[Therapeutic options for stress urinary incontinence following surgery for benign prostate enlargement]

Persistent stress urinary incontinence following surgical treatment of bladder outlet obstruction based on benign prostate enlargement (BPE) occurs at an incidence of approximately 2.2 %, although incidence rates vary significantly between different surgical options. Current evidence on SUI treatment of BPE patients is usually based on postprostatectomy incontinence patient cohorts or small subgroup analyses of greater patient collectives. Studies that focus on SUI after surgical treatment of BPE are still rare. Based on the current low-level evidence, it can be assumed that pelvic floor muscle training, implantation of an adjustable male sling system and implantation of an artificial urinary sphincter may be equally effective in PPI and post-BPE patients. The implantation of a retrourethral transobturator male sling, however, seems to provide lower success rates compared to PPI patients.

[Novel minimally invasive treatment options for male lower urinary tract symptoms]

The main objective of novel minimally invasive treatment options is to be equally effective to current reference techniques while providing a superior safety profile. Especially the preservation of sexual function, including ejaculatory function, is of great interest to patients facing surgical treatment of lower urinary tract symptoms (LUTS). Ideally, a truly minimally invasive procedure can be performed under local anaesthesia in an outpatient setting. Among emerging medical devices, the prostatic urethral lift (PUL; Urolift) demonstrated rapid and durable relief of LUTS in selected patients without a prominent middle lobe. Compared to the reference method TURP, it was superior in terms of preservation of sexual function and recovery experience. The first clinical evaluation of the "Temporary Implantable Nitinol Device" (TIND) proved its feasibility, efficacy and safety for the treatment of LUTS over a 3-year follow-up period. However, prospective randomised controlled trials are still needed to evaluate its true benefit. New ablative technologies like Rezũm are based on convective water vapour energy and have shown good results in a sham-controlled randomised clinical trial for the treatment of LUTS over a follow-up period of 3 years. Of note, this procedure was also successful in patients with a prominent middle lobe, and no impairment of sexual function was reported after Rezũm. Innovative technologies like Aquablation (AquaBeam) are still in their infancy, but the first clinical outcomes are promising, even in comparison with the reference method TURP.

Inhibition of Prostate Smooth Muscle Contraction by Inhibitors of Polo-Like Kinases

Background: Prostate smooth muscle contraction plays an important role for pathophysiology and treatment of male lower urinary tract symptoms (LUTS) but is incompletely understood. Because the efficacy of available medication is limited, novel options and improved understanding of prostate smooth muscle contraction are of high demand. Recently, a possible role of polo-like kinase 1 (PLK1) has been suggested for smooth muscle contraction outside the lower urinary tract. Here, we examined effects of PLK inhibitors on contraction of human prostate tissue.

Methods: Prostate tissues were obtained from radical prostatectomy. RT-PCR, Western blot and immunofluorescence were performed to detect PLK expression and phosphorylated PLK. Smooth muscle contractions were induced by electric field stimulation (EFS), α₁-agonists, endothelin-1, or the thromboxane A₂ analog U46619 in organ bath.

Results: RT-PCR, Western blot, and immunofluorescence suggested expression of PLK1 in the human prostate, which may be located and active in smooth muscle cells. EFS-induced contractions of prostate strips were reduced by SBE 13 (1 μM), cyclapolin 9 (3 μM), TAK 960 (100 nM), and Ro 3280 (100 nM). SBE 13 and cyclapolin 9 inhibited contractions by the α₁-agonists methoxamine, phenylephrine, and noradrenaline. In contrast, no effects of SBE 13 or cyclapolin 9 on endothelin-1- or U46619-induced contractions were observed.

Conclusion: Alpha1-adrenergic smooth muscle contraction in the human prostate can be inhibited by PLK inhibitors. PLK-dependent signaling may be a new pathway, which promotes α₁-adrenergic contraction of prostate smooth muscle cells. As contractions by endothelin and U46619 are not susceptible to PLK inhibition, this reflects divergent regulation of adrenergic and non-adrenergic prostate smooth muscle contraction.

Long-term Safety and Efficacy of Mirabegron and Solifenacin in Combination Compared with Monotherapy in Patients with Overactive Bladder: A Randomised, Multicentre Phase 3 Study (SYNERGY II)

BACKGROUND

The long-term potential of solifenacin and mirabegron combination treatment for patients with overactive bladder (OAB) has not been previously assessed.

OBJECTIVES

To evaluate the safety and efficacy of solifenacin succinate 5mg plus mirabegron 50mg tablets (combination treatment) versus solifenacin or mirabegron monotherapy in patients with OAB over 12 mo.

DESIGN, SETTING, AND PARTICIPANTS

Randomised, double-blind, multicentre, phase 3 trial (SYNERGY II) of patients with "wet" OAB symptoms (urinary frequency and urgency with incontinence) for ≥3 mo. The study was conducted from March 2014 to September 2016; with 1829 patients randomised. The full analysis set was comprised of 1794 patients.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary objective was safety, measured as treatment-emergent adverse events (TEAEs). Efficacy was measured as the change from baseline to the end of treatment in the mean number of incontinence episodes/24h and micturitions/24h.

RESULTS AND LIMITATIONS

The median age was 60 yr (range 19-86 yr) and 1434 patients (80%) were female. Overall, 856 patients (47%) experienced ≥1 TEAE. TEAE frequency was slightly higher in the combination group (596 patients, 49%; mirabegron 126 patients, 41%; solifenacin 134 patients, 44%). Serious TEAEs were reported by 67 patients (3.7%); one was considered possibly treatment-related (mirabegron group, atrial fibrillation). Dry mouth was the most common TEAE (combination 74 patients, 6.1%; solifenacin 18 patients, 5.9%; mirabegron 12 patients, 3.9%). Combination therapy was statistically superior to mirabegron and solifenacin for the number of incontinence episodes (vs mirabegron: adjusted mean difference [AMD] -0.5, 95% confidence interval [CI] -0.7 to -0.2, p<0.001; vs solifenacin: AMD -0.1, 95% CI -0.4 to 0.1, p=0.002) and micturitions (vs mirabegron: AMD -0.5, 95% CI -0.8 to -0.2, p<0.001; vs solifenacin: AMD -0.4, 95% CI -0.7 to -0.1, p=0.004).

CONCLUSIONS

Mirabegron and solifenacin combination treatment for OAB symptoms was well tolerated over 12 mo and led to efficacy improvements over each monotherapy. This innovative combination is a treatment option that could become widely used in the clinic.

PATIENT SUMMARY

This study looked at the safety and efficacy of a combination of solifenacin succinate 5mg plus mirabegron 50mg tablets over 12 mo in patients with the overactive bladder (OAB) symptoms of increased urination frequency, heightened urgency to urinate, and unintentional passing of urine. We compared this treatment with solifenacin succinate 5mg or mirabegron 50mg alone, and found that the combination treatment was well tolerated by patients and led to greater improvements in symptoms. This novel combination could be an improved treatment option in the clinical setting for patients with OAB. This study is registered at ClinicalTrials.gov as NCT02045862.

Clinical Trials in Benign Prostatic Hyperplasia: A Moving Target of Success

Benign prostatic hyperplasia (BPH) affects over 50% of men above the age of 50 yr. With half of these men having bothersome lower urinary tract symptoms, this area represents a hot bed of novel treatments. Many BPH therapies have favorable short-term outcomes but lack durability or well-defined adverse events (AEs). Clinical trials are a gold standard for comparing treatments. We characterized all BPH clinical trials registered worldwide from inception to 2017. A total of 251 clinical trials were included. Of the studies, 30.1% used patient-reported outcomes such as the American Urological Association Symptom Score. Approximately 70% of clinical trials studied medical interventions, while the remaining trials investigated surgical approaches. Seventy-nine percent of trials were industry sponsored, while a minority were funded without commercial interest. Only 42% of trials had 12-mo follow-up, with the majority with <3 mo of follow-up. No trials evaluated prevention, diet, behavior, or alternative methods Overall, only 23% of trials reported results. Management options for BPH need unified benchmarks of success, AEs, durability, and standard reporting for all clinical trials, regardless of outcomes. PATIENT SUMMARY: We found that the majority of clinical trials were medical intervention, with very few trials evaluating prevention, diet, behavior, or alternative methods Furthermore, a few trials reported results in peer-reviewed journals. All clinical trials need to report results regardless of outcome, and in conclusion, standardized methods are needed in order to document the successes, adverse events, and durability for all clinical trials.

Inhibition of human prostate smooth muscle contraction by the LIM kinase inhibitors, SR7826 and LIMKi3

BACKGROUND AND PURPOSE

In men with benign prostatic hyperplasia, increased smooth muscle tone in the prostate may lead to bladder outlet obstruction and subsequent lower urinary tract symptoms. Consequently, medical treatment aims to inhibit prostate smooth muscle contraction. However, the efficacy of the treatment options available is limited, and improved understanding of mechanisms of prostate smooth muscle contraction and identification of new targets for medical intervention are mandatory. Several studies suggest that LIM kinases (LIMKs) promote smooth muscle contraction; however, this has not yet been examined. Here, we studied effects of the LIMK inhibitors on prostate smooth muscle contraction.

EXPERIMENTAL APPROACH

Human prostate tissues were obtained from radical prostatectomy. Phosphorylation of cofilin, a LIMK substrate, was examined using a phospho-specific antibody. Smooth muscle contractions were studied in organ bath experiments.

KEY RESULTS

Real-time PCR, Western blot and immunofluorescence suggested LIMKs are expressed in smooth muscle cells of prostate tissues. Two different LIMK inhibitors, SR7826 (1 μM) and LIMKi3 (1 μM), inhibited contractions of prostate strips, which were induced by electrical field stimulation, α₁ -adrenoceptor agonists phenylephrine and methoxamine and the TXA₂ analogue, U46619. LIMK inhibition in prostate tissues and cultured stromal cells (WPMY-1) was confirmed by cofilin phosphorylation, which was reduced by SR7826 and LIMKi3. In WPMY-1 cells, SR7826 and LIMKi3 caused breakdown of actin filaments and reduced viability.

CONCLUSIONS AND IMPLICATIONS

Smooth muscle tone in the hyperplastic human prostate may underlie the effects of LIMKs, which promote contraction. Contraction of prostate strips can be inhibited by small molecule LIMK inhibitors.

Adreno-muscarinic synergy in the male human urinary outflow tract

AIM

To examine putative interaction between adrenergic and muscarinic contractile activation in the human urinary outflow tract.

METHODS

Tissue from the trigone and prostatic urethra was obtained from 12 cystectomy and 16 prostatectomy specimen. Contractions were elicited by exposure to exogenous agonists before and after inhibition of Rho kinase and protein kinase c (PKC). Immunofluorescence and Western-blot studies were performed using antibodies to muscarinic M3-receptors (M3-R) and alpha1A-adrenoreceptors (alpha1A-AR). The study is registered with ClinicalTrials.gov, number NCT01227447.

RESULTS

There was strong co-localization of M3-R and alpha1A-AR on trigonal and urethral myocytes. Western blot analysis revealed a significantly higher expression of alpha1A-AR in the superficial than in the deep trigone. Phenylephrine (PE, 1 μm) augmented contractions induced by carbachol (CA, 3 μm) to more than threefold control in the male superficial trigone, and to about sevenfold control in the proximal urethra. No such potentiation could be detected in female bladder outlet. Both PKC inhibitor GF 109203X and Rho kinase inhibitor Y-27632 reduced responses to 1 μM PE as well as to 3 μM CA significantly. However, the synergistic effect of the combined intervention remained proportionally unaffected.

CONCLUSIONS

Muscarinic and adrenergic receptor activation exerts a strong synergistic effect in the male human bladder trigone and proximal urethra.

Cardiovascular Safety of the β3 -Adrenoceptor Agonist Mirabegron and the Antimuscarinic Agent Solifenacin in the SYNERGY Trial

There have been concerns that treatment of overactive bladder with β₃ -adrenoceptor agonists may potentially have detrimental cardiovascular (CV) side effects. We evaluated the CV safety of mirabegron, a β₃ -adrenoceptor agonist, alone and in combination therapy with the antimuscarinic agent solifenacin. The SYNERGY trial was a multinational, multicenter, randomized, double-blind, parallel-group, placebo and active-controlled phase 3 trial. Patients were randomized to receive solifenacin 5 mg + mirabegron 50 mg (combination 5 + 50 mg), solifenacin 5 mg + mirabegron 25 mg (combination 5 + 25 mg), solifenacin 5 mg monotherapy, mirabegron 25 mg monotherapy, mirabegron 50 mg monotherapy, or placebo for a 12-week double-blind treatment period. A total of 3398 patients were included in the study. Mean changes from baseline to the end of therapy in ECG parameters were similar across treatment groups, although there was an increase in heart rate of 1 beat/minute in the mirabegron treatment groups. There were no clinically meaningful differences in change from baseline in QTcF between monotherapies and placebo and between monotherapies and combination therapy. There were very few major CV events: 1 of 853 (0.1%) with a nonfatal myocardial infarction in the combination 5 + 25 mg group, 2 of 848 (0.2%) with a nonfatal stroke in the combination 5 + 50 mg group, and no events in the other groups. This CV safety analysis of the combination of mirabegron and solifenacin showed rates of CV events comparable with those for monotherapy treatments based on assessments of vital signs, electrocardiograms, and adjudicated CV events.

68Gallium-Prostate-Specific Membrane Antigen PET/Computed Tomography for Primary and Secondary Staging in Prostate Cancer

Prostate-specific membrane antigen (PSMA) PET has been recently introduced for the diagnosis of patients with metastatic prostate cancer (PCa). Until today, staging of patients with PCa relied mostly on morphologic features, such as size or shape, resulting in low detection rates in disease recurrence. PSMA PET imaging provides molecular information and, in combination with conventional imaging, offers improved sensitivity and specificity. This review discusses the benefits and limitations of PSMA imaging in the setting of primary staging and detection of recurrent disease in comparison with standard-of-care imaging techniques.

[Cytoreductive, radical prostatectomy in metastatic prostate cancer]

The resection of the primary tumor in patients with metastatic prostate cancer is controversially debated. Retrospective clinical studies indicate survival benefits and prevention of secondary, locoregional complications; however, results of ongoing multicenter prospective studies are still lacking. This review highlights the rationale behind the cytoreductive prostatectomy and summarizes current clinical study results.

Salvage lymph node dissection after 68Ga-PSMA or 18F-FEC PET/CT for nodal recurrence in prostate cancer patients

The management of patients with biochemical recurrence (BCR) after definitive treatment for prostate cancer remains controversial. Our aim was to determine survival rates and complications of salvage lymph node dissection (sLND) in patients with recurrent prostate cancer after radical prostatectomy, while evaluating biochemical response (BR) with two different positron emission tomography/computed tomography (PET/CT) tracers used for preoperative imaging. sLND was performed in 104 patients diagnosed with isolated nodal recurrence on either ¹⁸F-fluoroethylcholine (¹⁸F-FEC) or ⁶⁸Ga-PSMA-HBED-CC (⁶⁸Ga-PSMA) PET/CT. Surgical complications, BR, clinical recurrence (CR), and cancer-specific survival (CSS) were evaluated. Logistic regression was used to determine predictors of complete BR (cBR) and CR after sLND and survival rates were assessed. Median follow-up was 39.5 months. Median patient age and prostate-specific antigen (PSA) at sLND were 64 years and 4.1 ng/mL. Median number of lymph nodes (LNs) removed was 13; median number of positive LNs was 3 per patient. Rate of Clavien-Dindo Grade III complications was low (4.8%). 29.8% of patients developed cBR (PSA < 0.2 ng/mL), and 56.7% partial BR (PSA postoperative < PSA preoperative) after sLND. Patients with LN metastases diagnosed on ⁶⁸Ga-PSMA PET/CT showed a higher rate of cBR compared to ¹⁸F-FEC PET/CT (45.7 vs. 21.7%, p = 0.040). PSA at sLND (p = 0.031) and choice of PET tracer (p = 0.048) were independent predictors of cBR. The 5-year BCR-free, CR-free and CSS rates were 6.2%, 26.0%, and 82.8%, respectively. While preoperative staging with ⁶⁸Ga-PSMA seems superior, only a limited number of patients developed cBR after surgery. Most patients experienced BCR and CR during follow-up.