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Cyproterone acetate (CPA) is a synthetic steroid hormone used in the therapy of prostate cancer in men and different forms of acne and hirsutism in women. CPA has been shown by 32P-postlabeling analysis to bind covalently to hepatic DNA of rats in vivo and in vitro. A prerequisite for DNA adduct formation of CPA is metabolic activation of the drug to a reactive intermediate. In the present study bile was collected from [3H]CPA-treated female rats and, following chromatographic separation of bile extracts, fractions of the eluate were examined for the presence of reactive metabolites which were able to form adducts with calf thymus DNA in vitro. The formation of adducts was detected by 32P-postlabeling analysis. One major metabolite of CPA present in the bile extracts was isolated and, following a thorough structural elucidation by mass spectrometry and 1H-NMR, this metabolite was identified as 3 alpha-hydroxy-cyproterone acetate (3 alpha-OH-CPA). This metabolite was able to form the same major adduct in vitro which has been observed before in CPA-treated rats in vivo and in rat hepatocytes in vitro. A number of already known or putative metabolites of CPA were available as authentic standards and these were also examined for their propensity to form adducts in vitro. A positive result was obtained for 3-O-acetyl-cyproterone acetate, which formed the same major adduct as 3 alpha-OH-CPA. However, the presence of this putative metabolite in rat bile could not be demonstrated. Besides 3 alpha-OH-CPA, additional reactive metabolites of CPA were present in the bile extracts, however, since these were only minor components, their chemical structures could not be elucidated.
15-beta-hydroxy cyproterone acetate could be identified by thin layer chromatography, mass spectrum, NMR and IR spectrum as a major unconjugated metabolite of cyproterone acetate in plasma and urine of dog, monkey and man. This metabolite has been found to interferein the Mattingly method for the determination of 11-hydroxy-corticosteroids which suggests, that this method is inadequate in controling the adrenal function of subjects treated with cyproterone acetate.
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Prasad and his coworkers emphasized that microquantities of cyproterone acetate (CPA) when continuously available developed functional sterility in male rats by interfering the epididymal physiology. In our experimental rats either 2 or 3 capsules containing CPA as per the specification of Prasad were implanted subcutaneously and left for 300 and 250 days, respectively. Fertility test was made every month and it was observed that all the experimental animals were able to impregnate female rats throughout the experiment. Excepting the epididymis the weight of testes and other accessory glands did not differ from the controls in the animals which had 2 CPA capsules for 300 days; On the other hand, the animals which received 3 CPA capsules for 250 days showed significant reduction in weight of all the acessory glands including the testes.
Cyproterone acetate (CPA) and 15 beta-hydroxy-cyproterone acetate (15 beta-OH-CPA) have been quantitated in human plasma by a selective, automated HPLC assay in 8 young female subjects. Subjects received a single oral dose of 100 mg CPA and four weeks later, a single intramuscular dose of 300 mg CPA. Plasma levels in seven subjects could be evaluated pharmacokinetically. After intramuscular administration maximum CPA serum levels of 191 +/- 49 ng/ml were reached between 2 and 3 days. Postmaximal levels declined with a half-life of 4.3 +/- 0.7 days. After oral administration maximal serum levels of 255 +/- 110 ng/ml were measured between 2 and 3 h. CPA levels decayed biphasically with a terminal half-life of 3.6 +/- 1.3 days. Bioavailability after oral administration was nearly complete (88 +/- 20%). Metabolite levels were below CPA levels until 4 days (i.m.) and 6 h (p.o.) and exceeded CPA levels later on. 15 beta-OH-CPA levels declined with half-lives similar to those of corresponding CPA levels, indicating that terminal half-life of the metabolite in serum reflects its rate of formation rather than its rate of elimination. Areas under the metabolite serum level curves after intramuscular and oral administration were 10 to 15% higher than the corresponding areas for unchanged CPA. Since CPA and 15 beta-OH-CPA contribute to the antiandrogenetic efficacy there is good reason to assume that the intramuscular administration of CPA might be equally effective in the therapeutical use as the oral administration.
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Cyproterone acetate (CPA) is a widely used drug in the treatment of advanced prostatic carcinoma. Although it is generally well tolerated, liver toxicity has been recognised as a complication of long-term use. We report 3 patients with severe hepatocellular damage due to CPA therapy, 2 with fatal fulminant hepatitis.
Cyproterone acetate (CPA) is a synthetic antiandrogenic compound which is widely used in clinic but suspected to be hepatocarcinogenic. CPA is also mitogenic in rat liver. Using genetic labeling of dividing cells, we examined whether hepatocytes dividing in response to acute CPA administration could give rise to preneoplastic foci after administration of a tumor promoter: phenobarbital. CPA was administered orally to rats and dividing hepatocytes were genetically labeled using retroviral vectors carrying the beta-galactosidase gene. After labeling rats were given phenobarbital for 10 months and sacrificed. The presence of beta-galactosidase labeled hepatocytes as well as preneoplastic hepatocytes was assessed by immunohistochemistry. Genetic labeling of hepatocytes was obtained in all animals. At the end of phenobarbital administration, no hepatic tumors were observed. Preneoplastic foci were not increased in treated animals as compared to control rats. Moreover beta-galactosidase positive hepatocytes were never detected in preneoplastic foci. Finally, the size of the beta-galactosidase positive clusters was smaller in treated animals as compared to control rats. We conclude that acute CPA administration is not carcinogenic in rat liver and does not initiate preneoplastic hepatocytes capable to give rise to foci after phenobarbital promotion. Therefore the mitogenic property of CPA is distinct from its putative carcinogenic activity. Finally, analysis of the size of beta-galactosidase positive cells clusters demonstrate that phenobarbital does not induce hepatocyte proliferation in rats.
Five patients with prostatic carcinoma (stages T3N0M0) were injected intramuscularly with 300 mg of cyproterone acetate (CPA) (Androcur-Depot) at weekly intervals. The concentrations of CPA, testosterone, LH, FSH, and prolactin in plasma after the first, third, and fifth injection were measured by specific radioimmunoassays. After five injections of Androcur-Depot, CPA levels were slightly higher than in previous determinations, suggesting that a balance between active substance release from the depot and excretion could be achieved after eight to twelve injections, with only slightly higher levels of active substance attained. Testosterone levels clearly were reduced after the first injection of CPA, but the lowest values were registered only after three injections. Plasma concentrations of FSH and LH were slightly diminished, whereas the prolactin level increased after CPA therapy.
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The study was performed to investigate direct embryotoxic effects of maternal progestin treatment during the preimplantation period. In the first experiment pregnant mice received a single subcutaneous injection of either cyproterone acetate (CA) or medroxyprogesterone acetate (MPA) on day 2 of pregnancy (5-600 mg/kg). In a second experiment four-cell embryos were exposed to CA or MPA in vitro (3 or 30 micrograms/ml medium). Our results revealed: (1) After maternal treatment the number of live embryos was reduced after the highest CA dose. Development into blastocysts was inhibited in a dose-related manner after CA but not after MPA. The number of cells in morulae, blastocysts, and of the inner cell mass (ICM) of late blastocysts was not affected. (2) When morulae and blastocysts were cultured in vitro after maternal treatment, hatching, attachment, and trophoblast outgrowth were inhibited after high doses, but development and differentiation of the ICM were inhibited even after low doses. (3) Application of 30 micrograms/ml of CA or MPA in vitro was directly embryolethal. Three micrograms/ml did not affect development into blastocysts, but ICM development and differentiation were again inhibited during subsequent culture in hormone-free medium. (4) Qualitative protein synthesis was altered in morulae and blastocysts 24 hours after maternal CA treatment. According to our results high doses of progestins are embryotoxic before implantation, low doses have delayed effects on embryonic development that are particularly evident after implantation in vitro.
Cyproterone acetate, a widely used synthetic progestagen with antiandrogenic activity, is known for years to produce liver tumours in rats, with a higher incidence in females. This effect was attributed to a rodent-specific tumour promoting mode of action based on the detection of a strong hepato-mitogenic activity of cyproterone acetate. However, more recent studies have demonstrated that cyproterone acetate is sex-specifically activated to (a) DNA-damaging intermediate(s) in the liver of female rats which result in the formation of DNA adducts, induction of DNA repair, and increased levels of micronuclei and gene mutations. Consistent with a sex-specific genotoxicity, cyproterone acetate showed a tumour-initiating potential in a liver foci assay with female rats but not with male rats. Most important, cyproterone acetate was found to induce formation of DNA adducts in primary cultures of human hepatocytes indicating that human liver cells have the capacity to activate cyproterone acetate to genotoxic intermediates. However, the overall assessment of the preclinical data presented in this review suggests that induction of liver tumours in female rats most probably depends on both, genotoxic and mitogenic effects which would suggest a non-linear mode of action with regard to tumour formation. With the exception of DNA adduct formation all other adverse effects induced by cyproterone acetate in rat liver, including gene mutations and liver tumours, can be detected at very high dose levels only. Hence, a cancer risk estimate based on a simple linear extrapolation from high dose to low exposure conditions of recommended clinical use would be questionable. Human data from pharmacoepidemiological studies that specifically addressed the question of possible liver cancer risk in patients treated with cyproterone acetate do in principle support this interpretation. In agreement with these considerations the regulatory authorities of the European Union came to the common conclusion that a possible cancer risk associated with the clinical use of cyproterone acetate, if any, appears to be low and the risk-benefit ratios for the currently authorised indications remain favourable.
Cyproterone acetate, characterised by its antiandrogen and antigonadotrophin actions, is indicated in the treatment of advanced prostatic cancer. It can be used alone or in combination with surgical or chemical castration. This paper reviews the literature concerning the cardiovascular safety of this drug. Metabolic studies evaluating the impact of cyproterone acetate on lipids and certain clotting parameters indicate the absence of any harmful effects on these cardiovascular risk factors. The two trials conducted by the EORTC (30761 and 30 762) demonstrated that the cardiovascular safety of cyproterone acetate was better than that of diethylstilboestrol. Cardiovascular adverse effects were reported in less than 5% of cases. This figure was confirmed by a large number of published studies. A comparable incidence of cardiovascular complications was also observed in series of patients treated by orchidectomy, LHRH agonists and/or pure antiandrogens. It is difficult to formally demonstrate the responsibility of antihormonal treatment in this elderly population in which ischaemic heart disease and cerebral vascular accidents are frequent causes of death.
Cyproterone acetate is a progestational antiandrogen with potent antigonadotropic activity that results in rapid suppression of serum testosterone. Used as a single agent, cyproterone acetate yields a total androgen blockade. It may be combined with low-dose diethylstilbestrol, orchiectomy, or LHRH agonists to improve, in theory, the results of such therapy. In clinical testing, cyproterone acetate has proved equivalent to diethylstilbestrol with markedly less toxicity. It is useful in conjunction with LHRH agonists, either transiently to block the flare phenomenon, or continuously to block peripheral androgen receptors; the necessity for this latter action has not yet been proved. Cyproterone acetate may afford transient objective improvement in patients not responding to other forms of hormone deprivation. Experience in this role is limited. The drug may be used to suppress the hot flushes associated with orchiectomy or LHRH agonist therapy. Cyproterone acetate induces local tumor regression; owing to its reversible effects, it is useful as neoadjuvant or adjuvant androgen withdrawal therapy in patients with lower-stage disease undergoing radical surgery or radiotherapy. Adverse effects are mostly those related to hormone withdrawal, namely, impotence, infertility, and lassitude. Gynecomastia and breast tenderness occur in less than 18% and cardiovascular complications in approximately 10% of treated men.
Cyproterone and cyproterone acetate exert the corticoid-like effect on the adrenal and spleen weight in the mice. When compared with prednisone, cyproterone acetate has approximately 1/5 of the corticoid potency of prednisone, expressed by the decrease of the spleen weight.
Cyproterone acetate [6-chloro-1beta,2beta-dihydro-17alpha-hydroxy- 3'H-cyclopropa(1,2)-pregna-1,4,6-triene-3,20-dione acetate] is a powerful antiandrogen used in the treatment of women suffering from disorders associated with androgenization such as hirsutism and acne. A fast, sensitive, and robustness method is developed for the determination and quantitation of cyproterone acetate in human blood plasma by liquid chromatography coupled with tandem mass spectrometry. Cyproterone acetate is extracted from 0.2 mL human plasma by liquid-liquid extraction. The method has a chromatographic run of 4.5 min, using a C18 analytical column (100- yen 2.1-mm i.d.), and the linear calibration curve over the range is linear from 1 to 500 ng/mL (r2 > 0.994). The between-run precision, based on the relative standard deviation replicate quality controls, is 96.2% (3 ng/mL), 97.5% (120 ng/mL), and 99.1% (400 ng/mL). The between-run accuracy was +/- 2.7%, 3.1%, and 4.8% for the previously mentioned concentrations, respectively. The method is employed in a bioequivalence study of two tablet formulations of cyproterone acetate (100 mg).
OBJECTIVES: To assess the effect of neoadjuvant hormone treatment before radical prostatectomy on: tumor/prostate volume, prostate-specific antigen (PSA) and testosterone levels, surgical margin status and tumor stage, and the ease of surgery following treatment. METHODS: Patients with clinically localized prostatic carcinoma were randomized to receive leuprolide acetate depot 3.75 mg once a month for 3 months and cyproterone acetate 300 mg once a week for 3 weeks prior to surgery (group A). A control group of patients had surgery without any pretreatment (group B). RESULTS: 167 patients were evaluated for the efficacy parameters. In group A, 31% of patients had a reduction in tumor/prostate volume following hormone therapy. PSA and testosterone levels were significantly reduced (p = 0.0001) in patients in group A compared to basal values. Centralized histopathological data evaluated in 145 patients (group A and 75 group B) showed that more patients in group B had tumors at stages T3A and T3B than in group A; this difference was close to significance (p = 0.057). Positive surgical margins were more common in group B (60% of patients) compared to group A (39% of patients). Similarly lymph node involvement was more common in group B compared to group A (11 versus 3%). There was little difference between the 2 study groups for the other surgical parameters assessed (ease of dissection, duration of surgery, blood loss). CONCLUSIONS: Neoadjuvant hormone therapy before radical prostatectomy has some effects in the treatment of prostate cancer. However, long-term follow-up of patients is needed to assess the impact of this therapy on morbidity and mortality.