People newly diagnosed with lung cancer should not take the lung cancer drug Iressa, according to new limitations placed on the drug by the FDA.

Following results of a large study that showed Iressa did not help people with the disease live longer, the FDA says only lung cancer patients already using Iressa whose doctors believe it is helping them should continue to use the drug.

New lung cancer patients will only be able to use Iressa as part of strictly controlled clinical trials.

Iressa was approved for treating lung cancer in May 2003 under a special FDA program that allows drugs that appear promising to be approved despite absolute proof that they increase survival. Astra Zeneca, Iressa’s manufacturer, is a WebMD sponsor.

Read WebMD's "10 Important Questions to Ask Your Doctor About Lung Cancer"

Drug Didn’t Meet Expectations

Initial studies of Iressa showed that 10 percent of people with lung cancer responded to the drug in terms of slower tumor growth after other available treatments failed.

But two studies that were published after Iressa’s approval have shown that the drug didn’t live up to its expectations, and people taking the drug did not live any longer than those taking a placebo.

Officials say that since 2003, other drugs, such as Tarceva, have been approved and shown to prolong the lives of difficult-to-treat lung cancer patients.

The FDA says it is not considering taking Iressa off the market, and the results of new and ongoing studies of the drug will determine its role in lung cancer treatment.

Read WebMD's "Mental Tasks May Be Harder for Cancer Survivors"

By Jennifer Warner, reviewed by Michael W. Smith, MD

SOURCE: FDA.