Ofatumumab Maintenance Treatment vs No Further Treatment in Relapsed Chronic Lymphocytic Leukaemia (CLL) Responding to Induction Therapy (PROLONG)

INTERVENTION: Patients entering into the study will be randomised to one of the two treatment arms ‐ Treatment Arm A and Treatment Arm B. Arm A patients will receive study drug (Ofatumumab/GSK1841157) whereas Arm B patients will receive no further treatment (i.e. observation only, as per standard of care) Ofatumumab/GSK1841157 Treatment: First dose 300 mg intravenous infusion (IV) followed by 1000 mg IV a week later and 1000 mg IV every 8 weeks for up to 2 years. CONDITION: Leukaemia, Lymphocytic, Chronic PRIMARY OUTCOME: Progression‐free survival (PFS). PFS is defined as the time from randomisation to the date of disease progression (as defined by the investigator based on International Workshop for Chronic Lymphocytic Leukaemia (IWCLL) updated National Cancer Institute‐sponsored Working Group (NCI‐WG) guidelines (Hallek, 2008)) or death due to any cause. SECONDARY OUTCOME: Clinical benefit, safety, tolerability. These outcomes will be assessed by: ; ‐ CT scans ; ‐ Bone marrow biopsy and flow cytometry (only as part of complete response (CR) evaluation for patients entering or during the study in CR). ; ‐ Laboratory assessments i.e. haematology, biochemistry, liver function tests, pregnancy test (if applicable) ; ‐ Blood sampling to assess prognostic factors ; ‐ Physical examination including vital signs assessment, Eastern Cooperative Oncology Group (ECOG) performance status value, constitutional symptom assessment and lymph node & organ examination ; ‐ Patient reported outcomes i.e. quality of life questionnaires ; ‐ Assessment of adverse and serious adverse events during the course of study ; ‐ Documentation of concomitant medications taken by patients during the course of study ; ‐ Pharmacokinetic samples and human anti‐human antibody (HAHA) samples collected (from Ofatumumab treatment arm only) during the course of study Overall survival Pharmacokinetic‐plasma ofatumumab concentrations (Patients on Ofatumumab treatment only) INCLUSION CRITERIA: 1. Adults with documented diagnosis of CLL based on the modified IWCLL updated NCI‐WG guidelines (Hallek, 2008) 2. Atleast PR according to the revised 2008 NCI‐WG CLL criteria within 3 months of the response assessment after the last dose of 2nd/3rd line treatment 3. The anti‐leukemic treatment before study entry should have been for at least 3 months or 3 cycles 4. ECOG Performance Status of 0‐2 5. Signed written informed consent prior to performing any study‐specific procedures