MRD measured via MFC in BMAs is marginally associated with relapse risk after allo-HCT and augmented when adding recipient chimerism data. (A) The proportion of MRD cells identified via MFC in BMA-derived total white cells within the first 540 days after allo-HCT, excluding time points at which relapsed disease was already present and/or time points that self-fulfilled the relapse prophecy (see “Methods”). (B) Probability (cumulative incidence) of relapse with follow-up in a 5-year window (1825 days) post-allo-HCT for MRD status (via MFC). (C) Comparison of MRD levels (via MFC) vs ultrasensitive recipient chimerism measurements in BMAs. P values (D) and HRs (E) from the Cox proportional hazard regression (unadjusted and adjusted for confounding covariates) with the combination of MRD and chimerism levels as a time-dependent covariate, computed over a range of thresholds of chimerism proportions incrementally increasing between 1.0e–5 and 0.5. The comparison of the categories MRD positive and chimerism above threshold vs MRD negative and chimerism below threshold is represented. (F) Probability (cumulative incidence) of relapse with follow-up in a 5-year window (1825 days) after allo-HCT for combination of MRD and chimerism status. Ticks represent individuals who were censored using the interval censoring approach. A generalized additive model was used to smooth fit the P values (blue line), which were truncated when HRs gave infinite CIs; the HR gray ribbon represents the 95% CI; thresh, threshold; Chim, chimerism proportion (recipient); n.max, the maximum number of patients at risk; Not-Det, not detected; adj, adjusted; pos, positive; neg, negative.