Improved outcomes with “7+3” induction chemotherapy for acute myeloid leukemia over the past four decades: analysis of SWOG trial data

Abstract

We have previously shown that complete response (CR) rates and overall survival of patients with acute myeloid leukemia have improved since the 1980s. However, we have not previously evaluated how the length of first CR (CR1) has changed over this time period. To address this, we analyzed 1,247 patients aged 65 or younger randomized to "7+3" arms from five SWOG studies: S8600 (n=530), S9031 (n=98), S9333 (n=57), S0106 (n=301), and S1203 (n=261). We evaluated length of CR1 and survival after relapse from CR1 over the four decades that these studies represent. Both length of CR1 and survival after relapse from CR1 have improved over the last four decades. The relative benefit associated with CR1 and the relative detriment associated with relapse have decreased over this period; while achieving CR1 and relapse from CR1 still have strong prognostic associations with outcomes, the magnitude of the association has decreased over time. Possible explanations for these patterns include higher CR rates with salvage therapies after relapse, more frequent use of hematopoietic cell transplant, and better supportive care.