Results of a long awaited clinical trial of ImClone Systems Inc's Erbitux, called Flex, give hopes to lung cancer patients, as it was found to prolong their lives by up to five weeks when combined with chemotherapy.

Erbitux, also known as cetaximub, is designed to block a protein called epidermal growth factor that is believed to play a role in cancer cell growth. The drug was already approved to treat colon cancer in 2004 as well as head and neck tumors in April 2004.

The findings, announced at the annual meeting of the American Society of Clinical Oncology held Saturday in Chicago, were based on a study of 1,125 patients, almost all of whom had stage IV cancer, who were treated either with Erbitux and chemotherapy or with chemotherapy alone. The trial was sponsored by ImClone’s European Marketing partner Merck KGaA. The trial showed that overall survival was 11.3 months for patients on the combination therapy, compared with 10.1 months for the group receiving just chemotherapy.

According to the American Cancer Society, lung cancer is the most common type of cancer in the U.S., being diagnosed in more than 215,000 people annually. Worldwide, the World Health Organization estimates it kills 1.3 million people a year.

“Patients with advanced non-small cell lung cancer have limited treatment options and life expectancy is short. The survival increase shown in this study is an important step for these patients,” lead researcher Robert Pirker, associate professor of medicine at the Medical University of Vienna in Austria said as quoted by Bloomberg.

Erbitux faces fierce competition from Genentech Inc and Roche Holding AG’s Avastin, which blocks blood supply to the tumor and is currently the only targeted therapy approved for lung cancer.