A DLT was defined as the following toxicological findings, according to the Common Terminology Criteria for Adverse Events (AE) v3.0: any treatment-related Grade (G) >=3 non-hematotoxic AE, occurrence of G3 infusion reaction (treatment-related AE) at the day of infusion in a participant who received pre-medication or appropriate management during infusion (glucocorticoid) (the severity of the AE must have remained as >= G3 until the next day); and any of following: >= G4 hematotoxic treatment-related AEs (neutropenia lasting 7 days or more, febrile neutropenia).

All Subjects Population: all participants who received at least one dose of investigational drug. The first 3 participants enrolled in the study were evaluated for DLT according to study design.

Par. were evaluated in accordance with the National Cancer Institute-sponsored Working Group. CR: no lymphadenopathy (Ly)/hepatomegaly/splenomegaly/constitutional symptoms; neutrophils >=1.5*10^9/liter (L), platelets >100*10^9/L, hemoglobin >11.0 grams/deciliter, lymphocytes (LC) <4.0*10^9/L, bone marrow (BM) sample must be normocellular for age, <30% LC, no lymphoid nodule. CRi: CR criteria, persistent anemia/thrombocytopenia/neutropenia unrelated to chronic lymphocytic leukemia but related to drug toxicity. PR: >=50% decrease in LC, Ly, size of liver and spleen, etc. nPR: nodules in BM.

All Subjects Population

PFS is defined as the time from the start of treatment to the first documented sign of progressive disease (PD) or death due to any cause (whichever occurs earlier).

All Subjects Population: only those participants who progressed or died during the study were evaluated.

Duration of response is defined as the time from the first documented evidence of PR or better until the first documented sign of PD or death due to any reason in participants with PR or better.

All Subjects Population: only those participants classified as responders for the assessment of objective response were evaluated.

Overall survival is defined as the time from the first infusion of investigational drug to death due to any cause.

All Subjects Population

Time to response is defined as the time from the first infusion of investigational drug to the first response (PR or better).

All Subjects Population: only those participants classified as responders for the assessment of objective response were evaluated.

Time to next CLL therapy is defined as the time from the first infusion of investigational drug to the first administration of the next CLL treatment. CLL therapy includes anti-cancer chemotherapy, anti-cancer radiotherapy, radio-immunotherapy, and antibody therapy.

All Subjects Population: only those participants who received CLL therapy were evaluated.

Blood samples of the participants were collected for the assessment of hemoglobin.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

Blood samples of the participants were collected for the assessment of lymphocytes.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

Bone marrow (BM) aspiration was performed, and the bone marrow smears were prepared for the assessment of lymphocytes in the BM.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

Blood samples of the participants were collected for the assessment of total neutrophils.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

Blood samples of the participants were collected for the assessment of platelets.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

SERC assessed bone marrow infiltration with the bone marrow smears of participants provided by trial sites.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

SERC assessed lymphocytes based on the data provided by trial sites.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

SERC assessed lymphocytes in the bone marrow (BM) based on the data with BM smears provided by trial sites.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

SERC assessed total neutrophils based on the data provided by trial sites.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

CD19+ CD20+ cells in the peripheral blood were counted as measures of malignant B-cells and were measured by flow cytometry. Flow cytometry is a technique for counting and examining microscopic particles with an electronic detection apparatus.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

CD20+ CD23+ cells in the peripheral blood were counted as measures of malignant B-cells and were measured by flow cytometry. Flow cytometry is a technique for counting and examining microscopic particles with an electronic detection apparatus.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

CD19+ CD23+ cells in the peripheral blood were counted as measures of malignant B-cells and were measured by flow cytometry. Flow cytometry is a technique for counting and examining microscopic particles with an electronic detection apparatus.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

CD19+ CD5+ cells in the peripheral blood were counted as measures of malignant B-cells and were measured by flow cytometry. Flow cytometry is a technique for counting and examining microscopic particles with an electronic detection apparatus.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

CD20+ CD5+ cells in the peripheral blood were counted as measures of malignant B-cells and were measured by flow cytometry. Flow cytometry is a technique for counting and examining microscopic particles with an electronic detection apparatus.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

CD23+ CD5+ cells in the peripheral blood were counted as measures of malignant B-cells and were measured by flow cytometry. Flow cytometry is a technique for counting and examining microscopic particles with an electronic detection apparatus.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

Peripheral blood Ig kappa and Ig lambda were measured using flow cytometry. Abnormality of a ratio of Ig kappa and Ig lambda indicates clonality of lymphocytes. A normal range of this parameter is between 1.0 and 3.2.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

Night sweats are one of the clinical characteristics of CLL. B symptoms are systemic symptoms of fever, night sweats, weight loss, and extreme fatigue, which can be associated with CLL. Participants who had night sweats at BL, and still had night sweats at Week 1, for example, are represented in the BL, yes; Week 1, yes category. Participants who had night sweats at BL, but did not have night sweats at Week 1 are represented in the BL, yes; Week 1, no category.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

Weight loss is one of the clinical characteristics of CLL. B symptoms are systemic symptoms of fever, night sweats, weight loss, and extreme fatigue, which can be associated with CLL. Participants who had weight loss at BL, and still had weight loss at Week 1, for example, are represented in the BL, yes; Week 1, yes category. Participants who had weight loss at BL, but did not have weight loss at Week 1 are represented in the BL, yes; Week 1, no category.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

Fever is one of the clinical characteristics of CLL. B symptoms are systemic symptoms of fever, night sweats, weight loss, and extreme fatigue, which can be associated with CLL. Participants who had fever at BL, and still had fever at Week 1, for example, are represented in the BL, yes; Week 1, yes category. Participants who had fever at BL, but did not have fever at Week 1 are represented in the BL, yes; Week 1, no category.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

Extreme fatigue is one of the clinical characteristics of CLL. B symptoms are systemic symptoms of fever, night sweats, weight loss, and extreme fatigue, which can be associated with CLL. Participants who had extreme fatigue at BL, and still had extreme fatigue at Week 1, for example, are represented in the BL, yes; Week 1, yes category. Participants who had extreme fatigue at BL, but did not have extreme fatigue at Week 1 are represented in the BL, yes; Week 1, no category.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

Immunoglobulins, or antibodies, are large proteins used by the immune system to identify and neutralize foreign particles such as bacteria and viruses. Their normal blood levels indicate proper immune status. Low levels indicate immuno-suppression. IgA, IgG, and IgM were measured in the blood samples of the participants.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

HAHA are indicators of immunogenicity to ofatumumab.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

ECOG PS is used to assess how a participant's disease is progressing, to assess how the disease affects the daily living abilities of the participant, and to determine appropriate treatment and prognosis. The grades for the scale range from 0 (fully active) to 4 (completely disabled), with increasing severity.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

Blood sampling on Day 1 and at Weeks 7 and 24 for pharmacokinetic (PK) evaluation was performed at the following time points: 0.5 hour (hr) before infusion; end of infusion; and 10 minutes (min), 1 hr, 2 hr, 24 hr (1 day), 72 hr (3 days), and 120 hr (5 days) after infusion of ofatumumab. At Weeks 7 and 24, blood sampling was also performed 168 hr (7 days) and 336 hr (14 days) after infusion of ofatumumab.

PK Parameter Population: all participants who received at least one dose of investigational drug, and in whom PK data were available and allowed parameter estimations. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

Blood sampling at Weeks 7 and 24 for PK evaluation was performed at the following time points: 0.5 hr before infusion; end of infusion; and 10 min, 1 hr, 2 hr, 24 hr (1 day), 72 hr (3 days), 120 hr (5 days), 168 hr (7 days), and 336 hr (14 days) after infusion of ofatumumab.

PK Parameter Population

Blood sampling on Day 1 and at Weeks 7 and 24 for PK evaluation was performed at the following time points: 0.5 hr before infusion; end of infusion; and 10 min, 1 hr, 2 hr, 24 hr (1 day), 72 hr (3 days), and 120 hr (5 days) after infusion of ofatumumab. At Weeks 7 and 24, blood sampling was also performed 168 hr (7 days) and 336 hr (14 days) after infusion of ofatumumab.

PK Parameter Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

t1/2 of ofatumumab is the time required for the plasma concentration of ofatumumab to decrease by half. Blood sampling on Day 1 and at Weeks 7 and 24 for PK evaluation was performed at the following time points: 0.5 hr before infusion; end of infusion; and 10 min, 1 hr, 2 hr, 24 hr (1 day), 72 hr (3 days), and 120 hr (5 days) after infusion of ofatumumab. At Weeks 7 and 24, blood sampling was also performed 168 hr (7 days) and 336 hr (14 days) after infusion of ofatumumab.

PK Parameter Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

AUC(0-t) was evaluated from the plasma concentration versus time curve from time zero to the last measurable time point (time t). Blood sampling on Day 1 and at Weeks 7 and 24 for PK evaluation was performed at the following time points: 0.5 hr before infusion; end of infusion; and 10 min, 1 hr, 2 hr, 24 hr (1 day), 72 hr (3 days), and 120 hr (5 days) after infusion of ofatumumab. At Weeks 7 and 24, blood sampling was also performed 168 hr (7 days) and 336 hr (14 days) after infusion of ofatumumab.

PK Parameter Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

Blood sampling at Week 7 for PK evaluation was performed at the following time points: 0.5 hr before infusion; end of infusion; and 10 min, 1 hr, 2 hr, 24 hr (1 day), 72 hr (3 days), 120 hr (5 days), 168 hr (7 days), and 336 hr (14 days) after infusion of ofatumumab.

PK Parameter Population

Blood sampling at Week 24 for PK evaluation was performed at the following time points: 0.5 hr before infusion; end of infusion; and 10 min, 1 hr, 2 hr, 24 hr (1 day), 72 hr (3 days), 120 hr (5 days), 168 hr (7 days), and 336 hr (14 days) after infusion of ofatumumab.

PK Parameter Population. Only participants contributing evaluable data at the indicated time points were analyzed.

Blood sampling on Day 1 and at Weeks 7 and 24 for PK evaluation was performed at the following time points: 0.5 hr before infusion; end of infusion; and 10 min, 1 hr, 2 hr, 24 hr (1 day), 72 hr (3 days), and 120 hr (5 days) after infusion of ofatumumab. At Weeks 7 and 24, blood sampling was also performed 168 hr (7 days) and 336 hr (14 days) after infusion of ofatumumab.

PK Parameter Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

CL of ofatumumab from plasma of participants was evaluated. Blood sampling on Day 1 and at Weeks 7 and 24 for PK evaluation was performed at the following time points: 0.5 hr before infusion; end of infusion; and 10 min, 1 hr, 2 hr, 24 hr (1 day), 72 hr (3 days), and 120 hr (5 days) after infusion of ofatumumab. At Weeks 7 and 24, blood sampling was also performed 168 hr (7 days) and 336 hr (14 days) after infusion of ofatumumab.

PK Parameter Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

Vz for ofatumumab was calculated as a ratio of the amount of ofatumumab in the body during the terminal phase to the plasma concentration during the terminal phase. Blood sampling on Day 1 and at Weeks 7 and 24 for PK evaluation was performed at the following time points: 0.5 hr before infusion; end of infusion; and 10 min, 1 hr, 2 hr, 24 hr (1 day), 72 hr (3 days), and 120 hr (5 days) after infusion of ofatumumab. At Weeks 7 and 24, blood sampling was also performed 168 hr (7 days) and 336 hr (14 days) after infusion of ofatumumab.

PK Parameter Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

Vss for ofatumumab was calculated as a ratio of the amount of ofatumumab in the body in equilibrium conditions to steady-state plasma concentrations. Blood sampling on Day 1 and at Weeks 7 and 24 for PK evaluation was performed at the following time points: 0.5 hr before infusion; end of infusion; and 10 min, 1 hr, 2 hr, 24 hr (1 day), 72 hr (3 days), and 120 hr (5 days) after infusion of ofatumumab. At Weeks 7 and 24, blood sampling was also performed 168 hr (7 days) and 336 hr (14 days) after infusion of ofatumumab.

PK Parameter Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

MRTinf is the average amount of time that ofatumumab spends in the body. Blood sampling on Day 1 and at Weeks 7 and 24 for PK evaluation was performed at the following time points: 0.5 hr before infusion; end of infusion; and 10 min, 1 hr, 2 hr, 24 hr (1 day), 72 hr (3 days), and 120 hr (5 days) after infusion of ofatumumab. At Weeks 7 and 24, blood sampling was also performed 168 hr (7 days) and 336 hr (14 days) after infusion of ofatumumab.

PK Parameter Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.

The CH50 is the serum complement to lyse 50% of sensitized red blood cells; it's is a marker of complement activation. A high CH50 level suggests evidence for complement activation, whereas a low CH50 level suggests lack of complement activation.

All Subjects Population. Only participants remaining in the study and contributing evaluable data at the indicated time points were analyzed.