Positive outcomes with first onabotulinumtoxinA treatment persist in the long term with repeat treatments in patients with neurogenic detrusor overactivity.

OBJECTIVE

To examine whether response to first treatment with onabotulinumtoxinA is predictive of long-term treatment outcome in patients with neurogenic detrusor overactivity (NDO).

PATIENTS AND METHODS

Patients with NDO who were enrolled in a 3-year extension study (after a 52-week phase III study) received onabotulinumtoxinA 'as needed', based on fulfilment of prespecified retreatment criteria. This post hoc analysis included patients who received only the 200-U dose during the phase III and extension studies. Data on mean percent reduction from baseline in urinary incontinence (UI) episodes at week 6 after the first treatment were analysed, and the patients were stratified into three response groups: <50% (group 1; n = 33), 50-74% (group 2; n = 23), and 75-100% (group 3; n = 139). The following were assessed: change from baseline in mean percent UI reduction; proportions of patients who achieved ≥50% and 100% UI reduction after each subsequent treatment, and patients who achieved ≥50% UI reduction after all subsequent treatments; change from baseline in Incontinence Quality of Life (I-QOL) total summary score; and the proportion of patients who achieved or exceeded the minimally important difference (MID; +11 points) in I-QOL score. Adverse events (AEs) were also assessed.

RESULTS

The majority of the patients (83.1%; 162/195) experienced a ≥50% UI reduction after onabotulinumtoxinA treatment 1. Baseline characteristics were largely similar across the groups. After treatment 1, the mean percent reduction in UI remained consistent in subsequent treatments 2-6 for patients in response group 2 (range: 64.5-83.5%) and group 3 (range: 79.4-88.0%), but increased for those in the low response group (range: 36.3-60.3%). After treatment 1, the proportion of patients who achieved ≥50% reduction in UI episodes was consistent with subsequent treatments 2-6 in group 2 (range: 75.0-100%) and group 3 (range: 87.3-97.1%), but increased in the low response group (range: 48.3-72.7%). Even among those who achieved a low response after treatment 1, 37.9% of patients achieved ≥50% UI reduction in all subsequent treatments. Improvements in I-QOL scores in groups 2 and 3 were consistently 2-3 times the MID. In the low response group, at least 50% of the patients achieved or exceeded the MID with treatments 2-6. AEs were similar across all response groups and consistent across repeated treatments.

CONCLUSION

Patients with NDO with a ≥50% UI reduction after their first onabotulinumtoxinA treatment continued to experience consistent improvements in UI and quality of life with subsequent treatments over the duration of 4 years. A <50% UI reduction after first treatment did not necessarily predict low response with subsequent treatments. Thus, these results underscore the importance of attempting at least a second treatment with onabotulinumtoxinA before deeming patients unsuitable for onabotulinumtoxinA therapy.