UC Irvine

Background

Fludarabine, cyclophosphamide, and rituximab (FCR) result in durable responses in patients with previously untreated chronic lymphocytic leukemia (CLL). Previous reports have suggested that in patients with relapsed CLL, a dose-intensified rituximab regimen increases response rates in comparison with standard-dose rituximab. It is unknown whether rituximab intensification of the FCR regimen will result in improved response rates and patient outcomes in patients with previously untreated CLL.

Methods

A single-arm study was conducted to evaluate the safety and efficacy of a modified FCR regimen with multiple-dose rituximab (FCR3) in 65 patients with previously untreated CLL. The results were compared with those for a historical cohort treated with FCR.

Results

The overall response rate to FCR3 was 97%, with 75% of the patients achieving a complete remission. Minimal residual disease negativity was achieved for 62% of the patients according to flow cytometry. The median time to progression (TTP) was 81 months, and the median overall survival (OS) was not reached, with 58% of the patients still alive at a median survivor follow-up of 9.7 years. Grade 3 or 4 neutropenia, grade 3 or 4 thrombocytopenia, and major infections were observed with 45%, 5%, and 1.9% of the FCR3 courses, respectively. Therapy-related myelodysplastic syndrome (t-MDS) or therapy-related acute myelogenous leukemia (t-AML) developed in 7 patients (11%; P < .01 vs the historical FCR cohort).

Conclusions

In patients with previously untreated CLL, FCR3 resulted in response rates, TTP, and OS similar to those of a historical cohort of patients treated with FCR. FCR3 was associated with an increased incidence of t-MDS/t-AML.