Laetrile: The Making of  a Myth

FDA Consumer
December 76 / January 1977

Repeated tests have failed to produce any evidence that Laetrile is effective in the treatment
of cancer. But that has not stopped its promoters from urging cancer victims to forego
conventional treatment in favor of Laetrile. Patients who do may pay with their lives.

Cancer is an ugly word. It evokes a picture of pain, prolonged and discomforting treatment, and possibly disfigurement. Some people equate the disease with sure death. Only a few years ago cancer was hardly discussed above a whisper and few people who had it would openly discuss their illness.

But the picture is changing. As people learn more about cancer, the myths are disappearing. People are learning that many cancer victims can lead normal lives, and that significant progress is being made in saving and extending the lives of its victims through early detection, improved surgical techniques, x-ray treatments, and new drugs. Detected early and treated properly, cancer no longer means certain death.

Yet among some people, a myth persists that there are effective but suppressed remedies for cancer-remedies that responsible physicians cannot provide. For years some people have put their faith in unproven treatments whose backers promise something they can't possibly deliver—quick, painless, sure cures. Twenty years ago promoters tried to persuade the public that a substance called Krebiozen could cure cancer. Today, it has been replaced by Laetrile.

Laetrile is the chemical amygdalin, which occurs naturally in the pits of peaches, apricots, and bitter almonds, and in other plant material. In its 25-year history Laetrile has developed from the brainchild of a father-son team in California into big business on an international scale.

Ernest T. Krebs, Sr., a California physician, was the first to try apricot pits as a cancer treatment in 1920. But the substance he used was highly toxic. His son, Ernest T. Krebs, Jr., a biochemist, claimed to have developed a purified form of Laetrile, safe for injection, in 1952. Krebs, Sr. joined his son in advocating the purified form as an effective treatment for cancer.

Krebs, Jr., theorized that Laetrile works by seeking out a substance which is found in cancer cells but not in normal cells. This substance, he contended, causes Laetrile to release hydrocyanic acid which destroys the cancer cell. Normal cells, Krebs said, contain a substance that protects them from the hydrocyanic acid. Later, Krebs changed the theory, claiming that cancer is caused by a deficiency of vitamin B17, and that Laetrile is vitamin B17. Some Laetrile advocates now claim that it prevents as well as cures cancer.

Scientists never have been able to find any valid basis for either of the Krebses' theories. Laetrile is not a vitamin. N a evidence has ever been found that it has any effect on cancer. The Cancer Commission of the California Medical Association investigated Laetrile and declared it ineffective in 1953. Ten years later, the California State Department of Public Health, acting on a report by its Cancer Advisory Council that Laetrile was of no value in the diagnosis, treatment, alleviation, or cure of cancer, issued a regulation prohibiting its usc in that State.

Undeterred by this decision, the Krebses continued to produce Laetrile. But they had more to reckon with than State laws. During the 1960's they were repeatedly charged in Federal courts with shipping Laetrile and other unapproved drugs in interstate commerce. After one conviction, leftover supplies of Laetrile were distributed by FDA for investigational use to U.S. physicians and to the McNaughton Foundation in Montreal, headed by Andrew R. L. McNaughton. The McNaughton Foundation had been established as a nonprofit organization to fund independent and unorthodox research. McNaughton and his Foundation are now among the leading proponents and distributors of Laetrile.

Neither the U.S. Food and Drug Administration, the Canadian Food and Drug Directorate, the National Cancer Institute, the American Cancer Society, nor any other reputable organization has found any evidence to substantiate the use of Laetrile in the treatment or prevention of cancer. Laetrile may not be sold in the United States and Canada because both nations have laws requiring that drugs be proved effective before they can be marketed. It is available in some other countries because their laws do not prohibit the marketing of unproven drugs.

In the United States, proof of safety and effectiveness must be demonstrated by precise and thorough testing. Initial tests are made in animals, and if these tests show that the drug holds promise, the sponsor can file an Investigational New Drug (lND) application with FDA. This application must summarize the results of the animal tests (and any human testing done outside the United States) and describe the sponsor's plans to test the drug in human subjects.

If FDA approves the application, clinical testing with human volunteers can proceed. If these tests demonstrate to FDA the drug's safety and effectiveness, and other requirements of the law are met, the drug is approved by the Agency for marketing. If not, approval of the application is withheld and the drug may not be shipped in interstate commerce.

Several attempts have been made by promoters of Laetrile to get FDA approval to distribute the drug. The last was by the McNaughton Foundation of California which in 1970 submitted an application to test Laetrile in humans. FDA found the application inadequate and rejected it. Proponents of Laetrile claimed FDA was prejudiced. To assure objectivity, an independent panel of cancer experts reviewed the application and interviewed Andrew McNaughton. They concluded that the evidence was not adequate to justify testing the drug on humans.

This is not just the opinion of one committee of experts. From the beginning, Laetrile has been tested and found wanting. It is, in fact, one of the most tested cancer "cures" ever. In addition to the investigations of the California Department of Public Health and Canadian authorities the National Cancer Institute tested Laetrile in animals on five separate occasions between 1957 and 1975. None produced evidence that Laetrile is effective against cancer. Four independent cancer research centers undertook additional studies in 1975 and found no evidence that Laetrile could cure cancer or inhibit malignant growths. In an effort to put the matter to rest—scientifically—one of the four labs, the Memorial Sloan Kettering Cancer Center of New York City, is conducting a "double blind" test in which not even the investigators will know which of the animals being tested arc given Laetrile and which arc receiving "placebos."

 The "evidence" presented by Laetrile supporters has consisted of testimonials from people who believe Laetrile has cured them of cancer, prolonged their life, or reduced pain. How is it possible to have such testimonials and still no scientific proof that Laetrile is effective? Part of the answer lies in the nature of the disease. Cancer is not a single disease, but a combination of about 100 different clinical entities, each following its own natural and sometimes erratic course. Skin cancer, for example, is different in its development, effects, and treatment than lung cancer. Patients sometimes have remissions—periods when certain symptoms disappear. If they take Laetrile during a remission, it will appear as if Laetrile helped them. In other cases, patients have taken Laetrile while also getting effective forms of treatment and may believe that the Laetrile was at least partially responsible for relief of symptoms.

Many people who claim Laetrile has helped them are sincere in their belief. But objective evidence to support their opinion has never been developed. One foreign doctor, Ernesto Contreras of Tijuana, Mexico, was asked by FDA to provide the most dramatic examples of success with Laetrile. He submitted 12 case histories. Of nine patients whose records FDA and the National Cancer Institute could obtain and review, six had died of cancer, one still had cancer that had spread since Laetrile had been taken, one had used approved drugs and radiation therapy, and one had died of another disease after having had the cancer removed surgically.

Despite all efforts by cancer researchers and the Federal Government to give Laetrile a fair hearing, its advocates maintain that the medical profession, the American Cancer Society, and the Federal Government conspire to suppress Laetrile because they are bound to conventional treatment by profit or other motives. Yet FDA has been on record for years as being prepared to approve human tests of Laetrile if experts in cancer found evidence to justify them. And the National Cancer Institute is committed to pursuing any evidence that may provide a basis for clinical trials in human patients.

Lack of Federal approval has not stopped promotion of Laetrile, which is carried out primarily by four organizations. One is the National Health Federation, a promoter of health foods. Another is the International Association of Cancer Victims and Friends (IACVF). This group publishes the Cancer News Journal. An offshoot of this organization is the Cancer Control Society, which publishes Cancer Control Journal. The fourth group is the Committee for Freedom of Choice in Cancer Therapy. It was founded by Robert Bradford, a physicist who regards efforts to regulate Laetrile and similar unproven remedies as an invasion of privacy and an unwarranted interference with individual freedom.

Among other promotional efforts, Laetrile advocates hold conventions open to the public where speakers extoll the virtues of unorthodox cures and printed material is readily available. They hope that growing popular support will force the Government to accept Laetrile.

Exploiting the demand created by the advocates of Laetrile, manufacturers and distributors have attempted to market amygdalin or products containing it with labeling designed to circumvent the law against the sale of unapproved drugs. The labeling has described the products as food or food supplements and has avoided any claims that the products are useful in the treatment of disease. One company tried distributing amygdalin in a milk shake mix called Seventeen. The product's package featured a picture of a bee with the word "Seventeen" (B17). The company claimed that the product was a food. In May 1975, U.S. District Court Judge Malcolm Lucas barred further distribution of the product after ruling it was an unapproved and misbranded drug.

Less than a year later, Judge Vincent P. Biunno of the U.S. District Court for the District of New Jersey enjoined two other companies from marketing amygdalin labeled as "Bitter Food Tablets." This product was supposedly intended to cut the sweet taste of fruit drinks. Judge Biunno found that calling amygdalin a bitter flavor was a "patently absurd and transparent attempt to avoid the drug labeling provisions of the Federal Food, Drug, and Cosmetic Act," and said its sale for any food or drug use constituted a fraud on the public.

Such legal actions stop some but by no means all of the distribution of amygdalin or Laetrile in its various forms. Pills and capsules made from amygdalin, or defatted apricot pits, sometimes are available in health food stores. They may be displayed openly, or kept under the counter.

The smuggling of Laetrile into the United States has become big business. On the black market, Laetrile sells for 600 to 700 percent above the manufacturer's cost. A month's treatment in Mexico can cost more than $1,000. U.S. Customs officials recently have made more than 20 major seizures and secured the conviction of a physician charged with smuggling amygdalin into the country from Mexico. In May 1976, a Federal grand jury in San Diego indicted nine Americans, six Mexicans, and a Canadian for running a Laetrile smuggling ring. Included in the 16 were Andrew McNaughton of the McNaughton Foundation, Robert Bradford, president of the Committee for Freedom of Choice in Cancer Therapy, and Dr. Contreras.

Laetrile also finds its way into the United States via the luggage of cancer victims who have sought help in clinics in those countries where the drug is legal. The most popular and most accessible clinic to Americans is just across the California border in Tijuana, Mexico-the Centro Medico del Mar, operated by Dr. Contreras.

Thousands of Americans have come to Tijuana, some from as far away as Alaska. Many are in the last stages of their illness, still seeking hope and relief from pain. Others have forms of cancer that could be controlled by early, effective treatment. In many cases their journey south is arranged by the International Association of Cancer Victims and Friends or the Committee for Freedom of Choice in Cancer Therapy. The Laetrile administered to them is produced by Cyto-Farma, a Tijuana company owned at one time by Andrew McNaughton and one of the major sources of Laetrile in the Western Hemisphere.

A basic argument advanced by many Laetrile advocates is that patients have a right to choose the therapy they arc to have. "Freedom of choice" has become the rallying cry of many Laetrile supporters. Much like the hucksters of old who promoted their patent medicines with patriotic pictures, Laetrile supporters have made the drug a symbol of alleged Government suppression.

How much "freedom" is involved in choosing Laetrile over conventional therapy is open to question. Cancer victims rarely decide to use Laetrile entirely on their own. They are persuaded to demand it by false claims that it is effective in controlling cancer. Slick sales techniques used at conventions readily convince the frightened, sick, and the gullible that Laetrile is not only a cure but a preventive measure as well.

Another argument made in favor of lifting the ban on Laetrile is that there can be no harm in allowing terminally ill people to have a seemingly harmless-though-worthless substance if it makes them feel better psychologically. But the line between the terminally ill and the patient who may benefit from effective therapy, or from new approaches to treatment that have genuine promise, cannot be so finely drawn as to reliably separate the terminally ill from the treatable. And once an unproven substance is made legal for one group of patients, there would be no way to prevent access by others. Patients who have cancer in an early and controllable state could be putting their lives on the line by taking a worthless substance instead of seeking an effective treatment. Indeed, Laetrile now is being promoted as a treatment for cancer in its early stages.

There is some question, as well, about the claims that Laetrile is harmless. Laetrile is amygdalin, and amygdalin contains cyanide, one of the most toxic substances known. Some health food advocates eat seeds and kernels containing amygdalin, and there have bcen reports in scientific literature that these kernels have produced symptoms of toxicity.

To allow the importation and interstate distribution of any unapproved substance could have far reaching effects on laws which were designed to protect consumers against drugs that are of no value in treating illness. If one such product could be sold, untold numbers of others would appear, their promoters claiming immunity from the law on the same basis as Laetrile. The result would be chaos in medical care, with no one able to distinguish a valuable medicine from a worthless but well-promoted substance.

Despite the success of a number of regulatory efforts, cancer quackery is on the rise. One reason is that the promoters of Laetrile and similar products have been able to develop and exploit much more effective means of reaching their potential victims than have those who are concerned with protecting the public from the dangers of unproven "cures."

These promoters prey on the real and understandable fear of cancer victims, fear not only of the disease itself but of the effects of surgery, radiation, or chemotherapy that may be a necessary part of effective treatment. Under these circumstances it is not hard to understand the appeal of painless, nonsurgical, nontoxic "remedies". The problem is they are not effective remedies, and they are not harmless. When they delay or interfere with swift diagnosis and prompt treatment they are potentially lethal.

As long as there are diseases that are frightening, and that resist fully effective management or cure, people will turn to those who traffic in false hope. And there will always be someone to turn to. It may be a huckster at home,

a psychic surgeon abroad, or a cancer clinic in Mexico. There is no way to measure the cost of such quackery—in human terms or dollars and cents. Anyone who is concerned about cancer should turn for help to a physician experienced in treatment of the disease.

For its part, FDA—along with other Government health agencies and responsible health professionals—will continue to try to bring the facts about cancer and its treatment to the public. And as the Agency responsible for approving drugs FDA is firmly committed to assuring that any new discovery that meets proper scientific standards will become available to all Americans.

This article was posted on March 5, 2006.

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