A small study raises the possibility that new and highly anticipated lung cancer drugs may help more people than just those with certain gene mutations as has been believed.
Scientists testing one such drug, Tarceva, found that people with these mutations were more likely to have their tumors shrink but not to live longer than people without the mutations.
Although the study is too small to be conclusive, it suggests that disappointment may have been premature that Tarceva and a similar drug, Iressa, seemed to shrink tumors in only about 1 in 10 patients. Many of the rest may have equally good survival odds, even if their tumors merely stabilized.
The government just restricted access to Iressa because it failed to help most patients.
Both drugs are part of a new generation of medicines that more specifically target cancer without harming healthy cells.
Doctors had expected these drugs to help most lung cancer patients and were chagrined when research found they worked primarily in people with certain mutations, which for some reason occur most often in Asians, nonsmokers and women.
In Thursday's New England Journal of Medicine, doctors led by the National Cancer Institute of Canada published previously released results showing that Tarceva extended survival by an average of 2 months in tests on about 700 people with advanced lung cancer.
They also published a fresh, smaller study on some of these patients, looking at how genetic factors affected results.
To the surprise of many, they found that having the genetic mutation didn't guarantee better survival.
The findings ``are actually very encouraging'' and suggest that the proportion of cancer patients who might be helped by Tarceva ``is not as narrow as has been portrayed,'' said Dr. David Johnson, a Vanderbilt University lung cancer expert who is president of the American Society of Clinical Oncology.
He had no role in this study but has done research and consulted in the past for the makers of Tarceva and Iressa. Iressa is made by AstraZeneca PLC; Tarceva is co-marketed by OSI Pharmaceuticals Inc. and Genentech Inc.
Unlike Tarceva, Iressa failed a key study intended to show it could improve survival.
Johnson and Dr. James Doroshow, director of cancer treatment and diagnosis at the National Cancer Institute in the United States, said Iressa seems less potent and might need to be given in a higher dose to be effective.
``That's almost certainly playing a role here,'' Johnson said of why two such similar drugs could produce different results. ``You could argue that Iressa got unlucky.''