Clinical characteristics, efficacy, and survival analysis of IgD-type multiple myeloma

Objective To investigate the clinical characteristics, treatment efficacy, survival outcomes, and prognostic factors in patients with IgD multiple myeloma (MM). Methods Retrospective analysis was conducted on the clinical data of 56 IgD-type MM patients who were treated at the Affiliated Hospital of Xuzhou Medical University between March 2016 and August 2024. Their treatment efficacy and survival outcomes were analyzed. Results Among the 56 patients, 40 were male (71.4%) and 44 were aged ≤65 years (78.6%). The λ light chain type was observed in 53 cases (94.3%). Of 37 staged patients, 18 were in ISS stage Ⅲ (48.7%). Cytogenetic abnormalities were present in 23 of 27 tested patients (85.2%), with 1q21+ being the most common (74.1%, 20/27). Among 37 patients treated with proteasome inhibitor (PI)-based regimens, 34 achieved partial remission (PR) or better, with an overall response rate (ORR) of 91.9%. Complete remission (CR) or better was achieved in 20 cases (54.1%). The median follow-up time was 41 months, while the median progression-free survival (PFS) and median overall survival (OS) were 24 and 67 months, respectively. Univariate Cox analysis showed that age >65 years, platelet count <100×10⁹/L, creatinine ≥177 μmol/L, lactate dehydrogenase >250 U/L, bone marrow plasma cell proportion ≥60%, and 17p deletion were adverse prognostic factors for OS, with 17p deletion also being an adverse factor for PFS and an independent prognostic factor for OS. Ten patients underwent autologous stem cell transplantation (ASCT), with a median OS of 67 months, slightly better than the non-transplant group (52 months, P=0.068). Fifteen patients received CAR-T therapy; the median OS was not reached and was superior to that of the non-CAR-T group (52 months, P=0.036). The median PFS after CAR-T was 28 months. Conclusions IgD-type MM predominantly occurs in males ≤65 years old, mainly with λ light chain expression. Patients often present with advanced disease at diagnosis and exhibit frequent cytogenetic abnormalities. The 17p deletion is an independent adverse prognostic factor for OS. In the era of novel therapies, ASCT and CAR-T therapy may contribute to prolonged survival in patients with IgD MM.