Trimeris stock (Nasdaq:TRMS) surged more than 29 poercent today, up $11.53 to $50.78, after the company said early today that its lead anti-HIV drug performed even better than expected in Phase III clinical trials.

The company’s stock rose as high as $52.75 in morning trading. Trading volume was more than 9 million shares.

Trimeris is developing the new class of anti-AIDS drugs called “fusion inhibitors,” along with Nutley, N.J.-based Hoffman La-Roche Inc. The companies said their experimental drug, T-20, combined with other HIV treatments, showed “a significant additional decrease in the amount of virus in the blood.”

Roche Head of Pharmaceuticals William M. Burns said in the Trimeris statement: “These Phase III results are even better than the positive results of earlier studies had led to expect.”

Most AIDS drugs work on the HIV virus after it has already infected a cell, but the Trimeris-Roche fusion inhibitors prevent the virus from melding with the cell in the first place.

Trimeris and Roche will use the data from the three clinical trials of their lead compound, T-20 to submit a new drug application to the U.S. Food and Drug Administration. The drug, which may help AIDS victims who have developed a tolerance for the anti-HIV treatments currently available, could be on the market by sometime next year.