Mature Results of a Phase II Study of Rituximab Therapy for Nodular Lymphocyte–Predominant Hodgkin Lymphoma

Abstract

Purpose Universal expression of CD20 by malignant cells in nodular lymphocyte–predominant Hodgkin lymphoma (NLPHL) led us to evaluate rituximab (R) as a therapeutic option. Patient and Methods Patients with previously treated or newly diagnosed NLPHL were treated with R (375 mg/m2 once per week for 4 weeks) or, after a protocol amendment, with R plus R maintenance (MR; administered once every 6 months for 2 years). Primary and secondary outcome measures were progression-free survival (PFS) and overall response rate (ORR), respectively. Results A total of 39 patients were enrolled (R, n = 23; R + MR, n = 16). After four once-per-week treatments, ORR was 100% (complete response, 67%; partial response, 33%). At median follow-ups of 9.8 years for R and 5 years for R + MR, median PFS were 3 and 5.6 years (P = .26), respectively; median overall survival (OS) was not reached. Estimated 5-year PFS and OS for patients treated with R versus R + MR were 39.1% (95% CI, 23.5 to 65.1) and 95.7% (95% CI, 87.7 to 100) versus 58.9% (95% CI, 38.0 to 91.2) and 85.7% (95% CI, 69.2 to 100), respectively. Nine of 23 patients experiencing relapse had evidence of transformation to aggressive B-cell lymphoma; six of these patients had infradiaphragmatic involvement at study entry. Conclusion R is an active agent in NLPHL. Although responses are not durable in most patients, a significant minority experience remissions lasting > 5 years. R + MR results in a nonsignificant increase in PFS compared with R. R may be considered in the relapsed setting for NLPHL. The potential for transformation of NLPHL to aggressive B-cell lymphoma underscores the importance of rebiopsy and long-term follow-up.