August 11, 2006

Sirna Therapeutics has reported the final results from its Phase I trial for Sirna-027, a therapy for age-related macular degeneration. Single ascending doses of Sirna-027 were safe and well-tolerated, and all 26 patients showed visual acuity stabilization eight weeks after a single injection. In addition, at the same time point, five of 26 patients experienced clinically significant improvement in visual acuity, indicated by an increase of at least three lines on an eye chart.

Patients received a single intra-vitreal injection of the drug in doses ranging from 100 to 1,600 micrograms. Three months after a single injection, 24 of 26 patients showed visual acuity stabilization, with four of 26 patients experiencing clinically significant improvement in visual acuity. Only two of 26 patients experienced a reduction in visual acuity of three lines or more. A decrease in foveal thickness was observed in some patient groups, which is an indication of biological activity of Sirna-027.

The potential for a long-lasting effect on visual acuity after a single dose of Sirna-027 could be due to the catalytic mechanism of short-interfering RNA, and could give this compound a more favorable dosing regimen than other approved products.