Efficacy and safety study of Chinese botulinum toxin A 100U in patients with overactive bladder: a prospective, multicenter, double-blind and randomized controlled trial / 中华泌尿外科杂志

ABSTRACT

Objective:To assess the efficacy and safety of 100 units of botulinum toxin A (BTX-A) intradetrusor injection in patients with overactive bladder.Methods:From April 2016 to December 2018, 17 tertiary hospitals were selected to participate in this prospective, multicenter, randomized, double-blind, placebo-controlled study. Two phases of study were conducted the primary phase and the extended phase. This study enrolled patients aged 18 to 75 years who had been inadequately managed by anticholinergic therapy (insufficient efficacy or intolerable side effects) and had spontaneous voiding with overactive bladder. Exclusion criteria included patients with severe cardiac, renal and hepatic disorders, patients with previous botulinum toxin treatment for 6 months or allergic to BTX-A, patients with urinary tract infections, patients with urinary stones, urinary tract tumors, diabetes mellitus, and bleeding tendency. Eligible patients were randomly assigned to BTX-A group and placebo control group in a ratio of 2∶1. Two groups of patients received 20 intradetrusor injections of BTX-A 100U or placebo at the depth of the submucosal muscle layer respectively under cystoscope, including 5 injections at the base of the bladder, 3 injections to the bladder triangle, 5 injections each to the left and right walls and 2 injections to the top, sparing the bladder neck. As a placebo control group, patients received same volume of placebo containing no BTX-A and only adjuvant freeze-dried preparations for injection with the same method. A combination of gelatin, sucrose, and dextran served as adjuvants. Average micturition times per 24 hours, urinary incontinence (UI) episodes per day, average micturition volume per day, OAB symptom score(OABSS), and quality of life (QOL) score were recorded at baseline and the 2nd, 6th and 12th week after treatment. The primary efficacy endpoint was the change from baseline in the average micturition times per 24 hours at the 6th week after treatment. The secondary efficacy endpoints included the change from baseline in the average micturition times per 24 hours at 2nd and 12th week, as well as the change from baseline in the OABSS, QOL score, average frequency of urgency and UI episodes per day, urgency score, average micturition volume per day at 2nd, 6th and 12th week after treatment. Patients were followed for 12 weeks to assess adverse events (AEs). After assessed at week 12, if the micturition times has decreased less than 50% compared to baseline and the patient is willing to receive retreatment, then patients could enter the extended trial phase. In that phase, patients in both groups were injected with 100 units BTX-A from 12th week onwards and then followed up the same indicators for 12 weeks.Results:216 patients were enrolled in this trial (144 cases in the BTX-A group and 72 cases in the placebo control group). Baseline characteristics such as age (47.75±14.20 in the BTX-A group and 46.39±15.55 in the control group), sex (25 male/117 female in the BTX-A group and 10/61 in the control group), and disease duration (0.51 years in the BTX-A group and 0.60 years in the control group) were balanced between the two groups( P>0.05). A marked reduction from baseline in average micturition times per 24 hours was observed in all treatment groups at the 6th week and the reduction of the two groups was statistically different ( P<0.001 and P=0.008 respectively). Compared with the baseline, the average micturition times per 24 hours at the 6th week decreased from baseline by 2.40(0.70, 4.60)times for the BTX-A group and 0.70(-1.00, 3.30) times for the placebo control group respectively, and the difference between the two groups was considered to be statistically significant ( P=0.003). The change rates of average micturition times per 24 hours from baseline at the 6th week of the two groups were (16±22)% and (8±25)% respectively, and the difference between the two groups was statistically significant ( P=0.014). Compared with the baseline, the average micturition times per 24 hours at 2nd and 12th week decreased by 2.00(0.00, 4.00)and 3.30(0.60, 5.03)for the BTX-A group, 1.00(-1.00, 3.00)and 1.70(-1.45, 3.85)for the placebo control group respectively. The difference between two groups was considered to be statistically significant ( P=0.038 and P=0.012); the changes of average urgency times per day for the BTX-A group and the control group at the 2nd, 6th and 12th week were 2.00(0.00, 4.30)and 2.40(0.30, 5.00), 3.00(0.30, 5.70)and 0.70(-1.30, 2.70), 0.70(-1.30, 3.00) and 1.35(-1.15, 3.50), respectively. There were significant differences between two groups at the 2nd, 6th and 12th week, ( P=0.010, P=0.003 and P=0.025, respectively). The OABSS of the BTX-A group and the control group at the 6th week decreased by 1.00(0.00, 4.00)and 0.50(-1.00, 2.00) compared with the baseline, and the difference between the two groups was statistically significant ( P=0.003). 47 cases of BTX-A group and 34 cases of placebo control group entered the extended trial phase, and 40 and 28 cases completed the extended trial phase, respectively. The average micturition volume per 24 hours changed by -16.60(-41.60, -0.60)ml and -6.40(-22.40, 13.30)ml, (-35.67±54.41)ml and(-1.76±48.69)ml, (-36.14±41.51)ml and (-9.28±44.59)ml, (-35.85±43.35)ml and(-10.41±40.29)ml for two groups at the 12th, 14th, 18th and 24th week, and the difference between two groups was statistically significant at each follow-up time ( P=0.01, 0.006, 0.012 and 0.016, respectively). There was no significant difference in other parameters( P>0.05). However, adverse reactions after intradetrusor injection included increased residual urine volume (27 in the BTX-A group and 3 in the control group), dysuria (21 in the BTX-A group and 6 in the control group), urinary infection (19 in the BTX-A group and 6 in the control group), bladder neck obstruction (3 in the BTX-A group and 0 in the control group), hematuria (3 in the BTX-A group and 1 in the control group), elevated alanine aminotransferase (3 in the BTX-A group and 0 in the control group), etc. During the follow-up period, there was no significant difference in the other adverse events between two groups except the increase of residual urine volume( P<0.05). In the primary trial phase, among the 27 cases with increased residual urine volume in BTA group, only 1 case (3.70%) with PVR more than 300 ml; the PVR of 3 patients in the placebo group was less than 100 ml. The increase of residual urine volume caused by the injection could be improved or disappeared with the passage of time. Conclusions:Intradetrusor injection of Chinese BTX-A improved the average micturition times per 24 hours, the average daily urgent micturition times, OABSS, and average micturition volume per time, and reduced the adverse effects in patients with overactive bladder.Chinese BTX-A at dose of 100U demonstrated durable efficacy and safety in the management of overactive bladder.