Phase II Trial of Proteasome Inhibitor Bortezomib in Patients With Relapsed or Refractory Cutaneous T-Cell Lymphoma

To determine the antitumor activity of the proteasome inhibitor bortezomib in patients with cutaneous T-cell lymphoma (CTCL) or peripheral T-cell lymphoma unspecified (PTCLU) with isolated skin involvement. From May 2005 to June 2006 at our institute, we treated patients with previously pretreated CTCL or PTCLU using bortezomib as a single agent, at a dose of 1.3 mg/m2 intravenously on days 1, 4, 8, and 11, every 21 days for a total of six cycles. Fifteen patients were registered, of whom 12 (10 CTCL, all mycosis fungoides, and two PTCLU with isolated skin involvement) were assessable. The overall response rate was 67%, with two (17%) complete remissions and six (50%) partial remissions. The remaining four patients had disease progression. Histologically, the responder patients were seven with CTCL and one with PTCLU with isolated skin involvement. All responses were durable, lasting from 7 to 14 or more months. Overall, the drug was well tolerated, with no grade 4 toxicity. The most common grade 3 toxicities were neutropenia (n = 2), thrombocytopenia (n = 2), and sensory neuropathy (n = 2). This study suggests that bortezomib was well tolerated and has significant single-agent activity in patients with cutaneous T-cell lymphoma.