Long-Term Follow-Up of Multiple Myeloma Patients Treated with Tandem Autologous Transplantation Following Melphalan and Upon Recovery, Total Marrow Irradiation.

Total body irradiation in combination with melphalan for multiple myeloma (MM) has been shown to be prohibitively toxic. To ameliorate toxicity, total marrow irradiation (TMI) has been administered as the sole ablative modality during the second cycle of tandem autologous stem cell transplantation (TASCT) for MM patients on a phase I-II trial. Patients with MM in response or with stable disease and ≤18 months from diagnosis received melphalan 200 mg/m2 and autologous stem cell transplantation (ASCT) (cycle 1) and then, after recovery, TMI and another ASCT (cycle 2), followed by maintenance with an immunomodulatory drug (ImiD) and dexamethasone for up to 12 months. TMI doses were escalated from 1000 cGy to 1800 cGy in 200-cGy increments. Fifty-four patients were to receive TASCT between 2004 and 2011; 8 patients received single ASCT because of patient or physician preference. The median time between melphalan and TMI was 65 days (range, 47 to 125 days). Thirty patients (55.6%) underwent TASCT at the maximum tolerated dose of 1600 cGy. The complete response and very good partial response rates were 48.1% and 22.2%, respectively, following ASCT and maintenance. The median follow-up among survivors was 12.3 years (range, 9.2 to 15.5+ years). Progression-free survival (PFS) and overall survival at 10 years were 20.4% (95% confidence interval [CI], 10.9% to 31.9%) and 38.8% (95% CI, 25.9% to 51.5%), respectively. Secondary neoplasms included (1 each) acute myelogenous leukemia, papillary thyroid and prostate carcinoma, and melanoma, and there was 1 case of ductal carcinoma in situ and 4 cases of nonmelanoma skin cancers. TMI as part of TASCT was well tolerated, and TASCT was associated with a 20.4% PFS plateau. The inclusion of TMI as a conditioning regiment for MM before ASCT warrants further study in the context of modern induction and maintenance therapies.

Late relapses following reduced intensity allogeneic transplantation in patients with multiple myeloma: a long-term follow-up study.

We analysed the long-term outcomes of 60 multiple myeloma patients who underwent reduced intensity allogeneic stem cell transplantation between August 2000 and March 2008. Regimens included fludarabine and melphalan conditioning (flu-mel regimen) for allogeneic haematopoietic cell transplant (HCT) or a planned tandem regimen consisting of high-dose melphalan conditioning for autograft followed by low-dose total body irradiation conditioning for allogeneic HCT (auto-allo regimen). Donors included human-leucocyte-antigen-matched siblings (n = 55) or matched unrelated donors (n = 5). With a median follow-up of 9·8 years, 7-year overall survival (OS) and progression-free survival (PFS) were 60% and 31%, respectively. By multivariate Cox regression analysis, disease status of complete response (CR) or partial response (PR) at transplant and the presence of chronic graft-versus-host disease were significantly associated with improved OS. Only disease status was significantly associated with improved PFS. We noted a surprising number of very late relapses, with six patients (10%) relapsing between 6 and 12 years post-transplant. Among the six late relapse patients, all were transplanted within 14 months of diagnosis, five had normal karyotypes, and five were in CR/PR. Our data provide additional evidence that, while survival may be extended by reduced intensity allogeneic transplant, ultimately, it may not offer a cure.