Progression-free survival is defined as the time from randomization to the date of disease progression (PD) or death due to any cause. PD was determined by the investigator according to the definitions of response in the International Workshop for Chronic Lymphocytic Leukemia (IWCLL) updated National Cancer Institute-Sponsored Working Group (NCI-WG) guidelines. According to the guidelines, PD is characterized by at least one of the following: lymphadenopathy (appearance of any new lesion such as enlarged lymph nodes (>1.5 centimeter [cm]), spleen or liver or other infiltrates or an increase by 50% or more in the greatest diameter of any previous site); an increase by 50% or more in the previously noted enlargement of the liver or spleen; an increase by 50% or more in the numbers of blood lymphocytes with at least 5000 lymphocytes per microliter; transformation to a more aggressive histology, or occurrence of cytopenia attributable to chronic lymphocytic leukemia.

Intent-to-Treat (ITT) Population: all participants who were randomized in the study.

Progression-free survival is defined as the time from randomization to the date of disease progression (PD) or death due to any cause. PD was determined by the IRC according to the definitions of response in the International Workshop for Chronic Lymphocytic Leukemia (IWCLL) updated National Cancer Institute-Sponsored Working Group (NCI-WG) guidelines. According to the guidelines, PD is characterized by at least one of the following: lymphadenopathy (appearance of any new lesion such as enlarged lymph nodes (>1.5 centimeter [cm]), spleen or liver or other infiltrates or an increase by 50% or more in the greatest diameter of any previous site); an increase by 50% or more in the previously noted enlargement of the liver or spleen; an increase by 50% or more in the numbers of blood lymphocytes with at least 5000 lymphocytes per microliter; transformation to a more aggressive histology, or occurrence of cytopenia attributable to chronic lymphocytic leukemia.

Intent-to-Treat (ITT) Population: all participants who were randomized in the study.

Overall survival is defined as time from randomization to date of death.

ITT Population

Improvement in response was assessed by calculating the percentage of participants who changed from partial response (PR) at Baseline to complete response during the study.

ITT Population. Only participants who had PR at study entry were analyzed.

Time to next therapy is defined as the time from randomization to the date of receiving the next CLL treatment.

ITT Population

Progression-free survival after next-line therapy is defined as the time from randomization until progression or death following the next-line therapy and counted as events deaths prior to next-line therapy. Participants who received next-line therapy and who did not have progression or death after next-line therapy were censored at their last date of contact. Participant who died prior to next-line therapy, was counted as an event.

ITT Population. Only participants who received next-line therapy and subjects who died prior to receiving next-line therapy were analyzed.

Time to progression after next-line therapy is defined as the time from progression following randomization until progression or death following next-line therapy and counted as events deaths prior to next-line therapy. Participants who received next-line therapy with a PD prior to receiving next line therapy and who did not had progression or death after next-line therapy were censored at their last date of contact. If a participant died prior to next-line therapy, this was counted as an event.

ITT Population. Only participants who received next-line therapy and who also had PD prior to next line therapy were analysed. Participants who died prior to next-line therapy were also included for analysis.

The EORTC QLQ-CLL16 is comprised of 16 questions that address 5 domains of health-related quality of life (HRQoL) important in CLL. There are 4 multi-item scales - fatigue (2 items), treatment side effects ([TSE], 4 items), disease symptoms (disease effects scale [DES], 4 items), and infection (4 items) - and single-item scales (social activities [Social Problems (SP) Scale] and future health worries [Future Health (FH) Scale]). These are measured on a four-point Likert scale, where 1 = not at all and 4 = very much. These scores are transformed to give a rating from 0 - 100, where 0 = no symptoms or problems and 100 = severe symptoms or problems. Changes from Baseline were analyzed by a mixed model-repeated measures analysis of covariance (ANCOVA).

ITT Population

The EORTC QLQ-C30 is a self-reported, 30-item cancer-specific instrument that assesses 15 domains: physical functioning (5 items), role functioning (2 items), emotional functioning (4 items), cognitive functioning (2 items), social functioning (2 items), pain (2 items), fatigue (3 items), nausea and vomiting (2 items), five single-item symptom scores (insomnia, loss of appetite, constipation, diarrhea, and dyspnea), a single item asking about financial difficulties, and global health status/quality of life (QOF) consisting of 2 items. Functional and symptoms scales were measured on a four-point Likert scale, where 1 = not at all and 4 = very much, whereas global health status or QOF was assessed using a 7-item Likert scale, ranging from "poor" (worse quality of life) to "excellent" (better quality of life). Changes from Baseline were analyzed by mixed model-repeated measures ANCOVA.

ITT Population

EQ-5D is comprised of a 5-item health status measure and a visual analogue scale (VAS) and is used to generate two scores: the utility score and the thermometer score. The utility score measures mobility, self-care, usual activities, pain, discomfort, and anxiety/depression. Responses to each of the 5 health states are measured on a 3-point scale (level 1 = no problem; level 2 = some or moderate problem[s] and level 3 = unable, or extreme problems). Responses are typically converted into health utilities or valuations on a scale ranging from 0 (worst health) to 1 (perfect health). The thermometer score ranges from 0 (worst imaginable health state) to 100 (best imaginable health state). Changes from Baseline were analyzed by mixed model-repeated measures ANCOVA. A negative adjusted mean change from Baseline represents a worsening of quality of life.

ITT Population

Improvement is defined as a decrease from Baseline by at least one step on the ECOG performance status scale (improvement categorized as yes or no). Improvement in ECOG performance status was measured.

ITT Population. Only those participants available at the specified time points were analyzed.

Participants with the indicated constitutional or B-symptoms (night sweats [without signs of infection]; unintentional weight loss >= 10% within the previous 6 months; recurrent, unexplained fever of > 38 degrees celcius or 100.5 degrees fahrenheit for 2 weeks; and extreme fatigue) were presented. The proportion of participants with no night sweats, no weight loss, no fever and no extreme fatigue were summarized.

ITT Population. Only those participants available at the specified time points were analyzed (represented by n=X, X in the category titles). Different participants may have been analyzed at different time points, so the overall number of participants analyzed reflects everyone in the ITT population.

Participants with Grade 3, Grade 4 and Grade 5 adverse event of infection are presented. Adverse events were graded according to the National Cancer Institute (NCI) Common Toxicity Criteria for Adverse Events (CTCAE) grade, version 4.0 (1=mild; 2=moderate; 3=severe; 4=life-threatening/disabling; 5=death).

Safety Population: all participants who were randomized in the study and analyses were done based on the treatment the participant received regardless of how they were randomized.

An AE is defined as any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a medicinal product. An SAE is defined as any untoward medical occurrence that, at any dose, results in death, is life threatening, requires hospitalization or prolongation of existing hospitalization, results in disability/incapacity, is a congenital anomaly/birth defect, or important medical events that may not be immediately life-threatening or result in death or hospitalization but may jeopardize the participant or may require medical or surgical intervention to prevent one of the other outcomes listed. Refer to the general Adverse AE/SAE module for a complete list of AEs and SAEs.

Safety Population

Myelosuppression is defined as the decrease in the ability of the bone marrow to produce blood cells. Number of participants who reported myelosuppression (anemia [low hemoglobin count], neutropenia [low neutrophil count], and thrombocytopenia [low platelet count]) are presented. AEs were graded according to NCI common terminology criteria for adverse events (CTCAE) grade, version 4.0 (1, mild; 2, moderate; 3, severe; 4, life-threatening/disabling; 5, death).

Safety Population.Only those participants available at the specified time points were analyzed (represented by n=X, X in the category titles). Different participants may have been analyzed at different time points, so the overall number of participants analyzed reflects everyone in the safety population.

Participants who received at least one transfusion (any blood products or blood supportive care product) during the study are presented.

Safety Population

AIHA is a disease where the body's immune system fails to recognize red blood cells as "self" and begins destroying these red blood cells. The number of participants diagnosed with AIHA are presented.

Safety Population

All serum samples for analysis of HAHA were first tested in a screening step; positive samples from the screening were further evaluated in a confirmation test. The confirmed positive samples were reported as HAHA positive and further evaluated in the titration test to obtain a titer of HAHA. A confirmed positive result at any time point means the participant is positive for HAHA.Results are reported as the number of participants positive for HAHA.

Safety Population. Only those participants with post-ofatumumab HAHA results 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. Baseline IgA, IgG, and IgM values are the last pre-dose assessment values performed on Cycle 1 Day 1. Change from Baseline was calculated as the post-baseline value minus the Baseline value.

Safety Population. Only those participants available at the specified time points were analyzed (represented by n=X, X in the category titles). Different participants may have been analyzed at different time points, so the overall number of participants analyzed reflects everyone in the safety population.

MRD refers to small number of leukemic cells that remain in the participant during treatment or after treatment at the time the participant achieved a confirmed complete remission. Number of participants who were positive and negative for minimal residual disease (MRD) at any visit is presented.

ITT Population. Only those participants with data available at the specified time point were analyzed.

CD5+CD19+ cells were counted by flow cytometry. Flow cytometry is a technique for counting and examining microscopic particles with an electronic detection apparatus. Baseline CD5+CD19+ and CD5-CD19+ cell count value is the last pre-dose assessment values performed on Cycle 1 Day 1. Change from Baseline was calculated as the post-Baseline value minus the Baseline value.

ITT Population. Only those participants available at the specified time points were analyzed (represented by n=X, X in the category titles). Different participants may have been analyzed at different time points, so the overall number of participants analyzed reflects everyone in the ITT population.

Blood samples were collected for the assessment of the following prognostic markers at Baseline (BL) and upon relapse: immunoglobulin heavy chain variable region (IgVH) mutational status; VH3-21 usage; Cytogenetics (by fluorescent in situ hybridization [FISH]) including 6q-, 11q-, +12q, 17p-, 13q- deletions; beta 2 microglobulin. Cox-regression model was used to explore the relationship between progression-free survival and the following explanatory variables: treatment group, cytogenetics (analyzed by FISH) at BL, IgVH mutational status at BL, beta 2 microglobulin at BL, BL CD20 and BL complement level. For each covariate, a hazard ratio <1 indicates a lower risk on the first effect tested compared with the other effects tested. Cytogenetics Group (based on >=20%)=CY G.

ITT Population

Blood samples were collected to assess the plasma concentration of ofatumumab. Maximum concentration (Cmax) and observed drug concentration prior to the next dose (Ctrough) were determined. Blood samples were collected at pre-dose and 0.5 hours after the end of the infusion at treatment on Month 1 Week 1 (Day 1), Month 1 Week 2 (Day 8), and at every second infusion.

Pharmacokinetic (PK) Population: all participants in the ITT Population for whom a PK sample was obtained and analyzed. Only those participants available at the indicated time points (indicated by n=X in the category titles) were analyzed.

Plasma clearance is defined as the plasma volume that is cleared of drug per unit of time.

PK Population. Only those participants available at the indicated time points (indicated by n=X in the category titles) were analyzed.

Area under the concentration time curve over the dosing interval (AUC[0-tau]) is a measure of the drug exposure over time.

PK Population. Only those participants available at the indicated time points (indicated by n=X in the category titles) were analyzed.

Volume of distribution at steady state (Vss) is defined as the apparent volume of distribution of a drug between plasma and the rest of the body at steady state. Data from all time points collected were used to calculate one Vss value for each individual.

PK Population. Only those participants available at the indicated time points were analyzed.

The terminal half life (t1/2) of ofatumumab is defined as the time required for the plasma concentration of ofatumumab to reach half of its original value.

PK Population. Only those participants available at the indicated time points (indicated by n=X in the category titles) were analyzed.