Drug Shows Near-Total Success Against Rare Type of Leukemia
A new anti-cancer drug has shown near-total effectiveness against a rare form of leukemia without the debilitating side effects that usually accompany chemotherapy, San Diego researchers say.
Reporting in today’s issue of the New England Journal of Medicine, the Scripps Research Institute scientists were careful to point out that the cancer they studied, hairy-cell leukemia, is diagnosed in only 500 to 600 people a year in the United States.
Nonetheless, they believe that the dramatic effectiveness of 2-CdA makes it a harbinger of similar “designer drugs” in cancer therapy.
A single seven-day treatment with 2-CdA killed all detectable cancer cells in 11 of 12 hairy-cell leukemia patients studied over the last four years, the scientists reported.
The 12th subject had a partial remission and refused further treatment. Similar results since have been recorded in another dozen patients at Scripps and several in Houston, the researchers said.
The only two drugs commonly used against hairy-cell leukemia are alpha interferon and pentostatin. Both are less effective, require longer treatments and cause toxic and debilitating side effects, doctors say.
The Scripps drug, whose full name is 2-chlorodeoxyadenosine, was developed by Dr. Dennis A. Carson in the late 1970s. Since that early work by Carson, chemists at Scripps and elsewhere have turned to supercomputers to design drugs that eventually could be used specifically against cancer and other diseases.
Side effects from 2-CdA were limited to a fever lasting an average of five days. No one experienced nausea, hair loss or other traditional chemotherapy side effects.
Although the treatment destroyed all of the body’s white blood cells, the patients’ immune systems were back to normal within eight weeks, the researchers reported.
The drug also appears to result in partial remission in about half of patients with certain lymphomas and chronic lymphocytic leukemia. It is also in very early tests at Scripps on melanoma patients.
Hairy-cell leukemia is a cancer in which abnormal lymphocytes, or white blood cells, begin growing uncontrollably. Eventually they take over the bone marrow, destroying its ability to make clotting and infection-fighting cells.
Although the disease is regarded as eventually fatal, it often grows so slowly that patients can live up to 25 years. It strikes four times as many men as women, usually in middle age.
So far, 2-CdA is available only at Scripps, UC San Francisco, the M.D. Anderson Institute in Houston and the Karolinska Institute in Sweden, Piro said.
