Treatment: Bevasiranib
Maker: Acuity Pharmaceuticals
Stage: Phase II completed, phase IIb or III expected to begin mid-2007

Why It Matters

The leading cause of irreversible vision loss in the developed world is wet age-related macular degeneration (AMD), which is expected to become increasingly common as the population grows older. An estimated 1.65 million people in the United States have wet AMD, and an estimated eight million worldwide will have it by 2013.

How It Works

Bevasiranib targets vascular endothelial growth factor (VEGF), which stimulates the overgrowth of blood vessels that leads to vision loss in wet AMD. Specifically, it employs small interfering RNAs (siRNAs), which silence the genes they match--in this case, those that produce VEGF. In its phase II trial, Bevasiranib was able to stop new blood vessel growth linked to wet AMD for more than three months following an injection. Current drugs against wet AMD require injections about every four weeks, says Acuity chairman, president and CEO Dale Pfost. Because Acuity Pharmaceuticals's therapy stops VEGF production, while current drugs soak up existing VEGF, both could be used together.

Bevasiranib is the first siRNA therapy to enter clinical trials. "The discovery of small interfering RNAs just got the Nobel Prize in Medicine this year, and now building off that is the possibility of helping millions affected by this major health problem," says Stephen Rose, chief research officer for the Foundation Fighting Blindness. He notes Sirna Therapeutics also has an siRNA therapy against wet AMD, in phase II.

Return to Special Report: 10 Promising Treatments for World's Biggest Health Threats