ROCHESTER, MINN. -- The early findings of a Mayo Clinic study, published this month in the journal Leukemia, indicate the drug thalidomide can stop or slow the progression of multiple myeloma in patients newly diagnosed with this cancer of the blood.
The Mayo Clinic study is the first published report to document the effectiveness of thalidomide, which was found to cause birth defects 30 years ago, as a first-line treatment for multiple myeloma. Patients in the study were considered to have either smoldering or indolent multiple myeloma. Previous studies at Mayo Clinic and other research centers have confirmed the usefulness of thalidomide for treating patients with advanced myeloma who had failed the standard treatments of chemotherapy and bone marrow transplant.
"Fourteen of 16 patients with previously untreated early-stage multiple myeloma enrolled in our study either had or continue to have a positive response to treatment with thalidomide," says Vincent Rajkumar, M.D., a Mayo Clinic hematologist and lead researcher on the study.
"Eleven of 14 patients had a 25 percent or higher response in the myeloma protein levels with thalidomide," says Dr. Rajkumar. "Six of the patients showed a reduction in the myeloma protein levels by 50 percent or more. Only two patients had progressive worsening of myeloma while receiving thalidomide."
Dr. Rajkumar and nine other Mayo Clinic hematologists began the study in 1999.
"We intended to conduct the study for one year to learn how a few newly-diagnosed early-stage myeloma patients responded to thalidomide, but the encouraging results coupled with patients wanting to stay on the drug prompted us to continue the study and to publish our early findings," he says. "Several patients in the study are now in their third year of receiving thalidomide to control their myeloma."
Although the Mayo Clinic study indicates thalidomide significantly affects early-stage multiple myeloma, Dr. Rajkumar sounds a note of caution.
"We currently do not recommend routine use of any medication to treat myeloma at its very early (smoldering or indolent) stage because some patients can be stable for several months or years without any therapy," he says. "Given the encouraging results of our study with thalidomide, we are recommending additional randomized trials be conducted to determine if thalidomide can uniquely delay myeloma from progressing to the active, advanced stage."
He also says that, as with any anti-cancer drugs, the risks and benefits of thalidomide treatment need to be weighed for each patient.
"No treatment is without risk or side effects," says Dr. Rajkumar. "Seven of the 16 patients in our study experienced skin rash, 15 felt fatigued, 15 had constipation and 13 had mild numbness or tingling in their hands and feet. However, in most cases these symptoms are mild and can be usually relieved by supportive care measures and by reducing the dose of thalidomide."
Because of the adverse birth effects, women in the childbearing age group must undergo pregnancy testing before starting thalidomide treatment. During treatment, patients must abstain from sexual intercourse or use two highly effective contraceptive methods.
"On the benefit side, thalidomide involves taking a pill as opposed to receiving intravenous chemotherapy or a bone marrow transplant," says Dr. Rajkumar. "It also may extend the length of time before a patient is required to undergo those treatments."
Multiple myeloma is not one of the major cancers, but it is among the most deadly and difficult to treat. About 14,000 Americans are diagnosed with the cancer each year. The cancer occurs predominantly in older people, with the average patient being age 65 years. The average life expectancy for a patient with the disease is three to four years.
Thalidomide was first marketed in 1956 as a sleeping pill and subsequently was found to be effective in reducing morning sickness from pregnancy. The drug was taken off the market worldwide in 1962 for causing birth defects. It has regained prominence in the past couple of years as a promising treatment for multiple myeloma.
Materials provided by Mayo Clinic. Note: Content may be edited for style and length.
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