Chantiya Chanswangphuwana, Wasithep Limvorapitak, Sirorat Kobbuaklee, Patsita Kansuwan, Kitsada Wudhikarn, Ponlapat Rojnuckarin, Weerapat Owattanapanich, Thanawat Rattanathammethee, Adisak Tantiworawit, Panachai Silpsamrit, Kannadit Prayongratana, Thanakrit Piyajaroenkij, Dusit Jit-Ueakul, Chantana Polprasert
MRD positivity at 3 months post-treatment strongly predicted relapse, supporting its use to guide therapeutic modifications of B-ALL. Apart from NGS-based IGH clonality assays, 10-color flow cytometry offers an alternative in resource-limited settings.
AIMS: Measurable residual disease (MRD) is a key prognostic marker for patient survival. This study evaluated concordance between 10-color flow cytometry and next-generation sequencing (NGS)-based immunoglobulin heavy chain (IGH) gene assays for MRD detection and to assess prognostic significance in adult B-cell acute lymphoblastic leukemia (B-ALL).
METHODS: This multicenter prospective study enrolled 51 patients with newly diagnosed B-ALL. Bone marrow samples were obtained at diagnosis, post-induction (1 month), and post-early consolidation (3 months). Flow cytometry and NGS-IGH were performed at three timepoints to assess MRD B-ALL.
RESULTS: Patients were classified as high risk according to white blood cell count and cytogenetic features in 37.3% and 64.7% of patients, respectively. Treatment protocols included pediatric-inspired regimens (41.2%), adult-ALL protocols (52.9%), and low-intensity chemotherapy. All 16 Philadelphia chromosome-positive patients received tyrosine kinase inhibitors. Twenty patients underwent allogeneic hematopoietic cell transplantation (HCT) in first complete remission (CR). Median relapse-free survival (RFS) and overall survival were 19 and 39 months, respectively. MRD negativity at 3 months by either method correlated with significantly superior RFS. Allogeneic HCT also conferred RFS benefit. MRD positive patients without HCT had the worst RFS. Flow cytometry MRD positivity at 3 months independently predicted inferior RFS (HR 3.81; 95% CI 1.01-14.43). The overall concordance between flow cytometry and NGS was 80.7%.
CONCLUSION: MRD positivity at 3 months post-treatment strongly predicted relapse, supporting its use to guide therapeutic modifications of B-ALL. Apart from NGS-based IGH clonality assays, 10-color flow cytometry offers an alternative in resource-limited settings.