JUST IN THE LAST few months, on the basis of tests on animals, the Food and Drug Administration has pronounced Laetrile worthless as a cancer cure, the American Medical Association has said it has no proven value, the Battelle Memorial Institute has said it is useless and the Sloan-Kettering Cancer Center has concluded it has no effect one way or the other. Such is the appeal of this forbidden fruit to terminal cancer patients, however, that demand for it continues to grow and its legalization by state legislatures proceeds apace. The medical establishment, fearing that Laetrile inspires false hope and diverts patients from more effective treatments, seems powerless to turn back the tide.

Given the determination of many Laetrile supporters to treat all objections as proof of a conspiracy, it may well be impossible for reason to fully prevail. But that is no reason why the effort should not be made. The appropriate response of public health authorities ought now to be to conduct comprehensive tests of the substance on human cancer patients, not just on animals. Sen. Edward Kennedy (D-Mass.) has just added his voice to the many commending that course. It offends conscientious medical people to be asked to conduct what their knowledge and experience tells them is a gratuitous procedure. But the Laetrile cult has spread so widely that there seems no acceptable alternative. If, as non-cultists believe, human tests confirm that Laetrile is without value, then these results should make it easier to persuade at least some cancer patients to turn elsewhere.

On the leaders of the Laetrile cult, however, such tests are unlikely to make an impression.That much was made clear in their appearance before Sen. Kennedy the other day. Questions on the specific value of Laetrile drew answers on the general theme of freedom of medical choice. The only Kinds of human tests they were willing to countenance were those they knew to be unacceptable to the critics. No one could fail to note that those pushing Laetrile the hardest have made profits in the hundreds of thousands of dollars from peddling the stuff to desperate cancer sufferers.