Novel P2X3 Antagonist Shown Effective for Interstitial Cytitis/Bladder Pain Syndrome: Presented at ICS

By Nancy A. Melville

MONTREAL -- October 8, 2015 -- AF-219, a novel P2X3 antagonist, shows efficacy in the treatment of symptoms related to interstitial cycstitis/bladder pain syndrome (IC/BPS) in women, according to a study presented here on October 7 at the 2015 Annual Meeting of the International Continence Society (ICS).

“We found encouraging results,” said lead author Robert Moldwin, MD, the Smith Institute for Urology, New Hyde Park, New York. “Treatment with AF-219 was associated with significant reductions in urinary urgency, with a reduction in pain as assessed by the Numerical Pain Rating Scale [NPRS] and the Genitourinary Pain Scale [GPS].”

For the double-blind, dose titration study, 74 women with IC/BPS involving moderate to severe pain for more than six months were randomised to AF-219 (n = 36) or placebo (n = 38) starting at 50 mg twice daily, titrating up by 50 mg twice daily every day until reaching 300 mg or the highest tolerable dose.

As many as 50% of patients treated with AF-219 reached a final dose of at least 250 mg twice daily, while 18% in the placebo group did not reach the maximum dose.

The study met its primary endpoint of significant reduction in mean pain intensity after 4 weeks, with patients treated with AF-219 who completed titration showing a mean decrease in the NPRS from 6.2 at baseline to 3.3, compared with 6.5 to 4.5 in the placebo group (P = .01).

The treatment group also had a significant reduction in mean urinary urgency (P = .017)

Similar reductions were seen in measures of Worst Pain and Global Response Assessment.

Five patients had Hunner lesions on cystoscopy, and 3 of 4 patients with the lesions who were treated with AF-219 showed a greater than 1 point reduction on the NRPS and 2 of 4 with a greater than 5-point reduction at week 4.

There were no reports of serious adverse events (AEs), and AEs were generally mild. The most common reported AE in treated patients was dysgeusia/hypogeusia, occurring in 83% of patients in the treatment group and 13% in the placebo group.

“We found the tolerability, apart from taste disturbances, and safety profile to be remarkable, especially for the IC/BPS population,” said Dr. Moldwin. “The results show that AF-219 has the potential to be an important treatment option in patients with IC/BPS.”

Funding for this study was provided by Afferent Pharmaceuticals, Inc.

[Presentation title: A Phase 2 Study in Women With Interstitial Cystitis/Bladder Pain Syndrome (IC/BPS) of the Novel P2x3 Antagonist AF-219. Abstract 23]

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