Significance of maintenance therapy after HDT/ASCT in symptomatic multiple myeloma: A multicenter retrospective analysis in Kansai Myeloma Forum

A total of 129 symptomatic patients with multiple myeloma (MM) who underwent high‐dose chemotherapy with autologous stem cell transplantation (HDT/ASCT) were analyzed. The 4‐year overall survival (OS) of patients with maintenance (n = 82) was 80%, whereas that of patients without maintenance (n = 47) was 72% (p = 0.426). The 4‐year progression‐free survival (PFS) of patients with maintenance was 38%, whereas that of patients without maintenance was 27% (p = 0.088). Multivariate analysis revealed that an International Staging System score ≥2 was associated with worse PFS (hazard ratio 1.62, p = 0.043). Among the 129 patients, two were excluded owing to early relapse, 50 patients achieved complete response (CR), and 77 patients failed to achieve CR. Patients who achieved CR showed better 4‐year PFS than those who failed to achieve CR (41% vs. 30%, p = 0.027); however, 4‐year OS was not different (76% vs. 82%, p = 0.971). In patients who achieved CR, 4‐year OS with/without maintenance was 74%/81% (p = 0.357), 4‐year PFS with/without maintenance was 42%/40% (p = 0.954). In patients who failed to achieve CR, the 4‐year OS with/without maintenance was 97%/91% (p = 0.107), and 4‐year PFS with/without maintenance was 36%/16% (p < 0.001). In patients who failed to achieve CR, maintenance significantly improved the PFS. Maintenance after HDT/ASCT can prolong PFS in patients who fail to achieve CR in real‐world settings.