A pilot study of rituximab in patients with recurrent,classic Hodgkin disease

BACKGROUND: To explore the potential role of infiltrating benign B cells in classic Hodgkin disease (HD) lesions in supporting the survival of malignant Hodgkin and Reed-Sternberg (H/RS) cells, the authors initiated a pilot study of rituximab. Rituximab is used to primarily deplete normal B cells from HD lesions. METHODS: Patients with recurrent, classic HD who had received a minimum of two prior treatment regimens, regardless of whether H/RS cells expressed CD20, were treated with 6 weekly doses of 375 mg/m2 rituximab to selectively deplete infiltrating benign B cells. Objective tumor response was determined 3 weeks after completion of the last dose of rituximab and every 3 months thereafter. Serum samples were collected from patients before they started rituximab therapy and 3 weeks after the final course of rituximab. Serum cytokine levels of interleukin 6 (IL-6), IL-10, IL-12, IL-13, and interferon gamma were determined using commercially available enzyme-linked immunosorbent assay kits. RESULTS: Twenty-two patients with nodular sclerosis histology were evaluable for treatment response. Five patients (22%) achieved partial or complete remission that lasted for a median of 7.8 months (range, 3.3-14.9 months). Remissions were observed in patients only at lymph node and splenic sites, but not at extranodal sites, and were irrespective of CD20 expression by H/RS cells. Furthermore, systemic (B) symptoms resolved in six of seven patients after therapy. In two patients, partial remissions were associated with a decline in serum IL-6 levels. CONCLUSIONS: The current data suggest that rituximab therapy in patients with recurrent, classic HD can alter serum IL-6 cytokine levels, can improve B symptoms, and may result in clinical remissions.