing drug exposure in castration-resistant prostate cancer.Clin Cancer Res. 2012 Jul 1;18(13):3571-9.
PURPOSE: Treatment with abiraterone (abi) acetate prolongs survival in castration-resistant prostate cancer (CRPC). Resistance to abi invariably occurs, probably due in part to upregulation of steroidogenic enzymes and/or other mechanisms that sustain dihydrotestosterone (DHT) synthesis, which raises the possibility of reversing resistance by concomitant inhibition of other required steroidogenic enzymes. On the basis of the 3β-hydroxyl, Δ(5)-structure, we hypothesized that abi also inhibits 3β-hydroxysteroid dehydrogenase/isomerase (3βHSD), which is absolutely required for DHT synthesis in CRPC, regardless of origins or routes of synthesis. EXPERIMENTAL DESIGN: We tested the effects of abi on 3βHSD activity, androgen receptor localization, expression of androgen receptor-responsive genes, and CRPC growth in vivo...
2 . Abiraterone. After prostate cancer treatment failure: 4-month survival advantage.Prescrire Int. 2012 Jun;21(128):147-9.
There is no standard treatment for metastatic prostate cancer that progresses despite castration and cytotoxic chemotherapy. Abiraterone inhibits both testicular and extratesticular androgen synthesis. It has been approved in the European Union for use in this situation, in which treatment options are extremely limited. Clinical evaluation is based on a double-blind comparative trial of good methodological quality that included 1195 patients. The median overall survival time was 4 months longer in the group treated with abiraterone + prednisone (or prednisolone) than in the group treated with placebo + prednisone (or prednisolone): 15.8 versus 11.2 months. The addition of prednisone (or prednisolone) reduced but did not eliminate the effects of hyperaldosteronism induced by abiraterone; oedema occurred in 26.7% of patients, arterial hypertension in 8.5%, and hypokalaemia in 17.1%. Moderate hepatotoxicity was reported with abiraterone and needs to be better assessed. Abiraterone was also associated with cardiac arrhythmias (7.2% versus 4.6% with placebo) and heart failure (1% versus 0.3%). Abiraterone is metabolised by cytochrome P450 isoenzyme CYP3A4 and inhibits isoenzyme CYP2D6, resulting in a high potential for drug interactions. Treatment is somewhat inconvenient. Abiraterone must be taken between meals, serum potassium levels must be monitored, and care must be taken to avoid interactions. Overall, the known risks of abiraterone appear to be acceptable in view of its efficacy, but patients must be carefully monitored. Abiraterone is one option to discuss with patients with metastatic prostate cancer after other treatments fail.
3 . Schweizer MT, Antonarakis ES.Abiraterone and other novel androgen-directed strategies for the treatment of prostate cancer: a new era of hormonal therapies is born.Ther Adv Urol. 2012 Aug;4(4):167-78.
The number of life-prolonging therapies proven effective in the treatment of metastatic castrate-resistant prostate cancer (CRPC) has been limited until recently. In the past 2 years several such therapies have come to market. In 2010, the autologous immunotherapy sipuleucel-T and the next-generation taxane cabazitaxel were approved in this setting. However, abundant evidence has shown that CRPC growth continues to be driven through androgen-dependent signaling. Both of these drugs fail to take advantage of this targetable oncogenic pathway. Potent specific inhibitors of cytochrome P450-17 have been engineered with the aim of suppressing androgen synthesis beyond that seen with the luteinizing hormone-releasing hormone agonists/antagonists. Abiraterone acetate was developed by rational design based on a pregnenolone parent structure. Its approval by the US Food and Drug Administration (FDA) was granted in 2011 based on phase III data demonstrating an overall survival advantage compared with placebo. More recently, other drugs that act along the androgen signaling pathway, such as orteronel (TAK-700), galeterone (TOK-001), enzalutamide (MDV3100) and ARN-509, have shown promise in clinical trials. Some of these are expected to gain FDA approval in the near future. Here, we review abiraterone and other novel androgen-directed therapeutic strategies for the management of advanced prostate cancer.
4 . Attard G et al Selective inhibition of CYP17 with abiraterone acetate is highly active in the treatment of castration-resistant prostate cancer. J Clin Oncol. 2009 Aug 10;27(23):3742-8.
PURPOSE:It has been postulated that castration-resistant prostate cancer (CRPC) commonly remains hormone dependent. Abiraterone acetate is a potent, selective, and orally available inhibitor of CYP17, the key enzyme in androgen and estrogen biosynthesis. PATIENTS AND METHODS:This was a phase I/II study of abiraterone acetate in castrate, chemotherapy-naive CRPC patients (n = 54) with phase II expansion at 1,000 mg (n = 42) using a two-stage design to reject the null hypothesis if more than seven patients had a prostate-specific antigen (PSA) decline of > or = 50% (null hypothesis = 0.1; alternative hypothesis = 0.3; alpha = .05; beta = .14). Computed tomography scans every 12 weeks and circulating tumor cell (CTC) enumeration were performed. Prospective reversal of resistance at progression by adding dexamethasone 0.5 mg/d to suppress adrenocorticotropic hormone and upstream steroids was pursued. ...
5 . Pinto-Bazurco Mendieta, Mariano A. E.; Synthesis, Biological Evaluation, and Molecular Modeling of Abiraterone Analogues: Novel CYP17 Inhibitors for the Treatment of Prostate Cancer. Journal of Medicinal Chemistry (2008), 51(16), 5009-5018.
Abiraterone, a steroidal cytochrome P450 17alpha-hydroxylase-17,20-lyase inhibitor (CYP17), is currently undergoing phase II clinical trials as a potential drug for the treatment of androgen-dependent prostate cancer. Since steroidal compounds often show side effects attributable to their structure, we have tried to replace the sterane scaffold by nonsteroidal core structures. The design and synthesis of 20 new abiraterone mimetics are described. Their activities have been tested with recombinant human CYP17 expressed in E. coli. Promising compounds were further evaluated for selectivity against CYP11B1, CYP11B2, and the hepatic CYP3A4. Compounds 19 and 20 showed comparable activity to abiraterone (IC50 values of 144 and 64 nM vs 72 nM) and similar or even better selectivity against the other CYP enzymes. Selected compounds were also docked into our homology model, and the same binding modes as for abiraterone were found.