Assessment of minimal residual disease (MRD) improves the prediction of progression-free survival benefit in patients with chronic lymphocytic leukemia (CLL) who achieve either a complete response or a partial response (PR), according to a study published in the Journal of Clinical Oncology.1
For the study, investigators analyzed progression-free and overall survival data from 554 patients included in 2 clinical trials of the German CLL Study Group. In 1 study, patients were randomly assigned to receive fludarabine plus cyclophosphamide with or without rituximab, and in the other study, patients were treated with fludarabine and cyclophosphamide plus rituximab or bendamustine plus rituximab.
Results showed that patients with MRD-negative complete remission (CR), MRD-negative PR, MRD-positive CR, and MRD-positive PR experienced a median progression-free survival from a landmark at the end of treatment of 61 months, 54 months, 35 months, and 21 months, respectively.
Researchers found no significant difference in progression-free survival between MRD-negative CR and MRD-negative PR, but progression-free survival was significantly longer for MRD-negative PR than for MRD-positive CR (P =.048) and for MRD-positive CR compared with MRD-positive PR (P =.002).
The study further demonstrated that there was no significant difference on overall survival between MRD-negative CR and MRD-negative PR or MRD-positive CR; however, patients with MRD-positive PR had a significantly shorter overall survival than those with MRD-negative CR (P =.001).
In addition, persisting splenomegaly does not affect outcome in patients with MRD-negative PR while residual lymphadenopathy does.
The finding ultimately support the use of MRD assessments in conjunction with the evaluation of clinical response in patients with CLL who response to chemotherapy with or without immunotherapy.
1. Kovacs G, Robrecht S, Fink AM, et al. Minimal residual disease assessment improves prediction of outcome in patients with chronic lymphocytic leukemia (CLL) who achieve partial response: Comprehensive analysis of two phase III studies of the German CLL Study Group. J Clin Oncol. 2016 Aug 29. doi: 10.1200/JCO.2016.67.1305. [Epub ahead of print]