Online high-efficiency haemodiafiltration achieves higher serum free light chain removal than high-flux haemodialysis in multiple myeloma patients: preliminary quantitative study

High-cutoff hemodialysis in multiple myeloma patients with acute kidney injury

Multiple myeloma (MM), an incurable hematological malignancy with clonal proliferation of plasma cells, is mainly characterized by excessive production of monoclonal immunoglobulins and free light chains (FLCs). Kidney injury is one of the main clinical manifestations and is also a significant predictor of the prognosis of symptomatic MM patients, especially those who require dialysis-supported treatment. Overproduction of FLCs is the trigger for kidney injury, as they can induce the transcription of inflammatory and profibrotic cytokines in the proximal tubule and bind to Tamm-Horsfall protein in the distal tubules to form casts that obstruct the tubules, leading to kidney injury and even renal fibrosis. In addition to traditional antimyeloma treatment, high-cutoff hemodialysis (HCO-HD), which can effectively remove FLCs in vitro, has attracted much attention in recent years. Due to its greater membrane pore size, it has significant advantages in removing larger molecules and can be applied in rhabdomyolysis, sepsis, and even myeloma cast nephropathy. However, mounting questions have recently been raised regarding whether HCO-HD can truly provide clinical benefits in MM patients with acute kidney injury (AKI). Therefore, in this study, we discussed the pathological causes of AKI secondary to MM and summarized the current situation of HCO-HD in MM patients compared with other available extracorporeal techniques. In addition, pivotal clinical trials that reflect the ability of the clearance of FLCs and the side effects of HCO-HD are highlighted, and the relevant protocol of HCO-HD is also provided to assist clinicians in decision-making.

Light Chain Cast Nephropathy in Multiple Myeloma: Prevalence, Impact and Management Challenges

“Cast nephropathy” (CN) is a pathological feature of myeloma kidney, also seen to a lesser extent in the context of severe nephrotic syndrome from non-haematological diseases. The name relates to obstruction of distal tubules by “casts” of luminal proteins concentrated by intensive water reabsorption resulting from dehydration or high-dose diuretics. Filtered proteins form complexes with endogenous tubular Tamm-Horsfall glycoprotein. The resulting gel further slows or stops luminal flow upon complete obstruction of distal convoluted tubules and collecting ducts. Thus, a tubular obstructive form of acute kidney injury (AKI) is a common consequence of CN. The pathogenesis of CN will be reviewed in light of recent advances in the understanding of monoclonal disorders of B lymphocytes, leading to the release of immunoglobulin components (free light chains, FLC) into the bloodstream and their filtration across the glomerular basement membrane. Treatment aiming at reduction of the circulating burden of FLC may help recovery of renal function in a fraction of these patients, besides filling the void between the onset of AKI, histopathological diagnosis, and full response to pharmacologic treatment.

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Why and how high volume hemodiafiltration may reduce cardiovascular mortality in stage 5 chronic kidney disease dialysis patients? A comprehensive literature review on mechanisms involved

Online hemodiafiltration (HDF) is an established renal replacement modality for patients with end stage chronic kidney disease that is now gaining rapid clinical acceptance worldwide. Currently, there is a growing body of evidence indicating that treatment with HDF is associated with better outcomes and reduced cardiovascular mortality for dialysis patients. In this comprehensive review, we provide an update on the potential mechanisms which may improve survival in HDF treated patients. The strongest evidence is for better hemodynamic stability and reduced endothelial dysfunction associated with HDF treatments. Clinically, this is marked by a reduced incidence of intradialytic hypotensive episodes, with a better hemodynamic response to ultrafiltration, mediated by an increase in total peripheral vascular resistance and extra-vascular fluid recruitment, most likely driven by the negative thermal balance associated with online HDF therapy. In addition, endothelial function appears to be improved due to a combination of a reduction of the inflammatory and oxidative stress complex syndrome and exposure to circulating cardiovascular uremic toxins. Reports of reversed cardiovascular remodeling effects with HDF may be confounded by volume and blood pressure management, which are strongly linked to center clinical practices. Currently, treatment with HDF appears to improve the survival of dialysis patients predominantly due to a reduction in their cardiovascular burden, and this reduction is linked to the sessional convection volume exchanged.

Acute Kidney Injury in Monoclonal Gammopathies

Monoclonal gammopathies (MG) encompass a variety of disorders related to clonal expansion and/or malignant transformation of B lymphocytes. Deposition of free immunoglobulin (Ig) components (light or heavy chains, LC/HC) within the kidney during MG may result over time in multiple types and degrees of injury, including acute kidney injury (AKI). AKI is generally a consequence of tubular obstruction by luminal aggregates of LC, a pattern known as “cast nephropathy”. Monoclonal Ig LC can also be found as intracellular crystals in glomerular podocytes or proximal tubular cells. Proliferative glomerulonephritis with monoclonal Ig deposits is another, less frequent form of kidney injury with a sizable impact on renal function. Hypercalcemia (in turn related to bone reabsorption triggered by proliferating plasmacytoid B cells) may lead to AKI via functional mechanisms. Pharmacologic treatment of MG may also result in additional renal injury due to local toxicity or the tumor lysis syndrome. The present review focuses on AKI complicating MG, evaluating predictors, risk factors, mechanisms of damage, prognosis, and options for treatment.

Renal replacement therapy in cancer patients with acute kidney injury (Review)

Cancer patients are at high risk for developing acute kidney injury (AKI), which is associated with increased morbidity and mortality in these patients. Despite the progress made in understanding the pathogenic mechanisms and etiology of AKI in these patients, the main prevention consists of avoiding medication and nephrotoxic agents such as non-steroidal anti-inflammatory drugs, contrast agents used in medical imaging and modulation of chemotherapy regimens; when prophylactic measures are overcome and renal impairment becomes unresponsive to treatment, renal replacement therapy (RRT) is required. There are several methods of RRT that can be utilized for patients with malignancies and acute renal impairment; the choice of treatment being based on the patient characteristics. The aim of this article is to review the literature data regarding the epidemiology and management of AKI in cancer patients, the extracorporeal techniques used, choice of the appropriate therapy and the optimal time of initiation, and also the dose-prognosis relationship.

Management of acute kidney injury in symptomatic multiple myeloma

Symptomatic multiple myeloma is commonly complicated by acute kidney injury through various mechanisms. The most frequent is the precipitation of monoclonal free light chains with uromodulin in the distal tubules, defining light chain cast nephropathy. Early diagnosis and identification of the cause of acute kidney injury are required for optimizing management and avoiding chronic kidney injury that strongly affects quality of life and patient survival. In light chain cast nephropathy, often manifesting with severe acute kidney injury, renal recovery requires urgent intervention based on vigorous rehydration, correction of precipitating factors, and efficient anti-plasma cell chemotherapy to rapidly reduce the secretion of nephrotoxic free light chains. Currently, the association of the proteasome inhibitor bortezomib with high-dose dexamethasone is the standard regimen in newly diagnosed patients. The addition of another drug such as cyclophosphamide or an immunodulatory agent may improve free light chain response but raises tolerance concerns in frail patients. Further studies are warranted to confirm the role of anti-CD38 monoclonal antibodies, whose efficacy and tolerance have been documented in patients without renal impairment. Despite controversial results from randomized studies, recent data suggest that in patients with light chain cast nephropathy and acute kidney injury requiring dialysis, the combination of chemotherapy with free light chain removal through high-cutoff hemodialysis may increase renal response recovery rates. Kidney biopsy may be helpful in guiding management and assessing renal prognosis that appears to depend on the extent of cast formation and interstitial fibrosis/tubular atrophy. Because of continuous improvement in life expectancy of patients with multiple myeloma, renal transplantation is likely to be increasingly considered in selected candidates.

Early use of PEPA dialyzer for light chains removal and for the recovery from myeloma cast nephropathy: A case report

Chemotherapy and extracorporeal treatment reduce serum free light chains (FLCs) allowing the recovery of acute kidney injury (AKI) caused by myeloma cast nephropathy (MCN). We report the first case of recovery from AKI in a patient with MCN who underwent the removal of FLCs using the PEPA filter, with an undisclosed cut-off, combined with chemotherapy for multiple myeloma (MM).

Paraprotein-Related Kidney Disease: Evaluation and Treatment of Myeloma Cast Nephropathy

Nearly 50% of patients with multiple myeloma develop renal disease, most commonly from AKI caused by cast nephropathy. Development of AKI is associated with poor 1-year survival and reduces the therapeutic options available to patients. There is a great need for more effective therapies. Cast nephropathy is caused by the interaction and aggregation of filtered free light chains and Tamm-Horsfall protein causing intratubular obstruction and damage. The key to treating cast nephropathy is rapid lowering of free light chains, because this correlates with renal recovery. Newer chemotherapy agents rapidly lower free light chains and have been referred to as renoprotective. There is additional great interest in using extracorporeal therapies to remove serum free light chains. Small trials initially showed benefit of therapeutic plasma exchange to improve renal outcomes in cast nephropathy, but a large randomized trial of therapeutic plasma exchange failed to show benefit. A newer technique is extended high-cutoff hemodialysis. This modality uses a high molecular weight cutoff filter to remove free light chains. To date, trials of high-cutoff hemodialysis use in patients with cast nephropathy have been encouraging. However, there are no randomized trials showing the benefit of high-cutoff hemodialysis when used in addition to newer chemotherapeutic regimens. Until these studies are available, high-cutoff hemodialysis cannot be recommended as standard of care.

Effectiveness of Haemodiafiltration with Heat Sterilized High-Flux Polyphenylene HF Dialyzer in Reducing Free Light Chains in Patients with Myeloma Cast Nephropathy

INTRODUCTION

In cases of myeloma cast nephropathy in need of haemodialysis (HD), reduction of free light chains using HD with High-Cut-Off filters (HCO-HD), in combination with chemotherapy, may be associated with better renal recovery. The aim of the present study is to evaluate the effectiveness of haemodiafiltration (HDF) in reducing free light chain levels using a less expensive heat sterilized high-flux polyphenylene HF dialyzer (HF-HDF).

METHODS

In a single-centre prospective cohort study, 327 dialysis sessions were performed using a 2.2 m2 heat sterilized high-flux polyphenylene HF dialyzer (Phylther HF22SD), a small (1.1m2) or large (2.1 m2) high-cut-off (HCO) dialyzer (HCOS and HCOL) in a cohort of 16 patients presenting with dialysis-dependent acute cast nephropathy and elevated free light chains (10 kappa, 6 lambda). The outcomes of the study were the mean reduction ratio (RR) of kappa and lambda, the proportion of treatments with an RR of at least 0.65, albumin loss and the description of patient outcomes. Statistical analysis was performed using linear and logistic regression through generalized estimating equation analysis so as to take into account repeated observation within subjects and adjust for session duration.

RESULTS

There were no significant differences in the estimated marginal mean of kappa RR, which were respectively 0.67, 0.69 and 0.70 with HCOL-HD, HCOS-HDF and HF-HDF (P = 0.950). The estimated marginal mean of the proportions of treatments with a kappa RR ≥0.65 were 68%, 63% and 71% with HCOL-HD, HCOS-HDF and HF-HDF, respectively (P = 0.913). The estimated marginal mean of lambda RR were higher with HCOL-HDF (0.78), compared to HCOL-HD and HF-HDF (0.62, and 0.61 respectively). The estimated marginal mean proportion of treatments with a lambda RR ≥0.65 were higher with HCOL-HDF (81%), compared to 57% in HF-HDF (P = 0.042). The median albumin loss were 7, 21 and 63 g/session with HF-HDF, HCOL-HD and HCOL-HDF respectively (P = 0.044). Among survivors, 9 out of 10 episodes of acute kidney injuries became dialysis-independent following a median time of renal replacement therapy of 40 days (range 7-181).

CONCLUSION

Therefore, in patients with acute dialysis-dependent myeloma cast nephropathy, in addition to chemotherapy, HDF with a heat sterilized high-flux polyphenylene HF dialyzer could offer an alternative to HCO dialysis for extracorporeal kappa reduction with lower albumin loss.

Plasmapheresis in cast nephropathy: yes or no?

PURPOSE OF REVIEW

Renal failure is a frequent complication of multiple myeloma and portends a poor prognosis. Plasmapheresis has been suggested as an adjunct to chemotherapy to halt or reverse renal injury associated with multiple myeloma. The purpose of this article is to review the rationale for using plasmapheresis for this indication and then provide a discussion of the evidence regarding its use.

RECENT FINDINGS

The outcome of patients with multiple myeloma has improved considerably in recent years, mostly owing to the introduction of new highly effective chemotherapeutic agents. However, patients with renal failure who do not recover independent renal function continue to have very poor prognosis. Recent evidence now indicates that an early and sustained reduction in circulating free light chains (FLCs) is associated with improved renal recovery in patients with myeloma kidney. Extracorporeal removal of FLCs with plasmapheresis, or other techniques, can achieve rapid and sustained reduction in serum FLC concentration in patients with acute myeloma kidney. Unfortunately, there is currently no convincing evidence in the literature that the addition of mechanical removal of FLC to standard chemotherapy translates into clinical benefits for patients.

SUMMARY

Plasmapheresis is theoretically attractive as a means of rapidly lowering serum FLC burden in the hope of reducing nephrotoxicity in patients with multiple myeloma. However, the role of plasmapheresis in improving renal prognosis and patient survival remains to be demonstrated.

Hemodiafiltration improves free light chain removal and normalizes κ/λ ratio in hemodialysis patients

BACKGROUND/AIMS

Serum free light chain (FLC) levels are correlated with chronic kidney disease (CKD) stages and are highest in patients on hemodialysis (HD). Aim of this study was to assess the FLC removal efficiency of Elisio™-210H dialyzer using either high-flux HD or on line high efficiency hemodiafiltration (HDF) modalities in CKD-5D patients.

METHODS

In this prospective and comparative study, 20 CKD-5D patients free from multiple myeloma were randomized in two groups: HD versus on line HDF. All patients were dialyzed with Elisio™-210H dialyzer. Serum samples were collected before and after the midweek dialysis session, before randomization and at the end of the study to measure κ and λ FLC concentrations. Reduction ratios were corrected for net ultrafiltration.

RESULTS

For both HD and HDF mode, κ and λ FLC concentrations were significantly lower after dialysis than before but median reductions in κ and λ FLC levels were significantly higher in HDF versus HD groups (κ 73.5 vs. 65.5 %, p = 0.04 and λ 51.0 vs. 36.6 %, p = 0.07). After dialysis, all κ/λ ratio values were between 0.26 and 1.65 which is the reference range described in subjects with normal kidney function, for both HD and HDF groups (median κ/λ ratios were 0.80 [0.47-1.22] and 0.67 [0.50-0.79] respectively).

CONCLUSION

This study shows the superiority of on line HDF compared with HD to remove both κ and λ FLC. Moreover, all post-dialysis κ/λ ratios reached normal reference range.

Comparison between on-line high-efficiency hemodiafiltration and conventional high-flux hemodialysis for polyclonal free light chain removal

BACKGROUND

Polyclonal free light chains (FLC) are considered as middle molecular weight uremic toxins in chronic kidney disease. In this study, we investigate polyclonal FLC removal by comparing conventional high-flux hemodialysis (HD) and online high-efficiency hemodiafiltration (ol-HDF) in end-stage renal disease patients.

METHODS

We analyzed 31 chronic dialysis patients who were treated by HD then by postdilution ol-HDF during a prospective study. All patients were anuric and without monoclonal gammopathy. Serum pre- and postdialysis FLC were collected during 4 sessions: 1 HD session and 3 ol-HDF sessions. We calculated the reduction ratio using kinetic modeling.

RESULTS

The κ reduction ratio was higher with ol-HDF than with HD (66 ± 14 vs. 52 ± 13%, p < 0.001). However, the λ reduction ratio was not significantly higher with ol-HDF (37 ± 20 vs. 37 ± 15%, p = 0.67). Furthermore, predialysis κ- and λ-FLC increased with ol-HDF compared with HD (κ 155 ± 82 vs. 87 ± 47 mg/l, p < 0.05; λ 101 ± 46 vs. 72 ± 41 mg/l, p < 0.05). Postdialysis FLC levels were raised only for λ-FLC with ol-HDF (74 ± 39 vs. 53 ± 31 mg/l, p < 0.05) and were not significantly different for κ.

CONCLUSIONS

This study shows that κ-FLC removal is better in ol-HDF compared with HD, whereas there is no difference in λ-FLC removal. Surprisingly, predialysis κ and λ levels are both increased in ol-HDF, which is disturbing since polyclonal excess of λ-FLC is associated with mortality in chronic kidney disease.

Novel approaches for reducing free light chains in patients with myeloma kidney

Myeloma kidney is a tubulointerstitial pathology that accounts for approximately 80-90% of severe acute kidney injury in patients with multiple myeloma. Unless there is rapid intervention, progressive irreversible damage from interstitial fibrosis and tubular atrophy occurs. Work over the past decade has demonstrated that an early sustained reduction in serum concentrations of pathogenic monoclonal free light chains (FLCs) leads to improved renal recovery rates. In turn, an early improvement in renal function is associated with improved patient survival. An early reduction in FLC levels should therefore become standard of care, although the optimum mechanisms to achieve this depletion of FLCs remain to be determined. To provide a coordinated, cross-disciplinary approach to research in this disease, the International Kidney and Monoclonal Gammopathy Research Group was formed. In this Review, we address the current state of knowledge in the management of myeloma kidney.