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Nipent®, Cytoxan® and Rituxan® Effective for Untreated Poor Risk CLL
Researchers from Ohio State University and the Mayo Clinic have reported that the treatment combination consisting of Nipent (pentostatin), Cytoxan (cyclophosphamide) and Rituxan (rituximab) (PCR) demonstrates high activity in previously untreated patients with chronic lymphocytic leukemia (CLL) with high-risk factors. The details of this study appeared on September 28, 2006, as an early online publication in Blood .
One of the most active drug combinations for the treatment of CLL and low-grade NHL is Fludara® (fludarabine), Cytoxan and Rituxan. The main side effect of this regimen is an increased risk of infection. This has led to the substitution of Nipent for Fludara for the treatment of CLL. A previous study from the Memorial Sloan-Kettering Cancer Center reported that the PCR regimen has high activity in previously treated patients with CLL or low-grade non-Hodgkin’s lymphoma (NHL) (see related news). These authors suggested that patients receiving PCR had less grade 3-4 neutropenia, fewer infections and received more of the protocol dosing of drugs than patients receiving Fludara-based regimens.
The current study evaluated PCR in 64 patients with previously untreated high risk CLL. The median age was 63 years with the oldest patient being 80-years-old. Patients had high risk features by a variety of laboratory and clinical criteria. The treatment regimen consisted of 21 day cycles of PCR for a projected 6 cycles with Bactrim® and Zovirax® prophylaxis. The median follow-up of this study was 26 months.
These authors reported an overall response rate of 91% with a median duration of response of 34 months. The complete response rate was 41% and the partial response rate was 50%. Progression-free survival was 32.6 months. Eighty-six per cent of patients are alive at the time of this report, and 38% have progressive disease.
The death rate during treatment was 3.2%. Forty percent of patients had grade 3-4 neutropenia and 20% had grade 3-4 thrombocytopenia. Six patients had upper respiratory infections and one had fever without neutropenia. Life threatening infections did not appear to be a major problem.
Comments: These results appear to be comparable to Fludara-based regimens with possibly fewer infectious complications. Only a direct comparison can determine relative effectiveness and determine if there are fewer infections with Nipent-based versus Fludara based regimens.
Reference: Kay NE, Geyer SM, Call TG, et al. Combination chemoimmunotherapy with pentostatin, cyclophosphamide and rituximab shows significant clinical activity with low accompanying toxicity in previously untreated B-chronic lymphocytic leukemia. Blood First Edition Paper, prepublished online September 28, 2006:DOI 10.1182/blood-2006-07-033274.