Safety and tolerability of the β3 -adrenoceptor agonist mirabegron, for the treatment of overactive bladder: results of a prospective pooled analysis of three 12-week randomised Phase III trials and of a 1-year randomised Phase III trial

AIMS

To evaluate the safety and tolerability of the β3 -adrenoceptor agonist, mirabegron, in patients with overactive bladder (OAB).

METHODS

Tolerability and safety data from three 12-week, randomised, placebo-controlled, double-blind, Phase III trials (Studies 046, 047 and 074) were pooled by treatment group. The three studies were of a similar design, although the assessed doses of mirabegron [25, 50 or 100 mg once daily (qd)] varied, and tolterodine extended release (ER) 4 mg was included as an active-control arm in Study 046 only. Tolerability and safety data from a 1-year, randomised, double-blind, Phase III trial (Study 049) are also presented. Safety variables included the incidence and severity of treatment-emergent adverse events (TEAEs), vital signs and electrocardiogram data.

RESULTS

Mirabegron (25, 50 or 100 mg qd) was safe and well-tolerated in patients with OAB over 12-week (n = 2736) and 1-year (n = 1632) periods. The incidence of TEAEs and treatment discontinuations as a result of TEAEs was low; the majority were mild in severity and few were serious. Hypertension, nasopharyngitis and urinary tract infection were the most common TEAEs with mirabegron. The mirabegron tolerability profile was similar to that seen with placebo and tolterodine ER 4 mg, except for dry mouth, which occurred, on average, five times less frequently with mirabegron than tolterodine ER 4 mg. In the pooled 12-week analysis, mirabegron 50 mg was associated with placebo-adjusted mean increases of 0.4-0.6 mmHg in blood pressure and approximately one beat per minute in pulse rate, both reversible upon treatment discontinuation. The incidence of Major Adverse Cardiovascular Events as adjudicated by an independent cardiovascular committee was low and similar across treatment groups.

CONCLUSION

The favourable tolerability profile of mirabegron in patients with OAB may allow improved treatment compliance compared with antimuscarinics, with important implications for patient outcomes.

Multiple sclerosis produces significant changes in urinary bladder innervation which are partially reflected in the lower urinary tract functional status-sensory nerve fibers role in detrusor overactivity

BACKGROUND

Detrusor overactivity is often observed in patients with multiple sclerosis (MS), and neurotoxins are emerging as second-line therapies albeit with different degrees of success per patient basis.

OBJECTIVE

To investigate lower urinary tract (LUT) functional status and bladder innervation (calcitonin gene related peptide [CGRP] and substance P [SP] positive nerve fibers) in patients with MS.

METHOD

Eighteen MS patients with LUT symptoms underwent urodynamic investigations, and six non-MS patients undergoing cystoscopy due to microscopic hematuria served as controls. Cold cut bladder biopsies were taken from the bladder trigone region. Neurotransmitter expression was determined by individual immunohistochemical staining.

RESULTS

Two distinct groups could be distinguished: group 1 with pronounced neurogenic detrusor overactivity and mild outflow obstruction; group 2 with some degree of neurogenic detrusor overactivity, detrusor hypocontractility during voiding, and high degree of an outflow obstruction. The presence of SP and CGRP immunoreactive + fiber density was observed in greater numbers in group 1.

CONCLUSION

Density of CGRP and SP positive nerve fibers within the urinary bladder of patients with MS may be suggestive of functional status of the lower urinary tract, namely denser innervation is observed in patients with mild outflow obstruction and strong detrusor overactivity. This observation could be useful when planning second-line treatment (neurotoxins) in these patients. Patients with denser innervation probably will respond better to such a therapy.

Stage of bladder cancer in Central Europe - Polish perspective

Mortality rate from bladder cancer in Europe is the highest in its Central Region. This study is an attempt to find underlying factors by proper characterisation of large cohort of Polish patients with bladder cancer.This is a multicentre study enrolling 1360 consecutive patients diagnosed with primary urothelial carcinoma of the bladder in years 2012-2013 in Poland. All patients underwent transurethral resection of the bladder tumor. Data on staging and grading of all cancers were collected, as well as several demographic and clinical factors were tested for the association with muscle invasiveness of the cancer.Mean age of the cohort was 69.6 years, male to female ratio was 3:1. Bladder cancer stage Ta, T1 and muscle-invasive (MIBC) was diagnosed in 533 (39.2%), 516 (37.9%) and 296 (21.8%) patients, respectively. Patients with MIBC were older (73 vs. 68 years, p<0.05), had lower body mass index (25.4 vs. 26.5 kg/m2, p<0.05), lower haemoglobin concentration (12.2 vs. 13.4 mg/l, p<0.05), longer history of haematuria (86.2 vs. 74.4 days) and longer time interval from first symptom to diagnosis (118.0 vs. 88.2 days), compared to patients with Ta and T1 tumors.High mortality rate from bladder cancer in Central Europe can result from very high incidence of high-risk T1 tumors and high prevalence of prognostic factors of poor survival.

The influence of doxazosin on the contractility of the urinary bladder in female pigs with experimentally induced cystitis

The present in vitro study investigated the influence of doxazosin on the contractility of the urinary bladder in female pigs with experimentally induced cystitis. Fifteen juvenile female piglets (18-20 kg body weight) were randomly assigned into three groups (n=5 animals each): i) control (clinically healthy animals, without doxazosin treatment), ii) animals with induced inflammation of the urinary bladder, but without doxazosin treatment (experimental group I) and iii) animals with inflamed bladder, treated orally with doxazosin (0.1 mg/kg body weight for 30 days; experimental group II). Thereafter, the pigs were sacrificed and strips of the bladder trigone were suspended in organ baths. The tension and amplitude of the smooth muscles was measured before and after exposition to 5-hydroxytryptamine (5-HT; 10-6-10-4 M), acetylocholine (ACh; 10-5-10-3 M) and norepinephrine (NE; 10-9-10-7 M). 5-HT caused an increase in the tension of contractions in all the groups and the amplitude in the experimental groups, however, the effect was higher in the experimental group I than in group II as compared to that found in the pre-treatment period. ACh caused an increase in the tension in the control group and a decrease in the amplitude in both experimental groups; these changes significantly differed between the control and doxazosin-treated group. NE caused a decrease in the tension in both experimental groups and amplitude in all the groups, however, the effect was most strongly expressed in doxazosine-treated group. The present study has revealed that long-term administration of doxazosin causes a desensitization of the detrusor smooth muscle to in vitro applied mediators in the autonomic nervous system.

The influence of resiniferatoxin on the chemical coding of caudal mesenteric ganglion neurons supplying the urinary bladder in the pig

Resiniferatoxin (RTX) is used as experimental drug therapy for a range of neurogenic urinary bladder disorders. The present study investigated the chemical coding of caudal mesenteric ganglion (CaMG) neurons supplying the porcine urinary bladder after intravesical RTX instillation. The CaMG neurons were visualized with retrograde tracer Fast Blue (FB) and their chemical profile was disclosed with double-labelling immunohistochemistry using antibodies against tyrosine hydroxylase (TH), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), somatostatin (SOM), calbindin (CB), galanin (GAL) and neuronal nitric oxide synthase (nNOS). It was found that in both the control (n = 6) and RTX-treated pigs (n = 6), the vast majority (92.3 ± 2.7% and 93.1 ± 1.3%, respectively) of FB-positive (FB⁺) nerve cells were TH⁺. Intravesical instillation of RTX caused a decrease in the number of FB⁺ / TH ⁺ neurons immunopositive to NPY (91.0 ± 2.2% in control animals vs. 58.8 ± 5.0% in RTX-treated pigs) or VIP (1.7 ± 0.5% vs. 0%) and an increase in the number of FB⁺ / TH⁺ neurons immunoreactive to SOM (3.4 ± 1.5% vs. 20.6 ± 4.3%), CB (1.8 ±0.7% vs. 13.4 ± 2.3%), GAL (1.5 ± 0.6% vs. 7.5 ± 1.0%) or nNOS (0% vs. 10.9 ± 3.4%). The present results suggest that therapeutic effects of RTX on the mammalian urinary bladder can be partly mediated by CaMG neurons.

[Ambulatory diagnosis of urinary incontinence among women: the role of a one-hour pad weigh test]

The aim of our studies was the evaluation of diagnostic usefulness of the 1-hour pad weight test in the different types of female incontinence. We examined 189 women at the age from 16 to 74 with the incontinence in anamnesis. The test was performed accordingly to the I.C.S. guidelines. The positive result of the test (more that 2 grams increase in the pad weigh) was found in 136 (71.6%) of examined women; including moderate urine leak in 24%, big in 55.1% and severe in 20.6% of them. The biggest average increase in pad weigh was found in urinary incontinence associated with the urgency, corresponding to 88.9 g in mixed incontinence and to 67.4 g in genuine urge incontinence. The sensitivity, specificity and efficacy of the test was 78.6%, 72% and 77% respectively. The shortened 1-hour pad weigh test is a simple and effective examination, especially in the stress incontinence. It is less effective in genuine urge incontinence and giggle incontinence. The negative effect of the 1-hour test, when the patients complaints coexist, should be the indication to repeat the test or to perform the 24-hour test. In the doubtful cases, before the surgery, the diagnostics should be extended to the full urodynamic examination.

Distribution and neurochemical characterization of sensory dorsal root ganglia neurons supplying porcine urinary bladder

Pig has been used recently as an animal model for studying diseases of human urinary tract, however, the sensory innervations of urinary bladder in this species has not been yet described.

OBJECTIVE

The present study was aimed at neurochemical characterization of sensory neurons of dorsal root ganglia (DRGs) supplying porcine urinary bladder.

METHODS

Retrograde tracer Fast Blue (FB) was injected into the right half of the urinary bladder wall of six juvenile female pigs. Three weeks later ipsi- and contralateral DRGs of interest were harvested from all animals and a neurochemical characterization of retrogradely-labeled neurons was performed using routine single-immunofluorescence labeling technique on 10 microm-thick cryostat sections.

RESULTS

85% of spinal sensory neurons supplying porcine urinary bladder was located in ipsilateral sacral S3-S4 ganglia and in first coccygeal ganglion (Cq1),whereas rest of FB-positive (FB+) nerve cells were found in lumbar L3-L6 DRGs. FB+ neurons belonged mostly to the medium-sized (54%) and small-sized afferent perikarya (45%). Bladder sensory neurons contained substance P (SP), calcitonin gene-related peptide (CGRP), pituitary adenylate cyclase-activating peptide (PACAP), galanin (GAL), neuronal nitric oxide synthase (nNOS), somatostatin (SOM) and/or calbindin-28k (CB), and these neurons constituted 45%, 36%, 26%, 6%, 6%, 4% and 3% of all retrogradely traced DRGs perikarya, respectively. Distinct differences in the number of traced cells and their neuropeptide content were observed between the lumbar and sacral/coccygeal division of bladder-projecting DRG neurons. Thus, FB+ neurons expressing CGRP, GAL, nNOS or SOM were more numerous in lumbar DRGs (44%, 9%, 9% and 6%, respectively), than in sacral/coccygeal ganglia (23%, 2%, 1.5% and 0.3%, respectively). On the other hand, more FB+ cells expressed PACAP in sacral (31%) than in lumbar DRGs (23%). However, fractions of SP-IR or CB-IR bladder sensory neurons were similar in lumbar and sacral/coccygeal DRGs.

CONCLUSIONS

This novel description of both spatial and neurochemical organization pattern of porcine urinary bladder sensory innervation constitutes a basis for further functional studies aimed at unraveling neurogenic mechanisms of urinary bladder diseases.