Comparable efficacy seen with single vs. multiple OnabotulinumtoxinA injection sites in OAB

Data presented at Pelvic Floor Disorders Week 2024 showed no difference in efficacy between one 10 mL injection or ten 1 mL injections of OnabotulinumtoxinA in patients with idiopathic overactive bladder (OAB).¹

In total, the study enrolled 116 adult female patients with idiopathic OAB.

“Intradetrusor OnabotulinumtoxinA is an efficacious treatment for overactive bladder. However, the optimal number of injection sites is not well-known,” explained presenting author Carly A. Crowder, MD, an obstetrician-gynecologist at the University of California, Irvine. “While the FDA recommends a 20-injection protocol, we know that practice patterns vary widely, and there's limited data available to determine whether one technique truly outperforms another. We felt that focus on optimizing our injection technique is timely, especially given the shift away from a stepwise treatment approach for OAB.”

In total, the single-blinded, multi-center study enrolled 116 adult female patients with idiopathic OAB with and without urinary urgency incontinence. Patients were excluded from the study if they had neurogenic bladder, had received OnabotulinumtoxinA within 3 months prior to enrollment, had an active urinary tract infection (UTI), or had urinary retention. The trial also required a 2-week washout for other treatments.

Those included in the study had similar baseline symptom severity, quality of life, and post-void residual (PVR). Participants were randomly assigned 1:1 to receive either 1 injection of 10 mL OnabotulinumtoxinA (n = 58) or 10 injections of 1 mL OnabotulinumtoxinA (n = 58).

Crowder noted, “The overall injected volume, dose, and dilution was the same. The only difference was the number of injection sites.”

At 1 month follow-up, 53 patients from each arm were included in the primary analysis. At 3-month follow-up, 45 and 44 patients were included in the 1 injection arm and 10 injection arm, respectively.

Data showed no significant difference in the trial’s primary end point of the change in OAB-Q symptom severity subscale score from baseline to 1-month.

At this timepoint, the mean decrease in the OAB-Q symptom severity subscale score was -31.2 (± 26.25) in the 1-injection cohort vs -39.5 (± 23) in the 10-injection cohort (P = .09). At 3 months, the mean decrease was -31.0 (± 25.36) in the 1-injection arm compared with -39.3 (±25.71) in the 10-injection arm (P = .13).

The investigators also noted no significant difference between the arms in regard to the trial’s secondary end points of health-related quality of life, pain, PVR, estimated blood loss (EBL), and adverse events.

Specifically, at 1 month, the average improvement in OABQ health related quality of life subscale score was 26.9 (± 26.17) in the 1-injection arm vs 33.5 (±22.47) in the 10-injection arm (P = .11). At 3 months, the mean improvement remained clinically meaningful in both arms, with a change of 31.4 (± 25.13) and 34.8 (±20.64) in the 1- and 10-injection cohorts, respectively (P = .34).

VAS-pain scores immediately following the procedure were 25.7 (±27.87) in the 1-injection arm vs 31.7 (±26.47) in the 10-injection arm (P = .09). At 1 month, the average PVR values were 83.4 mL (±82.45) and 83.5 mL (±75.48) in the 1- and 10-injection cohorts, respectively (P = .84). EBL of 5 mL and less than 5 mL were similar between both arms.

The rate of adverse events, including UTI (P = .07), urinary retention (P = .99), and catheterization (P = .99), were also similar between both cohorts.

References

1. Crowder C, Whitcomb EL, Guaderrama N, et al. OnabotulinumtoxinA for OAB via 1 vs 10 Injections: A randomized clinical trial. Presented at: Pelvic Floor Disorders Week 2024. October 22-25, 2024. Washington, DC