Stephen Harding

Treatment of Acute Renal Failure Secondary to Multiple Myeloma with Chemotherapy and Extended High Cut-Off Hemodialysis

BACKGROUND AND OBJECTIVES Extended hemodialysis using a high cut-off dialyzer (HCO-HD) removes large quantities of free light chains in patients with multiple myeloma. However, the clinical utility of this method is uncertain. This study assessed the combination of chemotherapy and HCO-HD on serum free light chain concentrations and renal recovery in patients with myeloma kidney (cast nephropathy) and dialysis-dependent acute renal failure. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS An open-label study of the relationship between free light chain levels and clinical outcomes in 19 patients treated with standard chemotherapy regimens and HCO-HD. RESULTS There were sustained early reductions in serum free light chain concentrations (median 85% [range 50 to 97]) in 13 patients. These 13 patients became dialysis independent at a median of 27 d (range 13 to 120). Six patients had chemotherapy interrupted because of early infections and did not achieve sustained early free light chain reductions; one of these patients recovered renal function (at 105 d) the remaining 5 patients did not recover renal function. Patients who recovered renal function had a significantly improved survival (P < 0.012). CONCLUSION In dialysis-dependent acute renal failure secondary to myeloma kidney, patients who received uninterrupted chemotherapy and extended HCO-HD had sustained reductions in serum free light chain concentrations and recovered independent renal function.

Quantitative Assessment of Serum and Urinary Polyclonal Free Light Chains in Patients with Chronic Kidney Disease

BACKGROUND AND OBJECTIVES Monoclonal free light chains (FLC) frequently cause kidney disease in patients with plasma cell dyscrasias. Polyclonal FLC, however, have not been assessed in patients with chronic kidney disease (CKD) yet could potentially play an important pathologic role. This study describes for the first time polyclonal FLC in patients with CKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS A sensitive, quantitative immunoassay was used to analyze serum and urinary polyclonal FLC in 688 patients with CKD of various causes. RESULTS Serum kappa and lambda FLC concentrations increased progressively with CKD stage (both P < 0.001) and strongly correlated with markers of renal function, including cystatin-C (kappa: R = 0.8, P < 0.01; and lambda: R = 0.79, P < 0.01). Urinary FLC concentrations varied significantly between disease groups (kappa: P < 0.001; lambda: P < 0.005) and also rose significantly with increasing CKD stage (both FLC P < 0.0001). Urinary FLC concentrations were positively correlated with their corresponding serum concentration (kappa: R = 0.63; lambda: R = 0.65; both P < 0.001) and urinary albumin creatinine ratio (kappa: R = 0.58; lambda: R = 0.65; both P < 0.001). The proportion of patients with abnormally high urinary FLC concentrations rose with both the CKD stage and the severity of albuminuria. CONCLUSIONS This study demonstrates significant abnormalities of serum and urinary polyclonal FLC in patients with CKD. These data provide the basis for studies that assess the contribution of polyclonal FLC to progressive renal injury and systemic inflammation in patients with kidney disease.

Serum free light chain measurement aids the diagnosis of myeloma in patients with severe renal failure.

BackgroundMonoclonal free light chains (FLCs) frequently cause rapidly progressive renal failure in patients with multiple myeloma. Immunoassays which provide quantitative measurement of FLCs in serum, have now been adopted into screening algorithms for multiple myeloma and other lymphoproliferative disorders. The assays indicate monoclonal FLC production by the presence of an abnormal κ to λ FLC ratio (reference range 0.26–1.65). Previous work, however, has demonstrated that in patients with renal failure the FLC ratio can be increased above normal with no other evidence of monoclonal proteins suggesting that in this population the range should be extended (reference range 0.37–3.1). This study evaluated the diagnostic sensitivity and specificity of the immunoassays in patients with severe renal failure.MethodsSera from 142 patients with new dialysis-dependent renal failure were assessed by serum protein electrophoresis (SPE), FLC immunoassays and immunofixation electrophoresis. The sensitivity and specificity of the FLC ratios published reference range was compared with the modified renal reference range for identifying patients with multiple myeloma; by receiver operating characteristic curve analysis.ResultsForty one patients had a clinical diagnosis of multiple myeloma; all of these patients had abnormal serum FLC ratios. The modified FLC ratio range increased the specificity of the assays (from 93% to 99%), with no loss of sensitivity. Monoclonal FLCs were identified in the urine from 23 of 24 patients assessed.ConclusionMeasurement of serum FLC concentrations and calculation of the serum κ/λ ratio is a convenient, sensitive and specific method for identifying monoclonal FLC production in patients with multiple myeloma and acute renal failure. Rapid diagnosis in these patients will allow early initiation of disease specific treatment, such as chemotherapy plus or minus therapies for direct removal of FLCs.

Serum Free‐Light Chain Removal by High Cutoff Hemodialysis: Optimizing Removal and Supportive Care

In multiple myeloma the predominant cause of irreversible renal failure is cast nephropathy, secondary to excess kappa or lambda serum free light chains (FLCs). These molecules are efficiently cleared by hemodialysis (HD) using the Gambro HCO 1100 dialyzer. To optimize the removal of FLCs by this dialyzer we have studied the effect of dialyzers in series, dialyzer change, and hemodiafiltration in 14 patients with multiple myeloma and renal failure. The clearance rates of both kappa FLCs and lambda FLCs were significantly increased on two dialyzers from 19 (7.3-34)-15.3 (9-28) mL/min to 47 (17-79)-35.5 (20-57) mL/min, respectively. Clearance rates of both FLCs decreased over the course of the dialysis sessions (both P < 0.001). Changing the dialyzer during a HD session increased lambda FLC clearance rates (22.5 [6-41] to 37.6 [9-52] mL/min; P < 0.001) and decreased kappa FLC clearance rates (39.6 [9-72] to 19 [8-59] mL/min; P < 0.003). Ultrafiltration during HD increased the clearance rates of kappa FLCs (R 0.52, P < 0.01) but not lambda FLCs (R -0.25; P < 0.076). Hemodiafiltration increased the clearance rates of both kappa (19 [SD 6.8] to 32 [SD 9.8] mL/min) and lambda FLCs (15 [SD 7.8] to 20 [SD 7.7] mL/min). Albumin replacement requirements for 8 h of HD increased from 12 g for a single dialyzer to 45 g for two dialyzers in series (P < 0.001). Different protocols are required to optimize the removal of kappa and lambda FLCs in patients with myeloma and renal failure.

Bortezomib, low‐dose intravenous melphalan, and dexamethasone for patients with relapsed multiple myeloma

This multicenter phase I/II study investigated the maximum tolerated dose (MTD), safety, and efficacy of low dose intravenous (IV) melphalan in combination with bortezomib for patients with relapsed multiple myeloma (MM). Patients received bortezomib 1·3 mg/m2 on days 1, 4, 8, and 11 and escalating doses of IV melphalan (2·5–10·0 mg/m2) on day 2 of a 28‐day cycle for a maximum of eight cycles. Dexamethasone 20 mg was added for progressive or stable disease. Fifty‐three patients were enrolled. The MTD was defined at melphalan 7·5 mg/m2 and bortezomib 1·3 mg/m2. The overall response rate (ORR) was 68% (23% complete or near‐complete responses [CR/nCR]) whilst at the MTD (n = 33) the ORR was 76% (34% CR/nCR). After median follow‐up of 17 months, the median progression free survival was 10 months, rising to 12 months at the MTD (P < 0·05 vs. non‐MTD regimens). The median overall survival was 28 months, but was not yet reached at the MTD. Grade 3/4 adverse events included thrombocytopenia (62%), neutropenia (57%), infection (21%), and neuropathy (15%). Bortezomib and low‐dose IV melphalan combination therapy is a safe and highly effective regimen for patients with relapsed MM. These data suggest further investigation of this combination is warranted.

Abnormal serum free light chain ratios are associated with poor survival and may reflect biological subgroups in patients with chronic lymphocytic leukaemia.

The measurement of immunoglobulin serum free light chains (sFLC) has prognostic significance in plasma cell dyscrasias but its role in chronic lymphocytic leukaemia (CLL) is unknown. This retrospective study from three UK hospitals analysed sFLC in 181 untreated/pre‐treatment CLL patients and 78 treated CLL patients, with samples taken later in their disease. An abnormal sFLC ratio was significantly associated with poor overall survival for the 181 untreated/pre‐treatment patients (P = 0·0001) and for all patients (P = 0·002), irrespective of cause of death. Using multivariate analysis (n = 194), four independent prognostic variables for overall survival were identified namely Zap‐70 (P = 0·0001), β2M (P = 0·01), IGHV mutation status (P = 0·017) and an abnormal sFLC ratio (P = 0·024). For CLL patients with unmutated IGHV genes, elevated κ/λ ratios were adversely prognostic. For patients with mutated IGHV genes, reduced κ/λ ratios were adversely prognostic and associated with the poor prognostic IGHV3‐21, IGHV3‐48 and IGHV3‐53 subgroups, suggesting an abnormal sFLC ratio may reflect biological subgroups within CLL. Abnormal sFLC ratios need to be studied prospectively in CLL patients and the biological rationale for their abnormality investigated.

Elevated, combined serum free light chain levels and increased mortality: a 5-year follow-up, UK study

Aims Abnormal serum free light chain (FLC) ratios are diagnostically important in almost all plasma cell disorders. However, absolute increases in polyclonal FLC levels are often discarded as inconsequential. Here we report an association between increased combined polyclonal FLC (cFLC: FLCκ plus FLCλ) concentrations and mortality. Methods 723 patients sent for 30 routine haematological assessments were enrolled. Patients with a confirmed monoclonal gammopathy were removed. The remaining 527 patients were followed up for up to 4.5 years. Statistical analysis was performed using SPSS (V.19). Results During follow-up, there were 99 deaths (18.8%). Kaplan-Meier survival analysis revealed 29% of these deaths occurred within the first 100 days (N=29). Multivariate analysis identified only cFLC >65 mg/l, albumin <33 g/l and estimated glomerular filtration rate <30 ml/min/1.73 m2 to be independently associated with mortality within 100 days and 4.5 years with, cFLC having the highest HR of 7.1. A simple risk stratification model based only on albumin and cFLC identified 86% mortality within 100 days and 62% over 4.5 years. Conclusions Elevated cFLC is significantly associated with increased mortality and with albumin can be used to identify patients at risk of mortality at 4.5 years with high-risk patients detected within 100 days.

IgA kappa/IgA lambda heavy/light chain assessment in the management of patients with IgA myeloma

Accurate quantification of immunoglobulin A (IgA) monoclonal immunoglobulins by serum protein electrophoresis (SPEP) can be difficult and can impact the assessment of response among patients with multiple myeloma (MM). Therefore, there is a need to identify new assays that better reflect disease burden and response to treatment, and correlate with patient outcome. IgA Hevylite (HLC) measures IgA kappa and IgA lambda separately and provides precise quantitative measurements of the monoclonal IgA expression and polyclonal‐isotype matched suppression. In the current study, the authors assessed the usefulness of these assays in the diagnosis of IgA MM and sought to comment on the prognostic value of the assays.

Novel M-Component Based Biomarkers in Waldenström's Macroglobulinemia

Waldenstroms macroglobulinemia (WM) is an indolent B-cell lymphoma of the lymphoplasmacytic type accompanied by a serum IgM component. However, conventional IgM quantification lacks sensitivity, does not precisely reflect tumor burden of WM, and, although being the main marker for monitoring response to treatment, may not be accurate. New serum M-component based biomarkers were developed for routine practice in recent years, such as the Freelite® test and more recently the Hevylite test®. Studies have shown that Freelite was a prognostic marker for time to treatment in WM that helps monitoring disease response or progression. Hevylite measures IgMkappa and IgMlambda, separately, and might provide true quantitative measurement of the IgM M-spike. Although current data are preliminary, Hevylite® might replace the current technique to measure IgM M-spike in the years to come. We summarize herein studies conducted to delineate the role of these tests in WM.

Aggregated serum free light chains may prevent adequate removal by high cut-off haemodialysis

Free light chain (FLC) removal by high cut-off haemodialysis has been described as an adjuvant therapy for the management of patients with severe renal failure complicating multiple myeloma. The two cases reported here are the first patients in whom this treatment did not remove FLCs. In both patients sera, size-exclusion chromatography identified large FLC aggregates, with molecular weights above the cut-off of the dialyser. It is important for clinicians to be aware of FLC aggregates as a reason for failure to remove FLCs by this new modality.