The study will be published in the Nov. 1, 2002, issue of the Journal of Clinical Oncology. It is the first study to show that the oral combination of the drugs thalidomide plus dexamethasone provides treatment benefits equal to and in some cases better than the usual chemotherapy regimens administered to patients who are newly diagnosed with multiple myeloma. Previous studies at the University of Arkansas, Mayo Clinic and other cancer centers in the United States confirmed the use of thalidomide as an effective treatment for patients with relapsed multiple myeloma who had failed all other standard treatments.
The new study was a phase II clinical trial of 50 patients with newly diagnosed, active multiple myeloma. These patients ranged in age from 33 to 78. Of the 50 patients, 32 patients (64 percent) achieved a 50 percent or greater reduction in the amount of their tumor with the thalidomide plus dexamethasone treatment.
"The goal of both the standard chemotherapy approach and our research on the use of thalidomide plus dexamethasone is to reduce the amount of the cancer so patients can undergo stem cell retrieval and transplantation," says Vincent Rajkumar, M.D., a Mayo Clinic hematologist/oncologist and lead researcher on the study.
"Our study with thalidomide plus dexamethasone represents a significant advancement because physicians now have an alternative to the more toxic and cumbersome chemotherapy regimens used to treat patients with newly diagnosed myeloma," says Dr. Rajkumar. "For patients who are newly diagnosed with multiple myeloma, the study means they may not need to receive the series of intravenous chemotherapy treatments, and they won't experience the side effects often seen with such chemotherapy, including nausea, vomiting and hair loss."
"The toxicity of thalidomide plus dexamethasone appears lower and the response rate is as good or better than that obtained using complex combinations of chemotherapy regimens," he says. "The most serious side effect seen in six patients in the study involved blood clots in the legs. Other side effects included constipation, skin rash, numbness in the hands and feet, and sleepiness."
He added that patients who are not candidates for stem cell transplantation may have the option to continue the thalidomide plus dexamethasone treatment at reduced doses.
Despite these encouraging and promising results, Dr. Rajkumar cautions that further studies are needed before the thalidomide plus dexamethasone treatment can be recommended for routine clinical use in patients. For that purpose, Dr. Rajkumar is now leading an Eastern Cooperative Oncology Group phase III clinical trial to investigate the effectiveness of thalidomide plus dexamethasone versus only dexamethasone for treatment of patients newly diagnosed with multiple myeloma. The results of this randomized trial will help establish the role of thalidomide plus dexamethasone in the initial treatment of multiple myeloma.
Although multiple myeloma accounts for only one percent of all cancers, it is among the most difficult cancers to treat and cure. This year, about 14,000 new cases of the cancer will be diagnosed in the United States, and more than 11,000 patients will die from it. The average survival time for a patient diagnosed with multiple myeloma is about three to four years.
But there is significant hope based on promising results seen with thalidomide and other novel agents that the survival time can be significantly improved.
Thalidomide entered the medical treatment field in the mid-1950s as a sleeping pill. The drug was subsequently found to effectively control morning sickness during pregnancy. Later, the drug was found to cause severe malformations of the arms, legs and organs in an unborn child. By 1962, thalidomide was taken off the market worldwide.
In the last 10 years, researchers began studying thalidomide again as an anti-cancer agent. Although the exact mechanism of action in multiple myeloma is still unknown, researchers have found the drug effectively decreases the blood supply to cancers. It also boosts the immune system to better fight cancer.
Dexamethasone is a steroid medication that has been used for decades as the cornerstone of myeloma therapy.
Tuesday, Oct. 29, 2002
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