Pomalidomide therapy for cGVHD: trial highlights and immunomodulatory targets. FFS, failure-free survival; GVT, graft-versus-tumor; IL-2, interleukin-2; ITT, intent-to-treat; LLS, Lee symptom scale; ORR, overall response rate; PROs, patient-reported outcomes; QOL, quality of life; Tregs, regulatory T-cells.