Neutralizing Antibody Formation with OnabotulinumtoxinA (BOTOX®) Treatment from Global Registration Studies across Multiple Indications: A Meta-Analysis

Though the formation of neutralizing antibodies (NAbs) during treatment with botulinum neurotoxin is rare, their presence may nonetheless affect the biological activity of botulinum toxin and negatively impact clinical response. The goal of this updated meta-analysis was to evaluate and characterize the rate of NAb formation using an expanded dataset composed of 33 prospective placebo-controlled and open-label clinical trials with nearly 30,000 longitudinal subject records prior to and following onabotulinumtoxinA treatment in 10 therapeutic and aesthetic indications. Total onabotulinumtoxinA doses per treatment ranged from 10 U to 600 U administered in ≤15 treatment cycles. The NAb formation at baseline and post-treatment was tested and examined for impact on clinical safety and efficacy. Overall, 27 of the 5876 evaluable subjects (0.5%) developed NAbs after onabotulinumtoxinA treatment. At study exit, 16 of the 5876 subjects (0.3%) remained NAb positive. Due to the low incidence of NAb formation, no clear relationship was discernable between positive NAb results and gender, indication, dose level, dosing interval, treatment cycles, or the site of injection. Only five subjects who developed NAbs post-treatment were considered secondary nonresponders. Subjects who developed NAbs revealed no other evidence of immunological reactions or clinical disorders. This comprehensive meta-analysis confirms the low NAb formation rate following onabotulinumtoxinA treatment across multiple indications, and its limited clinical impact on treatment safety and efficacy.

Pathophysiology, assessment, and treatment of overactive bladder symptoms in patients with interstitial cystitis/bladder pain syndrome

INTRODUCTION

Interstitial cystitis/bladder pain syndrome (IC/BPS) is prevalent, difficult to treat, and has close symptom overlap with overactive bladder (OAB). A review of the pathophysiology, assessment, and treatment of IC/BPS patients with overlapping OAB symptoms has not been summarized recently in the published literature.

METHODS

A review of the published literature on the overlap of IC/BPS and OAB was conducted using MeSH terminology (1992-2022).

RESULTS

The pathophysiology of IC/BPS is not fully understood. Animal research has found the bladder trigone and base are richly populated by afferent fibers, including many small unmyelinated C-fibers that may be upregulated in IC/BPS. Successful therapies with multimodal effects on OAB symptoms in patients with IC/BPS are likely to exert beneficial effects on both pain and lower urinary tract symptoms. Potentially efficacious therapies for the treatment of OAB in IC/BPS include pelvic floor physical therapy, oral pharmacotherapy (antimuscarinics and beta-3 agonists), sacral neuromodulation, percutaneous tibial nerve stimulation, and botulinum toxin A (BTA). Antimuscarinics and beta-3 agonists have yielded partial efficacy in IC/BPS, although may help differentiate symptoms of OAB from those associated with IC/BPS. The transvaginal trigone treatment (T3) intradetrusor injection approach allows for delivery of therapeutics to the bladder without the need for a cystoscope and appears to be feasible.

CONCLUSIONS

Further research is needed to understand the pathophysiology of IC/BPS and symptom overlap with OAB, which in turn should enable the development of more personalized therapeutics.

Agitation predicts response of depression to botulinum toxin treatment in a randomized controlled trial

In a randomized, controlled trial (n = 30), we showed that botulinum toxin injection to the glabellar region produces a marked improvement in the symptoms of major depression. We hypothesized that the mood-lifting effect was mediated by facial feedback mechanisms. Here we assessed if agitation, which may be associated with increased dynamic psychomotor activity of the facial musculature, can predict response to the treatment. To test this hypothesis, we re-analyzed the data of the scales from our previous study on a single item basis and compared the baseline scores in the agitation item (item 9) of the Hamilton Depression Rating Scale (HAM-D) between responders (n = 9) and participants who did not attain response (n = 6) among the recipients of onabotulinumtoxinA (n = 15). Responders had significantly higher item 9 scores at baseline [1.56 + 0.88 vs. 0.33 + 0.52, t (13) = 3.04, d = 1.7, p = 0.01], while no other single item of the HAM-D or the Beck Depression Inventory was associated with treatment response. The agitation score had an overall precision of 78% in predicting response in a receiver operating characteristic (ROC) analysis (area under the curve, AUC = 0.87). These data provide a link between response to botulinum toxin treatment with a psychomotor manifestation of depression and thereby indirect support of the proposed facial feedback mechanism of action. Moreover, it suggests that patients with agitated depression may particularly benefit from botulinum toxin treatment.