Epidemiology of light-chain amyloidosis in Latin America: a retrospective analysis of 212 patients. Grupo Latinoamericano de Estudio del Mieloma Múltiple (GELAMM).

MARIA LOURDES POSADAS MARTINEZ

Simposio; XVIIIth International Symposium on Amyloidosis; 2022

Epidemiology of light-chain amyloidosis in Latin America: a retrospective analysis of 212 patients. Grupo Latinoamericano de Estudio del Mieloma Múltiple (GELAMM). Brulc Erika B,1,Riva Eloísa2, Carretero Marcelina1, Garrido David3, Posadas-Martinez Lourdes1, Aguirre Adela1, Peña Camila4, Ríos Oliday5, Duarte Patricio6, Martinez Lina7, Enciso Leonardo7, Martínez Humberto7, Fernández Julio8, Nucifora Elsa1 1Hospital Italiano de Buenos Aires, Argentina2Hospital Británico, Montevideo, Uruguay3Hospital de Clínicas Dr. Manuel Quintela, Montevideo, Uruguay.4Hospital del Salvador, Santiago de Chile, Chile.5Hospital Hermanos Ameijeiras, La Habana, Cuba6Hospital Universitario CEMIC, Argentina.7Instituto Nacional de Cancerología, Bogotá, Colombia.8Hospital Dr Gustavo Aldeguería Lim, Cienfuegos, Cuba. Background: Light-chain amyloidosis (AL) is the most common and severe subtype (70%) of amyloidosis. Very limited data have been published on this topic in Latin America (LATAM). Objective: to describe the epidemiology and frontline therapy of patients diagnosed with AL amyloidosis in the last ten years in LATAM.Material & Methods: a retrospective cohort of all consecutive patients with newly diagnosed AL amyloidosis based on the Latin American Multiple Myeloma Study Group (GELAMM) registry, from January 2009 to December 2019 in centers from Argentina, Chile, Colombia, Cuba, México, Paraguay and Uruguay. Categorical variables were described as percentages and absolute frequency. Quantitative variables were described as the median and interquartile range (IQR).Results: Two hundred and eleven patients were included. The majority (55%) were diagnosed after 2014. Median age at diagnosis was 62 years (IQR 17) and 52% were male. Median bone plasma cell infiltration was 10% (IQR 15), 67% were lambda chain AL. Initial histological site of positive biopsy was detailed in 181 cases, as shown in Table 1. A second site was biopsied in 47 cases, mostly bone marrow (49%). Cytogenetic analyses (conventional and/or FISH for t(4;14); t(14;16)and del17p) were reported in 60 cases being abnormal in 4, without any predominance. All individuals were symptomatic at diagnosis. Asthenia, heart failure, nephrotic syndrome, and weight loss were the most frequent symptoms, present in 56%, 49%, 46% and 43%, respectively. Other symptoms include periorbital purpura (38%), dysautonomia (36%), peripheral neuropathy (34%), macroglossia (33%), and liver involvement (26%). Mass spectrometry was performed in 9 patients, in all confirming the diagnosis and subtype of Ig. Serum free light-chains (sFLC) were reported in 119 and cardiac biomarkers in 114 patients. Frontline chemotherapy was proteasome inhibitors-based in 44% (VCD 34%), and non-bortezomib based in 56% (including melphalan-based in 33% and other in 23). Thirty three (18%) patients received autologous stem cell transplantation, in 32 as frontline consolidation and in 1 as the only treatment. Eighteen patients (9%) received cardiac transplants. No data regarding renal transplants were obtained. Overall response rate (≥PR) to frontline treatment was 44%. The best hematologic response was CR in 36% patients, VGPR in 10% patients, PR in 20% patients and NR in 16 % patients. The main limitations of this study are due to its retrospective design and the insufficient data to assess prognosis and response, considering sFLC were not available in 44% of cases. Similarly to international reports, ASCT is done in < 20% of patients. Cardiac and renal involvement were lower than reported, probably reflecting the limitations of a multicenter registry and a suboptimal organ involvement evaluation. Overall, diagnosis and prognostic evaluation are suboptimal due to the limited availability of cardiac biomarkers and adequate typing techniques.Summary & Conclusion:This study provides real-world data of AL amyloidosis in the last 10 years in LATAM countries. Bortezomib-based frontline therapies are the most commonly used. ASCT is done in a minority of patients. We need to improve the quality of diagnosis and stratification and increase the availability of novel therapies. References:Giovanni Palladini, et al. Systemic Light Chain Amyloidosis across Europe: Key Outcomes from a Retrospective Study of 4500 Patients. Blood 2021; 138 (Supplement 1): 153. doi: https://doi.org/10.1182/blood-2021-152675Support/Funding: none