AVI BioPharma Shares Drop on Early Data From Hepatitis C Drug Trial NEW YORK (AP) -- Shares of AVI BioPharma Inc. dropped Wednesday after early reported results from a clinical trial for the biotech drug maker's hepatitis C treatment were not as robust as some investors expected.

AVI shares fell $2.23, or 30.7 percent, to $5.03 in midday trading on the Nasdaq at more than four times their average volume. Over the past 52 weeks, shares have risen from a low of $2.05 during the summer to hit a high of $9.20 in February.

Hepatitis C virus concentrations in the blood, known as viral loads, fell only slightly on average based on early data gathered on five patients taking the company's antisense compound AVI-4065 for 14 days. Antisense drugs interfere with genetic processes to stop the manufacture of harmful proteins.

The Portland, Ore.-based company stressed that the data was preliminary and that formal results would be out by the end of the year. The study is expected to test the drug in about 40 patients.

AVI said that a longer treatment period could be the key to reducing viral loads further.

Rodman & Renshaw analyst Ren Benjamin, who rates AVI "Market Outperform," said in an interview that investors sold on a combination of lower-than-expected efficacy results and the "news mentality" of the release.

"It's still pretty early," Benjamin said. "There's a lot of expectation built into the stock. Primarily, investors expected a bigger load decrease."

Benjamin said he is currently reviewing his price target on the stock.