HLA-Identical Allogeneic Stem Cell Transplantation (alloSCT) for Patients with Primary Cutaneous T-Cell Lymphoma (CTCL): A Retrospective Analysis of the Lymphoma Working Party of the European Group for Blood and Marrow Transplantation (EBMT-LWP).

Patients with aggressive forms of Mycosis Fungoides (MF), Sézary syndrome (SS) and other less common subtypes of primary CTCL have a dismal prognosis with conventional therapy. A potential role for alloSCT in these patients has been suggested by a number of case-reports and small series. We conducted a retrospective registry analysis of 64 recipients who received an alloSCT from HLA-identical donors (52 related, 12 unrelated) for advanced CTCL reported to EBMT between 1997 and 2006: 23 MF, 21 SS, 16 primary cutaneous anaplastic large cell lymphoma and 4 subcutaneous panniculitis-like T-cell lymphoma; 38 patients were male, 26 were female; median age was 46 years (5–65); median follow up of survivors was 28 months. AlloSCT was performed at a median of 22 (3–313) months from initial diagnosis, following a median of 3 (1–8) prior lines of therapy, the stem cell source was PB in 54 cases and BM in 10 cases, reduced-intensity conditioning (RIC) was used in 41 (64%) cases. Twenty-three percent of patients were in complete response (CR) and 26% in partial response (PR) at the time of alloSCT. All other patients were primary refractory (RE, 25%) or progressed after a previous response (PG, 26%). Non-relapse mortality was 24% at 3 years, and appeared higher in patients receiving myeloablative conditioning (MAC) than in those receiving RIC alloSCT (35% vs 16%; p=0.06). Acute graft versus host disease (GVHD) occurred in 37% of patients at risk, and chronic GVHD in 69% of patients alive at day +100. The cumulative incidence of disease relapse (36% at 3 years) was significantly higher in patients with advanced disease status at alloSCT (RE/PG 46% vs CR/PR 21%; p=0.01), but similar in patients with related and unrelated donors (p=0.39) and receiving MAC or RIC (p=0.6). Progression free survival (PFS) at 3 years was 41%, with a significant advantage for patients in CR/PR at alloSCT (58% vs 26%; p<0.01), but not for type of conditioning (MAC 45% vs RIC 44%; p=0.4) or donor type (related 46% vs unrelated 33%; p=0.2). Out of 22 patients who relapsed, 10 remain alive and 4 of these were in CR at last follow up, possibly indicating that a proportion of patients achieved a better control of CTCL following relapse after alloSCT. Overall survival for the whole series was 55% at 3 years, with a trend towards an improved OS for patients with disease in CR/PR at transplant (65% vs 46%; p=0.1). Overall, outcome after allogeneic transplantation appears superior to that expected for such patients under conventional therapy. Our analysis reinforces the important role of alloSCT in advanced stage CTCL in a relatively large registry-based series.