Genitope ( GTOP), a small biotech outfit with no commercial products, got a lot smaller Friday after the company said a study of its lead therapeutic candidate might have to run until late next year. The Redwood City, Calif., company said in a press release issued just before midnight EDT that its independent data safety monitoring board recommended that the trial of MyVax continue as planned. That wasn't what shareholders wanted to hear. Shares of Genitope were sinking $2.55, or nearly 46%, to $3.03 on volume that was more than 10 times heavier than a normal entire session. The panel's decision came after it reviewed the second planned interim analysis of data from a phase III clinical trial looking at MyVax's effectiveness as a treatment for follicular non-Hodgkin's lymphoma. As a result, Genitope said, the trial will be completed by December 2007. RBC Capital Markets downgraded Genitope to sector-perform from outperform following the company's statement. Biotech investors want clinical trials to be promising enough to end sooner rather than later, and when continuing studies are recommended, they often head for the exits, as was the case with Genitope. The trial is evaluating the safety and effectiveness of MyVax, a personalized immunotherapy, compared with patients receiving a nonspecific immune system treatment. MyVax is based on the unique genetic makeup of an individual patient's tumor and is designed to activate the immune system to identify and attack cancer cells.