Primary cutaneous T-cell lymphomas (CTCL) are a group of lymphoproliferative disorders characterized by localization of neoplastic T cells to the skin at presentation. Mycosis fungoides (MF) and its leukemic variant Sezary syndrome (SS) are the most prevalent forms of CTCL. While early stage MF is restricted to patches and plaques involving the skin, most patients eventually develop cutaneous tumors, generalized erythroderma, or dissemination to peripheral blood, lymph nodes or visceral organs. Currently existing therapy of tumor-stage and disseminated CTCL is palliative, with most patients dying within 1-5 years. The presence of CD8+ cells in close proximity to dermal neoplastic infiltrates in early stages of the disease, and the clinical response seen with some immunomodulatory agents suggests that CTCL may be potential targets for immunotherapy-based interventions.

Allogeneic stem cell transplantation is a curative treatment modality successfully employed in a number of hematologic malignancies. The curative effect of this approach is in part mediated by donor-derived T lymphocytes with reactivity for patient leukemic cells. The power of this graft versus leukemia effect (GVL) is best illustrated in patients with relapsed Chronic Myeloid Leukemia (CML) after an allogeneic bone marrow transplant, in whom a single donor lymphocyte infusion (DLI) can induce remission. We hypothesize that neoplastic T cells in MF/SS may similarly be susceptible to a graft vs. tumor (GVT) effect. Unfortunately, advanced patient age and a 25% to 35% risk of transplant related mortality (TRM) preclude the use of conventional 'dose- intensive' allogeneic peripheral blood stem cell transplantation (PBSCT) in patients with advanced CTCL who might otherwise benefit from this approach. The risk of TRM related to conditioning can be circumvented at least partially by using a reduced-intensity conditioning regimen to prepare the patient for transplantation.

In this study, we will treat male and non-pregnant female subjects between the ages of 18 and 70 years (both inclusive) suffering from advanced MF/SS with an allogeneic peripheral blood stem cell (PBSC) transplant from an HLA-matched family donor or an HLA matched (10/10 allele level match) unrelated donor. A low intensity, nonmyeloablative conditioning regimen employing the anti-CD52 monoclonal antibody Campath-1H (alemtuzumab) and fludarabine will be used to induce host immunosuppression to facilitate donor hematopoietic and lymphoid engraftment. We anticipate minimal host myelosuppression and consequently reduced early transplant toxicity with this conditioning regimen. Immune and hematopoietic reconstitution will be achieved by infusion of unmanipulated donor-derived granulocyte colony stimulation factor (G-CSF) mobilized peripheral blood stem cells. Infusion of donor lymphocytes in incremental doses will be used to promote engraftment or disease regression when indicated. Cyclosporine A (CSA) will be used as prophylaxis against graft vs host disease (GVHD), with dose adjustments made as necessary to favor complete donor chimerism and disease regression.

A total of up to 25 subjects (transplant recipients) will be treated on this protocol. The primary end point of this study is efficacy (proportion of subjects achieving a complete response). Other end points include assessment of donor-host chimerism in various hematopoietic and lymphoid cells, overall response, incidence of acute and chronic GVHD, graft failure, assessment of lymphoid subset reconstitution, transplant related morbidity and mortality and disease-free and overall survival and the outcomes of transplantation by the donor type (related vs. unrelated).