Study: NCT00691652

Intervention type: BIOLOGICAL
Group type: EXPERIMENTAL
Intervention: rituximab
Description: Administered weekly times 4 weeks and then monthly during the study for up to 8 cycles and will be given on day 1 of clofarabine. A peripheral or central intravenous (IV) line will be established. The initial dose rate at the time of the first infusion should be 50/mg/hr for the first hour. If no toxicity is seen, the dose rate may be gradually escalated (50 mg/hr increments at 30 minute intervals) to a maximum of 300 mg/hr. If the first dose of rituximab is well tolerated, the starting flow rate for the administration of subsequent doses will be 100 mg/hr then gradually increased (100 mg/hr increments at 30 minute intervals) not to exceed 400 mg/hr.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: clofarabine
Description: Phase 1 dosing: Initially, 3 patients will be enrolled into a dose level during the dose escalation portion. Level 1: 2mg fixed dose times 14 days for up to 8 cycles. Level 2: 4mg fixed dose times 14 days for up to 8 cycles. Level 3: 6mg fixed dose times 14 days for up to 8 cycles. Phase II dosing: The phase II dose of oral clofarabine will be determined from the phase 1.

Intervention type: GENETIC
Group type: EXPERIMENTAL
Intervention: DNA methylation analysis
Description: We will use an HPLC assay developed by Yu et al31 to determine the DNA methylation (DMI) index in peripheral blood and bone marrow of patients entering this trial and after treatment with clofarabine and rituxan

Intervention type: GENETIC
Group type: EXPERIMENTAL
Intervention: gene expression analysis
Description: Total RNA will be processed for determination of gene expression by microarray

Intervention type: GENETIC
Group type: EXPERIMENTAL
Intervention: microarray analysis
Description: we will scan the microarray slides with an Axon scanner, and quantify data using the GeneSight software. Local background is subtracted and data points with no signal, high background, or spot asymmetry are eliminated. We will adjust genes with low expression and low signal intensity to a minimal raw value of 5: This avoids unwarranted mathematical distortions due to division by decimals \<\< 1. After calculating the ratio of the Cy5 /Cy3 fluorescence signal intensity for each gene, we normalize the data relative to the mean intensity from all genes.

Intervention type: GENETIC
Group type: EXPERIMENTAL
Intervention: polymerase chain reaction

Intervention type: OTHER
Group type: EXPERIMENTAL
Intervention: high performance liquid chromatography
Description: Fifteen µg of DNA will be sonicated for 60 seconds on ice into 200 bp-1000 bp fragments. Samples are then denatured at 1000C for 5 minutes and cooled on ice to prevent re-annealing. Sixty units of nuclease S1 (Invitrogen) and 112.5 mu of snake venom phosphodiesterase I (Sigma) in 12 µl of S1 dilution buffer is then added to the samples and incubated at 370C for 18 hours. Samples are reheated to 1000C for 5 minutes, snap cooled again on ice, and another sixty units of nuclease S1 and 112.5 mu of snake venom phosphodiesterase I are added and incubated at 370C for another 4 to 6 hours. The pH of each sample was raised to 8.5 with 0.5 M Tris, pH 10. Two and a half units of alkaline phosphatase (Sigma) are added and incubated for 2 additional hours at 370C. One hundred µl of 0.05M potassium phosphate, pH 7 is added to final samples before 50 µl of the clear supernatant is injected into the reverse-phase high performance liquid chromatography (HPLC).

Intervention type: OTHER
Group type: EXPERIMENTAL
Intervention: laboratory biomarker analysis
Description: 50 µl of the clear supernatant is injected into the reverse-phase high performance liquid chromatography (HPLC).