In an international Phase III clinical trial involving 1,466 lung cancer patients from 24 countries who had undergone previous chemotherapy, researchers at the University of Texas M.D. Anderson Cancer Center compared daily doses of the cancer-fighting pill Iressa to docetaxel, a chemotherapy drug that’s administered by IV every three weeks. While the survival for both groups was about the same, 7.6 months for those taking Iressa compared with eight months for patients receiving docetaxel, there were significant differences in the side effects. Among patients taking Iressa, the most common side effects were rash or acne, compared with fatigue, personality disorders, hair loss, severe diarrhea and a blood disorder called neutropenia for patients receiving docetaxel. “This is the largest study in lung cancer comparing an oral biologic therapy to chemotherapy, and shows, for the first time, that an oral biologic therapy is just as effective as chemotherapy,” said lead researcher Dr. Edward Kim, an assistant professor in M. D. Anderson`s Department of Thoracic Head and Neck Medical Oncology. These findings should offer physicians reassurance that they are not compromising effective therapy by using a pill, Kim said.
“There are now two options that one can select from for patients in order to offer treatment that helps a bit following failure of first-line chemotherapy,” said Dr. Michael Cullen, from the University Hospital Birmingham in the United Kingdom, author of a journal comment accompanying the study results. “Survival overall is very poor, and, in fact, it’s almost certainly the case that only a small minority of patients respond to either of the two treatments.” Cullen noted that Iressa is far less toxic than chemotherapy and believes that, because survival time is short, doctors might want to decide which treatment to use based on how well the patient tolerated chemotherapy. “If they didn’t tolerate chemotherapy very well, maybe the oncologist would opt for the oral therapy, whereas if they responded well to chemotherapy, the best choice might be to go with the chemotherapy.”
Iressa is not available in the United States, but a similar drug, Genentech’s Tarceva, is. First developed by AstraZeneca, Iressa was the first in a new class of cancer-fighting drugs known as EGFR tyrosine kinase inhibitors (TKI) to become commercially available. After two Phase II trials found the drug to be efficacious, Iressa was fast-tracked to the FDA and received approval May 5, 2003 as a treatment for patients whose advanced lung cancer had continued to progress despite treatment with platinum-based and docetaxel chemotherapy. However, after Iressa failed a large randomized trial in 2005, the drug’s labeling was altered by the FDA and since then only patients who were already taking the medicine or those enrolled in clinical trials that were under way at the time were allowed to continue taking the drug. “Based on our findings, I’m hopeful that Iressa can return as a treatment for lung cancer in the United States, offering some patients a therapy with far fewer side effects,” said Dr. Kim, adding that “Chemotherapy will never be eliminated, but we are getting more options for targeted therapy; and people can live as normal a life as they can bearing the weight of lung cancer.”