HuMax-CD20 in B-Cell Chronic Lymphocytic Leukemia (B-CLL) Patients Failing Fludarabine and Alemtuzumab

Par. with complete remission (CR), nodular partial remission (nPR), and partial remission (PR) were classified as responders, while those with stable disease (SD) and progressive disease (PD) were classified as non-responders. Per the NCIWG guideline (1996): CR; no lymphadenopathy/hepatomegaly/splenomegaly/constitutional symptoms, normal hematology, bone marrow sample as normocellular for age, <30% lymphocytes (LC), no lymphoid nodule; PR: a >=50% decrease in LC/lymphadenopathy; nPR: persistent nodules in bone marrow; PD: new lesion or increase by >=50% from baseline; SD: no CR, PR, or PD.

Duration of response is defined as the time from the initial response (first visit at which response is observed) to progression or death. If the participant had progression between scheduled visits, no progression at the end of the trial, treatment discontinuation for undocumented progression, treatment discontinuation for toxicity or other reason, new anti-cancer treatment, and experienced death or progression after two or more missed visits in a row the endpoint was censored.

PFS is defined as the time from randomization until progression/death. Per the IRC, if the participant had progression between scheduled visits, died before the first assessment, or died between adequate visits, the endpoint was considered progressed. If there was no progression at the end of the trial, treatment discontinuation for undocumented progression, treatment discontinuation for toxicity/other reason, new anti-cancer treatment, and death/progression after 2 or more missed visits in a row, the endpoint was censored. Clinical progression is not considered as progression endpoint.

Time to next chronic lymphocytic leukemia (CLL) treatment is defined as the time from treatment allocation/randomization (Visit 2) until the time of the first administration of the next CLL treatment other than ofatumumab (or HuMaxCD20, a fully human monoclonal antibody to CD20 that is expressed on the surface of B-cells).

OS is defined as the time from allocation to death. OS will also be subgrouped for responders and non-responders.

The peripheral blood for each participant was collected and analyzed for CD5+CD19+ cell counts. CD is "cluster of differentiation," is a cell surface marker for immunophenotyping, and, in this case, is a surrogate for B cell malignancy (indicates malignant B cells). Percent change from Visit 2 (Week 0, Baseline) = (value at Week 7 minus value at Week 0 divided by value at Week 0) x 100.

The peripheral blood for each participant was collected and analyzed for CD5+CD20+ cell counts. CD is "cluster of differentiation," is a cell surface marker for immunophenotyping, and, in this case, is a surrogate for B cell malignancy (indicates malignant B cells). Percent change from Visit 2 (Week 0, Baseline) = (value at Week 7 minus value at Week 0 divided by value at Week 0) x 100.

Tumor size and change in tumor size will be measured by the absolute value of and the percent change in the sum of products of the diameters of the largest abnormal lymph nodes from Baseline to Week 24 (Visit 14). Percent change from Visit 2 (Baseline, Week 0) = (value at Week 24 minus value at Week 0 divided by value at Week 0) x 100.

Participants with complete resolution of constitutional symptoms were those in whom no constitutional symptoms, such as night sweats, weight loss, and fever or extreme fatigue, were observed.

Participants with complete resolution of lymphadenopathy (disease involving the lymph nodes) were defined as those in whom all observed lymph nodes were of normal size (all nodes <1 centimeters) as determined by physical examination assessed by the investigator. All palpable lymph node sizes were recorded.

ECOG performance status is a measure of the participant's ability to carry out activities of daily living on 6-point scale (0=fully active, 1=restricted in physically activity, ambulatory, 2=ambulatory [>50% of waking hours], 3=capable of only limited self care, 4=completely disabled, 5=Dead). Improvement in ECOG performance status is defined as a decrease from baseline by at least one score on the ECOG scale.

The number of participants (par.) who were positive, negative, or had missing data for the following prognostic factors indicative of altered responsiveness to treatment and/or survival was measured: 17p-, 11q-, +12q, 6q-, 13q-. Par. were assessed by FISH for these chromosomal abnormalities known tobe prognostic for time to treatment and survival when detected at diagnosis. Par. were categorized by the chromosomal abnormality detected: 17 p deletion, 11q deletion (but not 17 p deletion), 12 q trisomy (but not 17 p or 111q deletion), 13q deletion only, and no chromosomal abnormalities found.

The number of participants (par.) who had improvement in hemoglobin levels >=11 grams (g)/deciliter (dl) (6.8 millimoles/liter) or 50% improvement over baseline was measured.

Improvement in thromb. is defined as a decrease from Visit 2 by >=1 National Cancer Institute Common Terminology Criteria (NCI CTC) grade. Thromb. is defined as low platelet counts resulting from refractory CLL, damage from prior treatment, advanced age, or reduced bone marrow function and can be considered as an adverse condition. Adverse events (AEs) such as thromb. in a cancer indication are graded on a scale determined by the NCI called the NCI CTC: lowest, grade 1; highest, grade 5 (death). Changes in this grading can assess improvements or declines in the severity of the AE.

Participants with complete resolution of enlarged liver (hepatomegaly) were defined as those with an enlarged palpable liver at baseline followed by the absence of hepatomegaly post- baseline (i.e., the liver was of normal size). Liver size was assessed by physical examination and documented as "centimeters" under the costal margin with relative changes in spleen size in 1 dimension calculated based on palpated numeric measurements (as per the 1996 NCIWG guidelines).

Low levels of neutrophils (neutropenia) may increase the risk of developing serious infections and may be considered an adverse condition and evaluated on the NCI CTC with a grade. Improvement in neutropenia is defined as a decrease from Visit 2 (baseline) by at least one NCI CTC grade. Improvement is defined as a decrease from Visit 2 by at least one NCI CTC grade.

Participants with complete resolution of enlarged spleen (splenomegaly) were defined as those with an enlarged palpable spleen at baseline followed by the absence of splenomegaly post-baseline (i.e., the spleen was of normal size). Spleen size was assessed by physical examination and documented as "centimeters" under the costal margin with relative changes in spleen size in 1 dimension calculated based on palpated numeric measurements (as per the 1996 NCIWG guidelines).

An adverse event (AE) was defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which did not necessarily have a causal relationship with the treatment. A list of AEs experienced in the study with a frequency threshold of 5% can be found in the AE section of this results record.

Cmax is defined as the maximum concentration of drug in serum samples. Ctrough is defined as the trough serum concentration (measured concentration at the end of a dosing interval [taken directly before the next administration]). No drug was present before the first infusion; therefore, there are no Ctrough results for Dose 1

AUC is defined as the area under the ofatumumab concentration-time curve as a measure of drug exposure. AUC(0-inf) is AUC from the start of infusion extrapolated to infinity. AUC(0-tau) is AUC from the start of infusion over the dosing interval.

Half-life ( t1/2) is defined as the terminal half-life and is the time required for the amount of drug in the body to decrease by half.

CL is the clearance of drug from serum, which is defined as the volume of serum from which the drug is cleared per unit time.

Vss is defined as the volume of distribution at steady state of ofatumumab.