High Dose Melphalan and Autologous Stem Cell Transplantation In Light Chain and Light and Heavy Chain Deposition Disease: Hematologic and Renal Outcomes.

Light chain deposition disease (LCDD) and light and heavy chain deposition disease (LHCDD) are plasma cell disorders characterized by pathologic aggregation and deposition of immunoglobulin components in tissues leading to organ dysfunction. Reported outcomes with conventional chemotherapy include high rates of end stage renal disease and death. High dose melphalan followed by autologous stem cell transplantation (ASCT) has been employed in an attempt to improve outcomes, but few published data are available to support this practice.

We conducted a retrospective review of all patients within our institutional database treated with ASCT for LCDD or LHCDD. Diagnosis was based in all cases upon renal biopsy. Associated multiple myeloma (MM) was diagnosed if bone marrow plasma cells were > 10% with concomitant anemia, hypercalcemia or lytic bone disease. Filgrastim was used for peripheral blood stem cell mobilization. All patients received melphalan conditioning at a reduced dose of 140 mg/m² (due to renal dysfunction) with the exception of one patient who received melphalan 200 mg/m². Response to treatment was adapted from the International Consensus Criteria (Gertz et al. 2005) designed for use in AL amyloidosis except that bone marrow biopsies were not performed to confirm complete hematologic remission. A renal response was considered to have been reached if proteinura decreased from 50% of baseline with stable creatinine or if creatinine decreased by 50% from its peak value.

We identified eight patients (7 LCDD, 1 LHCDD) treated with ASCT between August 2006 and November 2009. The median age at diagnosis was 48 years (range 40–62). Two patients had associated MM. All patients had come to medical attention as a consequence of renal dysfunction. The median serum creatinine at presentation was 192 μ mol/L (119-444) with two patients meeting criteria for nephrotic syndrome and a third having anasarca with nephritic syndrome. No patients were found to have associated AL amyloidosis, myeloma cast nephropathy, or extrarenal LCDD. Left ventricular ejection fraction was normal in all patients and none had evidence of cardiac infiltration. Kappa light chain restriction was present in seven patients with lambda light chain restriction in the eighth. Median kappa FLC level at diagnosis was 528 mg/L (range 42–1290, normal 3.3–19.4). Induction therapy consisted of dexamethasone in five patients and dexamethasone with bortezomib in two patients; one patient proceeded directly to ASCT without induction therapy. At the time of ASCT, the median serum creatinine was 183 μ mol/L (122-298). Stem cell mobilization was uncomplicated and ASCT was tolerated with no treatment related deaths or requirement for ICU admission. Significant toxicities included engraftment syndrome requiring steroids (2), bacteremia (2), sepsis with hypotension (1), pneumonia (1), grade 3 mucositis (1) and edema requiring ultrafiltration (1). One patient with a pre-ASCT creatinine of 298 μ mol/L went on to develop end stage renal disease and dialysis dependence two months after ASCT. Hematologic response was CR in two, PR in four, and not assessable in two patients due to insufficiently elevated baseline M-protein quantity for response determination. Seven patients had a renal response. After a median follow up from ASCT of 18 months (1-39 months), only one patient had experienced disease progression with increasing kappa FLC level. With the exception of the one dialysis dependent patient, no patients had symptoms related to renal disease at last follow up.

In selected patients with LCDD and LHCDD, high dose melphalan with ASCT produced a high rate of hematologic and renal response with acceptable toxicity. Longer follow up is needed to assess the durability of response.

No relevant conflicts of interest to declare.