Nonmyeloablative allogeneic transplantation achieves clinical and molecular remission in cutaneous T-cell lymphoma

The majority of patients with refractory, advanced-stage mycosis fungoides (MF) or Sézary syndrome (SS) have a life expectancy of <5 years. Here, we report a phase 2 study of a novel nonmyeloablative allogeneic transplantation strategy tailored for this patient population. This study has completed the enrollment, and 35 patients (13 MF, 22 SS) have undergone transplant as planned. The majority (80%) of the patients had stage IV disease and received multiple previous systemic therapies. All patients had active disease at the time of conditioning using total skin electron beam therapy, total lymphoid irradiation, and antithymocyte globulin, and received allograft infusion as outpatients. Cyclosporine or tacrolimus and mycophenolate mofetil were used for graft-versus-host disease (GVHD) prophylaxis. Patients tolerated the transplant well, with 1- and 2-year nonrelapse mortality of 3% and 14%, respectively. The day +180 cumulative incidence of grade 2 to 4 acute GVHD was 16%, and the 2-year incidence of moderate/severe chronic GVHD was 32%. With a median posttransplant follow-up of 5.4 years, the 2-, 3-, and 5-year overall survival rates were 68%, 62%, and 56%. Using high-throughput sequencing of the T-cell receptor for minimal residual disease monitoring, we observed that 43% achieved molecular remission, which was associated with a lower incidence of disease progression or relapse (9% vs 87%; P = .02). Our study also showed that patients who were aged ≥65 years at the time of allotransplant had similar clinical outcomes compared with younger patients. Thus, we have developed an alternative and potentially curative nonmyeloablative allogeneic transplant regimen for patients with advanced stage MF/SS. This trial was registered at www.clinicaltrials.gov as #NCT00896493.