[Retrospective clinical study on cryopreservation-free integrated autologous hematopoietic stem cell transplantation model for newly diagnosed multiple myeloma].

Objective: To explore the efficacy and safety of cryopreservation-free integrated autologous hematopoietic stem cell transplantation (HSCT) model for patients with multiple myeloma. Methods: A total of 96 patients with newly diagnosed multiple myeloma (NDMM) between July 31, 2020, and December 31, 2022, were retrospectively analyzed, of which 41 patients in the observation group received integrated non-cryopreserved transplantation mode. After hematopoietic stem cells were mobilized and collected, melphalan was started immediately for pre-transplant conditioning, and non-cryopreserved grafts from the medical blood transfusion refrigerator were directly injected intravenously into the patient within 24-48 h after the melphalan conditioning. The control group consisted of 55 patients who received traditional transplantation mode. After hematopoietic stem cells were collected, stem cell cryopreservation was performed in liquid nitrogen, and then the transplant plans were started at the right time. All patients received mobilization of autologous hematopoietic stem cells using the G-CSF combined with the plerixafor. Results: ① A total of 34 patients (82.9% ) with VGPR plus CR in the observation group were significantly higher than 33 patients (60.0% ) in the control group (P=0.016). ②Compared with the control group, the incidence of grade 1 oral mucosal inflammation was higher in the observation group (P<0.001) ; however, the incidence of grades 2 and 3 oral mucosal inflammation was lower (P=0.004, P=0.048), and neither group experienced grade 4 or above oral mucosal inflammation. The incidence of grade 1 diarrhea was higher in the observation group (P=0.002), whereas the incidence of grade 3 diarrhea was lower (P=0.007). No statistically significant difference was observed in the incidence of grade 4 diarrhea (P=0.506), and neither group experienced grade 5 diarrhea. ③ The incidence of bacterial infection in the observation group was lower than that in the control group (34.1% vs 65.5%, P=0.002), whereas no statistically significant difference was observed in the incidence of fungal infection (29.3% vs 31.4%, P=0.863) and viral infection (4.88% vs 3.64%, P=0.831). ④No statistically significant difference was observed in the implantation time of granulocytes and platelets between the observation and control groups [10 (8-20) days vs 11 (8-17) days, P=0.501; 13 (10-21) days vs 15 (10-20) days, P=0.245]. ⑤ All patients did not receive lenalidomide treatment 100 days post-transplantation. At 30 days post-transplantation, the CTL, NK, and Th cell counts in the observation group were lower than those in the control group (P<0.001, P=0.002, P=0.049), and the NKT cell counts were higher than those in the control group (P=0.024). At 100 days post-transplantation, the CTL, NKT, and Th cell counts in the observation group were higher than those in the control group (P=0.025, P=0.011, P=0.007), and no statistically significant difference in NK cell counts was observed between the two groups (P=0.396). ⑥ The median follow-up was 18 (4-33) months. The overall 2-year survival rates of the observation and control groups post-transplantation were 91.5% and 78.2%, respectively (P=0.337). The recurrence-free survival rates were 85.3% and 77.6%, respectively (P=0.386), and the cumulative recurrence rates were 9.8% and 16.9%, respectively (P=0.373) . Conclusion: In NDMM, the cryopreservation-free integrated autologous HSCT model can achieve similar therapeutic effects as traditional transplantation models, with lower rates of severe mucosal inflammation and infection compared with traditional transplantation models.