Pemetrexed delays progression of advanced non-small cell lung cancer by 50 percent when started as maintenance therapy three to six weeks after completing four cycles of platinum-based induction chemotherapy, according to a presentation at the annual meeting of the American Society of Clinical Oncology.

"This is the first study to show that lung cancer patients can benefit from maintenance therapy. The fact that this approach significantly increases the amount of time that patients have before their cancer progresses, without increasing additional side effects, is particularly significant," said lead author Tudor Eliade Ciuleanu, MD, PhD, associate professor at the University of Medicine and Pharmacy Iuliu Hatieganu in Romania.

"We recommend giving pemetrexed after a patient completes initial induction therapy, but before cancer progression occurs. This approach affords the greatest chance of killing stray cancer cells before they have a chance to contribute to tumor growth."

Until the current trial, maintenance chemotherapy had not been proven to be of value for patients with lung cancer and is not a part of the standard of care. Pemetrexed is currently approved by the U.S. Food and Drug Administration for treating disease that has progressed despite previous chemotherapy.

In the current study, researchers analyzed progression-free survival and overall survival among 663 patients with stage IIIB or IV disease that was stable following treatment with a platinum-containing drug such as cisplatin or carboplatin. A total of 441 patients were randomized to pemetrexed; 222 patients received a placebo.

Progression-free survival was significantly longer for pemetrexed (4.3 months) than for placebo (2.6 months). Overall survival was 13 months for pemetrexed compared with 10.2 months for placebo.

However, Ciuleanu cautioned that the findings on overall survival are preliminary, noting that final results will be necessary before researchers are able to draw conclusions about the impact of pemetrexed maintenance therapy on overall survival.

The incidence and severity of side effects were generally similar between the two groups. The most significant side effect was moderate to severe anemia, which occurred in 4.5 percent of the pemetrexed group and 1.4 percent of the placebo group.