Impressive response of CD30‐negative, treatment‐refractory mycosis fungoides to brentuximab vedotin

: Brentuximab vedotin is a CD30-antibody/drug conjugate which has demonstrated excellent response in treating CD30-positive mycosis fungoides (MF) and anaplastic large cell lymphoma (ALCL). In this report, we present a patient with CD30-negative MF refractory to multiple other lines of therapy who demonstrated a dramatic response to brentuximab. This paradoxical response may be due to inadequate detection of CD30 expression by immunohistochemical techniques. From this case we see that even in the setting of apparent CD30 negativity, brentuximab may be a viable treatment option for patients who require bridging to stem cell transplant or seek successful palliation. This case highlights the point that rigid inclusion criteria for MF trials without use of more sensitive techniques to confirm lack of CD30 expression may inappropriate.