Background: Induction therapy is recommended before autologous stem cell transplantation (ASCT) for AL amyloidosis patients with high disease burden [bone marrow plasma cells (BMPCs) > 10%], but the role of induction therapy before ASCT in patients with low disease burden (BMPCs ≤ 10%) is still unknown.
Methods: A total of 227 patients with AL amyloidosis were included in this study. Among 227 patients, 124 patients received bortezomib-based induction prior to ASCT and were defined as group A, 35 patients received other chemotherapeutic induction and were defined as group B, and the other 68 patients without induction were defined as group C. We compared the differences of efficacy and prognosis between the three groups.
Results: The haematological overall response rates (ORR) of groups A, B and C were 91%, 67% and 75%, respectively. The complete response rates (CR) of groups A, B and C were 50%, 25% and 20%, respectively. Both the ORR and CR rates of group A were significantly higher than those of groups B and C. The renal response rates of groups A, B and C were 64%, 46% and 47%, respectively. The cardiac response rates of groups A, B and C were 74%, 45% and 40%, respectively. The renal and cardiac responses rates of group A were also significantly higher than those of the other two groups. After a median follow-up of 44 months, the median OS was not reached. The 5-year estimated overall survival (OS) rates of groups A, B and C were 81%, 57% and 67%, respectively. The median progression-free survival (PFS) was 83 months for all patients. The 5-year estimated PFS rates of groups A, B and C were 61%, 38% and 49%, respectively. Both the OS and PFS of group A were higher than those of both group B and group C. On multivariate analysis, baseline dFLC > 50 mg/L was associated with worse survival, but induction with bortezomib was associated with better survival.
Conclusion: Our study demonstrated that low disease burden AL patients who are eligible for ASCT may benefit from bortezomib-based induction therapy.
Keywords: AL amyloidosis; bortezomib; induction; prognosis; stem cell transplantation.