RNAi’s Drugs

Pharmaceutical giant Merck’s purchase last fall of Sirna, a San Francisco biotech company specializing in RNA interference (RNAi), was just the latest indication that the technology is gaining momentum. Researchers are currently trying to use RNAi to do everything from treat flu to permanently remove hair. In RNAi therapy, small pieces of ­double-­stranded RNA shut down the genes whose sequences they match. Below is a sampling of RNAi therapies under investigation.

Disease/company

Approach

Status

Age-related macular

degeneration

Acuity (Philadelphia, PA) and Sirna (San Francisco, CA)

Eye injection of RNA that blocks a gene responsible for excessive growth of blood vessels

In phase II clinical trials

Viral lung infections

Alnylam (Cambridge, MA)

Inhalation of drug containing RNA that shuts down viral genes

Therapy for respiratory syncytial virus in phase I trials

Parkinson’s disease

Alnylam and Sirna

Injection of RNA to block a gene that kills brain cells

In preclinical development

Huntington’s disease

Sirna

Injection of RNA to block a gene that kills brain cells

In preclinical development

Hair removal

Sirna

Application of cream ­containing RNA that blocks hair growth genes

Application to begin clinical trials in progress