'Not Dead Yet'

At The New York Times' Prescriptions blog, Andrew Pollack says RNA interference "might not be dead yet." That Alnylam Pharmaceuticals recently announced it had established proof of concept for the efficacy of an RNAi-based drug in a phase 1 clinical trial "at least points to the possibility that the approach can be used in people," Pollack says. Alnylam CEO John Maraganore tells the Times that "this is actually the first time that we or anybody has shown the ability of silencing a disease-causing gene in humans with RNAi." This particular RNAi drug is being tested to treat a rare disease caused by mutations in TTR, which encodes transthyretin. "The mutation causes TTR-mediated amyloidosis, in which abnormal amyloid proteins build up in the body. In one version of the disease, the buildup of proteins damages nerves, and people eventually lose the ability to walk and then to breathe," Pollack says. Alnylam, he adds, reported results from 31 patients – 23 that received a single infusion of the drug designed to inactivate TTR and 8 controls – showing that the RNAi drug worked to depress TTR levels for at least 24 days.