U.S. Markets close in 6 hrs 7 mins

Alnylam rises on early clinical trial data

NEW YORK (AP) -- Shares of Alnylam Pharmaceuticals Inc. climbed Thursday after the company reported positive trial results for one of its experimental RNA interference drugs.

The data comes from an early-stage clinical trial of a drug called ALN-TTRsc. The drug is designed to treat transthyretin familial amyloidosis, a rare genetic condition in which a starchy protein called amyloid builds up in organs and tissues.

In the study ALN-TTRsc was evaluated as a treatment for a form of the disease that affects the nervous system and is normally treated with a liver transplant.

The Cambridge, Mass., company said the drug appeared safe and side effects were tolerable, and the drug was effective. Alnylam said it plans to start a late stage-trial of the drug in 2014. The company is developing the drug through a partnership with Sanofi's Genzyme unit.

Shares of Alnylam rose $6.12, or 16.3 percent, to $43.72 in afternoon trading. Earlier in the day the stock reached an all-time high of $44.65.

Alnylam's drugs use RNA interference, or RNAi, technology to turn off or silence disease-causing genes. Alnylam said there are about 10,000 people worldwide with familial amyloid polyneuropathy. It said patients typically live five to 15 years from the onset of symptoms.

By the end of 2013 the companies will start a mid-stage trial of the drug as a treatment for transthyretin familial amyloid cardiomyopathy, a related condition that can cause abnormal heartbeats and enlarged hearts. It affects about 40,000 people. Alnylam said patients typically survive about 2.5 years and there are no approved treatments.