REFILE-Erbitux adds 5 weeks to lung cancer survival-study

(Refiling to fix day in first paragraph)

CHICAGO, May 31 (Reuters) - Lung cancer patients treated in a large clinical trial with ImClone Systems Inc's IMCL.O Erbitux and chemotherapy lived about five weeks longer than patients treated with chemotherapy alone, according to results from the study released on Saturday.

The 1,125-patient trial, sponsored by ImClone's European marketing partner Merck KGaA (MRCG.DE), 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.

The companies had previously said the study was successful but Wall Street analysts and clinicians have been keen to see the full results in order to make comparisons with Genentech Inc's DNA.N Avastin, which is so far the only nonchemotherapy drug approved as an initial treatment for non-small cell lung cancer.

A pivotal trial of Avastin, which excluded certain patient groups, showed it boosted lung cancer survival by about eight weeks.

"Our eligibility criteria was not restricted ... From a clinical perspective, this is a significant result," said Martin Birkhofer, oncology medical lead at Bristol-Myers Squibb Co (BMY.N), which co-markets Erbitux in North America.

Tumors shrunk in 36.3 percent of patients treated with Erbitux, also known as cetuximab, compared with 29.2 percent of patients on chemotherapy alone, according to a statement from the American Society of Clinical Oncology.

The most frequent side effect was an acne-like rash. Moderate rash was seen in 10.4 percent of patients on the ImClone drug, compared with 0.2 percent of the chemotherapy-alone group.

Birkhofer said progression-free survival -- a measure of how long patients live before their disease gets worse -- was essentially the same at about 4.8 months for both arms of the trial.

Erbitux, an antibody designed to block a protein called epidermal growth factor, is already approved for treating colorectal as well as head and neck cancers. (Reporting by Deena Beasley; Editing by Braden Reddall and Bill Trott)