Prognostic impact of serial measurements of serum-free light chain assay throughout the course of newly diagnosed multiple myeloma treated with bortezomib-based regimens

Abstract

We retrospectively investigated the role of serial serum-free light chain (sFLC) evaluations in 150 multiple myeloma (MM) patients treated with first-line bortezomib-based regimens. Baseline sFLC ratio (sFLCR) identified three groups of patients – normal, lightly abnormal (<100), and highly abnormal (≥100) – with different progression-free survival (PFS: 3-year estimate 72% versus 61% versus 44%, respectively, p = 0.03). Moreover, the achievement of a normal sFLCR correlated with extended PFS (49 versus 17 months, p < 0.0001) and overall survival (75 versus 43 months, p < 0.0001) as compared with abnormal sFLCR, a gain maintained in a multivariate analysis for PFS. At relapse, a high sFLCR was associated with earlier start of salvage therapy compared with sFLCR <100 (3-month probability: 89% versus 64%, p = 0.0426). In 20% of patients, sFLC escape preceded the conventional relapse by a median of 3.8 months. Our results highlight the role of sFLC assay in the prognosis and follow-up of MM.

Keywords:

• Bortezomib
• escape
• multiple myeloma
• prognosis
• serum free light chain

Acknowledgements

M. C. has received honoraria and has been a member of the advisory board for Celgene, Janssen, Millennium-Takeda, and Amgen. All other authors declare to have no relevant financial interests in competing. The work had no specific funding.

Potential conflict of interest

Disclosure forms provided by the authors are available with the full text of this article at http://dx.doi.org/10.3109/10428194.2015.1124994.