Tekmira Pharmaceuticals announced last week that it has begun a phase I study of its siRNA-based treatment for hypercholesterolemia.
The company first reported that it had received clearance from the US Food and Drug Administration to begin testing the drug, called ApoB SNALP, in May (see RNAi News, 5/7/2009).
According to Tekmira, the trial will evaluate the safety, tolerability, and pharmacokinetics of escalating single doses of ApoB SNALP in about 30 patients with elevated low-density lipoprotein cholesterol. Each cohort will include four patients, three of whom will receive the drug and one of whom will receive a placebo.
"The trial is also designed to provide preliminary data on the ability of ApoB SNALP to lower serum LDL cholesterol levels," the company said. "Patients whose LDL cholesterol is reduced by greater than 15 percent from baseline will be followed until their LDL cholesterol levels return to baseline."
ApoB SNALP is an siRNA designed to silence apolipoprotein B. While apoB has been well validated, officials from Tekmira partner Alnylam Pharmaceuticals have recently cast doubts on it as a drug target.
In May, Alnylam CEO John Maraganore called his company's own cholesterol target, proprotein convertase subtilisn/kexin type 9, "more compelling" than apoB (see RNAi News, 5/14/2009). About a month later, Alnylam Vice President of Drug Discovery Muthiah Manoharan noted that his company had associated fatty liver disease with the down-regulation of apoB (see RNAi News, 6/11/2009).
"Our preclinical data package supports ApoB as an excellent target for LDL cholesterol lowering, and we believe ApoB SNALP is the most advanced RNAi therapeutic targeting a metabolic condition," Tekmira President and CEO Mark Murray said in a statement last week. "We expect to complete the Phase 1 clinical trial in early 2010."