Mechanism-based risk assessment strategy for drug-induced cholestasis using the transcriptional benchmark dose derived by toxicogenomics.

Cholestasis is one of the major causes of drug-induced liver injury (DILI), which can result in withdrawal of approved drugs from the market. Early identification of cholestatic drugs is difficult due to the complex mechanisms involved. In order to develop a strategy for mechanism-based risk assessment of cholestatic drugs, we analyzed gene expression data obtained from the livers of rats that had been orally administered with 12 known cholestatic compounds repeatedly for 28 days at three dose levels. Qualitative analyses were performed using two statistical approaches (hierarchical clustering and principle component analysis), in addition to pathway analysis. The transcriptional benchmark dose (tBMD) and tBMD 95% lower limit (tBMDL) were used for quantitative analyses, which revealed three compound sub-groups that produced different types of differential gene expression; these groups of genes were mainly involved in inflammation, cholesterol biosynthesis, and oxidative stress. Furthermore, the tBMDL values for each test compound were in good agreement with the relevant no observed adverse effect level. These results indicate that our novel strategy for drug safety evaluation using mechanism-based classification and tBMDL would facilitate the application of toxicogenomics for risk assessment of cholestatic DILI.

Histological assessment of follicular delivery of flutamide by solid lipid nanoparticles: potential tool for the treatment of androgenic alopecia.

CONTEXT: Flutamide is a potent anti-androgen with the several unwanted side effects in systemic administration, therefore, it has attracted special interest in the development of topically applied formulations for the treatment of androgenic alopecia. OBJECTIVE: The purpose of this study was to prepare and characterize the solid lipid nanoparticles (SLNs) of Flutamide for follicular targeting in the treatment of the androgenic alopecia. METHODS: Flutamide-loaded SLNs, promising drug carriers for topical application were prepared by hot melt homogenization method. Drug permeation and accumulation in the exercised rat skin and histological study on the male hamsters were performed to assess drug delivery efficiency in vitro and in vivo, respectively. RESULTS: The optimized Flutamide-loaded SLNs (size 198 nm, encapsulation efficiency percentage 65% and loading efficiency percentage 3.27%) exhibited a good stability during the period of at least 2 months. The results of X-ray diffraction showed Flutamide amorphous state confirming uniform drug dispersion in the SLNs structure. Higher skin drug deposition (1.75 times) of SLN formulation compared to Flutamide hydroalcoholic solution represented better localization of the drug in the skin. The in vivo studies showed more new hair follicle growth by utilizing Flutamide-loaded SLNs than Flutamide hydroalcoholic solution which could be due to the higher accumulation of SLNs in the hair follicles as well as slowly and continues release of the Flutamide through the SLNs maximizing hair follicle exposure by antiandrogenic drug. CONCLUSION: It was concluded Flutamide-loaded SLN formulation can be used as a promising colloidal drug carriers for topical administration of Flutamide in the treatment of androgenic alopecia.

Radical prostatectomy versus high-dose irradiation in localized/locally advanced prostate cancer: A Swedish multicenter randomized trial with patient-reported outcomes.

BACKGROUND: Treatment of localized prostate cancer (PC) is controversial. This is the first randomized study comparing an open surgery procedure (radical prostatectomy) with a combination of high-dose rate brachytherapy (2×10 Gy) and external beam radiotherapy (25×2 Gy) in PC patients in Sweden 1996-2001. The two randomization arms were compared regarding differences in patients-reported outcomes, such as complications and health-related quality of life (HRQoL). MATERIAL AND METHODS: The patients had localized/locally advanced PC, clinical category T1b-T3a, N0, M0 and PSA≤50 ng/ml. All underwent total androgen blockade (six months). Self-reported HRQoL and symptoms including urinary, bowel, and sexual side effects were investigated prospectively before randomization and 12 and 24 months after randomization. A total of 89 patients were randomized and completed the EORTC QLQ C-33 and EORTC PR-25 questionnaires. RESULTS: Over the study period, there were no discernible differences in HRQoL, or complications between the two groups. Emotional functioning, however, improved statistically significantly over time, whereas Social functioning decreased, and financial difficulties increased. No statistically significant differences in group-by-time interactions were found. The survival rate was 76%. Only eight patients (9%) died of PC. CONCLUSION: Open radical prostatectomy and the combined high-dose rate brachytherapy with external beam radiation appeared to be comparable in the measured outcomes. It was not possible to draw any conclusion on the efficacy of the two treatments due to insufficient power of the study.

A randomized phase IIb presurgical study of finasteride vs. low-dose flutamide vs. placebo in men with prostate cancer. Efficacy monitored by karyometry.

OBJECTIVE: Presurgical, window of opportunity trials have been proposed as a model to assess the activity of preventive and therapeutic interventions in a cost-effective manner in prostate cancer (CaP). The aim of the study was to explore karyometry as a method for monitoring the efficacy of intervention with preventive agents in patients with CaP. MATERIALS AND METHODS: The material used in this investigation was from the 2F study, i.e., an Italian prospective randomized phase IIb presurgical study of finasteride vs. low-dose flutamide vs. placebo in men with CaP. Image analysis was performed in 16 cases treated with finasteride, 24 with flutamide, and 20 with placebo. For all these cases, CaP and normal looking secretory epithelium were present in the pretreatment biopsies as well as the post-treatment ex-vivo biopsies obtained from the radical prostatectomy specimens. RESULTS: To establish a direction of nuclear change from normal to malignancy, i.e., the so-called line of progression, a discriminant function was derived with the normal looking epithelium in the pretreatment biopsies as one endpoint, and the CaP in the pretreatment biopsies as the other. The discriminant function was then applied to the post-treatment groups. The increase in relative nuclear area was the dominant feature. In the placebo group, 15 out of 20 CaP (75%) cases had a higher discriminant function score at the end of study, with a significant increase of the mean score by 90%. The flutamide treated CaP cases had increased discriminant function scores in 19 out of 24 cases (79%) and an increase of the mean score by 43%; the 5 cases with lower scores involved only minor reductions. In contrast, the finasteride treated CaP cases had increased discriminant function scores for 8 out of 16 cases (50%), but the increase in the mean score was by only 8%. CONCLUSION: This exploratory study establishes that karyometric monitoring can track the results of subtle nuclear changes induced by preventive interventions in men with CaP, thus allowing assessment of agent activity in a cost-effective manner.

Eliciting patient preferences for hormonal therapy options in the treatment of metastatic prostate cancer.

Treatment choices for metastatic prostate cancer are complex and can involve men balancing survival versus quality of life. The present study aims to elicit patient preferences with respect to the attributes of treatments for metastatic prostate cancer through a discrete choice experiment (DCE) questionnaire. Men with recently diagnosed localized prostate cancer were asked to envisage that they had metastatic disease when completing a survey. As expected, men with prostate cancer placed considerable importance on gains in survival; however, avoiding side effects of treatment was also clearly important. Survival gains should be considered alongside side effects when discussing treatment options in metastatic disease.

Comparison of the clinical efficacy of flutamide and spironolactone plus Diane 35 in the treatment of idiopathic hirsutism: a randomized controlled study.

OBJECTIVE: To compare the effectiveness of flutamide and spironolactone plus Diane 35 in the treatment of idiopathic hirsutism (IH). DESIGN: Prospective randomized clinical study. SETTING: Social Security Agency, Aegean Obstetrics and Gynecology Teaching Hospital, Department of Reproductive Endocrinology and Infertility, a tertiary referral center. PATIENT(S): Eighty women with IH who had been admitted to our center. INTERVENTION(S): Patients were randomly and equally assigned to receive flutamide (250 mg/d for the first 10 days of the cycle) and spironolactone plus Diane 35 (spironolactone 100 mg/d; Diane 35 is a combination tablet of 2 mg cyproterone acetate and 35 microg ethinylestradiol/d) for 9 months. MAIN OUTCOME MEASURE(S): Modified Ferriman-Gallwey (F-G) score and hormonal profile before treatment and at the end of treatment. RESULT(S): In spite of the fact that there were no statistically significant differences in modified F-G scores in between the two groups, a significant decrease in modified F-G scores was observed in the flutamide (from 19.93 +/- 4.31 to 15.58 +/- 4.28) and spironolactone plus Diane 35 (from 18.77 +/- 3.76 to 14.54 +/- 3.29) groups. There were also no differences between the two groups with respect to hormonal profiles including serum FSH, LH, free T, 17-OH-progesterone, and DHEAS levels. No major side effect, including liver toxicity, was observed in either group. CONCLUSION(S): Our data suggest that both therapies have similar effectiveness in the treatment of IH.

[Usefulness and positioning of MAB therapy for prostate cancer].

Prostate cancer is a relatively slow-growing disease compared to other cancers, and the patients tend to be older. Taking into consideration therefore life expectancy of the patients and risks of recurrence and progression, conservative treatments (mainly hormonal therapy) are often applied for early cases, as well as radical treatments (total prostatectomy and radiotherapy). Particularly in Japan, many patients start treatment with hormonal therapy alone, in both early and advanced cases. Hence, Maximal Androgen Blockade (MAB) therapy, in which surgical or medical castration (such as LH-RH agonist treatment) and anti-androgen treatment are combined, is widely exercised with the hope to enhance treatment effects. The usefulness of MAB therapy has been assessed in a number of randomized comparative studies, covering mainly metastatic cases. The efficacy of the therapy with the use of flutamide as non-steroidal anti-androgen has been confirmed in some of the studies, although the magnitude of the efficacy cannot be said major. In Phase III clinical studies of MAB therapy with bicalutamide being conducted in Japan for patients in Stages C and D, however, the patient group treated with MAB therapy demonstrated more favorable results compared to the group treated with LH-RH agonist alone, particularly in terms of time to progression (TTP) of the patients in Stage C. These are relatively new findings on the usefulness and adaptability of MAB therapy. In this Panel Discussion, views and experiences are exchanged on a wide variety of topics covering the real usefulness of MAB therapy, its adaptability, possible outcomes of hormonal therapy in early cases, and the future of MAB therapy, taking into account the prevailing opinions and current practices on prostate cancer in both the United States and Japan.

Effects of flutamide on puberty in male rats: an evaluation of the protocol for the assessment of pubertal development and thyroid function.

To establish a test protocol for the rodent 20-d thyroid/pubertal assay, flutamide, a non-steroidal androgen antagonist, was administered to intact male Sprague-Dawley rats from postnatal d 33 for 20 d, and several reproductive endpoints were examined to assess the sensitivity of a number of parameters with respect to the detection of endocrine-related effects. Immature male rats were divided into 4 groups and given flutamide once daily by oral gavage at doses of 0, 1, 5, or 25 mg/kg/d. Prepuce separation was significantly delayed in flutamide-treated rats (5 and 25 mg/kg/d). One day after the last dose, the rats were sacrificed. Flutamide treatment resulted in a significant reduction in the weights of epididymides, ventral prostate, seminal vesicles plus coagulating glands and fluid, levator ani plus bulbocavernosus muscles, Cowper's glands, and glans penis. The weight of adrenal glands decreased at 25 mg/kg/d, while testes and any other organ weights were unaffected. No microscopic changes were observed in the thyroid glands. Serum levels of testosterone were significantly increased in the flutamide-treated groups (5 and 25 mg/ kg/d) and serum levels of estradiol were also increased (25 mg/kg/d). No differences were observed in the serum thyroxine levels. These results indicate that flutamide delays puberty in the male rat, and its mode of action appears to be via altered secretion of steroids, which subsequently affect the development of the reproductive tract. Thus, this assay might be used as an alternative for screening antiandrogenic activities of chemicals.

Comparative study of the clinical efficacy of two dosing regimens of flutamide.

PURPOSE: We performed a randomized trial to compare the efficacy and toxicity of a new dose of flutamide (500 mg QD) with the currently recommended dose (250 mg q8h) in the treatment of advanced prostate cancer. The primary endpoints were percent of patients having normalization of prostate specific antigen (PSA), time to normalization, and percent change from baseline. Secondary endpoints were quality of life and toxicity. PATIENTS: Altogether, 440 men aged 46 to 94 years (mean 71 years) with confirmed stage M(1) disease, documented PSA rise >0.2 ng/mL, ECOG status 0 to 2, no second neoplasm, no liver function tests > or = 1.5-fold normal values, and no previous treatment for metastatic disease were entered in the trial. RESULTS: The PSA normalized by week 12 in 71% of the patients receiving 500-mg dose and 75% of those receiving the standard dose. The percent change in PSA was 89% and 96%, respectively. The treatment groups were not significantly different with respect to the incidence of adverse events: 71% v 68% in the 500-mg and 250-mg arms, respectively (P = 0.337). CONCLUSIONS: When combined with castration, 500 mg of flutamide appears to be equally effective in lowering serum PSA and is not significantly more toxic than conventional dosing. The use of 500 mg QD instead of the standard 250 mg q8h would result in a cost savings of 30%.

Salutary clinical response of prostate cancer to antiandrogen withdrawal: assessment of flutamide in an in vitro paradigm predictive of tumor growth enhancement.

Salutary clinical responses to withdrawal of flutamide have been widely reported, indicating the potential of this arylalkylamine antiandrogen to stimulate the growth of prostate cancer. Flutamide is known to inhibit cytochrome P450-mediated testosterone synthesis and metabolism. Our laboratory has shown that arylalkylamine potencies in three in vitro assays of P450 binding or function correspond to a propensity of the drugs to enhance tumor growth in vivo. Accordingly, we measured inhibition by flutamide of (a) histamine binding to cytochrome P450 in rat liver microsomes, as determined spectrally, (b) P450-mediated demethylation of aminopyrine, and (c) DNA synthesis in mouse spleen cells stimulated by concanavalin A, and we compared its potencies in these assays with those of other arylalkylamine pharmaceuticals. Flutamide inhibited histamine binding to P450 (Ki = 31 +/- 7 microM), aminopyrine demethylation (Ki = 39 +/- 2 microM), and mitogenesis (IC50 = 12 +/- 1 microM). In overall potency, it ranked with a group of eight drugs, including the antiestrogen tamoxifen, all linked with enhanced tumor growth. In the context of clinical observations that some patients with prostate cancer benefit from flutamide withdrawal, our findings underline concerns that many arylalkylamine drugs have the potential to stimulate the growth or development of malignancies, including prostate cancer. Tumor growth enhancement by flutamide and other arylalkylamines may result from drug perturbation and/or induction of histamine-binding P450 enzymes involved in the synthesis of steroid and eicosanoid mediators that regulate gene function and cell growth.

The clinical and endocrine assessment of three different antiandrogen regimens combined with a very long-acting gonadotrophin-releasing hormone analogue.

Tumor flare is reported in up to 40% of patients treated with gonadotrophin-releasing hormone analogues for prostate cancer. In order to investigate the optimal way to eliminate tumor flare, we have treated patients with one of three different antiandrogen regimens used in combination with gonadotrophin-releasing hormone (GnRH) agonist. The early results of this study are presented here. Thirty patients with advanced symptomatic disease were randomized to receive either cyproterone acetate 50 or 100 mg three times daily or flutamide 250 mg three times daily given for 1 week before and during the first month of GnRH agonist treatment. The endocrine profiles of these patients were compared with those of historic controls treated with depot agonist alone. Three patients treated with low-dose cyproterone acetate and one with flutamide developed a transient exacerbation of their disease. No patients treated with the higher-dose cyproterone acetate regimen developed tumor flare. No patients treated with cyproterone acetate had an increase in serum testosterone above baseline following depot GnRH agonist implantation. All patients treated with flutamide had increases in serum testosterone, but this did not significantly increase further with implantation. This study suggests that all patients receiving GnRH agonist treatment should be pretreated with cyproterone acetate 100 mg three times daily for 1 week before implantation and for the first treatment month.