Improving disease-specific survival for patients with Sezary syndrome in the modern era of systemic therapies.

Traditionally, Sezary syndrome (SS) has been associated with few therapeutic options and poor prognosis, with 5-year disease-specific survival (DSS) less than one-third in historical cohorts. However, newer therapies and combinations are associated with impressive time-to-next-treatment (TTNT), particularly allogeneic stem-cell transplantation (AlloSCT) and combination therapies notably those including extracorporeal photopheresis. In this multicentre, international study, we explored the prognostic outcomes of 178 patients exclusively managed for SS, diagnosed between 2012 and 2020, and treated in the modern therapeutic era. In this cohort, 58 different therapies were delivered, with 13.5% of patients receiving AlloSCT. Long-term survival exceeded historical reports with 5-year DSS and OS of 56.4% and 53.4% respectively. In those receiving AlloSCT, prognosis was excellent: 5-year DSS and OS were 90.5% and 78.0% respectively. Confirming the results from the Cutaneous Lymphoma International Consortium (CLIC), LDH and LCT had significant prognostic impact. Unlike earlier studies, stage did not have prognostic impact; we speculate that greater relative benefit favours patients with extensive lymphomatous nodal disease (Stage IVA2) compared to historical reports. For patients ineligible for AlloSCT, the prognosis remains relatively poor (5-year DSS 51.4% and OS 49.6%), representing ongoing unmet needs for more effective novel agents and investigation of improved therapeutic combinations.