Thalidomide Gives Boost to Myeloma Therapy
Once-maligned drug is proving a friend to those fighting blood cancer
WEDNESDAY, March 8, 2006 (HealthDay News) -- Adding the formerly banned drug thalidomide to treatment for the blood cancer multiple myeloma boosted patient response rates by nearly half, researchers report.
Overall survival was not improved, however, because further treatment was often futile when the patients taking thalidomide eventually relapsed, note researchers reporting in the March 9 issue of the New England Journal of Medicine.
"The mechanism of why survival was reduced is being intensely investigated by us," said Dr. Bart Barlogie, director of the Myeloma Institute for Research and Therapy at the University of Arkansas for Medical Sciences in Little Rock.
Meanwhile, doctors at the institute are routinely treating multiple myeloma patients with thalidomide as part of a regimen that includes the drug melphalan along with bone marrow stem cell transplant to replace cancerous cells with new, healthy cells.
According to the Leukemia and Lymphoma Society, more than 15,000 Americans are diagnosed with multiple myeloma annually. The disease affects blood cells called B-lymphocytes. While some myelomas are slow-moving and pose little immediate threat, others can be very aggressive.
Thalidomide was taken off the market in the 1960s because women who took it during pregnancy had a much higher rate of severe birth defects. However, studies suggesting it might help against cancer led to its reintroduction -- with strict controls -- in 1998.
The rehabilitation of this once-feared agent continues to be remarkable, said Dr. Raymond L. Comenzo, director of the cytotherapy laboratory at Memorial Sloan-Kettering Cancer Center, in New York City. In fact, the promising findings from the Little Rock trial are evidence that thalidomide may be a powerful new weapon against myeloma, and Comenzo believes that Barlogie and his team "deserve tremendous accolades for having done what they have done."
In their study, the Arkansas team tracked outcomes in 668 patients treated for multiple myeloma. All got standard therapy, but 323 were also given thalidomide from the outset.
Over an average follow-up of 42 months, 62 percent of those who got thalidomide responded completely, compared to 43 percent of those getting the standard treatment, the researchers report.
However, the overall five-year survival rate was the same for both groups -- 65 percent. That's because thalidomide patients who had relapses tended to have them earlier and died after an average of 1.1 years, compared to 2.7 years for those in the other group.
"There are some fundamental issues as to why treatment with a drug like this can make cancer cells refractory [resistant] to salvage maneuvers," Barlogie said. "We have a lot of data looking at gene expression in such cases. Activity of some genes is up-rated, activity of others is down-rated."
One thing is for sure, however: The overall results of the treatment, with or without thalidomide, were "outstanding," Barlogie said. "There has never been a report showing a survival curve as good as the one published here."
And Comenzo noted that a Memorial Sloan-Kettering study reported earlier this year showed that the response of patients given thalidomide "was better than historical."
There are two possible explanations for the failure of therapy to help thalidomide patients after a relapse, he said: "Either the cells are more resistant to other medications, or the cells become more aggressive."
Still, the rebirth of thalidomide as a powerful anticancer agent gives patients new hope, Comenzo said.
"Multiple myeloma was a disease for which no new drugs had been forthcoming for decades until thalidomide came on the scene in the late 1990s," he said. "It was like a shock to see what benefits it might provide and to look at how it might work. We still don't know how it works."
For more on multiple myeloma, head to the National Cancer Institute.