A Single Center Retrospective Study of Haemopoietic Stem Cell Transplantation on Multiple Myeloma Patients: An Analysis of 14 Cases

Background: In order to evaluate the efficacy and transplantation-related complications of autologous stem cell transplantation (ASCT) and Allogeneic stem cell transplantation (Allo-SCT) in multiple myeloma (MM), the clinical outcome from 14 MM patients who received haemopoietic stem cell transplantation HSCT in our department during the last 6 years are summarized.

Methods: 8 patients received ASCT; 6 received Allo-SCT. The median age was 49 y/o. 7 patients were IgG type, 4 as IgA type, 1 as light-chain type, 1 as non-secreting type, 1 as primary plasma cell leukemia (light-chain type). According to the Durie-Salmon system, 1 patient was classified as IIA, 12 as IIIA, 1 as IIIB. The major induction chemotherapies included VAD (Vincristin Adriamycin Dexamethasone), VMCP (Vincristine Melphalan Cyclophosphamide Prednisone), M2 (Vincristine Carmustine Melphalan Cyclophosphamide Prednisone), DVD (Doxil Vincristine Decadron), with a median of 5 (3–16) cycles. 2 patients achieved CR through VTD induction therapy. The other 3 achieved nCR, 7 achieved PR, 1 achieved SD; and 1 patient had progressive disease before transplantation. In ASCT patients, combined HD-CTX(3–4g/m2) {G-CSF therapy (n=3) or monotherapy of G-CSF (n=4) were used to mobilize the peripheral blood stem cells. The median CD34+ cell count was 2.57(1.1–5.61)×106/kg. Seven received HD-Mel (200mg/m2) monotherapy, 1 received combined therapy of bortezomib and HD-Mel. In the 6 Allo-SCT patients, all the donors were HLA-identical siblings. The median CD34+ cell count was 3.72 (2.44–6.19) ×106/kg. Three received HD-Mel monotherapy, 2 received combined therapy of bortezomib and HD-Mel, 1 received non-myeloablative transplantation using fludarabine plus ALG and HD-Mel.

Results: All the recipients achieved hematopoietic reconstitution. All 6 Allo-SCT patients revealed donor chimerism >90% with the STR test at one month post-transplantation. All 14 patients had Grade I–III mucositis, 6 patients had neutropenic fever. Two patients suffered from Grade I liver dysfunction. Among the 6 Allo-SCT patients, 1 who received non-myeloablative transplantation died from Grade IV aGVHD. One patient had Grade III aGVHD and chronic extensive GVHD, another one suffered from chronic local GVHD. The transplantation-related mortality rate was only 7.1%. Twelve (85.7%) patients achieved CR/nCR after transplantation. With a median time of follow-up of 28 months (8–60), the median time of survival was 18 months (1–60), and the median event-free survival duration was 17 months (1–51). The estimated 4-year EFS was 57.1% and OS was 64.3%. Of the 8 ASCT patients, 7 achieved CR/nCR after transplantation, 2 patients died of disease relapse, and 1 patient died from severe pneumonia at 22 months post-transplantation. Of the 6 Allo-SCT patients, 5 achieved CR/nCR, of whom 2 have relapsed. Among these relapses, 1 responded after subsequent bortezomib therapy, and 1 patient died one year after transplantation.

Conclusion: Haemopoietic stem cell transplantation shows efficacy and safety in the myeloma patients under 65 y/o. The patients underwent ASCT or Allo-SCT according the availability of available donors. The results suggest both ASCT and Allo-SCT significantly improve CR, EFS and OS for myeloma patients with relatively low transpantation-related mortality. There is no significant difference between ASCT and Allo-SCT. Disease relapse is still the major cause of death. In order to reduce the relapses, the use of novel agents such as bortezomib should be considered during induction and/or consolidation phases to improve the efficacy of HSCT on MM.