Measurable residual disease is not a universally reliable surrogate for progression-free survival in clinical trials of new chronic lymphocytic leukemia therapies.

Key Points

• The aim is to evaluate whether measurable residual disease (MRD) reliably predicts progression-free survival (PFS) across different therapy approaches in chronic lymphocytic leukemia.
• Analyzed correlation between MRD results and PFS in clinical trials.
• Performed sensitivity analyses stratified by treatment approach and type of therapy.
• Focused on different sampling sources to assess their impact on MRD validity.
• MRD testing had a correlation with PFS that was context-dependent, especially in fixed-duration therapies (R = -0.80, 95% CI -0.93 to -0.53).
• Data indicates that MRD should be interpreted cautiously for clinical and regulatory decision-making based on treatment approach and type.
• Overall validity for MRD as a surrogate approached but did not meet the pre-specified threshold for certain treatment contexts.