Mortality & inpatient hospitalizations amongst patients with cardiac light-chain amyloidosis: results from a US administrative claims database

Background Light chain (AL) amyloidosis is a rare hematologic disorder in which misfolded light chain fibrils produced by clonal plasma cells aggregate, deposit, and cause organ dysfunction. Limited data exists, however, on real-world clinical outcomes amongst AL amyloidosis patients with cardiac involvement following the approval of daratumumab as first-line therapy and inclusion in clinical guidelines. Purpose The objective of this study is to assess mortality and condition-related hospitalization rates amongst patients with cardiac AL amyloidosis who were newly initiated treatment from January/2021 to March/2023. Methods This study included patients aged ≥18 identified in the US IQVIA PharMetrics database who were newly initiated pharmacological treatment (index date) with bendamustine, bortezomib, carfilzomib, cyclophosphamide, daratumumab, ixazomib, lenalidomide, melphalan, pomalidomide, or venetoclax 01Jan2021-31Mar2023.Patients were required to have ICD-10 diagnosis codes for AL (E85.81), heart failure (I50.*) or cardiomyopathy (I42.*-I43.*), as well as continuous medical+prescription insurance enrollment 1-year pre-index through 1-year post-index (or until death). 1-year post-index all-cause mortality & condition-related (AL/cardiac/renal) inpatient hospitalization rates were assessed amongst the overall population, those with cardiac-only involvement or cardiac+renal involvement (based on diagnosis/procedure codes), as well as daratumumab use during the 1-year post-index period. Results A total of 198 AL amyloidosis patients with cardiac involvement were included in this study (mean age:64.8 years; 70.7% male). The 1-year mortality and condition-related hospitalization rate amongst all patients was 9.1% (18/198) and 65.7% (130/198), respectively. When stratified by organ-involvement type, lower 1-year mortality and condition-related hospitalization rates were seen amongst the cardiac-only population (N=66; 33.3% of total sample) at 7.6% (5/66) and 45.5% (30/66), respectively. Patients with renal-involvement was 66.7% (132/198) of the full cardiac population, and had 1-year mortality and condition-related hospitalization rates of 9.8% (13/132) and 75.8% (100/132), respectively. Daratumumab-use was seen in 69.7% (138/198) of all cardiac-AL patients, with 1-year mortality and condition-related hospitalization rates of 7.2% (10/138) and 67.4% (93/138), respectively. No daratumumab use was noted in 30.3% (60/198) post-index of the cardiac-AL population, with 1-year mortality and condition-related hospitalization rates of 13.3% (8/60) and 61.7% (37/60), respectively. Conclusions Despite recent therapeutic advances mortality and condition-related inpatient hospitalization rates underscore the significant unmet need that remains amongst AL amyloidosis patients with cardiac involvement, particularly amongst patients with both cardiac and renal involvement.