Patients with lung cancer who took Genentech Inc.‘s cancer drug Avastin in combination with chemotherapy took longer to relapse than patients who took chemotherapy alone, researchers said on Friday.

Data released at the annual meeting of the American Society of Clinical Oncology in Orlando showed that the average length of time before tumors began regrowing in patients taking the combination therapy was 6.4 months compared with 4.5 months in those taking chemotherapy alone.

Avastin, which was approved to treat Colon cancer in combination with chemotherapy in 2004, was shown earlier this year to prolong overall survival in lung cancer patients to an average of 12.5 months from 10.2 months.

Data from the late-stage, or Phase III, trial is the first to show that chemotherapy plus Avastin, which works by shutting off the blood supply in the vessels that feed tumors, can slow progression of the disease in patients who have not previously been treated.

It also showed for the first time that 51.9 percent of patients were alive after one year of treatment, compared with 43.7 percent on chemotherapy alone. At two years, 22.1 percent of patients on the combination were alive compared with 16.9 percent on chemotherapy alone. The trial did not include patients with brain metastases.

Typically, only 30 percent of people diagnosed with non-small cell lung cancer, the most common form of the disease, are alive one year after diagnosis, said Dr. Alan Sandler, associate professor of medicine at Vanderbilt University and the study’s lead author.

The most serious side effect was life-threatening or fatal bleeding, mainly from the lungs. This occurred in 1.7 percent of patients in the Avastin group and did not occur at all in the chemotherapy alone group, Sandler said.

An earlier trial, which included patients with a type of cancer called squamous lung cancer, had shown life-threatening bleeding rates of up to 10 percent. By excluding the squamous patients, that rate has been substantially reduced to a level considered more likely to be acceptable to U.S. regulators.

In the latest trial, non-life threatening bleeding occurred in 5 percent of patients in the Avastin group compared to 1 percent in the chemotherapy alone group, Sandler said.

Genentech, which is majority owned by Swiss drugmaker Roche Holding AG said it is in discussions with the U.S. Food and Drug Administration about filing a supplemental application to market Avastin in lung cancer in advanced non-small cell lung cancer.

If lung cancer is diagnosed at an early stage, up to 80 percent of patients will survive for at least five years after diagnosis. However, almost 70 percent of patients are diagnosed at the advanced stage, the researchers said.