Studies Find Genetic Mutation Related to Benefits of Lung Cancer Medication Iressa
Two studies released on Friday found that about 15% of the 170,000 U.S. residents who develop lung cancer each year have a genetic mutation in their tumors that makes them more treatable with Iressa, a new cancer medication manufactured by AstraZeneca, the Los Angeles Times reports (Maugh, Los Angeles Times, 4/30). According to the New York Times, the studies have found a "crack in the genetic armor of lung cancer" and highlight the "way to what many experts say is the future of cancer care: drugs tailored for patients based on the genetics of their tumors." In one study, published online on Thursday by the journal Science, researchers from the Dana-Farber Cancer Institute and Nagoya City University Medical School in Japan, found the genetic mutation in all of the five tumors they examined from lung cancer patients who had responded to Iressa and in none of the four tumors from patients who had not responded to the medication. In a second study, published online on Thursday by the New England Journal of Medicine, researchers at Massachusetts General Hospital found the genetic mutation in eight of the nine tumors they examined from lung cancer patients who had responded to Iressa and in none of the seven tumors from patients who had not responded to the medication. The genetic mutations "appear to be infrequent" the Times reports. The Dana-Farber study found the genetic mutation in one of 61 tumors from U.S. lung cancer patients and in 15 of 58, or 26%, of tumors from Japanese patients (Pollack, New York Times, 4/30). The study also found that the genetic mutations were more common among women, individuals who had never or had not recently smoked and those who have a subtype of lung cancer called bronchoalveolar cancer. However, because one lung cancer patient in the Massachusetts General study responded to Iressa but did not have the mutation, "there may be other Iressa-susceptible mutations to discover," the AP/Hartford Courant reports (Neergaard, AP/Hartford Courant, 4/30). Lung cancer patients who take Iressa, which blocks the biological signals that cause tumor growth, have median survival times of between less than six months and 18 months or longer (Dockser, Wall Street Journal, 4/30). According to the Boston Globe, only about 10% of lung cancer patients respond to Iressa (Mishra, Boston Globe, 4/30).
The results of the two studies "could allow doctors to better decide when and to whom to give Iressa" and save lung cancer patients without the genetic mutations about $2,000 per month for a medication "that is not likely to help them," the Times reports (New York Times, 4/30). No commercial test for the genetic mutation currently exists, but Massachusetts General researchers have begun to work with several companies to develop such a test (AP/Hartford Courant, 4/30). According to the New York Times, the studies could "hurt AstraZeneca by limiting use of Iressa to those with the mutation" (New York Times, 4/30).
David Carbone, an oncologist at Vanderbilt University who specializes in lung cancer, said that the results of the studies are "the single most important discovery to date in the genetic of lung cancer" (Wall Street Journal, 4/30). Dr. Ronald Blum, director of the Cancer Center at Beth Israel Medical Center, said, "This is something very exciting that we have long hoped for, that we would have a way of predicting who would respond to a therapy and who would not" (Los Angeles Times, 4/30). However, some "cancer experts noted that the two studies were comparatively small," USA Today reports (Szabo, USA Today, 4/30). Dr. Paul Bunn, director of the University of Colorado Cancer Center, said, "If you've got this mutation you should for sure get the drug," adding, "The question then is what if you don't have this mutation? I don't think there's enough information to say you shouldn't get the drug." According to the Times, AstraZeneca said in a statement on Thursday that the "mutation seemed to explain tumor shrinkage, but that Iressa also has helped other patients by stopping their tumors from growing or by reducing cancer symptoms" (New York Times, 4/30).
Several broadcast programs reported on the new Iressa research:
- CBS' "Evening News": The segment includes comments from Dr. David Johnson of the Cancer Center at Vanderbilt University and Dr. Thomas Lynch of Massachusetts General (Kaledin, "Evening News," CBS, 4/29). The complete segment is available online in RealPlayer.
- NBC's "Nightly News": Robert Bazell of NBC discusses the studies (Bazell, "Nightly News," NBC, 4/29). The complete segment is available online in Windows Media.
- NPR's "All Things Considered": The segment includes comments from Lynch and Dr. Matthew Meyerson of Dana-Farber (Knox, "All Things Considered," NPR, 4/29). The complete segment is available online in RealPlayer.
- NPR's "Morning Edition": The segment includes comments from American Cancer Society Chief Medical Officer Dr. Harmon Eyre, Lynch and Meyerson (Knox, "Morning Edition," NPR, 4/30). The complete segment is available online in RealPlayer.
- PBS' "NewsHour with Jim Lehrer": The segment includes comments from Dr. Brian Druker of Oregon Health & Science University; Dr. Daniel Haberr of the Massachusetts General Cancer Center; Dr. Bruce Johnson, a study co-author and a researcher at Dana-Farber; and Dr. William Sellers, a study co-author ("NewsHour with Jim Lehrer," PBS, 4/29). The complete transcript is available online.