Next-Generation Sequencing Clonality Assays: Clinical Validation for Minimal Residual Disease Monitoring in Multiple Myeloma.

Minimal residual disease (MRD) detection is crucial for managing lymphoid malignancies. This study introduces OriMIRACLE LTM, a novel next-generation sequencing (NGS)-based B-cell receptor (BCR) and T-cell receptor (TCR) clonality assay for MRD detection. We validated the assay using cell lines and clinical samples, including residual smears, from patients with Multiple Myeloma (MM). The BCR/TCR clonality assay demonstrated an over 90% positive detection rate in lymphoid malignancies. Validation studies in MM patients demonstrated an 81.36% (48/59) concordance rate between multicolor flow cytometry (MFC) and clinical response assessment in tumor cell detection. Notably, 61.11% (11/18) of MM patients positive for MRD by both NGS and MFC experienced disease progression or relapse. Patients with MRD detected solely by NGS exhibited lower clinical complete response rates, and some initially responsive MM patients relapsed after treatment cessation. These findings indicate that this NGS-based assay offers highly sensitive and specific MRD detection in lymphoid malignancies, even in MM patient-derived residual smear samples. It demonstrates advantages over MFC and proves valuable for MRD tracking. In conclusion, current evidence supports NGS as a complementary tool to MFC, particularly in MFC⁻/NGS⁺ patients, as NGS offers deeper risk stratification. However, the optimal intervention threshold remains to be determined by prospective studies.