"Laetrile has been tested. It is not effective."

In these blunt words, Dr. Charles G. Moertel of the Mayo Clinic yesterday announced the wholly negative results of a $500,000, federally financed study of the most controversial anti-cancer drug in medical history.

Of 156 patients, all with cancers that either had not responded or were not likely to respond to other treatments, 102 are now dead, just nine months after the beginning of the study last July at four medical centers.

All the other 54 have seriously "progressive cancer," which did not respond to Laetrile treatment.

These results, Moertel said, are "about the same" that would be expected if the doctors had given the patients either a placebo -- dummy pills with no effectiveness -- or "no treatment at all."

The results, Moertel said, are both "decisive" and "disappointing," given the fact that so many uncured patients have continued to seek out Laetrile as a last hope.

But "we hope," he added, that these results will end "the exploitation of desperate cancer patients" by some doctors and others who still offer patients Laetrile in the United States and abroad.

Moertel reported for the four centers taht made the study: the famed Mayo, where he is director of cancer treatment; Memorial Sloan-Kettering Cancer Center in New York; the University of California at Los Angeles, and the University of Arizona in Tucson.

He made the report to the American Society for Clinical Oncology, the country's cancer specialists, who yesterday opened a four-day meeting here.

Laetrile has been on the scene as a medically unaccepted cancer drug since the 1950s. Twenty-three legislatures and the federal courts have declared its use legal, despite the opposition of the federal Food and Drug Administration.

"Physicians who opposed Laetrile," Moertel said, "were portrayed as entering into an unholy conspiracy with regulatory agencies and drug companies to deprive cancer patients of beneficial treatment." To solve what he called this "major and unresolved public health problem . . . involving tens of thousands of cancer patients in direct treatment" with Laetrile, Moetrel and others urged the federally sponsored trial.

The trial, he said, was made with the same kind of Laetrile or amygdalin, a derivative of apricot pits, used by most Laetrile doctors in the United States and Mexico.

Also, all the patients were placed on the same "metabolic program" used by most Laetrile practitioners, a combination of enzymes and vitamins and advice to eat fresh fruits, vegetables and whole grains and restrict use of animal products, salt, alcohol and refined sugar and flour.

In all, 164 patients entered the study. Some died of caused unrelated to cancer or left the program.

Of the 156 treated for up to eight months, only five showed any improvement at all for more than two months, then they, too, began getting worse.

Among 140 who had any actual discomfort from their cancers before the treatment started, only 26 claimed that even their symptoms improved at any time. And after another 10 weeks only a fourth of these still said they felt any better. Laetrile advocates have often claimed their patients "feel better" even when their cancers remain.

The patients received Laetrile by injection for 21 days then took Laetrile pills three times a day. Few had any serious ill effects.

But Moertel warned that some Laetrile doctors are doubling their usual Laetrile dose and this "could be lethal."

At a news conference, a representative of a magazine sympathetic to Laetrile accused the centers of using an old, less than optimum form of Laetrile. Moertel and NIH specialists said the effect of both forms is just the same in the patients.