Utility of serum free light chain ratio in response definition in patients with multiple myeloma

The role of serum-free light chain ratios in the prediction of poor prognosis in multiple myeloma patients: a systematic review and meta-analysis

BACKGROUND

The association between the serum free light chain (sFLC) ratio and the prognosis of multiple myeloma (MM) patients is controversial.

AIM

The purpose of this study is to explore the relationship between the sFLC ratio and the prognosis of MM patients through meta-analysis.

METHODS

Online public databases were searched to find relevant studies. The retrieval time is limited from the establishment of the database to July 2021. The overall survival (OS) and progression-free survival (PFS) rates were compared. The results were described using hazard ratio (HR) and a 95% confidence interval (CI). Qualitative studies were also included.

RESULTS

A total of 9 studies involving 2864 participants were included. A pooled analysis based on four studies including newly-diagnosed MM patients, demonstrated that an abnormal sFLC ratio was associated with poor outcomes of OS (HR = 1.82, 95% CI: 1.15-2.90) and PFS (HR = 1.87, 95% CI: 1.20-2.90). Three qualitative studies showed that an abnormal sFLC ratio was related with poor outcomes of OS (studies all included newly diagnosed MM patients) and PFS (two studies included newly-diagnosed MM patients and one study included non-newly-diagnosed MM patients). Two studies stated that the sFLC ratio is not associated with OS (both studies included non-newly-diagnosed MM patients) and one study reported that the sFLC ratio is not associated with PFS (study included non-newly-diagnosed MM patients).

CONCLUSION

sFLC ratio could be used to predict adverse outcomes in newly-diagnosed MM patients, but is not suitable for non-newly-diagnosed MM patients.

Role of serum-free light chain assay for defining response and progression in immunoglobulin secretory multiple myeloma

The International Myeloma Working Group (IMWG) guidelines recommend using electrophoresis and immunofixation to define response and progressive disease (PD) in immunoglobulin (Ig) secretory multiple myeloma (Ig-MM), whereas the role of serum-free light chain (sFLC) is controversial. We retrospectively analyzed the value of adding sFLC assays in the definition of response and PD according to IMWG criteria in 339 Ig-MM patients treated with a first-line novel agent-based therapy (median follow-up 54 months). sFLC PD was defined according to conventional criteria plus increased sFLC levels, or sFLC escape (sFLCe); progression/sFLCe-free survival (ePFS) was the time from the start of treatment to the date of first PD or sFLCe, or death; overall survival after PD/sFLCe (OS after Pe) was the time from first PD or sFLCe to the date of death. 148 (44%) patients achieved a complete response and 198 (60%) a normal sFLC ratio (sFLCR). sFLCR normalization was an independent prognostic factor for extended PFS (HR = 0.46, p = 0.001) and OS (HR = 0.47, p = 0.006) by multivariable analysis. 175 (52%) patients experienced PD according to the IMWG criteria, whereas 180 (53%) experienced PD or sFLCe. Overall, a sFLCe was observed in 31 (9%) patients. Median PFS and ePFS were both equal to 36 (95% CI = 32-42, and 32-40, respectively) months. sFLC PD adversely affected the OS after Pe compared to PD with increasing monoclonal Ig only (HR = 0.52, p = 0.012). Our results support the inclusion of the sFLC assay for defining response and PD in Ig-MM.

Serum Free Light-Chain Ratio at Diagnosis Is Associated with Early Renal Damage in Multiple Myeloma: A Case Series Real-World Study

The serum free light-chain (FLC) ratio is a sensitive tool for the differential diagnosis of plasma cell disorders and is biomarker of multiple myeloma (MM) progression from premalignant conditions. Here, we investigate the potential role of FLC ratio at diagnosis in identifying early renal damage in MM patients and other correlations with clinical, laboratory, and molecular findings. A total of 34 MM patients who had undergone autologous stem cell transplantation were included in this retrospective case series study, and FLC quantification was performed with nephelometric assays. In our study, sFLC ratio was significantly associated with light-chain MM and β-2 microglobulin levels, likely indicating a high disease burden at diagnosis, especially in patients without heavy chain M-protein at serum electrophoresis. Moreover, the sFLC ratio was inversely correlated with glomerular filtration rate, possibly identifying early renal damage in MM patients. Our preliminary results confirm the importance of early sFLC evaluation, especially in patients with the light-chain MM type and low disease burden, to minimize the risk of late renal failure.

Prognostic Impact of Serum Free Light Chain Ratio Normalization in Patients with Multiple Myeloma Treated within the GMMG-MM5 Trial

Simple Summary

For multiple myeloma (MM) patients with measurable disease, there is no recommendation to monitor serum free light chains during therapy. However, this could provide important information in terms of prognosis. We investigated the prognostic impact of serum free light chain ratio (FLCr) normalization in 590 patients with secretory MM during first-line treatment within the German-Speaking Myeloma Multicenter Group MM5 trial. We are able to show that there is an increasing percentage of patients who achieve FLCr normalization during therapy. Importantly, we demonstrate that FLCr normalization at any time before the start of maintenance is significantly associated with prolonged progression-free and overall survival in multivariable time-dependent Cox regression analyses. This suggests that FLCr normalization during therapy is an important and simple way to assess prognostic factor in MM and supports the serial measurement of serum free light chains during therapy, even in patients with secretory MM.

Abstract

We investigated the prognostic impact of time-dependent serum free light chain ratio (FLCr) normalization in 590 patients with secretory multiple myeloma (MM) during first-line treatment within the German-Speaking Myeloma Multicenter Group MM5 trial. Serum free light chains (sFLC) were assessed by the Freelite test at baseline, after induction, mobilization, autologous blood stem cell transplantation, consolidation and every three months during maintenance or follow up within two years after the start of maintenance. The proportion of patients with a normal or normalized FLCr increased from 3.6% at baseline to 23.2% after induction and 64.7% after consolidation. The achievement of FLCr normalization at any one time before the start of maintenance was associated with significantly prolonged progression-free survival (PFS) (p < 0.01, hazard ratio (HR) = 0.61, 95% confidence interval (95% CI) = 0.47–0.79) and overall survival (OS) (p = 0.02, HR = 0.67, 95% CI = 0.48–0.93) in multivariable time-dependent Cox regression analyses. Furthermore, reaching immune reconstitution, defined as the normalization of uninvolved immunoglobulins, before maintenance was associated with superior PFS (p = 0.04, HR = 0.77, 95% CI = 0.60–0.99) and OS (p = 0.01, HR = 0.59, 95% CI = 0.41–0.86). We conclude that FLCr normalization during therapy is an important favorable prognostic factor in MM. Therefore, we recommend serial measurements of sFLC during therapy until achieving FLCr normalization, even in patients with secretory MM.

Free Immunoglobulin Light Chains in Patients with Tick-Borne Encephalitis: Before and after Treatment

Background: Tick-borne encephalitis (TBE) is inflammation of the central nervous system (CNS) caused by a viral infection which may be associated with increased synthesis of immunoglobulins. It can lead to inter alia, breakdown of the blood-brain barrier (BBB), or even death and, unfortunately, treatment is only symptomatic. Therefore, the aim of the present study was assessment of the concentrations of free light chains (FLC) kappa (κ) and lambda (λ in the cerebrospinal fluid (CSF) and serum of patients with TBE. Methods: A total of 58 cerebrospinal fluid and serum sample pairs were analyzed. Samples were collected from patients with TBE before and after treatment. FLC were measured using the turbidimetric method. The values of κIgG-index, λIgG-index, κFLC-index and λFLC-index were calculated using relevant formulas. Results: Pre-treatment serum λFLC concentrations were higher in comparison to post-treatment levels. Moreover, it was observed that CSF λFLC, TBEV IgM, TBEV IgG, and serum TBEV IgG, as well as the values of λFLC-index, κFLC-index, and λIgG-index were elevated after treatment. In the total study group, the concentrations of CSF κFLC and λFLC, and values of four indexes: κFLC-index, λFLC-index, κIgG-index, and λIgG-index correlated with each other and with CSF TBEV IgM and IgG antibodies. The CSF level of TBEV IgG was also associated with serum IgG TBEV and CSF IgM TBEV antibodies. Additionally, serum κFLC correlated with serum and CSF λFLC. Conclusion: This is the first study that demonstrates statistically significant differences in serum and CSF λFLC, as well as in the calculated values of three algorithms: λIgG-index, κFLC-index, and λIgG-index prior to and following treatment of TBE. Our findings may indicate that these differences reflect the intrathecal synthesis of immunoglobulins and increased permeability of BBB in patients with TBE. Moreover, it could provide the basis for developing new therapeutic strategies.

A comparison of the efficacy and safety of ixazomib and lenalidomide combined with dexamethasone in the treatment of multiple myeloma

OBJECTIVE

To explore the efficacy and safety of ixazomib and lenalidomide combined with dexamethasone (DXMS) in the treatment of multiple myeloma (MM).

METHODS

A total of 80 patients with newly diagnosed MM were randomly divided into the ID group (ixazomib + DXMS, n=40) and the RD group (lenalidomide + DXMS, n=40). All patients were given DXMS orally on the 1st, 8th, 15th, and 22nd day of the treatment cycle (20 mg each time). The patients in the ID group also received 4 mg of ixazomib citrate capsules orally on the 1st, 8th, and 15th day of the treatment cycle, whereas those in the RD group received 25 mg of lenalidomide capsules orally from the 1st to the 21st day of the treatment cycle continuously. The primary outcome measure was progression-free survival (PFS) within 5 years, and the secondary outcome measures were overall survival (OS), overall response rate (ORR), quality of life, and safety.

RESULTS

The median PFS and median OS in the ID group were similar to those in the RD group (30.03 and 50.21 months vs. 25.04 and 46.33 months, both P>0.05). The ID group had higher complete remission rate (13 cases vs. 5 cases, P<0.05), but similar ORR compared with the RD group (90.00% vs. 82.50%, P>0.05). After treatment, the pain intensity assessed by Numeric Rating Scale and the functional impairment measured by Karnofsky Performance Status Scale of the two groups were both relieved (both P<0.001), and no intergroup differences in these two markers were observed (both P>0.05). The incidence of grade 1-2 peripheral neuropathy in the ID group was higher than that in the RD group (30.00% vs. 20.00%, P=0.032). There were no differences in other adverse reactions between the two groups (all P>0.05).

CONCLUSION

Compared with the combination of lenalidomide and DXMS, ixazomib combined with DXMS can achieve higher complete remission rate and more improved PFS and OS in patients with newly diagnosed MM, which is a safe and effective method.

Measurable residual disease in multiple myeloma: ready for clinical practice?

The landscape of multiple myeloma (MM) has changed considerably in the past two decades regarding new treatments, insight into disease biology and innovation in the techniques available to assess measurable residual disease (MRD) as the most accurate method to evaluate treatment efficacy. The sensitivity and standardization achieved by these techniques together with unprecedented rates of complete remission (CR) induced by new regimens, raised enormous interest in MRD as a surrogate biomarker of patients' outcome and endpoint in clinical trials. By contrast, there is reluctance and general lack of consensus on how to use MRD outside clinical trials. Here, we discuss critical aspects related with the implementation of MRD in clinical practice.