Brentuximab Vedotin Demonstrates an Objective Response in a Patient with Refractory CD30+ Primary Mediastinal B-cell Lymphoma.

Diffuse large B-cell lymphomas (DLBCL) with MYC translocations combined with translocations involving BCL-2 or BCL-6 are referred to as double-hit lymphomas. These lymphomas are generally refractory to currently available therapies and have a poor prognosis. Primary mediastinal B-cell lymphoma (PMBL) is a rare subtype of DLBCL, which shares clinical, pathologic, and genetic similarities with classical Hodgkin's lymphoma. Unlike DLBCL, rearrangements involving MYC, BCL-2, and BCL-6 are typically absent in PMBL. We present a patient with PMBL who had increased gene copy numbers of MYC and BCL-2 along with increased protein expression of BCL-2 (c-Myc expression was about 15%-20% by immunostain). The disease was refractory to standard and salvage chemotherapies. The lymphoma, however, responded to brentuximab vedotin, a CD30-directed chemoimmunoconjugate.