The drug industry has heralded targeted cancer therapies, which attack a specific protein identified through molecular analysis, as the next wave in treatment. This strategy received a setback last December, when the European drugmaker AstraZeneca reported that its targeted therapy, Iressa (gefitinib), shrank tumors but was no more effective than a placebo at extending the lives of patients with lung cancer. In light of this study, which included 1,700 people, AstraZeneca withdrew its application for approval in Europe. The company's hopes of ever achieving blockbuster status for Iressa have now all but faded. The drug's future in the U.S., which approved it in 2003, is uncertain as the FDA deliberates whether to pull it off the market. Many patients have moved to Tarceva, a targeted treatment from Genentech and OSI Pharmaceuticals that has improved patient survival. AstraZeneca plans to continue studies of Iressa for other types of cancer.
This article was originally published with the title "Off Target" in Scientific American 292, 3, 30 (March 2005)