An open-label pilot study of pentostatin, mitoxantrone, and rituximab in patients with previously untreated, Stage III or IV, low-grade non-Hodgkin lymphoma.

BACKGROUND: In a previous study, the authors demonstrated that the combination of pentostatin (P) and rituximab (R) was well tolerated and was active in patients with low-grade non-Hodgkin lymphoma (NHL). In the current study, mitoxantrone (M) was added to P + R to evaluate the toxicity and efficacy of this three-drug combination (PMR). METHODS: Twenty-four previously untreated patients with histologically proven, Stage III or IV, low-grade NHL were registered between April and September, 2002. Patients received P (4 mg/m2), M (10 mg/m2), and R (375 mg/m2) every 28 days (M on Day 1; P and R on Days 1 and 8; in Cycle 1, R was given on Day 8 only). Eighty-three percent of patients had Stage IV disease, the median patient age was 62 years (range, 4-81 years), and the performance status was 0-2. RESULTS: Responses included 9 patients who achieved complete remission (CR) (38%), 3 patients with unconfirmed CR (CRu) (12%), 8 patients who achieved partial remission (33%), and 4 patients who achieved stable disease (17%); the overall response rate (CR + CRu + PR) was 83%. PMR appeared to result in comparable activity in all histologies. The median response duration was 10.0 months (range, 3.5-15.1 months). Patients received a median of 5 cycles (range, 1-10 cycles). Eighteen patients (75%) required dose reduction or delay due to toxicity, mainly neutropenia (the administration of growth factors was not permitted). Three patients died (two patients died of disease progression, and one patient died from unrelated cardiopulmonary arrest). Grade > or = 3 drug-related toxicities included neutropenia (67%), leukopenia and febrile neutropenia (17% each), and sepsis (8%), and 38% of neutropenic episodes occurred in Cycles 1 and 2. CONCLUSIONS: In this study, PMR was active and well-tolerated in patients with low-grade NHL, and the combination is deserving of further study.

Results of a phase II multicenter trial of pentostatin and rituximab in patients with low grade B-cell non-Hodgkin's lymphoma: an effective and minimally toxic regimen.

This study explored the efficacy and toxicity of the combination of pentostatin and rituximab, effective single agents in low-grade non-Hodgkin's lymphoma (NHL). Sixty patients with previously treated low-grade NHL were enrolled. Except for day 1, both drugs were administered weekly for 4 weeks, with week 5 off. During week 1 (day 1) only rituximab was given; subsequent weekly treatments included both drugs. Patients received a minimum of 2 five-week cycles in order to be evaluable for efficacy. Responses were evaluated on week 5 of cycle 2. If partial response (PR) or stable disease (SD) responses were noted, 2 additional cycles were administered. Final evaluations were done on week 5 of cycle 4. Of 60 patients, 58.3% had an Eastern Cooperative Oncology Group performance status (PS) of 0, and 41.7% had PS of 1; 31.7% and 51.7% had stage III or stage IV disease, respectively. Histology included follicular center, follicular, grade I (45%), II (21.7%), III (1.7%), and small lymphocytic (31.7%). Seventeen patients had prior chemotherapy, but no patients had received prior pentostatin or rituximab. Median age was 60.3 years (range, 32.5-84.7 years). Among 57 evaluable patients, 77% responded (22.3% complete response [CR], 3.5% unconfirmed CR, 35.1% PR, and 10.5% unconfirmed PR); 19.3% had SD, and 8.8% progressive disease (PD). Response rate among previously untreated patients was 83% versus 63% in previously treated patients. Median duration of response was 11 months (range, 2.3-22.2 months); median time to progression was 15 months (range, < 1-25 months). Neutropenia was the only adverse event experienced by >/= 10% of patients. Six deaths were caused by PD, and one death each was caused by acute respiratory distress, possibly related respiratory failure, and cardiac toxicity. These results suggest the combination of pentostatin/rituximab is well tolerated and active in low-grade lymphoma.