Early free light chain reduction following treatment initiation predicts favorable outcome in intact immunoglobulin myeloma

Response-Adapted Therapy for Newly Diagnosed Multiple Myeloma

PURPOSE OF REVIEW

The development of potent novel agents has improved outcomes for patients with multiple myeloma (MM). Heterogeneity of response to therapy, an expanding arsenal of treatment options, and cost are however major challenges for physicians making treatment decisions. Response-adapted therapy is hence an attractive strategy for sequencing of therapy in MM. Despite its successful application in other haematologic malignancies, response-adapted therapy is yet to become a standard of care for MM. We provide our perspective on response-adapted therapeutic strategies evaluated thus far and how they may be implemented and improved on in treatment algorithms of the future.

RECENT FINDINGS

While older studies suggested that early response based on International Myeloma Working Group response criteria could impact long-term outcomes, recent data have contradicted these findings. The advent of minimal residual disease (MRD) as a powerful prognostic factor in MM has raised the promise of MRD-adapted treatment strategies. The development of more sensitive techniques for paraprotein quantification as well as imaging modalities to detect extramedullary disease is likely to change response assessment in MM. These techniques combined with MRD assessment may provide sensitive and holistic response assessments which could be evaluated in clinical trials. Response-adapted treatment algorithms have the potential to allow an individualised treatment strategy, maximising efficacy, while minimising toxicities and cost. Standardisation of MRD methodology, incorporation of imaging into response assessment, and the optimal management of MRD positive patients are key questions to be addressed in future trials.

Clinical implication by differential analytical performances of serum free light chain quantitation analysis using fully automated analyzers

OBJECTIVES

Free light chain (FLC) is used for the diagnosis and prediction with regard to the progression risk of plasma cell disorders and Freelite reagent using the SPAplus analyzer (The Binding Site) has been one of the widely used option. However, N Latex FLC reagent with the Atellica CH 930 analyzer (Siemens Healthineers) has shown the advantages of automation and high throughput. We aimed to evaluated clinical implication by differential analytical performances of two assays.

METHODS

A total of 322 serum samples were collected from 193 patients requested for FLC analysis including 131 multiple myeloma patients. The precision, linearity, dilution recovery of N Latex FLC assay was evaluated. We compared the two assays and analyzed the monomer-dimer pattern for discrepant results.

RESULTS

The precision, linearity, and dilution recovery performance was appropriate for the routine use in clinical laboratories. Despite the good correlation within normal range, proportional bias up-to 170% was observed in samples with high concentrations especially for lambda. The higher value samples with N Latex FLC assay contained more monomer forms than controls. All opposite changes of FLC burden by the N Latex FLC assay proved to present concordant dynamic changes when assessed by serum protein electrophoresis.

CONCLUSIONS

Clinical laboratories should be aware of the inter-assay variability of FLC quantitative measurements using different platforms, especially for high concentrations of both kappa and lambda measurements, possibly due to monomer/dimer ratio diversity. Clinical interpretations for multiple myeloma disease status might not be dramatically affected only when the same assay is utilized during follow-up periods.

Intensity of cyclophosphamide-based bridging therapy before CAR-T therapy in myeloma

INTRODUCTION

Patients receiving autologous chimeric antigen receptor T-cell (CAR-T) therapies for multiple myeloma (MM) may require bridging therapy (BT) before CAR-T infusion to maintain some level of disease control. Alkylators such as cyclophosphamide (Cy) are often used as parts of BT regimens, either in high-intensity regimens such as modified hyperCVAD or once-weekly regimens such as KCd. However, there is no consensus around the optimal BT alkylator dose intensity in MM.

METHODS

We performed a single-center analysis of all instances of BT before planned autologous CAR-T for MM during a 5-year period ending April 2022. We classified bridging regimens into three cohorts: (1) hyperfractionated Cy (HyperCy) with inpatient Cy every 12-24 hours or as continuous intravenous infusions, (2) less intensive Cy dosing (WeeklyCy) such as KPd or KCd, and (3) NonCy, where no alkylators were used in BT. Demographic, disease-related, and treatment-related characteristics were collected for all patients. The three BT cohorts were compared using Fisher's exact tests, Kruskal-Wallis tests, and log-rank tests where appropriate.

RESULTS

We identified 70 discrete BT instances among 64 unique patients: 29 (41%) with HyperCy, 23 (33%) with WeeklyCy, and 18 (26%) with NonCy. Median total levels of Cy dosing during BT were 2100 mg/m², 615 mg/m², and 0 mg/m² respectively. Age, number of prior lines, triple-class refractory status, presence of high-risk cytogenetics, extramedullary disease, bone marrow plasma cell burden, involved free light chain (iFLC) kinetics before collection, and other measures of disease aggressiveness were comparable between cohorts. iFLC levels rose ≥25% and ≥100 mg/L during BT (approximating progressive disease) in comparable proportions (p=0.25) between cohorts: 52% HyperCy, 39% WeeklyCy, and 28% NonCy. All BT instances without subsequent CAR-T were due to manufacturing failures. Among 61 instances of bridging followed by CAR-T, vein-to-vein times were slightly longer (p = 0.03) with HyperCy (45 days) vs WeeklyCy (39 days) and NonCy (46.5 days). Neutrophil recovery timeframes were similar between cohorts, but platelet recovery took longer with HyperCy (64 days) vs WeeklyCy (42 days) and NonCy (12 days). PFS was comparable between cohorts, but median OS was not: 15.3 months with HyperCy versus 30.0 months with WeeklyCy and not reached with NonCy.

DISCUSSION

In our retrospective analysis of BT before CAR-T therapy in MM, HyperCy did not result in superior disease control than WeeklyCy despite a threefold higher dose of Cy. In contrast, HyperCy was associated with longer post-CAR-T platelet recovery and worsened OS despite comparable measurements of disease aggressiveness and tumor burden. Study limitations include our small sample size as well as confounding from gestalt markers of MM aggressiveness that might have led both to poorer outcomes as well as physicians' decisions to prescribe HyperCy. Given the rarity of objective disease responses to chemotherapy in relapsed/refractory MM, our analysis suggests that hyperfractionated Cy regimens do not outperform once-weekly Cy regimens for most patients who require BT before CAR-T therapy.

Combined Immune Defect in B-Cell Lymphoproliferative Disorders Is Associated with Severe Infection and Cancer Progression

B cell chronic lymphoproliferative diseases (B-CLPD) are associated with secondary antibody deficiency and other innate and adaptive immune defects, whose impact on infectious risk has not been systematically addressed. We performed an immunological analysis of a cohort of 83 B-CLPD patients with recurrent and/or severe infections to ascertain the clinical relevance of the immune deficiency expression. B-cell defects were present in all patients. Patients with combined immune defect had a 3.69-fold higher risk for severe infection (p = 0.001) than those with predominantly antibody defect. Interestingly, by Kaplan–Meier analysis, combined immune defect showed an earlier progression of cancer with a hazard ratio of 3.21, than predominantly antibody defect (p = 0.005). When B-CLPD were classified in low-degree, high-degree, and plasma cell dyscrasias, risk of severe disease and cancer progression significantly diverged in combined immune defect, compared with predominantly antibody defect (p = 0.001). Remarkably, an underlying primary immunodeficiency (PID) was suspected in 12 patients (14%), due to prior history of infections, autoimmune and granulomatous conditions, atypical or variegated course and compatible biological data. This first proposed SID classification might have relevant clinical implications, in terms of predicting severe infections and cancer progression, and might be applied to different B-CLPD entities.