Dutasteride

FDA-Approved Trifluoromethyl Group-Containing Drugs: A Review of 20 Years

As people around the world regard 2020 as the year of COVID-19, the medical community considers this year to be the second-best year, shared with the year 1996, with respect to the number of drug molecules approved by the US Food and Drug Administration (FDA). Both years, 2020 and 1996, had a record of 53 new drug molecules approved by the FDA. In the year 2020, 53 new chemical entities and 13 biological medicines were approved, including 10 monoclonal antibodies, 2 antibody-drug conjugates, 3 peptides, and 2 oligonucleotides. Among them, most of the compounds were found to have fluorine or fluorine-containing functional groups exhibiting numerous pharmacological activities. Herein, we summarized the trifluoromethyl (TFM, -CF3)-group-containing FDA-approved drugs for the last 20 years. This article specially features and details the previous 20-year literature data, covering CF3-incorporated potential drug molecules, including their syntheses and uses for various diseases and disorders. The review covers the detailed chemistry of 19 FDA-approved drugs in the past 20 years, which contains the TFM group as one of the pharmacophores.

LC-MS/MS determination of dutasteride and its major metabolites in human plasma

Dutasteride is a specific and selective inhibitor of both 5α-reductase isoforms used mainly in benign prostatic hyperplasia and lower urinary tract symptoms. Although the drug is extensively metabolized in humans, data on the concentrations of its main metabolites are lacking. There is also a lack of data on dutasteride stability in frozen plasma samples. Our method was used to determine dutasteride and its active metabolites: 4'-hydroxydutasteride, 6β-hydroxydutasteride, and 1,2-dihydrodutasteride in plasma after a single administration of 0.5 mg of dutasteride. We also assessed the long-term stability (two years in the freezer) of dutasteride in clinical samples. The developed method covered the range of 0.1-3.5 ng/mL for dutasteride and 0.08-1.2 ng/mL for 1,2-dihydrodutasteride, 4'-hydroxydutasteride, 6β-hydroxydutasteride. It was proved to be reliable as it met all validation criteria required by the European Medicine Agency for bioanalytical methods. 4'-hydroxydutasteride and 1,2-dihydrodutasteride concentrations in plasma were higher than 6β-hydroxydutasteride. Dutasteride was stable in the freezer for up to 2 years in clinical samples. Thus within 1014 days of storage (below - 65 °C), samples can be reanalyzed without the risk of unreliable results.

Efficacy and safety of dutasteride compared with finasteride in treating males with benign prostatic hyperplasia: A meta-analysis of randomized controlled trials

The present study was an updated meta-analysis that aimed to confirm the efficacy and safety of dutasteride (0.5 mg) and finasteride (5 mg) in treating males with benign prostatic hyperplasia (BPH) over a treatment period of at least 6 months. Randomized controlled trials were retrieved using the MEDLINE, EMBASE and the Cochrane controlled trials register databases. The references of the associated articles were also searched. A systematic review was performed by using the preferred reporting items for systematic reviews and meta-analyses. The data were analyzed with RevMan v5.3.0. A total of six articles including 2,041 participants were studied. The analysis demonstrated a significantly greater decrease in international prostate symptom score [IPSS; mean difference (MD), -0.86; 95% CI, -1.62 to -0.11; P=0.02] and prostate-specific antigen (PSA; MD, -0.13; 95% CI, -0.26 to -0.01; P=0.03) in the dutasteride group compared with that in the finasteride group, whereas no significant differences were observed in prostate volume (PV; P=0.64), maximum urine flow rate (Qmax; P=0.29) and post-void residual volume (PVRV; P=0.14). With regard to safety assessment, including any adverse event (P=0.66), decreased libido (P=0.39) and impotence (P=0.17), there was no significant difference between dutasteride and finasteride. In conclusion, in patients with BPH, dutasteride produced a greater decrease in IPSS and PSA compared with finasteride, whereas no significant differences were identified in PV, Qmax and PVRV. The two drugs appeared to have similar rates of adverse effects, particularly with regard to sexual dysfunction.

Neuropsychological Assessment in Elderly Men with Benign Prostatic Hyperplasia Treated with Dutasteride

BACKGROUND AND OBJECTIVE

Benign prostatic hyperplasia (BPH) is a common disease found in elderly men and 5α-reductase (5α-R) inhibitors are a commonly used treatment option. 5α-reduced steroids are compounds that play a role in several functions across different organs and systems. In the adult brain, 5α-R accounts for neuroactive steroid production. Whether neuropsychological impairment could be due to dutasteride treatment, a 5α-R inhibitor affecting the production of dihydrotestosterone (DHT), is still unknown. The aim of our study was to investigate neuropsychological features in men receiving dutasteride.

METHODS

The Mini Mental State Examination (MMSE), the Clock Drawing Test (CDT), the Frontal Assessment Battery (FAB), the Hamilton Anxiety Rating Scale (HAM-A), the Beck Depression Inventory second edition (BDI-II) and the Short Form-12 (SF-12) questionnaire were administered in order to explore both cognitive impairment and psychological features.

RESULTS

In a sample of BPH patients (n = 40; mean age 71.4 ± 7.4 years), men receiving dutasteride showed no significant differences during the neuropsychological assessment in comparison with an age-matched control group, consisting of BPH men not receiving dutasteride (p < 0.05). No significant associations were recorded between treatment duration and any of the administered tests.

CONCLUSIONS

This is the first study investigating the neuropsychological features in dutasteride users. Our preliminary data are consistent with the safety of dutasteride under a mental profile.

Meta-analysis of the efficacy and safety of combination of tamsulosin plus dutasteride compared with tamsulosin monotherapy in treating benign prostatic hyperplasia

BACKGROUND

We performed a meta-analysis to confirm the efficacy and safety of the combination of tamsulosin plus dutasteride compared with tamsulosin monotherapy in treating benign prostatic hyperplasia (BPH) during a treatment cycle of at least 1 year.

METHODS

Randomized controlled trials were searched by using MEDLINE, EMBASE, and the Cochrane Controlled Trials Register. Systematic review was carried out using the Preferred Reporting Items for Systematic Reviews and Meta-analyses. The data was evaluated and statistically analyzed by using RevMan version 5.3.0.

RESULTS

Five studies including 4348 patients were studied. The analysis found that the combination group was significantly greater effect in international prostate symptom score (mean difference [MD], - 1.43; 95% confidence interval [CI], - 2.20 to - 0.66; P = 0.0003), prostate volume (MD, - 10.13; 95% CI, - 12.38 to - 7.88; P < 0.00001), transitional zone volume (MD, - 3.18; 95% CI, - 3.57 to - 2.79; P<0.0001), maximum urine flow rate (MD, 1.05; 95% CI, 0.82 to 1.29; P < 0.00001), prostate specific antigen (MD, - 0.54; 95% CI, - 0.80 to - 0.29; P < 0.0001) and post-void residual volume (MD, - 3.85; 95% CI, - 4.95 to - 2.76; P < 0.00001) compared with the tamsulosin group. In terms of safety, including adverse events (odds ratio [OR], 2.06; 95% CI, 1.34 to 3.17; P = 0.001), erectile dysfunction (OR, 2.24; 95% CI, 1.73 to 2.92; P < 0.00001), ejaculation disorder (OR, 3.37; 95% CI, 1.97 to 5.79; P < 0.0001), retrograde ejaculation (OR, 2.30; 95% CI, 1.08 to 4.93; P = 0.03), decreased libido (OR, 2.25; 95% CI, 1.53 to 3.31; P < 0.0001) and loss of libido (OR, 3.38; 95% CI, 1.94 to 5.88; P<0.0001), the combination group showed poor tolerance than the tamsulosin group with the exception of dizziness (OR, 1.16; 95% CI, 0.75 to 1.80; P = 0.50). The combination group significantly reduced the risk of clinical progression than the tamsulosin group especially in incidence of BPH-related symptom progression (OR, 0.56; 95% CI, 0.46 to 0.67; P < 0.00001) and acute urinary retention (OR, 0.61; 95% CI, 0.38 to 0.98; P = 0.04).

CONCLUSION

The combination of tamsulosin plus dutasteride provides a preferable therapeutic effect for BPH with a higher incidence of sexual side effects, but combination-therapy can markedly reduce risk of BPH-related symptom progression and acute urinary retention relative to tamsulosin monotherapy.

Inhibition of 5α-reductase alters pregnane metabolism in the late pregnant mare

In the latter half of gestation in the mare, progesterone concentrations decline to near undetectable levels while other 5α-reduced pregnanes are elevated. Of these, 5α-dihydroprogesterone and allopregnanolone have been reported to have important roles in either pregnancy maintenance or fetal quiescence. During this time, the placenta is necessary for pregnane metabolism, with the enzyme 5α-reductase being required for the conversion of progesterone to 5α-dihydroprogesterone. The objectives of this study were to assess the effects of a 5α-reductase inhibitor, dutasteride on pregnane metabolism (pregnenolone, progesterone, 5α-dihydroprogesterone, 20α-hydroxy-5α-pregnan-3-one, 5α-pregnane-3β,20α-diol and allopregnanolone), to determine circulating dutasteride concentrations and to assess effects of dutasteride treatment on gestational parameters. Pregnant mares (n = 5) received dutasteride (0.01 mg/kg/day, IM) and control mares (n = 4) received vehicle alone from 300 to 320 days of gestation or until parturition. Concentrations of dutasteride, pregnenolone, progesterone, 5α-dihydroprogesterone, 20α-hydroxy-5α-pregnan-3-one, 5α-pregnane-3β,20α-diol, and allopregnanolone were evaluated via liquid chromatography–tandem mass spectrometry. Samples were analyzed as both days post treatment and as days prepartum. No significant treatment effects were detected in pregnenolone, 5α-dihydroprogesterone, 20α-hydroxy-5α-pregnan-3-one, 5α-pregnane-3β,20α-diol or allopregnanolone for either analysis; however, progesterone concentrations were increased (P < 0.05) sixfold in dutasteride-treated mares compared to control mares. Dutasteride concentrations increased in the treated mares, with a significant correlation (P < 0.05) between dutasteride concentrations and pregnenolone or progesterone concentrations. Gestational length and neonatal outcomes were not significantly altered in dutasteride-treated mares. Although 5α-reduced metabolites were unchanged, these data suggest an accumulation of precursor progesterone with inhibition of 5α-reductase, indicating the ability of dutasteride to alter progesterone metabolism.

Use of 5-alpha-reductase inhibitors as alternatives to luteinizing-hormone releasing hormone (LHRH) analogs or anti-androgens for prostate downsizing before brachytherapy

INTRODUCTION

Prostate hypertrophy, median lobe hypertrophy, and pubic arch interference (PAI) are relative contraindications to brachytherapy because of potential morbidity and technical considerations. GnRH analogs or non-steroidal anti-androgens are currently utilized to achieve prostatic downsizing prior to brachytherapy. However, such agents have been associated with effects on body habitus, metabolism, and quality of life. In contrast, 5-alpha reductase inhibitors (5-ARI) are far less frequently associated with these morbidities.

METHODS AND MATERIALS

Patients with large gland size, median lobe hypertrophy, or PAI were offered 5-ARI therapy. Repeat transrectal ultrasound was performed at 3 or 4 months, followed by brachytherapy if resolution was achieved. If downsizing was inadequate, patients were offered continuation of 5-ARI for additional 3 months, gonadotropin-releasing hormone analog (GnRH) agonist or antiandrogen therapy, or other curative treatment.

RESULTS

Of 59 patients with follow-up available, 42 (71%) were deemed to have adequate downsizing; 37 (63%) after 3 to 4 months of 5-ARI and 5 (8%) after 7 to 8 months. Seventeen patients (29%) received other treatments because of inadequate effect. Median volume reduction was 20%. Of 41 patients undergoing brachytherapy, 4 (9.7%) required temporary catheterization because of obstruction. Median follow-up after implantation was 25 months (range, 1-64). Median time for return to International Prostate Symptom Score ≤5 of baseline score was 7 months (interquartile ratio, 6-13). All but 1 patient who received brachytherapy remain biochemically controlled.

CONCLUSION

5-ARI monotherapy is an alternative for downsizing in patients with hypertrophy or PAI, with more than 70% achieving adequate downsizing without use of GnRH analogs or antiandrogens. Patients who received brachytherapy experienced typical rates of postimplant urinary morbidity.

The use of 5-alpha reductase inhibitors in the treatment of benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is characterized by an enlarged prostate, lower urinary tract symptoms (LUTS), and a decreased urinary flow rate. Common in older men, BPH is a progressive disease that can eventually lead to complications including acute urinary retention (AUR) and the need for BPH-related surgery. Both normal and abnormal prostate growth is driven by the androgen dihydrotestosterone (DHT), which is formed from testosterone under the influence of 5-alpha reductase. Thus, 5-alpha reductase inhibitors (5-ARIs) effectively reduce the serum and intraprostatic concentration of DHT, causing an involution of prostate tissue. Two 5-ARIs are currently available for the treatment of BPH—finasteride and dutasteride. Both have been demonstrated to decrease prostate volume, improve LUTS and urinary flow rates, which ultimately reduces the risk of AUR and BPH-related surgery. Therefore, either alone or in combination with other BPH medications, 5-ARIs are a mainstay of BPH management.

Relative Bioavailability of Fixed-Dose Combinations of Tamsulosin and Dutasteride: Results From 2 Randomized Trials in Healthy Male Volunteers

The relative bioavailabilities of dutasteride/tamsulosin hydrochloride 0.5 mg/0.2 mg fixed-dose combination (FDC) capsules compared with coadministered reference products (1 dutasteride 0.5-mg capsule [Avodart^® ] + 1 tamsulosin hydrochloride 0.2-mg orally disintegrating tablet [Harnal D^® ]) were investigated in 2 clinical trials under fasted and fed conditions (ClinicalTrials.gov NCT02184585 and NCT02509104). Both trials were open-label, randomized, single-dose, crossover studies in healthy male adults aged 18-65 years. Trial 1 evaluated 2 formulations (FDC1 and FDC2), and trial 2 evaluated a third formulation (FDC3). The primary end points were dutasteride area under the concentration-time curve from time 0 to t (AUC_(0-t) ) and peak plasma concentration (C_max ) and tamsulosin AUC_(0-∞) , AUC_(0-t) , and C_max . The formulations were considered to be bioequivalent if the 90%CIs for the geometric mean ratios for each end point were within the range of 0.80-1.25. For FDC1 in trial 1, bioequivalence criteria were not met for dutasteride C_max or AUC in the fasted state or for tamsulosin C_max in the fasted or fed states. For FDC2 in trial 1, all bioequivalence criteria were met except for tamsulosin C_max in the fasted state. For FDC3 in trial 2, bioequivalence criteria were met for all dutasteride and tamsulosin end points in both the fed and fasted states. Safety profiles were similar for all FDC formulations and combination treatments.

Preparation and in vivo evaluation of a dutasteride-loaded solid-supersaturatable self-microemulsifying drug delivery system

The purpose of this study was to prepare a dutasteride-loaded solid-supersaturatable self-microemulsifying drug delivery system (SMEDDS) using hydrophilic additives with high oral bioavailability, and to determine if there was a correlation between the in vitro dissolution data and the in vivo pharmacokinetic parameters of this delivery system in rats. A dutasteride-loaded solid-supersaturatable SMEDDS was generated by adsorption of liquid SMEDDS onto Aerosil 200 colloidal silica using a spray drying process. The dissolution and oral absorption of dutasteride from solid SMEDDS significantly increased after the addition of hydroxypropylmethyl cellulose (HPMC) or Soluplus. Solid SMEDDS/Aerosil 200/Soluplus microparticles had higher oral bioavailability with 6.8- and 5.0-fold higher peak plasma concentration (C_max) and area under the concentration-time curve (AUC) values, respectively, than that of the equivalent physical mixture. A linear correlation between in vitro dissolution efficiency and in vivo pharmacokinetic parameters was demonstrated for both AUC and C_max values. Therefore, the preparation of a solid-supersaturatable SMEDDS with HPMC or Soluplus could be a promising formulation strategy to develop novel solid dosage forms of dutasteride.

Relative adrenal insufficiency in mice deficient in 5α-reductase 1

Patients with critical illness or hepatic failure exhibit impaired cortisol responses to ACTH, a phenomenon known as 'relative adrenal insufficiency'. A putative mechanism is that elevated bile acids inhibit inactivation of cortisol in liver by 5α-reductases type 1 and type 2 and 5β-reductase, resulting in compensatory downregulation of the hypothalamic-pituitary-adrenal axis and adrenocortical atrophy. To test the hypothesis that impaired glucocorticoid clearance can cause relative adrenal insufficiency, we investigated the consequences of 5α-reductase type 1 deficiency in mice. In adrenalectomised male mice with targeted disruption of 5α-reductase type 1, clearance of corticosterone was lower after acute or chronic (eightfold, P<0.05) administration, compared with WT control mice. In intact 5α-reductase-deficient male mice, although resting plasma corticosterone levels were maintained, corticosterone responses were impaired after ACTH administration (26% lower, P<0.05), handling stress (2.5-fold lower, P<0.05) and restraint stress (43% lower, P<0.05) compared with WT mice. mRNA levels of Nr3c1 (glucocorticoid receptor), Crh and Avp in pituitary or hypothalamus were altered, consistent with enhanced negative feedback. These findings confirm that impaired peripheral clearance of glucocorticoids can cause 'relative adrenal insufficiency' in mice, an observation with important implications for patients with critical illness or hepatic failure, and for patients receiving 5α-reductase inhibitors for prostatic disease.

Influence of hydrophilic additives on the supersaturation and bioavailability of dutasteride-loaded hydroxypropyl-β-cyclodextrin nanostructures

The objectives of this study were to develop a novel solid dutasteride formulation with improved physicochemical properties and oral bioavailability, and to examine the correlation between its in vitro dissolution and in vivo pharmacokinetic parameters. Hydroxypropyl-β-cyclodextrin (HP-β-CD) nanostructures with or without hydrophilic additives were manufactured using the supercritical antisolvent process. The dutasteride-loaded HP-β-CD nanoparticles formed aggregates with a mean particle size of less than 160 nm and a specific surface area greater than 100 m(2)/g. Increases in the supersaturation and dissolution rate for dutasteride were dependent on the type of additive; increases in maximum solubility and extended supersaturation were observed in dutasteride-loaded HP-β-CD nanostructures with hydroxypropylmethyl cellulose, whereas the dissolution rate was the highest for nanostructures containing d-α-tocopheryl polyethylene glycol 1000 succinate. In rats, the oral bioavailability of dutasteride increased with the supersaturation induced by the HP-β-CD nanostructures. In addition, compared with the in vitro drug release rate, the in vivo pharmacokinetic parameters were more closely correlated with in vitro parameters related to supersaturation (solubility). Further, the bioavailability of the dutasteride-loaded HP-β-CD nanostructures with hydroxypropylmethyl cellulose was similar to that of the commercially available soft gelatin capsule (Avodart®). In conclusion, preparation of dutasteride-loaded HP-β-CD nanostructures using the supercritical antisolvent process affords a viable alternative solid dosage form for dutasteride.

Advances in the design and discovery of drugs for the treatment of prostatic hyperplasia

INTRODUCTION

Benign prostatic hyperplasia (BPH) is a common medical problem in nearly 80% of geriatric male population severely affecting the quality of life. Several strategies has been suggested in the past for the management of BPH, but only α-blockers and 5α-reductase inhibitors are in clinical use. This review aims to give deep insight into advances in the design and discovery of newer chemical entities as 'druggable' molecule for the management of BPH.

AREAS COVERED

In this review, the authors cover various classes of drugs that have shown their potential for management of BPH. These drugs include α-adrenergic antagonists, 5α-reductase inhibitors, phytochemical agents, phosphodiesterase inhibitor, luteinizing hormone releasing hormone antagonists and muscarinic receptor antagonists. Literature searches were carried out using Google Scholar, SciFinder and PubMed.

EXPERT OPINION

The exact etiology of BPH is unknown; however, several mechanisms may be involved in the progression of the disease. Beside surgery and watchful waiting, medical therapies to treat BPH include α-adrenergic antagonist and 5α-reductase inhibitors. Phytotherapeutic agents are also used in some countries. Various other chemical classes of drugs are proposed for the treatment of the disease, but none of them have reached the clinic. Many classes of drugs are currently undergoing clinical trials such as phosphodiesterase inhibitors, luteinizing hormone releasing hormone antagonists and muscarinic receptor antagonists. The current need is to develop a potent, efficacious and highly selective drug for the treatment of BPH.

Dutasteride treatment over 2 years delays prostate-specific antigen progression in patients with biochemical failure after radical therapy for prostate cancer: results from the randomised, placebo-controlled Avodart After Radical Therapy for Prostate Cancer Study (ARTS)

BACKGROUND

Rising prostate-specific antigen (PSA) levels after radical therapy are indicative of recurrent or residual prostate cancer (PCa). This biochemical recurrence typically predates clinically detectable metastatic disease by several years. Management of patients with biochemical recurrence is controversial.

OBJECTIVE

To assess the effect of dutasteride on progression of PCa in patients with biochemical failure after radical therapy.

DESIGN, SETTING, AND PARTICIPANTS

Randomised, double-blind, placebo-controlled trial in 294 men from 64 centres across 9 European countries.

INTERVENTION

The 5α-reductase inhibitor, dutasteride.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary end point was time to PSA doubling from start of randomised treatment, analysed by log-rank test stratified by previous therapy and investigative-site cluster. Secondary end points included time to disease progression and the proportion of subjects with disease progression.

RESULTS AND LIMITATIONS

Of the 294 subjects randomised (147 in each treatment group), 187 (64%) completed 24 mo of treatment and 107 discontinued treatment prematurely (71 [48%] of the placebo group, 36 [24%] of the dutasteride group). Dutasteride significantly delayed the time to PSA doubling compared with placebo after 24 mo of treatment (p<0.001); the relative risk (RR) reduction was 66.1% (95% confidence interval [CI], 50.35-76.90) for the overall study period. Dutasteride also significantly delayed disease progression (which included PSA- and non-PSA-related outcomes) compared with placebo (p<0.001); the overall RR reduction in favour of dutasteride was 59% (95% CI, 32.53-75.09). The incidence of adverse events (AEs), serious AEs, and AEs leading to study withdrawal were similar between the treatment groups. A limitation was that investigators were not blinded to PSA levels during the study.

CONCLUSIONS

Dutasteride delayed the biochemical progression of PCa in patients with biochemical failure after radical therapy for clinically localised disease. The safety and tolerability of dutasteride were generally consistent with previous experience.

CLINICAL TRIAL REGISTRY

ClinicalTrials.gov, NCT00558363.

The effect of pulsed electromagnetic fields and dehydroepiandrosterone on viability and osteo-induction of human mesenchymal stem cells

The hypothesis of this work was that human bone marrow-derived mesenchymal stem cells (MSCs) are regulated by pulsed electromagnetic fields (PEMFs) and by intracrine conversion of an adrenal prohormone to dihydrotestosterone. The effect of PEMF and dehydroepiandrosterone (DHEA) on viability and osteogenic differentiation of human MSCs and on the viability of osteoblastic SaOS-2 cells was evaluated. It was found that PEMF promoted the viability rate of both cell types, whereas DHEA decreased the viability rate in a concentration-dependent manner. PEMF did not have major effects on osteo-induction at this low seeding density level (3000 cells/cm(2) ). Instead, DHEA, after MSC-mediated and 5α-reductase-dependent conversion to dihydrotestosterone, clearly promoted the osteo-induction of MSCs induced with β-glyserophosphate, ascorbate and dexamethasone. Alkaline phosphatase (ALP), SMAD1, RUNX2, osteopontin (OP) and osteocalcin (OC) RNA levels were increased and alizarin red S- and hydroxyapatite-specific OsteoImage(TM) stainings disclosed a promoted mineralization process. In addition, DHEA increased OP and OC mRNA levels of non-induced MSCs. A sequential use of mitogenic PEMF early during the fracture healing, followed by later administration of DHEA with osteogenic differentiating effect, might be worth subjecting to a randomized clinical trial.

Targeting 5α-reductase for prostate cancer prevention and treatment

Testosterone is the most abundant circulating androgen, and can be converted to dihydrotestosterone (DHT), a more potent androgen, by the 5α-reductase enzymes in target tissues. Current treatments for prostate cancer consist of reducing androgen levels by chemical or surgical castration or pure antiandrogen therapy that directly targets the androgen receptor (AR). Although these therapies reduce tumor burden and AR activity, the cancer inevitably recurs within 18-30 months. An approach targeting the androgen-AR axis at different levels could, therefore, improve the efficacy of prostate cancer therapy. Inhibition of 5α-reductase is one such approach; however, the two largest trials to investigate the use of the 5α-reductase inhibitors (5ARIs) finasteride and dutasteride in patients with prostate cancer have shown that, although the incidence of cancer was reduced by 5ARI treatment, those cancers that were detected were more aggressive than in patients treated with placebo. Thus, the best practice for using these drugs to prevent and treat prostate cancer remains unclear.

A broader role for 5ARIs in prostate disease? Existing evidence and emerging benefits

5ARIs are recommended for men who have moderate-to-severe lower urinary tract symptoms (LUTS) and benign prostatic enlargement (BPE) secondary to benign prostatic hyperplasia. Studies have confirmed the utility of combining 5ARIs with alpha-blockers; the MTOPS study showed that risk of overall clinical progression was significantly reduced after 4.5 years with combination therapy (finasteride/doxazosin) in comparison with either monotherapy, while the ongoing CombAT trial (dutasteride/tamsulosin) has for the first time shown benefit in improving symptoms for combination therapy over monotherapies within 12 months of treatment. Data also suggest roles for 5ARIs in prostate cancer. Several studies indicate that treatment with a 5ARI improves the performance of PSA testing for identifying men with prostate cancer, while the PCPT showed a significant reduction in the risk of developing prostate cancer with finasteride. However, widespread use of finasteride in this setting has been tempered by an apparent increase in high-grade disease observed in the study. The ongoing REDUCE study will provide further insight into prostate cancer prevention with 5ARIs. 5ARI-containing regimens may have utility as less aggressive treatment options for patients who only have rising PSA after definitive local therapy, and in patients with disease resistant to androgen deprivation therapy who have PSA progression. Current evidence therefore shows that 5ARIs are effective in treating LUTS/BPE and preventing disease progression, and may also have a role in the prevention of prostate cancer. The overlap between BPE and prostate cancer may allow a more unified approach to managing these conditions, with 5ARIs having a central role.

5alpha-Reductase inhibitor treatment of prostatic diseases: background and practical implications

This literature review discusses the theoretical background of 5alpha-reductase inhibitor (5ARI) treatment and the resulting clinical implications. A Medline-based search for peer-reviewed articles addressing 5ARIs, benign prostatic hyperplasia and prostate cancer was performed. The 5ARIs Finasteride and Dutasteride, which specifically inhibit the production of dihydrotestosterone by acting as competitive inhibitors of 5alpha-reductase, are clinically well tolerated and represent an effective treatment option for benign prostatic obstruction. Finasteride is the first compound which has a proven efficacy in chemoprevention of prostate cancer. The aim of this review was to elucidate, if there are sufficient data available to point out clinically relevant differences between the drugs. Both compounds achieve a significant reduction of prostate volume, an improvement of symptoms and a lower risk of acute urinary retention. Whether the different pharmacokinetic and pharmacodynamic properties of Finasteride and Dutasteride are of clinical importance cannot be judged at this time.

Finasteride to evaluate the efficacy of dutasteride in the management of patients with lower urinary tract symptoms and enlarged prostate

Patients with lower urinary tract symptoms and enlarged prostate were randomized to receive, in a double blind fashion, either Finasteride 5 mg/day or Dutasteride 0.5 mg/day for a period of 12 weeks. IPSS score, Qmax, and Quality of Life were assessed at the end of 0 and 12 week periods. Dutasteride significantly improved Qmax, reduced IPSS score, and improved Quality of Life as compared to Finasteride at the end of the 12-week period. Dutasteride with its inhibitory effects on type 1 and 2 5alpha-reductase, produces significantly better results than Finasteride.

Drug Insight: 5alpha-reductase inhibitors for the treatment of benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is a common problem among older men, which is characterized by an enlarged prostate, lower urinary tract symptoms, and decreased flow of urine. It is a progressive disease that can lead to complications such as acute urinary retention (AUR) or a need for BPH-related surgery in some men. Dihydrotestosterone is the primary androgen involved in both normal and abnormal prostate growth and 5alpha-reductase inhibitors (5ARIs) inhibit the conversion of testosterone to dihydrotestosterone. There are two 5ARIs licensed for the treatment of BPH; dutasteride, which inhibits both type 1 and type 2 isoenzymes of 5alpha reductase, and finasteride, which inhibits the type 2 isoenzyme. Both 5ARIs have been shown to decrease prostate volume, improve urinary flow and lower urinary tract symptoms and reduce the risk of AUR and BPH-related surgery. The prevention of disease progression, by treating the underlying cause, and the alleviation of symptoms are important aims of BPH therapy. 5ARIs are the only currently available medical therapy that can reduce the risk of AUR and BPH-related surgery while providing long-term symptom control. This provides a mandate for their use in men with enlarged prostates (volume >or=30 ml), who are at increased risk of disease progression.

Dutasteride affects progesterone metabolizing enzyme activity/expression in human breast cell lines resulting in suppression of cell proliferation and detachment

Recent evidence indicates that progesterone metabolites play important roles in regulating breast cancer. Previous studies have shown that breast carcinoma and tumorigenic breast cell lines have higher 5alpha-reductase and lower 3alpha-hydroxysteroid oxidoreductase (3alpha-HSO) and 20alpha-HSO activities and mRNA expression levels than normal tissue and non-tumorigenic cell lines. The 5alpha-reduced progesterone metabolites such as 5alpha-dihydroprogesterone (5alphaP) promote both mitogenic and metastatic activity in breast cell lines in culture, whereas the 4-pregnene metabolites, 4-pregnen-3alpha-ol-20-one (3alphaHP) and 4-pregnen-20alpha-ol-3-one (20alphaHP) have the opposite (anti-cancer-like) effects. The 5alpha-reductase inhibitor dutasteride has been shown to inhibit 5alpha-reduction of testosterone to 5alpha-dihydrotestosterone in prostate tissue, resulting in decreased prostate volume. The aim of this study was to determine if dutasteride is an effective inhibitor of progesterone 5alpha-reduction in human breast cell lines and if such inhibition reduces mammary cell proliferation and detachment. The effect of dutasteride on progesterone metabolizing enzyme activities and mRNA expression were examined in tumorigenic MCF-7 and non-tumorigenic MCF-10A human breast cell lines. Dutasteride (10(-6)M) inhibited progesterone conversion to 5alpha-pregnanes by >95% and increased 4-pregnene production. The results indicated that effects of dutasteride on the progesterone metabolizing enzymes are due to direct inhibition of 5alpha-reductase activity and to altered levels of expression of 5alpha-reductase and HSO mRNAs. Treatment of cells with progesterone without medium change for 72 h resulted in significant conversion to 5alpha-pregnanes and increases in cell proliferation and detachment. The increases in proliferation and detachment were blocked by dutasteride and were reinstated by concomitant treatment with 5alphaP, providing proof-of-principle that the effects were due not to progesterone but to the 5alpha-reduced metabolites. This study provides the first evidence that dutasteride is a potent progesterone 5alpha-reductase inhibitor and that such inhibition may be beneficial in breast cancer.

Dutasteride: a dual 5-alpha reductase inhibitor for the treatment of symptomatic benign prostatic hyperplasia

OBJECTIVE

To review the pharmacology, pharmacokinetics, efficacy, safety, drug interactions, and dosing recommendations of dutasteride, a 5-alpha reductase inhibitor for benign prostatic hyperplasia (BPH).

DATA SOURCES

A MEDLINE search (1966-February 2006) was conducted to extract human research data in the English language on dutasteride. Search terms included benign prostatic hyperplasia, dutasteride, and finasteride. The reference lists of articles identified through this search process, the manufacturer's Web site, and dutasteride prescribing information were also examined.

STUDY SELECTION AND DATA EXTRACTION

All published studies and clinical data from the manufacturer were included, with emphasis placed on randomized, controlled trials.

DATA SYNTHESIS

Dutasteride is approved for the treatment of symptomatic BPH in men with an enlarged prostate to improve urinary symptoms, reduce the risk of acute urinary retention, and reduce the need for BPH-related surgical interventions. Compared with placebo, dutasteride has been shown to significantly improve BPH symptoms, reduce the incidence of acute urinary retention and BPH-related surgery, and improve BPH-related quality of life. Few published data exist comparing dutasteride with finasteride. The most common adverse effects of dutasteride include ear, nose, and throat infection; malaise; headache; dizziness; and musculoskeletal pain.

CONCLUSIONS

Clinical trials, sponsored primarily by the manufacturer, have shown dutasteride to be an effective treatment of BPH compared with placebo and to likely possess efficacy similar to that of finasteride. Further studies are needed to gain a more clear understanding of any clinically significant differences between dutasteride and finasteride.

Selective and rapid liquid chromatography–tandem mass spectrometry assay of dutasteride in human plasma

A simple, rapid, sensitive and specific liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of dutasteride (I), a potent and the first specific dual inhibitor of 5alpha-reductase, in human plasma. The analyte and internal standard (finasteride (II)) were extracted by liquid-liquid extraction with diethyl ether/dichloromethane (70/30, v/v) using a Glas-Col Multi-Pulse Vortexer. The chromatographic separation was performed on a reverse phase Xterra MS C18 column with a mobile phase of 10 mM ammonium formate/acetonitrile (15/85, v/v, pH adjusted to 3.0 with formic acid). The protonated analyte was quantitated in positive ionization by multiple reaction monitoring with a mass spectrometer. The mass transitions m/z 529.5 --> 461.5 and m/z 373.3 --> 317.4 were used to measure I and II, respectively. The assay exhibited a linear dynamic range of 0.1-25.0 ng/mL for dutasteride in human plasma. The lower limit of quantitation was 100 pg/mL with a relative standard deviation of less than 15%. Acceptable precision and accuracy were obtained for concentrations over the standard curve ranges. A run time of 1.2 min for each sample made it possible to analyze a throughput of more than 400 human plasma samples/day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability or bioequivalence studies.