Phase 2 Retinitis Pigmentosa Treatment Completed
R-Tech Ueno Ltd. (Tokyo, Japan) announced it has completed a phase 2 clinical trial of 0.15% UF-021 isopropyl unoprostone (Ocuseva), which is under development as a treatment for retinitis pigmentosa (RP). The trial investigated the possibility of improving visual function in the central part of the retina with UF-021 in patients with RP.
The randomized, multicenter, comparative study examined 112 patients with RP that had progressed to the mid-to late-stage, defined as a visual acuity of 0.5 or more with a narrow visual field. Patients received placebo or Ocuseva, instilled one drop per time or two drops per time (at a 5 minute interval), twice a day in the morning and evening for 24 weeks. The primary efficacy endpoint was the change in the mean retinal sensitivity of the central 2° of the ocular fundus measured with an MP-1 microperimeter (Nidek, Gamagori, Japan), according to a company news release. Retinal sensitivity by Humphrey perimeter (10-2), visual acuity, contrast sensitivity, and health-related quality of life, using a questionnaire on visual function (VFQ-25), were also evaluated.
After 24 weeks, positive change in the retinal sensitivity of the central 2° from baseline increased the most in the two-drops-per-time group, followed by the onedrop- per-time group. The placebo group had the least significant increase in sensitivity. The change in the retinal sensitivity from the pretreatment level by 4 dB or more was seen as improvement in 15.2% of patients in the placebo group, 7.9% in the one-drop-per-time group, and 18.4% in the two-drops-per-time group, whereas the change was seen as aggravation in 21.2% in the placebo group, 15.8% in the one-drop-per-time group, and 2.6% in the two-drops-per-time group. There were a significantly lower number of aggravated cases in the 2-drops-per-time group, compared with the placebo group, according to R-Tech Ueno. The retinal sensitivity measured with the Humphrey perimeter showed statistically significant improvement at weeks 4 and 8 in the two-drops-per-time group compared with the placebo group.
The main adverse effect of Ocuseva was ocular irritation, which, the company said, disappears several minutes after instillation.