The combination of Thalidomide and Dexamethasone ( Thal/Dex ), when used as initial therapy for multiple myeloma, slowed disease progression almost two-fold compared to Dexamethasone alone.
Mayo Clinic's S. Rajkumar, M.D., presented the results of the largest ever study looking at this treatment at the annual meeting of the American Society of Clinical Oncology. The findings were the result of an international, multicenter, randomized, double-blind, placebo-controlled clinical trial. They come after years of study by Vincent Rajkumar and his colleagues into the most effective treatments for multiple myeloma.
" Not only have we consistently shown that Thal/Dex reduces the amount of cancer cells in the bone marrow, but now we can state that primary therapy with this combination produces superior long-term results compared to Dexamethasone alone," said Rajkumar.
An earlier Eastern Cooperative Oncology Group randomized study, led by Rajkumar, showed that a significantly larger proportion of patients with newly diagnosed multiple myeloma responded to the Thal/Dex combination compared to Dexamethasone alone ( 63 percent versus 41 percent respectively ).
In this most recent study, Rajkumar's team found that the average time to disease progression ( increase in cancerous cells ) was approximately eight months for patients taking Dexamethasone alone, while patients on the Thal/Dex regimen had an average progression time exceeding 17 months. " The average progression time will likely increase, " said Rajkumar, " as follow up is still under way for many patients who have not yet begun to experience disease progression."
Of the 470 patients ( 235 in each treatment arm ), individuals were more likely to experience adverse events with the combination therapy, experiencing serious ( grade 4 ) adverse events 30 percent of the time compared to 23 percent with Dexamethasone alone.
One of the main side effects with Thal/Dex was deep vein thrombosis/pulmonary embolism, which occurred in 18 percent of patients receiving the combination compared to 4 percent of patients receiving Dexamethasone.
Other side effects that occurred more frequently with Thal/Dex compared to Dexamethasone included cerebral ischemia, myocardial ischemia and peripheral neuropathy.
While overall survival rates are not significantly different between the two arms at this point, the follow-up is too short to observe disparities.
Additional follow-up of this study is important.
Although multiple myeloma accounts for only 1 percent of all cancers, it is among the most difficult cancers to treat and cure.
The American Cancer Society reports that this year about 16,570 new cases will be diagnosed in the United States and more than 11,000 patients will die from it.
Average survival time for a patient diagnosed with multiple myeloma is about three to four years.
Source: Mayo Clinic, 2006