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Two thirds of patients with AL amyloidosis have renal involvement. First-line treatment consists of chemotherapy and/or autologous bone marrow transplantation to reduce light chain production. Renal response can be seen within 3 months of initiation. There are currently no regional studies published on the subject.
The objective was to estimate the percentage of patients with AL amyloidosis and renal involvement who achieved organ response after first-line treatment.
Retrospective cohort study. All consecutive patients with a diagnosis of AL amyloidosis and renal involvement belonging to the Institutional Registry of Amyloidosis of the Hospital Italiano de Buenos Aires with diagnosis up to 30/04/2022 were included. All individuals were followed up for 12 months. Complete renal response was defined as a decrease of at least 30% in 24-hour proteinuria (minimum 0.5 g/24hs) with no worsening of creatinine clearance greater than 25%. Progression of renal involvement was defined as a 50% increase in 24-hour proteinuria (minimum 1 g/24hs) to more than 1 g/24hs or 25% worsening of creatinine clearance. Those patients who were not classified in the complete response or renal progression group were considered as partial response.
Quantitative variables were described with their mean and standard deviation or median and interquartile range, according to distribution. Categorical variables were described as absolute and relative frequencies and reported with 95% confidence intervals. Renal response rate was estimated as a proportion with its 95% confidence interval.
The most frequent forms of clinical presentation were renal failure (56%) and nephrotic syndrome (58%).
Regarding the type of first-line treatment, 69.8% (n=30) of patients received chemotherapy exclusively and 30.2% (n=13) chemotherapy followed by autologous bone marrow transplantation. At 6-month follow-up, the renal response rate was 37.1% (95%CI 21.5-55.1%) and 31.4% (95%CI 16.8-49.3%) of patients had renal progression. On the other hand, at 1-year follow-up 36.7% (95% CI 19.9-56.1%) of patients had renal response and 43.3% (95% CI 25.5-62.6%) had renal progression.
When the groups were differentiated according to the first-line treatment regimen received, no differences were observed in renal response and progression at 6 months. In contrast, complete renal response was higher (63.6% vs 21%) and progression was lower (18.2% vs 57.9%) in the group that received chemotherapy followed by autologous bone marrow transplantation compared to the group that received chemotherapy alone at 12 months.
First-line treatment improved renal function (based on creatinine clearance) and reduced proteinuria in a large percentage of patients. This was mainly seen at 12 months follow-up in those patients who received chemotherapy followed by bone marrow transplantation as initial treatment.