Single-agent gemcitabine enabling successful bridging to allogeneic haematopoietic stem-cell transplantation in refractory peripheral T-cell lymphoma, not otherwise specified

A man in his 20s presented with fever, night sweats and marked leucocytosis (94×10 ⁹ /L). Cervical lymph node biopsy confirmed peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS). The disease was refractory to brentuximab vedotin plus cyclophosphamide, doxorubicin and prednisone, SMILE and pralatrexate. Subsequently, single-agent gemcitabine (1000 mg/m² on days 1, 8 and 15) induced complete remission, unconfirmed (CRu), after two cycles, enabling reduced-intensity allogeneic haematopoietic stem-cell transplantation from an HLA one-locus-mismatched related donor in the host-versus-graft direction. The patient remains in remission 36 months post-transplant. Throughout the course, serial leucocyte-to-lymphocyte ratio (LLR) measurements appeared to parallel disease activity, with elevation during refractory disease and normalisation in remission. This case suggests that single-agent gemcitabine may provide a feasible low-toxicity bridge to transplantation in selected refractory PTCL-NOS and that serial LLR measurements may represent a simple adjunctive marker of disease dynamics.