Eradication of minimal residual disease was associated with longer progression-free and overall survival in chronic lymphocytic leukemia patients on first-line chemoimmunotherapy, according to a study published in the journal Blood.
Dr. Paolo Strati and his associates studied 237 chronic lymphocytic leukemia (CLL) patients who were undergoing first-line treatment with fludarabine, cyclophosphamide, and rituximab (FCR). Bone-marrow minimal residual disease (MRD) was measured by flow cytometry in samples after the third course of treatment and 2 months after the last course. Results were categorized as either positive (greater than .01%) or negative (less than .01%), and assessment was performed on individuals who achieved complete or partial remission.
Results showed that 75% of participants received more than three courses of treatment with FCR and 25% received one to three courses. Complete remission was achieved in 65% of patients, complete remission with incomplete marrow recovery was achieved in 7%, nodular partial remission in 12%, and partial remission in 13%, reported Dr. Strati of the University of Texas MD Anderson Cancer Center, Houston, and his associates (Blood 2014 Apr. 4 [doi:10.1182/blood-2013-11-538116]).
At final assessment, 70 patients were MRD negative. MRD-negative status was achieved in 62 patients who had also achieved complete remission, 3 patients in complete remission with incomplete marrow recovery, and 5 patients in partial remission.
A multivariable analysis showed that progression-free survival was associated with MRD-negative status (hazard ratio, 0.1; 95% confidence interval, 0.01-0.8; P = .03), as was overall survival (HR, 0.6; 95% CI, 0.4-0.9; P = .02).
The improved outcomes in CLL patients on first-line chemoimmunotherapy treatment may indicate MRD-negative remission as a viable endpoint, the investigators wrote, though screening for MRD in blood versus bone marrow still needs to be studied. Early MRD eradication may be a desirable goal, prompting consideration of early discontinuation of treatment, they said.
The investigators did not disclose any conflicts of interest.