May 19, 2002 4 min read

ORLANDO, Fla. (AP) – A once-a-day pill that slows cancer by jamming its internal growth signals shows encouraging benefits in terminally ill lung cancer patients, quickly easing symptoms for many. Research released Saturday showed that the drug, called Iressa, can shrink tumors in some patients who have failed all other therapy. But perhaps even more important for these patients, it relieves cancer symptoms in one-third or more of cases.

The drug, not yet approved for routine use, is one of the new class of so-called targeted therapies that works by specifically interfering with cancer rather than all fast-growing tissue, as standard chemotherapy does. As a result, it carries far fewer side effects, and patients often can safely take it for months or even years.

Many experts doubt that Iressa and drugs like it will actually cure cancer alone, but they say it may help hold the disease in check – especially if given in early stages.

“This is a whole new way of treating lung cancer,” said Dr. Mark Kris of Memorial Sloan-Kettering Cancer Center in New York City. “People didn’t think this would work. It’s nothing short of amazing.” The data from the study, financed by drug manufacturer AstraZeneca, were made public by Kris at a meeting of the American Society of Clinical Oncology in Orlando.

In December, AstraZeneca applied for Food and Drug Administration approval to sell Iressa based on this and a similar study released in November. Meanwhile, two much larger studies are under way to test whether the drug can prolong survival when given as first-line therapy to people newly diagnosed with spreading lung cancer.

Kris said the drug is particularly striking for easing symptoms quickly. Most who responded began to feel better within two weeks. The drug relieved their shortness of breath, coughs, poor appetites and other cancer symptoms.

All the people studied had already failed to get better after receiving two different regimens of drugs for their spreading lung cancer. Treatment responses of any kind are rare in people with disease this advanced.

The volunteers’ symptom relief lasted an average of seven months. About one-quarter of the patients enrolled in the study are still alive after 18 months of treatment.

Dr. Karen Kelly of the University of Colorado said symptom relief ranged from moderate to dramatic. “The patients felt the improvement was significant to them. It translated to a better quality of life,” she said.

The drug is one of several in development called epidermal growth factor receptor inhibitors. Others include Tarceva, developed by OSI Pharmaceuticals, Genentech and Roche, and Erbitux from ImClone Systems. All work by interfering with HER-1, a docking post on cancer cells that receives a chemical signal that triggers tumors’ out-of-control growth. Long-established cancers may respond to a variety of different signals like this, so experts doubt that blocking just one will be a reliable cure.

Kris’ study tested two different doses of Iressa on 216 patients. The lower dose worked better. In 12 percent of these patients, tumors shrank by at least half, and 43 percent had improved symptoms.

A similar study was conducted in Europe and Japan on people who were somewhat less sick, because they had failed just one course of chemotherapy. Tumors shrank in 19 percent, and 39 percent felt better.

“It’s for real. I can tell you that,” said Dr. Roy Herbst of M. D. Anderson Cancer Center in Houston, a lung cancer specialist who has treated about 100 patients with the drug. “I have seen more than several benefit quite significantly”

Herbst is directing a study of 1,024 lung cancer patients. The goal will be to prove that the drug improves survival by at least one-third.

“That would be a home run,” he said.

Results from his study are expected in the fall or winter. Meanwhile, AstraZeneca hopes to win approval of the drug later this year.

Studies are also under way to see if Iressa can prevent the development of lung cancer in smokers. The drug is also being studied as a treatment for many other cancers, including breast, prostate and colon.

The drug’s most frequent side effect is an acne-like rash that is usually easy to control.

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EDITOR’S NOTE: Medical Editor Daniel Q. Haney is a special correspondent for the Associated Press.

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Meeting site: http://www.asco.org/