Updated from 9:33 a.m. EDT Roche announced Thursday that Herceptin, a breast cancer drug developed by Genentech ( DNA), helped prolong the lives of patients with a type of stomach cancer in a phase III trial."Based on the clear positive outcome from this clinical study, the addition of Herceptin to chemotherapy offers a new important option for patients with HER2-positive stomach cancer," said Eric Van Cutsem, a principal investigator in a large international trial examining Herceptin's use as the first therapy for patients with advanced and inoperable stomach cancer, in a press release from Roche, Genentech's majority stakeholder. Stomach cancer is the second most common cause of cancer-related death in the world, according to Roche, with more than 900,000 new cases diagnosed each year. The cancer often goes undiagnosed until it's in an advanced stage because patients frequently don't report symptoms before then. Herceptin sales totaled roughly $1.4 billion for 2008, according to Genentech, making it the third in the biotech firm's sales behind Avastin and Rituxan. Genentech shares were falling 0.1% to $93.79 in recent trading.