[Clinical characteristics and survival outcomes of patients with immunoglobulin A multiple myeloma in the bortezomib era: A single-center retrospective cohort study].

Objective: To analyze the clinical characteristics, treatment response, and prognosis of patients newly diagnosed with immunoglobulin A multiple myeloma (IgA MM), and to ascertain whether the IgA isotype remains a poor prognostic factor in the bortezomib era. Methods: This study retrospectively enrolled 155 patients newly diagnosed with IgA MM and 420 with non-IgA MM admitted to the Department of Hematology, the First Affiliated Hospital of Nanchang University from March 2014 to December 2021. We compared the two groups in terms of their clinical characteristics, prognoses, and progression-free survival (PFS) and overall survival (OS) following different treatment regimens. Results: Compared with the non-IgA group, the IgA group presented with more aggressive clinical features, including a higher proportion of patients with hemoglobin<85 g/L (61.3% vs 51.4%, P=0.035), extramedullary manifestations (20.0% vs 11.4%, P=0.008), and gain/amp (1q21) (48.6% vs 36.7%, P=0.032). Efficacy analysis revealed a lower overall response rate (ORR) in the IgA group than in the non-IgA group (83.2% vs 92.4%, P=0.001). Among patients treated with bortezomib-based regimens, the ORR was 91.2% in the IgA group and 94.8% in the non-IgA group, but the difference was nonsignificant (P=0.146). Survival analysis showed that the median PFS and OS were significantly shorter in the IgA group compared with the non-IgA group[23.5 (95% CI: 17.4-29.5) months and 48.8 (95% CI: 30.1-67.5) months vs 40.7 (95% CI: 33.8 - 47.6) months and not reached, respectively; P<0.001 and P=0.002]. In the subgroup of patients who received bortezomib-based therapy without subsequent autologous hematopoietic stem cell transplantation (auto-HSCT), the PFS and OS were significantly shorter in the IgA group compared with the non-IgA group[25.4 (95% CI: 18.7-32.1) months and 53.5 (95% CI: 35.4-71.6) months vs 41.0 (95% CI: 33.7-48.3) months and not reached; P=0.001 and P=0.011]. In patients who underwent bortezomib-based induction therapy followed by auto-HSCT, the 1-, 3-, and 5-year OS rates for the IgA group were 96%, 81%, and 81%, respectively, compared with 93%, 89%, and 79% for the non-IgA group, but the difference was nonsignificant (P=0.758) . Conclusion: In the bortezomib era, IgA MM is still associated with a poorer overall prognosis than non-IgA MM, likely due to its inherent high-risk biological characteristics. Although bortezomib-based regimens effectively improve the treatment response, they fail to completely bridge the survival gap between the two disease isotypes. Therefore, bortezomib-based therapy followed by auto-HSCT may be a key strategy to overcome the poor prognosis of IgA MM, potentially enabling these patients to achieve long-term survival comparable to that of their non-IgA counterparts.