Is lower-intensity chemotherapy effective before stem cell transplantation?

This study investigated the effectiveness of reduced intensity conditioning (RIC) before stem cell transplantation (SCT) in acute myeloid leukemia (AML). This study concluded that in the long-term RIC was as effective as more intense myeloablative conditioning (MAC).

Allogeneic SCT (transplant of immature blood cells from a donor) is a highly effective treatment for AML. SCT can lead to long-term survival for many patients. One study reported that patients who were alive and disease-free after 2 years had an 84% chance of being alive and AML free after 10 years following MAC and SCT.

Many older or less fit patients are not able to undergo the intense MAC (chemotherapy) needed prior to transplantation. RIC uses lower doses of chemotherapy that most patients can tolerate. The long-term success of SCT after RIC is not clear.

This study examined the long-term outcomes of patients who underwent SCT after MAC or RIC. The records of 1423 AML patients were examined. 701 patients were treated with MAC. 722 patients were treated with RIC. Patients were followed for an average of 10 years.

After MAC, 31% were leukemia free after 10 years. 32% of RIC patients were leukemia free. Leukemia-free survival was significantly higher in patients older than 55 (28%) treated with RIC compared to those treated with MAC (20%). There was no significant different in graft-versus-host disease (a condition in which the donor stem cells attack healthy tissue).

10-year overall survival (time from treatment until death from any cause) was 33% after MAC and 35% after RIC. After MAC, 71% of patients who were leukemia-free after 2 years remained that way at 10 years. 73% of RIC were still leukemia free.

This study concluded that RIC was as effective as MAC before donor SCT, particularly in patients over 55.