High FCRL5 expression predicts poor treatment response and survival in newly diagnosed multiple myeloma: a retrospective study

To investigate the association of FCRL5 expression with treatment response and survival outcomes in newly diagnosed multiple myeloma (NDMM) patients.

Study Design: Retrospective analysis of 54 NDMM patients treated at a single center from January 2024 to January 2025.
FCRL5 Measurement: Pretreatment FCRL5 expression was quantified by flow cytometry, with a median value of 75.15% used for patient stratification.
Outcome Assessment: Comparison of baseline characteristics, treatment response, and survival outcomes between high and low FCRL5 expression groups.

High FCRL5 expression correlated with lower rates of complete response (25.93% vs. 51.85%) and ≥very good partial response (33.33% vs. 70.37%).
Median progression-free survival (PFS) was significantly shorter in the high FCRL5 group (10.6 months vs. not reached, P = 0.002).
Overall survival (OS) was also shorter in the high FCRL5 group (13.2 months vs. not reached, P = 0.02).
High FCRL5 expression was confirmed as an independent adverse prognostic factor for both PFS (HR 7.32, P = 0.004) and OS (HR 9.82, P = 0.049).
The 1-year PFS rate was significantly lower in the high FCRL5 group (21.43% vs. 76.47%, P = 0.004).

The study is retrospective and conducted at a single center, which may limit generalizability.
Functional or immune landscape analyses were not included, preventing establishment of a direct causal link between FCRL5 and treatment failure.

Further prospective validation of FCRL5 as a prognostic biomarker in NDMM is required.