Imidafenacin, An Orally Active Muscarinic Receptor Antagonist, Improves Pulmonary Function In Patients With Chronic Obstructive Pulmonary Disease: A Multicenter, Randomized, Double-Blind, Placebo-Controlled 3×3 Crossover Phase II Trial

Background

Although long-acting muscarinic receptor antagonists are central to the management of chronic obstructive pulmonary disease (COPD), inhaled medicines may have technical difficulty in some patients and adherence barriers.

Methods

A multicenter, randomized, double-blind, placebo-controlled 3×3 crossover Phase II trial was performed to evaluate the efficacy and safety of oral administration of the antimuscarinic agent imidafenacin in patients with COPD. Twenty-seven male COPD patients with % forced expiratory volume in 1 s (FEV₁) ≥30% and <80% predicted were randomized to single oral dose of imidafenacin 0.1 mg, imidafenacin 0.2 mg, or placebo.

Results

Maximum change in FEV₁ with both doses of imidafenacin significantly improved from baseline to 24 hrs after administration when compared with a placebo. Area under the curve in FEV₁ during 24 hrs after administration with 0.2 mg, but not 0.1 mg dose, was significantly improved when compared with a placebo, and the improvement was significantly based on dose-dependent manners. Plasma imidafenacin level was positively correlated with change in FEV₁. All subjects with both doses of imidafenacin completed without moderate nor severe adverse events.

Conclusion

A single oral dose of imidafenacin 0.1 mg or imidafenacin 0.2 mg may contribute to the improvement of pulmonary function with excellent safety and tolerability in patients with COPD.

Trial registration

JapicCTI-121760 (Japan Pharmaceutical Information Center – Clinical Trials Information [JapicCTI]; http://www.clinicaltrials.jp/user/cteSearch_e.jsp).

Randomized, open-label, tolterodine-controlled, comparative study of the novel antimuscarinic agent imidafenacin in patients with overactive bladder

BACKGROUND

The role of the selective antimuscarinic imidafenacin in Caucasian patients with overactive bladder (OAB) has not been previously assessed.

OBJECTIVE

To evaluate the safety and efficacy of imidafenacin 0.2 mg vs tolterodine 4 mg per day in patients with OAB.

DESIGN SETTING AND PARTICIPANTS

This study was a randomized, open-label, tolterodine-controlled, comparative multicenter trial of 300 randomized patients with OAB symptoms for 12 weeks with full analysis of 289 patients.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Based on 5-day bladder diaries, the primary efficacy endpoint was the change in the mean number of micturitions per day. The secondary endpoints were the change in the mean incontinence episodes, voiding frequency, the OAB Awareness Tool score, and the European Quality of Life Questionnaire (EQ-5D) score. The superiority of tolterodine over imidafenacin in the mean number of micturitions/24 hours was the null hypothesis.

RESULTS AND LIMITATION

The median age was 46.6 years, and 82% of patients were female. After treatment, the change in the mean number of incontinence episodes was -2.1 ± 2.2 in the imidafenacin group and -1.9 ± 1.8 in the tolterodine group (P = .001). The change in the mean number of daytime incontinence episodes was -1.7 ± 1.7 and -1.5 ± 1.4 ( P = .01). The OAB Awareness Tool score decreased by 14.2 ± 8.5 and 14.5 ± 8.0, respectively ( P = 0.5). Most adverse events were mild and resolved without treatment.

CONCLUSIONS

The clinical efficacy and safety of imidafenacin are not inferior to those of tolterodine for the treatment of Caucasian patients with OAB.

PATIENT SUMMARY

Imidafenacin is as effective as tolterodine for the treatment of OAB.

[Imidafenacin for treatment of overactive bladder and urgent urinary incontinence: the results of open-label multicenter randomized controlled clinical trial]

INTRODUCTION

The analysis of the results of a multicenter, open, randomized comparative phase III clinical trial on the use of imidafenacin for treating patients with OAB was carried out. A clinical study was conducted according to GCP standards in 12 urological centers of the Russian Federation with the support of company AO "R-Pharm".

MATERIALS AND METHODS

A total of 296 patients (men and women) aged from 18 to 65 years with OAB and urgent urinary incontinence were included in the study. All patients were randomized into two groups. In Group 1 (n=148) patients received -cholinoblocker imidafenacin 1 tablet (0,1 mg) twice a day. Group 2 patients (n=148) were prescribed a comparison drug tolterodine 1 tablet (2 mg) twice a day, as well. The duration of treatment was 12 weeks.

RESULTS

The analysis of results showed a significant decrease in the OAB symptoms in both groups. In Group 1 a decrease of episodes of urge urinary incontinence was more pronounce compared to Group 2, as well as amount of day-time and night-time of episodes of urge urinary incontinence by the 2nd, 4th, 8th and 12th weeks of treatment in comparison with baseline scores. There were no differences between two groups in the severity of reducing average urinary frequency per day. Reducing the severity of urinary disturbances in patients of both groups was accompanied by an improvement in the quality of life. There was a significant and similar decrease in the average total score of both OAB Awareness Tool and EQ-5D questionnaires. Tolerability of treatment was satisfactory in both groups and there were no differences in the adverse events in Group 1 and 2.

CONCLUSION

Imidafenacin showed high clinical efficacy for treating patients with OAB, which is not inferior, and in some values, is superior in comparison to tolterodine. Both drugs had a similar safety and tolerability profile.

Novel Extended-Release Multiple-Unit System of Imidafenacin Prepared by Fluid-Bed Coating Technique

The objective of this study was to formulate once-a-day extended-release (ER) pellet system of imidafenacin (IDN), a recently approved urinary antispasmodic agent with twice-a-day dosing regimen. The sugar sphere pellets were firstly layered with IDN and hypromellose and then coated with Eudragit RS (copolymers of acrylic and methacrylic acid esters), employed as a release modifier, using a fluid-bed coater. Solid-state characterizations using solid-state X-ray diffraction and differential scanning calorimeter indicated that the antispasmodic agent was homogeneously layered onto the pellets in an amorphous state. Drug release from multiple-unit ER system was effectively retarded in proportion to the amount of Eudragit RS in the outer layer, with a high correlation value above 0.86. In a pharmacokinetic evaluation in beagle dogs, the plasma concentration profile of IDN was markedly protracted by ER pellets, exhibiting delayed the time needed to reach the maximum drug concentration and the elimination half-life in plasma, compared to the commercial immediate release form (Uritos® tablet, Kyorin Pharmaceutical Co., Ltd., Japan). Therefore, the novel ER pellets can be a promising tool for oral IDN therapy, providing a once-a-day dosing regimen, and thus, improving patient compliance.

Muscarinic receptors mediate cold stress-induced detrusor overactivity in type 2 diabetes mellitus rats

OBJECTIVES

This study determined if muscarinic receptors could mediate the cold stress-induced detrusor overactivity induced in type 2 diabetes mellitus rats.

METHODS

Ten-week-old female Goto-Kakizaki diabetic rats (n = 12) and Wister Kyoto non-diabetic rats (n = 12) were maintained on a high-fat diet for 4 weeks. Cystometric investigations of the unanesthetized rats were carried out at room temperature (27 ± 2°C) for 20 min. They were intravenously administered imidafenacin (0.3 mg/kg, n = 6) or vehicle (n = 6). After 5 min, the rats were transferred to a low temperature (4 ± 2°C) for 40 min where the cystometry was continued. The rats were then returned to room temperature for the final cystometric measurements. Afterwards, expressions of bladder muscarinic receptor M3 and M2 messenger ribonucleic acids and proteins were assessed by reverse transcription polymerase chain reaction and immunohistochemistry.

RESULTS

In non-diabetic Wister Kyoto rats, imidafenacin did not reduce cold stress-induced detrusor overactivity. In diabetic Goto-Kakizaki rats, just after transfer to a low temperature, the cold stress-induced detrusor overactivity in imidafenacin-treated rats was reduced compared with vehicle-treated rats. Within the urinary bladders, the ratio of M3 to M2 receptor messenger ribonucleic acid in the diabetic Goto-Kakizaki rats was significantly higher than that of the non-diabetic Wister Kyoto rats. The proportion of muscarinic M3 receptor-positive area within the detrusor in diabetic Goto-Kakizaki rats was also significantly higher than that in non-diabetic Wister Kyoto rats.

CONCLUSIONS

Imidafenacin partially inhibits cold stress-induced detrusor overactivity in diabetic Goto-Kakizaki rats. In this animal model, muscarinic M3 receptors partially mediate cold stress-induced detrusor overactivity.

Factors influencing patient satisfaction with antimuscarinic treatment of overactive bladder syndrome: results of a real-life clinical study

OBJECTIVES

To investigate patient satisfaction with antimuscarinic treatment of overactive bladder syndrome, and to identify factors having a significant influence on satisfaction.

METHODS

A cross-sectional questionnaire survey was carried out to assess treatment satisfaction among male and female patients with overactive bladder (age ≥20 years) in the Hokuriku district of Japan. The overactive bladder symptom scores, treatment efficacies, adverse events (dry mouth and constipation), and patient satisfaction scores were investigated and compared among patients using different antimuscarinic therapeutics.

RESULTS

In total, 977 survey respondents (52.6% men; mean age 73.6 years) received antimuscarinic treatment. The mean overactive bladder symptom score of these patients was 6.17; in addition, 32.3% patients were satisfied with their treatment, but 33.1% were dissatisfied. Factors having a significant influence on treatment satisfaction were sex (men were less satisfied), efficacy, adverse events and the overactive bladder symptom score. Constipation negatively influenced patient satisfaction to a greater extent than did dry mouth. Patient satisfaction varied according to the drug used. Constipation was less severe with the immediate-release-type agents (imidafenacin and oxybutynin) than with the extended-release-type (propiverine, solifenacin or tolterodine).

CONCLUSIONS

Just one-third of Japanese Hokuriku patients with overactive bladder seem to be satisfied with their antimuscarinic treatment. Patient satisfaction is impaired by poor efficacy and the presence of adverse events; furthermore, constipation should be recognized as an adverse event that negatively influences patient satisfaction to a greater extent than dry mouth. Patient satisfaction differs according to the antimuscarinic agent used, with higher patient satisfaction being associated with less severe constipation.

Experience with imidafenacin in the management of overactive bladder disorder

Overactive bladder (OAB) is a chronic syndrome defined by symptoms of urinary urgency with no underlying medical causes. First-line treatment of OAB comprises fluid intake advice and bladder training, supplemented by anticholinergic drugs if necessary. Owing to the chronic nature of OAB, the ideal anticholinergic treatment should have good long-term efficacy and tolerability. There are many anticholinergics available, although some of these are not specific for the bladder and can cause adverse effects such as dry mouth, constipation, blurred vision or cognitive impairment. Imidafenacin (a newer anticholinergic which has been marketed in Japan since 2007) was developed to improve the tolerability of anticholinergic therapy. This article summarizes the pharmacological properties, pharmacokinetics, clinical efficacy and tolerability of imidafenacin in the treatment of OAB. Data from key clinical studies of imidafenacin show that it has a fast onset of action and is effective for the treatment of OAB. It selectively binds to muscarinic receptors in the bladder and is associated with a good safety profile compared with other anticholinergics. The clinical efficacy, superior tolerability and adjustable dosing of imidafenacin make it a good anticholinergic for the treatment of OAB.

Long-term safety, efficacy, and tolerability of imidafenacin in the treatment of overactive bladder: a review of the Japanese literature

Imidafenacin is an antimuscarinic agent with high affinity for the M(3) and M(1) muscarinic receptor subtypes and low affinity for the M(2) subtype, and is used to treat overactive bladder. Several animal studies have demonstrated that imidafenacin has organ selectivity for the bladder over the salivary glands, colon, heart, and brain. In Phase I studies in humans, the approximately 2.9-hour elimination half-life of imidafenacin was shorter than that of other antimuscarinics such as tolterodine and solifenacin. Imidafenacin was approved for clinical use in overactive bladder in Japan in 2007 after a randomized, double-blind, placebo-controlled Phase II study and a propiverine-controlled Phase III study conducted in Japanese patients demonstrated that imidafenacin 0.1 mg twice daily was clinically effective for treating overactive bladder and was not inferior to propiverine for reduction of episodes of incontinence, with a better safety profile than propiverine. Several short-term clinical studies have demonstrated that imidafenacin also improves sleep disorders, nocturia, and nocturia-related quality of life. In addition, it is speculated that addon therapy with imidafenacin is beneficial for men with benign prostatic hyperplasia whose overactive bladder symptoms are not controlled by alpha-1 adrenoceptor antagonists. No cognitive impairment or influence of imidafenacin on the QTc interval has been observed. Although there have been very few relevant long-term clinical studies, the available information suggests the long-term efficacy, safety, and tolerability of imidafenacin, with less frequent severe adverse events, such as dry mouth and constipation. In addition, imidafenacin can be used safely for a long time even for cognitively vulnerable elderly patients with symptoms of overactive bladder. Thus, it is highly likely that imidafenacin is safe, efficacious, and tolerable to control symptoms of overactive bladder even over the long term. However, it remains unknown if the practical effectiveness of imidafenacin is applicable to ethnic groups other than Japanese.