Botox May Improve Idiopathic Detrusor Overactivity in Overactive Bladder

May 21, 2007 — Botulinum toxin type A (Botox) can improve idiopathic detrusor overactivity (IDO) in patients with symptoms of overactive bladder (OAB), according to the results of a randomized, double-blind, placebo-controlled study reported in the June issue of the Journal of Urology. Treatment benefits, including improved quality of life, were maintained for at least 24 weeks.

“The findings of this study are important because there is a need for new treatments for OAB patients who have unsatisfactory responses to therapies which are currently available and who do not want to consider invasive surgery,” principal investigator Arun Sahai, a research fellow at Guy’s Hospital, London, United Kingdom, says in a news release. “This study demonstrated that botulinum toxin type A may be a promising treatment option for patients with OAB symptoms.”

In this study, 34 patients with treatment-refractory OAB and confirmed IDO were randomized to intradetrusor injections of 200 U botulinum toxin A (n = 16) or placebo (n = 18). Participants had failed on a trial of anticholinergic therapy for 6 weeks or more because of poor efficacy or poor tolerability.

“This study showed that this treatment had real benefits for patients for whom previous treatments had not worked,” says coauthor Prokar Dasgupta, from King’s College, London. “These were patients who were seriously affected by their OAB symptoms. At baseline, 81% of patients in the botulinum toxin type A treatment group and 67% in the placebo treatment group were experiencing urge urinary incontinence daily.”

The main endpoint was change in maximum cystometric capacity, and secondary endpoints included changes in overactive bladder symptoms, postvoid residual, maximum detrusor pressure during filling cystometry, and reflex detrusor volume.

The Incontinence Impact Questionnaire short form and Urogenital Distress Inventory short form were used to measure quality of life. Follow-up evaluations were at 4 and 12 weeks after injection, when the study was unblended, with further follow-up in the botulinum toxin type A group at 24 weeks.

In patients treated with botulinum toxin type A, there were significant increases, compared with placebo, in maximum cystometric capacity at 4 weeks (difference, 144.69 mL; 95% confidence interval [CI], 100.95 to 215.75; P < .0001) and 12 weeks (difference, 95.71 mL; 95% CI, 47.47 to 172.45; P = .001). Botulinum toxin type A was associated with reduced frequency (P < .001, P = .003) and fewer episodes of urgency urinary incontinence (P = .03, P = .008) at 4 and 12 weeks, respectively. In the botulinum toxin type A group, urgency was reduced at 4 weeks (P = .005)

Overall, treatment with botulinum toxin type A was well tolerated without major complications. Postvoid residual increased at 4 weeks (P = .024) but became insignificant by 12 weeks (P = .406). Of the patients with increased postvoid residual, 6 required clean intermittent self-catheterization (CISC) and developed symptomatic urinary tract infection.

Botulinum toxin type A injection was associated with significant improvements in quality of life, and the extension study suggests that benefits were maintained for at least 24 weeks. Botulinum toxin type A “at 200 U appears to improve symptoms, urodynamic parameters, and [quality of life] in cases of IDO,” the authors conclude. “Careful patient counseling is necessary, especially concerning the possible need for CISC.”

Botulinum toxin type A is not currently approved by the US Food and Drug Administration for the treatment of any form of OAB, nor is it approved for this use by regulatory agencies in Europe.

Allergan, Inc and the British Urological Foundation funded this research.

J Urol. 2007;177:2231-2236.

Source: http://www.medscape.com/viewarticle/556982?src=mp