Intrarectal botox injections can halve faecal incontinence and urgency episodes in treatment-resistant patients, according to the first randomised-controlled trial to investigate the short-term efficacy of the potential new therapy.
French gastroenterologists recruited 200 adults with faecal incontinence who were considered refractory to first-line treatments and who had at least one urgency or faecal incontinence episode per week for at least three months.
The double-blind, placebo-controlled trial involved 10 injections of either intrarectal botulinum toxin type A (BoNTA, botox; Allergan) or saline (200 units in total) administered along the length of the rectum.
Findings showed that the mean number of faecal incontinence and urgency episodes per day in the BoNTA group (mean age 61, 92% female) decreased from 1·9 at baseline to 0·8 at three months after the injections based on self-reported bowel diaries.
The mean number of episodes per day for the placebo group (mean age 62, 92% female) decreased from 1·4 to 1·0 at three months.
The baseline-adjusted mean group difference at three months was −0·51.
Writing in The Lancet Gastroenterology & Hepatology [link here], the authors said a 50% or greater reduction in the number of faecal incontinence and urgency episodes per day was noted in 72% and 46% of the BoNTA and placebo groups.
Significant differences between the BoNTA and the placebo groups were also observed for delay to postpone defecation but not for daily bowel movements.
At six months, most patients in the BoNTA group reported finding the injection beneficial or useful (76% vs 43%) as well as improved quality of life (76% vs 37%), while both groups said they would ask for it again (86% vs 75%).
Coping and behaviour scores were significantly higher in the BoNTA group than in the placebo group at all visits and lifestyle scores at the three-month visit, while depression, self-perception and embarrassment scores did not significantly differ.
There were also no serious treatment-related adverse events, with the most frequently reported adverse event constipation (40%), followed by abdominal pain, asthenia, diarrhoea, bloating and anal pain, which were similar across both groups.
The authors said this suggested symptoms might be more related to the technique used and to the patient’s faecal incontinence than to the injected product itself.
“Altogether, these data indicate that the improvement in incontinence symptoms following the BoNTA treatment translated into beneficial effects on the lives of the patients,” said the authors.
“Further studies will be required to optimise the administration of the treatment, identify the best candidates to receive therapy, assess its duration of efficacy, and continue the evaluation of adverse effects.”
Writing in an accompanying editorial [link here], UK colorectal surgeon Professor Charles Knowles said with little meaningful therapeutic progress in the past 30 years, the study of the potential therapy represented “an important step forward in the field”.
“It helps challenge a dogma that has consistently underplayed the importance of the rectum in the pathophysiology of faecal incontinence,” said Professor Knowles from Cleveland Clinic London and Queen Mary University of London.
“Both SNM (sacral neuromodulation) and BoNTA focus on stabilising the function of the bladder or rectum to modify contractility while restoring aspects of normal filling perception. This concept is well established for the bladder, in which it is tied to an understanding of switching between filling and voiding phases.
“The current trial, therefore, provides further impetus to move away from the classical so-called passage and passenger model of faecal incontinence, which gives primacy to sphincter containment and optimised stool consistency while largely ignoring the rectum itself.”
Some authors declared receiving fees from pharmaceutical and medical device companies including Allergan’s parent company AbbVie.