This clinical trial shows that alkalinization of lidocaine improves absorption into the bladder and that the therapy decreases interstitial cystitis pain.
"This is the first time I have been able to stand up at the podium at AUA and actually been able to present a positive study powered enough to be able to show the benefit we had hoped to achieve," J. Curtis Nickel, MD, professor of urology at Queens University in Kingston, Ontario, told Urology Times.
Previously, a few small clinical trials have shown that alkalinization of lidocaine improves absorption into the bladder and that the therapy decreases pain. But this trial, using a proprietary combination and delivery system (PSD597), is the first randomized, placebo-controlled trial that put the therapy to the test.
On day 8, 30% of lidocaine patients were responders, rating their improvement as moderate or marked, compared with only 10% of placebo patients, a statistically significant difference. This was well after the acute effect of the lidocaine had worn off, Dr. Nickel pointed out.
On day 15, 24% were responders, compared with 12% of placebo patients, although that difference did not reach statistical significance. O'Leary-Sant Problem Index scores also were significantly better than those of placebo recipients, but O'Leary-Sant Symptom Index scores were not. Pain scores improved, although the difference with placebo was not statistically significant, but approached that level at day 15. There were no serious adverse events, and all were cases of urinary tract discomfort. To avoid the discomfort of voiding the bicarbonate, bladders were drained by catheter, Dr. Nickel explained.
Despite some measures not reaching statistical significance, patients voted resoundingly with their feet. Eighty-six percent chose to continue in the open-label trial, and 96% of them completed it. In that portion of the study, the response rate 3 days after the second treatment (on day 22) for those patients who had had active treatment in the controlled study rose to 65%, and the response for those who had received placebo rose to about 45%.
The patented aspect of the instillation is probably the particular type of lidocaine and bicarbonate delivery system, but investigators were not privy to that. Nevertheless, said Dr. Nickel, urologists and other physicians can apply the results of this study in their practice today, using generic lidocaine followed by generic bicarbonate.