Effect of severe hypoalbuminemia on toxicity of high-dose melphalan and autologous stem cell transplantation in patients with AL amyloidosis. Bone Marrow Transplant. 2016;51:1318-1322. [PMID: 27183092 DOI: 10.1038/bmt.2016.132]

A model for predicting day-100 stem cell transplant-related mortality in AL amyloidosis

Autologous stem cell Transplant (ASCT)-related mortality (TRM) in AL amyloidosis remains elevated. AL amyloidosis patients (n = 1718) from 9 centers, transplanted 2003-2020 were included. Pre-ASCT variables of interest were assessed for association with day-100 all-cause mortality. A random forest (RF) classifier with 10-fold cross-validation assisted in variable selection. The final model was fitted using logistic regression. The median age at ASCT was 58 years. Day-100 TRM occurred in 75 patients (4.4%) with the predominant causes being shock, high-grade arrhythmia, and organ failure. Ten factors were associated with day-100 TRM on univariate analysis. RF classifier using these variables generated a model with an area under the curve (AUC) of 0.72 ± 0.12. To refine the model selection using importance hierarchy function, a 4-variable model [NT-proBNP/BNP, serum albumin, ECOG performance status (PS), and systolic blood pressure] was built with an AUC of 0.70 ± 0.12. Based on logistic regression coefficients, ECOG PS 2/3 was assigned two points while other adverse predictors 1-point each. The model score range was 0-5, with a day-100 TRM of 0.46%, 3.2%, 5.8%, and 14.5% for 0, 1, 2, and ≥3 points, respectively. This model to predict day-100 TRM in AL amyloidosis allows better-informed decision-making in this heterogeneous disease.

Role of Autologous Stem Cell Transplantation in Systemic Light Chain Amyloidosis

Systemic light chain (AL) amyloidosis is a multisystem disorder characterized by extracellular deposition of misfolded insoluble amyloid fibrils resulting in progressive organ dysfunction. AL. amyloidosis most commonly affects the heart, kidneys, gastrointestinal tract and peripheral nerves. Early mortality is chiefly determined by the degree of cardiac involvement. The aim of therapy is to rapidly reduce amyloidogenic light chain production by targeting the underlying clonal plasma or lymphoma cell population. High dose therapy with melphalan followed by autologous peripheral blood stem cell transplant (ASCT) continues to remain a highly effective treatment and is considered a standard of care for transplant eligible patients, which offers long term disease control in patients with AL amyloidosis. In recent years, several new therapeutic options have emerged (including anti-CD38 monoclonal antibodies) which are very effective alone or in combination in eradicating clonal plasma cells. In this review, we discuss the role of ASCT in the current setting of a rapidly evolving treatment landscape for patients with AL amyloidosis and provide our practice recommendations.

Recent guidelines for high dose chemotherapy and autologous stem cell transplant for systemic AL amyloidosis: a practitioner's perspective

INTRODUCTION

High dose melphalan followed by autologous stem cell transplant (ASCT) has been transformative in treating AL amyloidosis since the early nineties. Recently, the European Haematology Association (EHA) and International Society of Amyloidosis (ISA) have developed a combined guideline for the management of patients undergoing an ASCT for AL amyloidosis.

AREAS COVERED

In this practitioner's perspective, we review the guideline, focussing on 6 major areas and offer practical advice for its application. We provide a perspective on the optimal use of ASCT and its potential application in the future.

EXPERT OPINION

The EHA-ISA guideline comprehensively outlines the practicalities of performing an ASCT in AL amyloidosis. The critical aspect is careful patient selection. Vigilant fluid balance assessments are crucial as associated complications are common and dangerous.The role of ASCT is changing with improving haematological responses associated with novel agents. Evidence is limited for the use of ASCT in patients who achieve a complete haematological response (CR). Therefore, ASCT should be considered for those who only achieve a very good partial response (VGPR)/partial response (PR) and fulfil the strict selection criteria. Future research identifying the cohort who would benefit most from ASCT in the era of novel therapies is warranted.

Stem Cell Mobilization and Autologous Transplant for Immunoglobulin Light-Chain Amyloidosis

Stem cell transplantation was one of the first proven effective regimens for the management of immunoglobulin light-chain amyloidosis. Criteria for patient selection and the mobilization regimen become important features in ensuring a safe outcome. The technique of stem cell transplantation has evolved considerably in parallel with the development of new chemotherapeutic agents for the management of amyloidosis. Optimal outcomes require both the use of effective novel agent induction and appropriate application of high-dose chemotherapy with subsequent stem cell reconstitution.

Autologous stem cell transplantation in patients with AL amyloidosis with impaired renal function

We retrospectively reviewed the impact of impaired renal function (eGFR < 45 ml/min/SA) on post-transplant outcomes in patients receiving ASCT for AL amyloidosis. Patients were grouped into two cohorts, those with normal renal function (NRF) eGFR ≥ 45 ml/min (n = 568) and those with impaired renal function (IRF) eGFR < 45 ml/min (n = 87). Patients with IRF had higher renal stage (>Stage 1: 100% IRF vs 37% NRF, p < 0.0001) and the majority received conditioning with melphalan <200 mg/m² (70% IRF vs 21% NRF, p < 0.0001). Forty-four patients (6.7%) required dialysis within 100 days of ASCT. Renal stage predicted for dialysis institution within 100 days of ASCT (3% Stage I vs 10% Stage II vs 22% Stage III, p < 0.0001). Dialysis within 100 days was higher in the IRF cohort (16% for IRF cohort vs 6% for NRF cohort, p = 0.0007. Patients with impaired renal function were more likely to be admitted to hospital (80% IRF vs 70% NRF, p = 0.03). The 100-day mortality was higher in the IRF cohort (14% IRF cohort vs 5% NRF cohort, p = 0.008). Median OS and PFS were similar between the two cohorts. Impaired renal function predicts for a higher rate of hospitalization, progression to dialysis and early mortality in patients receiving ASCT for AL amyloidosis.

Causal relationship between hypoalbuminemia and acute kidney injury

Our meta-analysis published in 2010 provided evidence that low levels of serum albumin (hypoalbuminemia) are a significant independent predictor of acute kidney injury (AKI) and death following AKI. Since then, a large volume of additional data from observational clinical studies has been published further evaluating the relationship between serum albumin and AKI occurrence. This is an updated review of the literature to re-evaluate the hypothesis that hypoalbuminemia is independently associated with increased AKI risk. Eligible studies published from September 2009 to December 2016 were sought in PubMed (MEDLINE) and forty-three were retained, the great majority being retrospective observational cohort studies. These included a total of about 68000 subjects across a diverse range of settings, predominantly cardiac surgery and acute coronary interventions, infectious diseases, transplant surgery, and cancer. Appraisal of this latest data set served to conclusively corroborate and confirm our earlier hypothesis that lower serum albumin is an independent predictor both of AKI and death after AKI, across a range of clinical scenarios. The body of evidence indicates that hypoalbuminemia may causally contribute to development of AKI. Furthermore, administration of human albumin solution has the potential to prevent AKI; a randomized, controlled study provides evidence that correcting hypoalbuminemia may be renal-protective. Therefore, measurement of serum albumin to diagnose hypoalbuminemia may help identify high-risk patients who may benefit from treatment with exogenous human albumin. Multi-center, prospective, randomized, interventional studies are warranted, along with basic research to define the mechanisms through which albumin affords nephroprotection.