Impact of autologous hematopoietic cell transplantation on disease burden quantified by next-generation sequencing in multiple myeloma treated with quadruplet therapy

The incremental impact of autologous hematopoietic cell transplantation (AHCT) on disease burden with quadruplet induction in newly diagnosed multiple myeloma (NDDM) can be reappraised with the serial assessment of minimal residual disease (MRD). We describe the impact of AHCT on MM burden assessed by next-generation sequencing (NGS) for patients enrolled in a clinical trial utilizing quadruplet induction, AHCT, followed by MRD-adapted consolidation. We describe quantitative changes in MRD burden with AHCT and explore patient and disease features influencing the magnitude of MRD reduction with AHCT. Among 123 included patients, 109 underwent AHCT and had MRD assessment pre and post AHCT. Forty percent achieved MRD < 10⁻⁵ post-induction, increasing to 70% after AHCT. Of the 65 patients (60%) who remained MRD positive post-induction, 54 (83%) had a reduction in MRD burden with AHCT. The median reduction in MRD with AHCT was 1.10 log₁₀ (range, −1.26 to 3.41). Patients with high-risk cytogenetic abnormalities (HRCA) had greater reduction in MRD burden (p =.02) after AHCT. Median relative reduction was 0.91 log₁₀ (range, −0.75 to 2.14), 1.26 log₁₀ (range, −0.21 to 3.26) and 1.34 log₁₀ (range, −1.28 to 3.41) for patients with 0, 1 and 2+ HRCA, respectively. The presence of HRCA was the only factor associated with greater than 1 log₁₀ reduction in MRD burden with AHCT. Serial NGS MRD demonstrates the incremental effect of AHCT in MM marrow burden in the context of quadruplet induction, particularly in high-risk MM.