The presence of minimal residual disease provided powerful prognostic information independent of other risk factors. This according to reverse-transcriptase quantitative polymerase-chain-reaction assays to detect minimal residual disease in 2,569 samples obtained from 346 patients with NPM1-mutated AML who had undergone intensive treatment. Researchers found:

• Persistence of NPM1-mutated transcripts in blood was present in 15% of the patients after the second chemotherapy cycle and was associated with a greater risk of relapse after 3 years of follow-up than was an absence of such transcripts (82% vs. 30%, respectively) and a lower rate of survival (24% vs. 75%, respectively).

• Presence of minimal residual disease was the only independent prognostic factor for death in multivariate analysis (HR=4.84).

• On sequential monitoring of minimal residual disease, relapse was reliably predicted by a rising level of NPM1-mutated transcripts.

• Although mutations associated with preleukemic clones remained detectable during ongoing remission after chemotherapy, NPM1 mutations were detected in 69 of 70 patients at the time of relapse and provided a better marker of disease status.

Citation: Ivey A, Hills RK, Simpson MA, et al. Assessment of minimal residual disease in standard-risk AML. [Published online ahead of print January 20, 2016]. NEJM. doi: 10.1056/NEJMoa1507471.