Double stem cell transplant after HDC improves survival in multiple myeloma patients.

Compared with a single autologous stem cell transplant after high-dose chemotherapy, double transplantation improves overall survival in patients with multiple myeloma, according to a report by French researchers.

After 7 years of follow-up, the probability of event-free survival and overall survival increased 2-fold in the double-transplant group compared with the single-transplant group: 42% vs 21%, wrote Michel Attal, MD of the Hopital Purpan in Toulouse and colleagues in the December 25 issue of the New England Journal of Medicine. The benefits were greatest among patients who had not had a very good partial response to their first transplant.

Multiple myeloma is the second most common hematologic cancer after non-Hodgkin's lymphoma. In the United States alone, more than 50,000 people have the disease. About half received the diagnosis when they were younger than 60 years of age, and increasingly, myeloma is detected in persons under age 40. Its diagnosis in relatively young and otherwise healthy patients has allowed the use of aggressive and potentially more effective therapies.

"Today, myeloma is the most common indication for hematopoietic stem cell transplantation in the world, and more data support the benefit of this procedure in myeloma than in any other disease," wrote Edward Stadtmauer, MD of the Abramson Cancer Center at the University of Pennsylvania, Philadelphia in an accompanying editorial.

Double autologous transplantation regimens have been used to treat myeloma for the past decade, but their advantage over single transplantation has been unclear until now, Stadtmauer said. The current study evaluated outcome in 399 previously untreated patients under age 60. Mortality rates were similar in the 2 groups. However, longer hospitalizations and an increased risk of toxic effects occurred in patients receiving double-transplants. Nonetheless, the researchers argue the survival benefit justifies these risks-and costs.

"The morbidity and costs of double transplantation justify [its] use...in patients who do not have a very good partial response within 3 months after undergoing a single transplantation. Indeed, the 7-year survival rate among such patients was 11% after single transplantation... and 43% in the double-transplant group."

Despite the favorable results reported by Attal et al, Stadmauer cautioned that progressive myeloma develops in almost 80% of patients within 7 years of undergoing double transplantation. This sobering statistic underscores the need for additional strategies to control the disease, the researchers concluded.