A Single-Arm Phase II Trial of Lenalidomide in Relapsing or Refractory Primary Cutaneous Large B-Cell Lymphoma, Leg Type.

Although the combination of rituximab and polychemotherapy has improved prognosis of primary cutaneous diffuse large B-cell lymphoma, leg type, the advanced age of patients limits therapeutic options in relapsing/refractory cases. A multicenter, single-arm, phase II trial was conducted to assess the benefits and safety of lenalidomide in refractory/relapsing primary cutaneous diffuse large B-cell lymphoma, leg type. The primary endpoint was the 6-month overall response rate. Secondary endpoints were 12-month overall response rate, overall and specific survival, duration of response, progression-free survival, safety, and identification of prognostic factors. Among the 19 patients included, the 6-month overall response rate was 26.3% (90% confidence interval [CI] = 11-47.6), including four complete responses and one partial response. At 12 months, there were still two complete responses and one partial response. Median progression-free survival was 4 months. Median overall and specific survivals were 19.4 and 23.8 months, respectively. Reduced doses tended to be associated with higher 6-month overall response rate and progression-free survival. Absence of the MYD88 mutation was associated with a higher overall response under treatment (80.0% vs. 33.3%; P = 0.05). The most common grade 3 adverse events were hematologic. Two grade 5 adverse events occurred (sepsis and pulmonary embolism). Lenalidomide at reduced doses may allow prolonged responses in a few patients and represents a therapeutic option in relapsing/refractory primary cutaneous diffuse large B-cell lymphoma, leg type.