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

OBJECTIVES

Limited research is currently available regarding the prognostic value of Fc receptor-like 5 (FCRL5) in newly diagnosed multiple myeloma (NDMM). This study aimed to investigate the association of FCRL5 expression with treatment response and survival outcomes in NDMM patients, with a goal of providing insights for early risk stratification.

METHODS

We retrospectively analyzed a cohort comprising 54 NDMM patients treated between January 2024 and January 2025 at a single center. Pretreatment FCRL5 expression was quantified by flow cytometry, and the median value (75.15%) was utilized to stratify patients into two groups: high expression group and low expression group for comparison of baseline characteristics, treatment response, and survival outcomes.

RESULTS

Baseline characteristics, including age and disease stage, were balanced between the two FCRL5 expression groups, with all P-values > 0.05. After four induction cycles, the group with high FCRL5 expression showed substantially lower rates of complete response (25.93% vs. 51.85%), ≥very good partial response (33.33% vs. 70.37%), and minimal residual disease negativity (29.63% vs. 70.37%) (P < 0.05 for all). At 10.3-month median follow-up, the median progression-free survival (PFS) (10.6 months in contrast to not reached, P = 0.002) and overall survival (OS) (13.2 months as opposed to not reached, P = 0.02), as well as 1-year PFS rate (21.43% vs. 76.47%, P = 0.004) were markedly shorter. Multivariate regression analysis confirmed high FCRL5 expression as an independent adverse prognostic factor for both PFS (HR 7.32, 95% CI 1.86 - 28.74, P = 0.004) and OS (HR 9.82, 95% CI 1.01 - 95.10, P = 0.049).

CONCLUSION

High FCRL5 expression was significantly associated with inferior response depth and survival in NDMM. Our findings suggested that FCRL5 may serve as a valuable biomarker for risk stratification, though further prospective validation is required.