Early serum free light chain normalization provides complementary prognostic data in multiple myeloma
The study reports a retrospective analysis of 701 patients with newly diagnosed multiple myeloma treated at a single Chinese center. Investigators found that serum free light chain ratio normalization during the first four induction cycles occurred in 61.8% of patients, with non-normalization independently associated with inferior progression-free (HR 2.10) and overall survival (HR 1.96) after adjusting for R-ISS stage and age. This early serum response remained prognostic after adjusting for minimal residual disease status, providing incremental risk stratification beyond standard bone marrow testing. The findings support routine sFLC monitoring as a pragmatic blood-based tool for early prognosis in multiple myeloma.
The original study
Early Serum Free Light Chain Response in Newly Diagnosed Multiple Myeloma: Documented Earlier Than MRD and Complementary in Prognosis.
- Authors
- Pan Y, Wang Y, Xiong Y, Li P, Yu C, Liu P
- Journal
- Hematological oncology
- Type
- Journal Article
- PMID
- 42549699
Original abstract
Minimal residual disease (MRD) is the standard for deep response assessment in multiple myeloma but requires bone marrow sampling. Whether early serum free light chain (sFLC) response provides independent prognostic information in real-world, predominantly non-transplant patients remains unclear. We retrospectively analyzed 701 patients with newly diagnosed multiple myeloma treated at a single Chinese center (2015-2021). sFLC ratio normalization (IMWG range 0.26-1.65) during the first four induction cycles was assessed using a 4-month landmark to mitigate immortal time bias. Multivariable Cox models adjusted for R-ISS and age, with prespecified sensitivity analyses and direct comparison with established markers and MRD. Among 701 patients (median age 64 years; ASCT 12.6%), 433 (61.8%) were classified as FLC-normalized during C1-C4. FLC non-normalization was associated with inferior PFS (HR 2.10, 95% CI 1.60-2.76) and OS (HR 1.96, 95% CI 1.32-2.90) after adjustment for R-ISS stage and age. The association persisted in baseline-abnormal patients and after MRD adjustment. Adding sFLC status produced a modest improvement in model discrimination, supporting a complementary rather than stand-alone prognostic role. sFLC normalization was documented earlier than MRD negativity, a pattern that persisted in a paired-visit-restricted sensitivity analysis, although timing comparisons remain subject to retrospective assessment schedules. Early sFLC response was associated with outcomes in newly diagnosed multiple myeloma and provided complementary, incremental prognostic information beyond established risk factors and MRD. These findings support further prospective evaluation of sFLC normalization as a pragmatic blood-based marker for early risk stratification.