Irinotecan in relapsed or refractory non-Hodgkin's lymphoma

Irinotecan (CPT-11, Camptosar) is a topoisomerase I inhibitor with a broad spectrum of antitumor clinical activity. Various schedules and doses have been studied, and major complications were delayed diarrhea and myelosuppression. We explored the activity of irinotecan in patients with relapsed or refractory non-Hodgkin's lymphoma, using a 3-week schedule of administration. Eligible patients had histologically proven relapse, had received no more than two previous regimens, were > or = 15 years and < or = 75 years old, had normal renal function, neutrophil count > 1,500/microL, platelet count > 100,000/microL, and no human immunodeficiency virus infection or central nervous system involvement. Patients were treated with irinotecan 300 mg/m2 i.v. every 21 days with intensive loperamide management of diarrhea. Responders received up to six treatment cycles. Of 25 patients registered so far, 22 are evaluable for response. The median age was 67 years (range: 25 to 74 years) and 11 were male. The median number of previous regimens was 2 (range: 1 to 4 regimens), and 16 patients had disease that was refractory to their last regimen. Serum lactate dehydrogenase level was high in 75%, and beta2-microglobulin was > 3.0 mg/L in 26% of patients. Responses were seen in 8 of 22 (36%) patients with non-Hodgkin's lymphoma. Response rates were 40% for indolent, 0% for mantle cell, 45% for relapsed aggressive, and 33% for refractory aggressive lymphomas. Grade 3/4 toxicities included myelosuppression, neutropenic fever, and delayed diarrhea. Irinotecan appears active and relatively well tolerated in patients with relapsed aggressive non-Hodgkin's lymphoma. Accrual to this study is continuing for better determination of the response rate in all histologic subtypes of non-Hodgkin's lymphoma.