Botulinum reinjection does not increase CIC risk

There appears to be no increased risk of clean intermittent catheterization (CIC) with reinjection of onabotulinumtoxinA (onabotA) in patients with overactive bladder (OAB), according to a recent large, pooled population study.

The study, presented at the Society of Urodynamics, Female Pelvic Medicine & Urogenital Reconstruction winter meeting in Austin, TX, showed the incidence of de novo CIC was consistently low after repeat treatment. In addition, OnabotA 100 U was found to be well-tolerated, improve urinary symptoms, and provide improvements in overall quality of life.

Study investigator Gary Lemack, MD, of the University of Texas Southwestern Medical Center, Dallas, said the likelihood of experiencing new-onset urinary retention requiring catheterization while not zero was quite low overall in patients who had not experienced new-onset urinary retention requiring a catheter after their first injection of Botox for OAB.

Also see:Many OAB patients not receiving advanced therapy

It is well known that there is a risk for CIC in OAB patients who receive onabotA. However, until now there has been no large, thorough investigation into the risk of CIC in patients undergoing repeat injections of onabotA. Dr. Lemack and colleagues conducted a post hoc analysis of pooled placebo-controlled trials to investigate the risk of CIC, and they also examined efficacy and quality of life (QoL) outcomes following reinjection with onabotA 100 units.

For this investigation, the authors looked at the incidence of CIC at week 12 following treatment cycles 1 and 2 in placebo-controlled trials. They assessed the patients for the mean change from baseline in urinary incontinence (episodes/day), and the percentage of patients with 100% reduction in urinary incontinence. They also examined the mean changes from baseline in King’s Health Questionnaire (KHQ) Role (RL) and Social Limitations (SL) domains at week 12 after treatment cycle 1 and 2. The investigation also included analysis of adverse events and improvements on the Treatment Benefit Scale (TBS).

Dr. Lemack, who presented the findings, said the rates of CIC in the first 12 weeks following the first treatment were found to be 5.6% for onabotA (n=697) and 0.2% for placebo (n=602). The authors were pleased to find that in the 12 weeks after the second treatment CIC rates dropped slightly. They were only 5.5% for those who received onabotA for both treatment cycles (n=382) and 3.8% for those who received their first onabotA treatment in cycle 2 (n=475). The study showed that 1% of patients who received two treatments with onabotA required CIC within 12 weeks following each treatment.

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“This gives clinicians the information they need to counsel patients regarding the low risk of requiring catheterization on subsequent Botox injections for OAB. Overall, the rate of needing catheterization is quite low, and if anything, this risk appears to decrease slightly with time,” Dr. Lemack told Urology Times.

The analysis showed that at 12 weeks after the first onabotA treatment, the mean change from baseline in urinary incontinence episodes/day was –3.1 compared to a baseline of 5.4. The study also showed that 29.7% of the patients were dry. The mean change from baseline in the KHQ RL was –28.4 and it was –18.6 for SL domains. The authors noted that both scores exceeded the minimally important difference of –5 points. The analysis turned up no unexpected safety signals and it demonstrated that the proportion of patients with improvement/great improvement on the TBS was 69.8% at 12 weeks.

Read:Beta-3 agonist significantly reduces urge incontinence

“One of the most common reasons cited by practitioners and patients for not considering Botox injections for refractory OAB conditions is the concern regarding the need for catheterization, both at the time of the initial injection, and after subsequent ones. These data help to better quantify that risk for patients to allow them to make an informed decision,” said Dr. Lemack.

Allergan provided funding for the study.