RNAi Therapeutic for Respiratory Virus

Researchers have shown that a single low dose of a new RNA interference (RNAi) therapeutic agent can inhibit respiratory syncytial virus (RSV) replication both as a prophylactic and as a treatment when administered by intranasal delivery in a liquid form.

The therapeutic agent, called ALN-RSV01, specifically silences an RSV gene required for viral replication. Preclinical studies in mice demonstrated that a single dose protected against subsequent RSV infection. The compound was also shown to be effective in the treatment of an existing RSV infection. Studies in mice showed that intranasal administration did not activate an interferon response. Ongoing and future studies are analyzing the topical delivery of the therapeutic to the lung by aerosolization via a nebulizer.

RSV is a highly contagious virus that causes repeated infections in both the upper and lower respiratory tract. It infects nearly every child at least once by the age of two years and is the major cause of hospitalization due to respiratory infection in children and people with compromised immune systems.

The new therapeutic was developed by Alnylam Pharmaceuticals, Inc. (Cambridge, MA, USA), which is developing novel therapeutics based on RNAi interference. Since many diseases are caused by the inappropriate activity of specific genes, the ability to silence and regulate such genes selectively through RNAi provides a way to treat a wide range of human diseases.

"Based on the encouraging pre-clinical data we have seen to date, we are driving ALN-RSV01 forward toward human clinical trials in the first half of 2006,” noted John Maraganore, Ph.D., president and CEO of Alnylam. The data were presented at the annual meeting of the American Academy of Allergy, Asthma and Immunology in San Antonio (TX, USA) in March 2005.