Experts Debate Thalidomide's Promise Against Myeloma
Two studies show a benefit, but offer conflicting results on patient survival
FRIDAY, March 10, 2006 (HealthDay News) -- The once-banned drug thalidomide appears to improve treatment for patients battling the blood cancer multiple myeloma, a new study shows, but the jury is still out on its impact on their long-term survival.
An Italian team at the University of Turin added thalidomide to standard therapy (melphalan plus prednisone) for newly diagnosed cases of the blood cancer in older patients.
Writing in the March 11 issue of The Lancet, they report a 76 percent treatment response rate for the 129 patients who got thalidomide compared to a 47.6 percent response rate for the 126 participants who did not get the drug.
Patients who got thalidomide also boosted their chance of event-free survival over two years -- 54 percent for those who got thalidomide vs. 27 percent for those who did not.
However, that finding is at odds with the result of an American trial reported in Thursday's New England Journal of Medicine. While both studies found that thalidomide provided short-term therapeutic benefit, the University of Arkansas study found that patients taking the drug had more adverse effects than patients not on the therapy, eliminating any benefit in terms of added survival.
The Italian researchers agree that more study is needed to sort this out. "Longer follow-up is needed to assess effect on overall survival," they wrote.
According to the Leukemia and Lymphoma Society, more than 15,000 Americans are diagnosed with multiple myeloma annually. The disease affects white blood cells (plasma cells). 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.
While everyone is encouraged by thalidomide's success over the short-term, the discordant results of the two studies regarding patient survival is a puzzle, noted Dr. Shaji Kumar, professor of hematology at the Mayo Clinic. His accompanying editorial in the journal hailed the Italian findings as a "historic moment in myeloma therapy."
But Kumar also noted that the two studies involved entirely different types of patients, which could explain the different results.
The American study, done at the University of Arkansas for Medical Sciences, involved giving thalidomide to myeloma patients who had undergone bone marrow transplants to replace diseased cancer cells, Kumar said. On the other hand, the Italian study included newly diagnosed patients who were not candidates for transplants for one reason or another.
For those patients, Kumar said, "[by] adding thalidomide to the age-old treatment, we are really seeing a dramatic improvement in terms of overall response."
As well, a recently published French study did show better overall survival for myeloma patients given thalidomide, he said.
Still, it's not clear which multiple myeloma patients should get thalidomide and at what time, said Kumar and Dr. George Somlo, director of the multiple myeloma program at the City of Hope Cancer Center in Duarte, Calif.
"We have a clinical trial in which we are prescribing thalidomide at the end of transplant," Somlo said. "The results are still preliminary. A previous study at this institute, in which thalidomide was used as maintenance therapy, gave encouraging results."
The Italian study shows that "upfront use has benefits in older patients," Somlo said. The Arkansas study, he added, "suggests that maintenance therapy, before or after transplant, has benefits. My personal bias is that it is useful either as upfront therapy or as maintenance therapy. I would be cautious in prescribing it during the transplant process."
In Kumar's view, thalidomide might help "patients who are not going on to transplant, especially elderly patients, and also younger patients who are not able to go to transplant." Its value after transplant remains less clear, he added. "We still don't know the value of adding thalidomide at that point," he said.
Thalidomide is just one of several drugs that are revolutionizing the treatment of myeloma, Kumar said.
"We have more options now, but we still don't know how these new medications change overall survival," he said.
For more on multiple myeloma, head to the National Cancer Institute.