More than 50% of patients stop botulinum treatment

San Francisco-Over half of patients stop intradetrusor botulinum toxin injections within 10 years, mostly due to lack of clinical efficacy, researchers say.

Secondary inefficiency occurs in one-third of patients who show improvement after the first two injections, according to Jean-Nicolas Cornu, MD, PhD, professor of urology at Charles Nicolle Hospital in Rouen, France, who presented the research at the AUA annual meeting in San Francisco.

"When you have neurogenic bladder and detrusor overactivity, [botulinum toxin] cannot be considered a lifelong treatment," he told Urology Times.

Intradetrusor injections of abobotulinumtoxinA (Dysport) and onabotulinumtoxinA (Botox) are effective in the short term, but few studies have followed patients for a longer term.

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To fill that gap, Dr. Cornu and his colleagues retrospectively analyzed records on all patients treated with abobotulinumtoxinA or onabotulinumtoxinA for neurogenic detrusor overactivity in three tertiary reference centers between 2002 and 2007. They excluded patients with a history of augmentation cystoplasty prior to the first injection of botulinum toxin.

The 140 patients were evenly divided between males and females. Sixty-four had spinal cord injuries, 46 had multiple sclerosis, 14 spina bifida, five suprapontine diseases, and 11 had other spinal diseases.

Seventy patients received abobotulinumtoxinA for the first injection, and 62 received onabotulinumtoxinA. Ninety-three had involuntary detrusor contraction. The average volume of their first uninhibited contraction was 184.8 mL. Their average maximum cystometric capacity was 301 mL, and verage maximum detrusor pressure was 53.5 cm H₂O.

After 5 years, 63.9% were still receiving the injections. At 7 years, that proportion dropped to 59.1% and at 10 years it was down to 49.1%.

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The authors looked at factors that might contribute to discontinuation, including gender, neurologic condition, duration from neurologic disease onset, maximal detrusor pressure, and volume of the first uninhibited detrusor contraction. Only spina bifida emerged as a statistically significant factor; patients with this condition were more likely to discontinue.

In 28% of discontinuations, the patient decided to stop despite what appeared to be a satisfactory outcome. In 27%, the reason for discontinuation was secondary failure. In 17%, it was primary failure. In 14%, improvements not related to botulinum toxin were the reason. In 12%, the reason was progression of the neurologic condition. And in 2%, it was an adverse event.

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Thirty-six percent of the patients turned to antimuscarinics after giving up on botulinum toxin. Twenty-eight percent had augmentation cystoplasty. Eleven percent had an ileal conduit, 6% suprapubic tube, 3% sacral neuromodulation, and 2% sphincterotomy. For 14%, the subsequent treatment was unknown.

"We thought we had found a solution," Dr. Cornu told Urology Times. "Now we have 10 years of evolution, and we have found that half have stopped."

Dr. Cornu reported consultant fees or travel grants from Allergan, Astellas, Boston Scientific, Bouchara-Recordati, Coloplast, Cousin Biotech, Medtronic, Mundipharma, Pfizer, Pierre Fabre Médicaments, SAP, and Takeda. He has been an investigator for Astellas, GT Urological, Medtronic, Ipsen, Coloplast, Cousin Biotech, and Allergan.