The Food and Drug Administration approved Alimta, the first drug for maintenance therapy of advanced or metastatic lung cancer.

Known generically as pemetrexed, Alimta may contain the progress of lung cancer from advancing after the size of the tumor has shrunk or been stabilized with chemotherapy the FDA said.

Traditional treatment of patients with advanced lung cancer that has spread to other parts of the body involves four to six rounds of chemotherapy, which is stopped in patients whose tumors either stop growing or shrink.

An Eli Lilly & Co. drug, Alimta works by disrupting metabolic processes, which depend on the B-vitamin folate for cell replication. Alimta was approved in 2004 for treatment of mesothelioma, a cancer caused by exposure to toxic asbestos, and later approved for treating non-small cell lung cancers in patients whose conditions worsened before chemotherapy. The drug also was previously approved for initial treatment of advanced non-small cell lung cancer.

Doctors typically waited until tumors started growing again before starting more treatment till earlier this year studies were released showing that drugs like Alimta can prolong lives without the side effects of initial treatment with chemotherapy.

Richard Pazdur, M. D., director, Office of Oncology Drug Products in the FDA's Center for Drug Evaluation and Research said, "This drug represents a new approach in the treatment of advanced non-small cell lung cancer."

According to the FDA a study of Alimta showed the drug improved survival rates of some patients who took it for maintenance therapy. 600 patients with various types of non-small lung cancer survived an average of 15.5 months after chemotherapy compared to just 10.3 months for patients who were given inactive placebo pills instead of Alimta.

However the FDA said patients with predominately squamous cell cancer did not benefit from treatment with Alimta in the study.

The FDA has given doctors the official green signal to treat patients with certain types of non-small cell lung cancer, the most common form of the disease with Alimta.

Alimta, considered a less-toxic chemotherapy drug, is initially given with cisplatin to treat lung cancer.

Side effects of Alimta include fatigue, nausea, loss of appetite, numbness or a tingling sensation in the hands and feet, skin rash, and damage to blood cells.