Researchers at the National Institutes of Health said today that an amino acid compound had proved in laboratory tests to be a ''very, very promising'' drug for the treatment of tumors.
One of the researchers, Hynda K. Kleinman, said a peptide synthesized in the laboratory prevented the formation of lung cancer tumors in rats and in test-tube experiments.
She said the peptide also had been shown to be effective against Kaposi's sarcoma, a cancer that often strikes patients with AIDS.
A report on the study at the institutes, in Bethesda, Md., appears in Friday's issue of the journal Science. Patent Being Sought
''We characterize it as very, very promising,'' Dr. Kleinman said of the compound, called peptide-11. ''There have been other peptides described, but this is the most potent one we know of.''
Dr. Kleinman said that a patent had been applied for on the peptide compound but that it could take many more years of laboratory experiments before the new drug is available for tests on human cancer patients.
A peptide is a compound made up of amino acids. Proteins are composed of chains of peptides.
Dr. Kleinman said the compound seems to have the ability to prevent cancer cells from penetrating the walls of blood vessels and invading an organ. Prevents Attachment to Wall
''The cancer cell when it is traveling in a blood vessel is really in a sealed pipe,'' she said. To bore through the vessel wall, the cancer cell first attaches itself to laminin, a membrane in the vessel wall. When it is attached, the cancer cell erodes the membrane until it is able to move through the wall.
Dr. Kleinman said peptide-11 appeared to be able to prevent the cancer cell from sticking to the vessel wall and thus blocks the cell from boring through. This strands the cancer cell inside the vessel, where it eventually will die or be killed by the body's immune system. In this way, the cancer is unable to spread.
In a laboratory experiment, the research team injected two groups of rats with lung cancer cells. In one group, the researchers also injected peptide-11.
Three weeks later, the rats were killed and their lungs examined. Rats receiving high doses of the peptide showed no lung tumor development, and even small doses significantly inhibited lung tumor growth. The rats that received no peptide averaged 51 lung tumors each. Tested on Variety of Tumors
Dr. Kleinman said researchers were testing the substance on a variety of tumors. So far, she said, it has been found to have few side effects.
''It disrupts the formation of organs and tissues,'' she said. ''So I would predict it will probably be nontoxic in an adult but it may have some effects on pregnancy.''
Dr. Kleinman said the peptide works in a different way than the drugs now used to fight cancer. Those drugs typically are toxic to the cancer cells, but they also can damage normal cells and cause serious side effects.
Dr. Kleinman and six other scientists tested the drug at the institutes'. Others participating in the experiments were Yukihide Iwamoto, Jeannette Graf, Makoto Sasaki, Yoshihiko Yamada and George R. Martin, all of the institutes, and Frank A. Robey of the Food and Drug Administration.