Sustained MRD‐Negative Complete Remission of T‐PLL With CNS Involvement Following Treatment With Systemic and Intrathecal Alemtuzumab

Background T‐cell prolymphocytic leukaemia (T‐PLL) with central nervous system (CNS) involvement is uncommon and evidence guiding its treatment is limited. Case summary We describe the successful treatment of T‐PLL with leptomeningeal involvement using intrathecal alemtuzumab followed by allogeneic haematopoietic stem cell transplantation. Residual disease monitoring of T‐cell receptor clonotypes by next‐generation sequencing was performed to assess treatment response and guide post‐SCT intervention. At 24 months post‐SCT, the patient remains in sustained molecular remission. Conclusion This case adds to the limited literature supporting activity of intrathecal alemtuzumab in refractory CNS disease and highlights the utility of molecular monitoring following SCT. Trial Registration: The authors have confirmed clinical trial registration is not needed for this submission.