‘Magic Bullet’ Therapy for Lung Cancer Will Be Tested

LA JOLLA —  Scientists at the Research Institute of Scripps Clinic announced Thursday that they will begin clinical testing of a new therapy to treat lung cancer, the nation’s leading cancer killer.

The treatment, which involves using laboratory-produced monoclonal antibodies to activate the body’s immune system, has been tested with limited success on patients with colon, bone, breast, skin and lymph cancer and leukemia. This is the first time the treatment will be tried on humans with lung cancer, the scientists said.

Monoclonal antibodies, also called “magic bullets,” are specialized proteins made by the body’s immune system that can recognize and attack specific foreign substances. Scientists believe they may be effective in treating cancer because they can seek out and destroy specific malignant cells while leaving healthy cells and tissue untouched.

Lab Experiments

Dr. Richard Timms, director of the division of chest medicine at Scripps Clinic, who is heading the study, and other researchers on the project said the treatment has been effective in stopping the growth of human lung cancer in laboratory mice, but they were cautious about its potential effects on humans.

“This is a terrible cancer, it kills people quickly and we see it every week. We don’t have any unusual or crazy expectations for this trial,” Timms said. “We think it’s a first step, learning to crawl or perhaps even to walk a little bit in the area of this problem.”

Dr. Lawrence E. Kline, a researcher on the test project, said the Food and Drug Administration has approved the test treatment using the monoclonal antibodies alone. A second stage of the trial, using the antibodies in conjunction with the potent anti-cancer drug methotrexate, is still under consideration by the FDA.

Combination Never Used

The researchers said the antibody-and-drug-compound therapy never has been tested on humans, but they expect FDA approval within months.

The research was financed by the National Cancer Institute and private donors. The clinical test is expected to cost about $500,000.

About 126,000 Americans are expected to die of lung cancer this year, and another 144,000 cases will be diagnosed, the scientists said. Most lung cancer patients die within two years of the diagnosis of their disease.

The researchers said 15 to 25 patients will be treated during the study, which is expected to last 1 to 1 1/2 years.

Timms said the trial “will allow us to examine how well the monoclonal antibodies locate, attach to and enter the patients’ cancer cells. Finally, if we are successful, we want to determine the efficacy of the therapy in reducing or eradicating the disease.”

Results of Tests

In 20-day tests on human lung tumors transplanted into laboratory mice, the researchers found that the antibody alone suppressed the growth of the tumor by 25%; the drug alone suppressed the growth by 50% and the combination of the drug and antibody suppressed the growth of the tumor by 80%.

In other tests on humans of the monoclonal antibodies for other forms of cancer there has been no harm to the patient, according to a researcher on the project, Ralph A. Reisfeld, of Scripps’ Department of Immunology. The other trials have been “encouraging,” he said, but added that the new field is “embryonic.”