Intravesical interferon instillation appears to benefit women with interstitial cystitis (IC), with a recent study showing that the approach helps improve patient-reported and objective outcomes compared with hyaluronic acid without serious adverse events.
The phase II/III study included 52 female patients (mean age 50.0 years) who had had IC for more than 6 months. These patients were randomly assigned to receive intravesical instillation of interferon (n=26) or hyaluronic acid treatment (n=26).
The primary endpoint was change in visual analogue scale pain score, whereas secondary endpoints included changes in voiding frequency, functional bladder capacity, symptom index, and global response assessment. Researchers kept a close eye on any adverse events.
At month 6, the visual analogue pain score was significantly lower in the interferon group than in the hyaluronic acid group (−1.3, 95 percent confidence interval [CI], −2.3 to −0.3; p=0.02) at month 6, with 77 percent of patients achieving at least a 30-percent reduction in pain relative to baseline.
No significant between-group differences were observed in voiding frequency, functional bladder capacity, and nocturia episodes. Nevertheless, the interferon group had a significantly greater reduction in the Interstitial Cystitis Symptom Index (−3.0, 95 percent CI, −5.3 to −0.7; p=0.01) and the Problem Index (−2.5, 95 percent CI, −4.5 to −0.4; p=0.02) at month 6, with 85 percent of patients presenting as moderately or markedly improved.
Adverse events occurred with similar frequency between the two treatment groups. One patient in the hyaluronic acid group discontinued treatment due to inadequate response.