2' Deoxycoformycin (pentostatin) for refractory non-Hodgkin's lymphoma: a CALGB phase II study

Seventy-six eligible patients with relapsed or refractory non-Hodgkin's lymphoma (NHL) were treated with 2'-deoxycoformycin (pentostatin) at a dose of 4 mg/m2 intravenously weekly for three weeks and then every other week for a minimum of five total treatments. All patients had measurable disease, near normal hematologic, renal, and hepatic function, and a performance status of 0 or 1. Severe hematologic toxicity was observed in 13% of patients; severe renal or neurologic toxicity was observed in less than 5% of patients. There were no treatment-related deaths. Objective therapeutic responses were seen in 16% of patients (five complete response [CR] and seven partial response [PR]). However, in three of the patients achieving CR and one patient achieving PR, dexamethasone was employed as an anti-emetic, making the response of these patients to pentostatin difficult to evaluate. There were eight responses (3 CR) in patients with diffuse histologies and four responses (2 CR) in patients with nodular or mixed histologies. Three responses were in patients with a T-cell phenotype. Three of five patients with diffuse well-differentiated lymphoma (IWF A) responded. We conclude that 2' deoxycoformycin is only minimally active at this dose and schedule against refractory or relapsed NHL. The possibility that low grade B- and T-cell malignancies are more sensitive to 2' deoxycoformycin deserves further investigation.