Prolonged follow-up after initial therapy with 2-chlorodeoxyadenosine in patients with indolent non-Hodgkin lymphoma: Results of cancer and leukemia group B study 9153

BACKGROUND. The objective of this study was to determine the efficacy and toxicity of 2-chlorodeoxyadenosine (2-CdA) in patients with untreated, indolent non-Hodgkin lymphoma (NHL). METHODS. For this multicenter, single-arm, Phase II study, 44 patients with treatment-naive, stage III or IV, indolent NHL (International Working Formulation subtypes A, B, and C) were enrolled. Patients received 0.14 mg/kg per day of 2-CdA as a 2-hour bolus infusion for 5 consecutive days every 28 days until maximal response or a total of 6 cycles. RESULTS. Thirty-eight patients were eligible for response evaluation. The overall response rate was 100% (95% confidence interval [95% CI], 90.8-100%), and the complete response rate was 31.6% (95% CI, 17.5-48.7%). In the intent-to-treat population, the median failure-free survival was 2.0 years (95% CI, 1.3-3.4 years), and the overall survival rate was 7.0 years (95% CI, 4.3-9.4 years). Six patients had sustained remissions that lasted a median of 8.7 years (range, from 5.9 years to ≥11 years). Although 68% of patients experienced at least 1 grade 3 or 4 event, consisting primarily of myelosuppression, severe infections were rare, with only 8 grade 3 infections. Four late malignancies (prostate adenocarcinoma, ductal carcinoma in situ, and myelodysplasia) and 4 patients with large cell transformation were reported. CONCLUSIONS. 2-CdA is an active, well-tolerated therapy for patients with untreated, indolent NHL.