Neural stimulation, anticholinergic comparable in overactive bladder

October 15, 2008

In overactive bladder, percutaneous tibial nerve stimulation performs just as well as well as the most frequently prescribed drug.

Orlando, FL-In overactive bladder, percutaneous tibial nerve stimulation (PTNS) performs just as well as well as the most frequently prescribed drug, according to results of a controlled trial presented at the AUA annual meeting in a late-breaking news session.

This minimally invasive neuromodulation therapy, known as Urgent PC (Uroplasty, Minneapolis), offers patients a non-drug treatment option that avoids the side effects of constipation and dry mouth.

Lead author Kenneth M. Peters, MD, chairman of urology at William Beaumont Hospital in Royal Oak, MI, presented the results of the multicenter study, dubbed the Overactive Bladder Innovative Therapy (OrBIT) trial. OrBIT randomized 100 patients (94 women, 6 men) with overactive bladder at 11 centers to receive either 12 weekly PTNS treatments or extended-release tolterodine (Detrol LA), 4 mg daily for 12 weeks. The patients were well matched in terms of age, gender, race, weight, years of symptoms (mean, 9 to 10 years), frequency, leaking, and incontinence episodes.

At the end of 12 weeks, patients did equally well with either therapy, based on objective measurements. There were no statistically significant differences in the improvements in the number of voids per day, incontinence episodes, nocturia, urge incontinence, or voided volume.

Subjectively, however, patients' and their physicians' assessments favored PTNS significantly over drug therapy. Thirty-five of the 43 PTNS patients (80%) said they were cured or had improved compared with 23 of the 42 patients (55%) who took tolterodine. Physicians judged that 75% of patients were cured and 4% improved in the PTNS group compared with 56% cured and 5% improved in the tolterodine group. (Physician definition of cure was eight or fewer voids per day and no urge incontinence.)

Constipation and dry mouth were statistically significantly less in PTNS patients than in tolterodine patients. The only adverse events reported by the PTNS patients were pain, discomfort, or redness at the ankle.

Considering that the therapies are equivalent, urologists could offer either as initial therapy, said Dr. Peters. "But I think this gives a minimally invasive approach to managing those patients who maybe have tried drug therapy and either didn't do well with it or were intolerant of it."

But that is a strong reason for many patients, Dr. Peters explained.

"The key is that 70% of people who are put on drugs stop it within a year," he said. "That speaks volumes about drug therapy. It's either not efficacious enough, has too many side effects, or is too costly for patients compared with the benefit they perceive. They may be leaking 50% less, but if that 50% happens when they're sitting in church, they're going to say, 'What's the difference?' "

At least in the first 12 weeks, up-front costs do not favor PTNS. Although much depends on reimbursement, the approximate costs are $100 per month for tolterodine (or $300 over 12 weeks) and $170 per PTNS treatment (average Medicare reimbursement) totalling $2,040 for 12 weeks of initial therapy. How costs compare in the long term, when patients have occasional maintenance PTNS therapy, is unknown.

That should become clearer with the results of the ongoing study. After the initial 12 weeks of treatment, patients are stepped down to a maintenance protocol. Dr. Peters and his colleagues at the participating centers will assess how often maintenance therapy is needed and how well results are maintained for 1 year.

"If a patient has to come in only once a month, if the benefit is maintained and we're not having 70% dropping out at a year the way we see with drugs, that would suggest PTNS may be a good treatment for these chronic conditions in the long run," Dr. Peters said.

Whether PTNS could perform as well as combination drug therapy isn't known. If it does compare well, that could make the cost much more competitive and could prevent the even higher rate of side effects of multiple anticholinergic drugs.

The total cost of PTNS could drop dramatically and could compete with drug therapy if it could be administered at home, but representatives of Uroplasty told Urology Times that the company has no current plans to invest in studies of PTNS home use for potential FDA approval. Another step toward home use might be an implantable device that could then be activated at the patient's discretion.

Dr. Peters is an investigator for Pfizer and Uroplasty.