LOS ANGELES, 07 dec 2008 – A combination of Genentech Inc's cancer drug Rituxan and chemotherapy reduces by 41 percent the risk of death or cancer progression, compared with chemotherapy alone, for patients with a common form of leukemia, the company said on Saturday. Results from the pivotal- or final-stage trial found that previously untreated patients given the combination therapy had a median progression-free survival of 42.8 months, compared with 32.3 months for those on chemotherapy alone, Genentech said. The trial involved 817 patients with chronic lymphocytic leukemia, or CLL, the most common form of adult leukemia. A separate trial of 552 CLL patients who had stopped responding to chemotherapy found the combination reduced the risk of death or cancer progression by 35 percent. The studies, presented in San Francisco at a meeting of the American Society of Hematology, were sponsored by Genentech's majority owner Roche Holding AG, which markets Rituxan outside the United States under the brand name MabThera. The drug, co-marketed in the United States by Genentech and Biogen Idec Inc, is approved to treat non-Hodgkin's lymphoma and rheumatoid arthritis. Rituxan, which had U.S. sales of $655 million in the third quarter, is an antibody designed to bind to a protein on the surface of B-cells where it recruits the body's natural defenses to attack and kill the marked cells. GlaxoSmithKline PLC and Genmab are developing a similar antibody, called ofatumumab. Results from a smaller Phase 3 trial of that drug in CLL patients who have stopped responding to chemotherapy will be presented at the hematology conference on Monday.