Effects of Steroidal Antiandrogen or 5-alpha-reductase Inhibitor on Prostate Tissue Hormone Content

Early investigational agents for the treatment of benign prostatic hyperplasia'

INTRODUCTION

Benign prostatic hyperplasia (BPH), as a clinical entity that affects many people, has always been in the forefront of interest among researchers, pharmaceutical companies, and physicians. Patients with BPH exhibit a diverse range of symptoms, while current treatment options can occasionally cause adverse events. All the aforementioned have led to an increased demand for more effective treatment options.

AREAS COVERED

This review summarizes the outcomes of new medications used in a pre-clinical and clinical setting for the management of male lower urinary tract symptoms (LUTS)/BPH and provides information about ongoing trials and future directions in the management of this condition. More specifically, sheds light upon drug categories, such as reductase‑adrenoceptor antagonists, drugs interfering with the nitric oxide (NO)/cyclic guanosine monophosphate (GMP) signaling pathway, onabotulinumtoxinA, vitamin D3 (calcitriol) analogues, selective cannabinoid (CB) receptor agonists, talaporfin sodium, inhibitor of transforming growth factor beta 1 (TGF-β1), drugs targeting the hormonal control of the prostate, phytotherapy, and many more.

EXPERT OPINION

Clinical trials are being conducted on a number of new medications that may emerge as effective therapeutic alternatives in the coming years.

Multiple ageing effects on testicular/epididymal germ cells lead to decreased male fertility in mice

In mammals, females undergo reproductive cessation with age, whereas male fertility gradually declines but persists almost throughout life. However, the detailed effects of ageing on germ cells during and after spermatogenesis, in the testis and epididymis, respectively, remain unclear. Here we comprehensively examined the in vivo male fertility and the overall organization of the testis and epididymis with age, focusing on spermatogenesis, and sperm function and fertility, in mice. We first found that in vivo male fertility decreased with age, which is independent of mating behaviors and testosterone levels. Second, overall sperm production in aged testes was decreased; about 20% of seminiferous tubules showed abnormalities such as germ cell depletion, sperm release failure, and perturbed germ cell associations, and the remaining 80% of tubules contained lower number of germ cells because of decreased proliferation of spermatogonia. Further, the spermatozoa in aged epididymides exhibited decreased total cell numbers, abnormal morphology/structure, decreased motility, and DNA damage, resulting in low fertilizing and developmental rates. We conclude that these multiple ageing effects on germ cells lead to decreased in vivo male fertility. Our present findings are useful to better understand the basic mechanism behind the ageing effect on male fertility in mammals including humans.

Estrogen and G protein-coupled estrogen receptor accelerate the progression of benign prostatic hyperplasia by inducing prostatic fibrosis

Benign prostatic hyperplasia (BPH) is the most common and progressive urological disease in elderly men worldwide. Epidemiological studies have suggested that the speed of disease progression varies among individuals, while the pathophysiological mechanisms of accelerated clinical progression in some BPH patients remain to be elucidated. In this study, we defined patients with BPH as belonging to the accelerated progressive group (transurethral resection of the prostate [TURP] surgery at ≤50 years old), normal-speed progressive group (TURP surgery at ≥70 years old), or non-progressive group (age ≤50 years old without BPH-related surgery). We enrolled prostate specimens from the three groups of patients and compared these tissues to determine the histopathological characteristics and molecular mechanisms underlying BPH patients with accelerated progression. We found that the main histopathological characteristics of accelerated progressive BPH tissues were increased stromal components and prostatic fibrosis, which were accompanied by higher myofibroblast accumulation and collagen deposition. Mechanism dissection demonstrated that these accelerated progressive BPH tissues have higher expression of the CYP19 and G protein-coupled estrogen receptor (GPER) with higher estrogen biosynthesis. Estrogen functions via GPER/Gαi signaling to modulate the EGFR/ERK and HIF-1α/TGF-β1 signaling to increase prostatic stromal cell proliferation and prostatic stromal fibrosis. The increased stromal components and prostatic fibrosis may accelerate the clinical progression of BPH. Targeting this newly identified CYP19/estrogen/GPER/Gαi signaling axis may facilitate the development of novel personalized therapeutics to better suppress the progression of BPH.

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.

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.

Phosphodiesterase inhibitors for lower urinary tract symptoms consistent with benign prostatic hyperplasia

BACKGROUND

Benign prostatic hyperplasia (BPH) refers to non-malignant enlargement of the prostate gland that may cause bothersome lower urinary tract symptoms (LUTS). Alpha-blockers (ABs) and 5-alpha reductase inhibitors (5-ARIs) are the mainstay of medical treatment. Recently, phosphodiesterase inhibitors (PDEIs) that so far have been used mainly to treat erectile dysfunction were introduced to treat male LUTS.

OBJECTIVES

To assess the effects of PDEIs compared to placebo and other standard of care drugs (ABs and 5-ARIs) in men with LUTS consistent with BPH.

SEARCH METHODS

We conducted a systematic search of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Web of Science, and clinical trials registries of the World Health Organization (WHO) and the National Institutes of Health (NIH) (updated 2 August 2018). We performed citation tracking and handsearching of abstracts and conference proceedings. We also contacted study authors to ask for additional information.

SELECTION CRITERIA

We considered for inclusion in this systematic review randomised controlled trials (RCTs) comparing PDEIs versus placebo, ABs, or 5-ARIs for at least four weeks in men with BPH-LUTS.

DATA COLLECTION AND ANALYSIS

Three review authors independently screened the literature and extracted data. Primary outcomes were effects on urinary symptoms as assessed by the International Prostate Symptom Score (IPSS-total; score ranging from 0 to 35, with higher values reflecting more symptoms), urinary bother as assessed by the Benign Prostatic Hyperplasia Impact Index (BPHII; score ranging from 0 to 13, with higher values reflecting more bother), and adverse events (AEs). We used GRADE to rate the quality of evidence. We considered short-term (up to 12 weeks) and long-term (12 weeks or longer) results separately.

MAIN RESULTS

We included a total of 16 randomised trials in this review. The results for primary outcomes are as follows.PDEI versus placebo: PDEIs may result in a small improvement in IPSS-total score (mean difference (MD) 1.89 lower, 95% confidence interval (CI) 2.27 lower to 1.50 lower; n = 4293; low-quality evidence) compared to placebo, and may reduce the BPHII score slightly (MD 0.52 lower, 95% CI 0.71 lower to 0.33 lower; n = 3646; low-quality evidence). Rates of AEs may be increased (risk ratio (RR) 1.42, 95% CI 1.21 to 1.67; n = 4386; low-quality evidence). This corresponds to 95 more AEs per 1000 participants (95% CI 47 more to 151 more per 1000). Study results were limited to a treatment duration of six to 12 weeks.PDEI versus AB: PDEIs and ABs probably provide similar improvement in IPSS-total score (MD 0.22 higher, 95% CI 0.49 lower to 0.93 higher; n = 933; moderate-quality evidence) and may have a similar effect on BPHII score (MD 0.03 higher, 95% CI 1.10 lower to 1.16 higher; n = 550; low-quality evidence) and AEs (RR 1.35, 95% CI 0.80 to 2.30; n = 936; low-quality evidence). This corresponds to 71 more AEs per 1000 participants (95% CI 41 fewer to 264 more per 1000). Study results were limited to a treatment duration of six to 12 weeks.PDEI and AB versus AB alone: the combination of PDEI and AB may provide a small improvement in IPSS-total score (MD 2.56 lower, 95% CI 3.92 lower to 1.19 lower; n = 193; low-quality evidence) compared to AB alone. We found no evidence for BPHII scores. AEs may be increased (RR 2.81, 95% CI 1.53 to 5.17; n = 194; moderate-quality evidence). This corresponds to 235 more AEs per 1000 participants (95% CI 69 more to 542 more per 1000). Study results were limited to treatment duration of four to 12 weeks.PDEI and AB versus PDEI alone: the combination of PDEI and AB may provide a small improvement in IPSS-total (MD 2.4 lower, 95% CI 6.47 lower to 1.67 higher; n = 40; low-quality evidence) compared to PDEI alone. We found no data on BPHII or AEs. Study results were limited to a treatment duration of four weeks.PDEI and 5-ARI versus 5-ARI alone: in the short term (up to 12 weeks), the combination of PDEI and 5-ARI probably results in a small improvement in IPSS-total score (MD 1.40 lower, 95% CI 2.24 lower to 0.56 lower; n = 695; moderate-quality evidence) compared to 5-ARI alone. We found no evidence on BPHII scores or AEs. In the long term (13 to 26 weeks), the combination of PDEI and 5-ARI likely results in a small reduction in IPSS-total score (MD 1.00 less, 95% CI 1.83 lower to 0.17 lower; n = 695; moderate-quality evidence). We found no evidence about effects on BPHII scores. There may be no difference in rates of AEs (RR 1.07, 95% CI 0.84 to 1.36; n = 695; low-quality evidence). This corresponds to 19 more AEs per 1000 participants (95% CI 43 fewer to 98 more per 1000).We found no trials comparing other combinations of treatments or comparing different PDEI agents.

AUTHORS' CONCLUSIONS

Compared to placebo, PDEI likely leads to a small reduction in IPSS-total and BPHII sores, with a possible increase in AEs. There may be no differences between PDEI and AB with regards to improvement in IPSS-total, BPHII, and incidence of AEs. There appears to be no added benefit of PDEI combined with AB compared to PDEI or AB alone or PDEI combined with 5-ARI compared to ARI alone with regards to urinary symptoms. Most evidence was limited to short-term treatment up to 12 weeks and of moderate or low certainty.