A Phase I/II, Open-label Study of Ofatumumab Added to Chlorambucil in Previously Untreated Japanese Patients With Chronic Lymphocytic Leukemia

Tolerability of ofatumumab in combination with chlorambucil was evaluated based on the number of participants who developed toxicity requiring discontinuation from study treatment during Cycle 1. The treatment was considered tolerable when 0 of 3 participants, or <=2 of 6 participants developed toxicity which required discontinuation of study treatment during Cycle 1. The toxicity requiring discontinuation was determined based on the pre-defined withdrawal criteria.

Response evaluated as per International Workshop for Chronic Lymphocytic Leukemia (IWCLL) National Cancer Institute-sponsored Working Group (NCI-WG) Guidelines, 2008. Overall response rate (ORR) is defined as percentage of par. achieving complete remission (CR), nodular partial remission (nPR), CR-incomplete (CRi) or PR. CR (>=2 months after last treatment): lymphocytes (LC) <4000 per microliter (μL), no lymphadenopathy (Ly)>1.5 cm/hepatomegaly/splenomegaly/constitutional symptoms; neutrophils (N)>1500/µL, platelets (PL)>100,000/µL, hemoglobin (Hb)>11 grams/deciliter (g/dL), bone marrow (BM) sample must be normocellular for age,<30% LC, no lymphoid nodule (LN). PR:>=50% decrease in LC, Ly, size of liver and spleen; and at least one of these: N>1500/μL, PL>100,000/µL or 50% improvement over Baseline (BL), Hb>11 g/dL or 50% improvement over BL. nPR: persistent nodules BM. CRi: CR criteria, persistent anemia/thrombocytopenia/neutropenia unrelated to CLL but related to drug toxicity.

Response was determined according to the IWCLL updated NCI-WG guidelines, 2008. According to the guidelines, CR (all the criteria at least 2 months after last treatment): peripheral blood lymphocytes below < 4,000/μL, no Ly > 1.5 cm/ hepatomegaly/ splenomegaly/ constitutional symptoms; Neu >1500 /µL, PL >100,000/µL, Hb >11 g/dL, BM sample must be normocellular for age, <30% lymphocytes, no LN. PR: >=50% decrease in peripheral blood lymphocytes, Ly, size of liver and spleen; and blood count showing at least one of the following results: Neu>1500/μL, PL >100,000/µL or 50% improvement over BL, Hb >11 g/dL or 50% improvement over BL. No increase in LN and no new LN.

Progression free survival is defined as the time from start of treatment until disease progression (PD) or death due to any cause. PD was determined by the IRC or investigator according to the definitions of response in the IWCLL updated NCI-WG guidelines, 2008. 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 per microliter B-lymphocytes; transformation to a more aggressive histology; or occurrence of cytopenia attributable to chronic lymphocytic leukemia. PFS was censored at the last visit with adequate assessment for participants who were alive and had not progressed.

Overall survival is defined as time from start of treatment until death due to any cause. For participants who did not die, time to death was censored at the time of the last date of contact.

Time to response is defined as the time from start of treatment until the first response (CR/CRi/nPR/PR). Response was determined according to the IWCLL updated NCI-WG guidelines, 2008. This analysis only included participants who had a response while in the study, there was no censoring.

Duration of response is defined as the time from the first documented evidence of CR, CRi, nPR or PR until the first documented sign of PD or death in participants with CR, CRi, nPR or PR. For participants who did not progress or die, duration of response was censored on the date of last assessment.

Time to next CLL therapy is defined as the time from start of treatment until the first administration of the next CLL treatment other than chlorambucil administrations scheduled in this study. Time to next CLL therapy was restricted to the subgroup of the population who receive a next CLL therapy after experiencing disease progression.

The number of participants with no B-symptoms (no night sweat [without signs of infection], no unexplained, unintentional weight loss >= 10% within the previous 6 months, no recurrent, unexplained fever of greater than 38 degrees celcius for 2 weeks and no extreme fatigue) and the number of participants with at least one of the B-symptoms are summarized by assessment time. The presence of the B-symptoms was assessed at Baseline, Day 1 of each treatment cycle and follow-up (FU). Baseline was the last pre-dose assessment performed at Cycle (C) 1-Day (D) 1.

ECOG PS is a scale to assess disease progression, extent to which disease affects the daily living abilities and determines appropriate treatment and prognosis. It is scored on a scale of 0 to 5 as, 0 (fully active), 1 (restricted in physically strenuous activity but ambulatory and able to carry out work of a light or sedentary nature), 2 (ambulatory and capable of all self cares but unable to carry out any work activities, up and about > 50% of waking hours), 3 (capable of only limited self cares, confined to bed or chair > 50% of waking hours), 4 (completely disabled, cannot carry on any self cares, totally confined to bed or chair), 5 (death). Improvement is defined as decrease from Baseline by at least one step on the ECOG performance status scale (yes/no). Baseline was the last pre-dose assessment performed on Cycle 1-Day 1(C1-D1). When C1-D1 was missing, the last assessment performed prior to pre-dose C1-D1 was used. It was performed on Day 1 of each cycle and follow-up (FU).

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.

Adverse events were graded according to the National Cancer Institute (NCI) Common Toxicity Criteria for Adverse Events (CTCAE) grade, version 4.03 (1=mild; 2=moderate; 3=severe; 4=life-threatening/disabling; 5=death). AEs not in the list of CTCAE were graded at discretion of the investigator.

Adverse events were graded according to the National Cancer Institute (NCI) Common Toxicity Criteria for Adverse Events (CTCAE) grade, version 4.03 (1=mild; 2=moderate; 3=severe; 4=life-threatening/disabling; 5=death). AEs not in the list of CTCAE were graded at discretion of the investigator. Myelosuppression is defined as the decrease in the ability of the bone marrow to produce blood cells. Participants with Grade (G)3 or G4 adverse event of infection and myelosuppression (anemia, neutropenia, and thrombocytopenia) are presented. Also presented are number of participants with autoimmune hemolytic anemia (AIHA). 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.

HAHA are indicators of immunogenicity induced by ofatumumab. Blood samples were taken from participants at Screening, Cycle 4-Day 85, FU 1-PDFU 1, and FU 169-PDFU 169. The presence of HAHA in human serum was determined using a validated electrochemiluminescent assay in a multi-tier assay format. The results are presented as participants with HAHA results as positive, negative or confirmation required.

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. Immunoglobulins were measured at Cycle 1-Day 1, FU 1-PDFU 1, and FU 169-PDFU 169 for participants in CR, PR, and stable disease (SD).

MRD refers to small number of leukemic cells that remain in the participant's body during treatment or after treatment in participants who achieved a confirmed complete remission. MRD assessment in bone marrow aspiration sample was perfrmed by flow cytometry (cluster of differentiation [CD]5, CD19, CD20, CD23). The absence of MRD was defined as less than one CLL cell per 10,000 leukocytes. The number of participants who were positive and negative for MRD are presented.

CD5+CD19+ cells were counted in peripheral blood by flow cytometry. 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. B-cell monitoring (CD5+CD19+ and CD5-CD19+) was performed at Cycle 1 (Day 1, Day 15) and Cycle 2 (Day 29, Day 43), on Day 1 of Cycle 3, 4, 5, 6, 9 and 12 (Day 57, Day 85, Day 113, Day 141, Day 225, Day 309), 28 days after the first day of the last treatment cycle (FU 1-PDFU 1) for all participants depending on the number of cycles administered, and 84 and 168 days after the day of FU 1-PDFU 1 for participants in CR, PR, and SD.

Beta-2-microglobulin is a protein present on the surface of most cells. Higher levels indicate a poor prognosis of CLL. Beta-2 microglobulin was measured at Cycle 1-Day 1.

The CH50 is the serum complement to lyse 50% of sensitized red blood cells; it 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. Peripheral blood samples were collected for analysis at Cycle 1-Day 1 and Cycle 4-Day 85.

Maximum (peak) plasma drug concentration of ofatumumab was determined at Cycle 1-Day 1 and Cycle 3-Day 57. Samples were collected at Cycle 1-Day 1 (pre-dose, end of infusion, 10 min, 1hr, 2 hr, 24 hr, 72 hr, 120 hr), and Cycle 3-Day 57 (pre-dose, end of infusion, 10 min, 1 hr, 2 hr, 24 hr, 72 hr, 120 hr, 168 hr).

Cmax of serum chlorambucil was assesed at Cycle 1-Day 1, Cycle 1-Day 4 and Cycle 3-Day 57. In each sampling, blood samples were collected at pre-dose, and 15 min, 30 min, 1 hr, 1.5 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, and 10 hr.

Cmax of chlorambucil metabolite phenyl acetic acid mustard was assesed at Cycle 1-Day 1, Cycle 1-Day 4, and Cycle 3-Day 57. In each sampling, blood samples were collected at pre-dose, and 15 min, 30 min, 1 hr, 1.5 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, and 10 hr.

Minimum plasma drug concentration of ofatumumab was determined at Cycle 1-Day 8, Cycle 2-Day 29, Cycle 3-Day 57, Cycle 4-Day 85, Cycle 5-Day 113, and Cycle 6-Day 141. Samples were collected at Cycle 1-Day 1 (pre-dose, end of infusion, 10 min, 1hr, 2 hr, 24 hr, 72 hr, 120 hr), Cycle 2-Day 29 (pre-dose), Cycle 3-Day 57 (pre-dose, end of infusion, 10 min, 1 hr, 2 hr, 24 hr, 72 hr, 120 hr, 168 hr), Cycle 4-Day 85 (pre-dose, 30 min post end of infusion), Cycle 5-Day 113 (pre-dose and end of infusion) and Cycle 6-Day 141 (pre-dose and end of infusion).

Cmin of chlorambucil was assesed at Cycle 1-Day 4 and Cycle 3-Day 57. In each sampling, blood samples were collected at pre-dose, and 15 min, 30 min, 1 hr, 1.5 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, and 10 hr.

Cmin of chlorambucil metabolite phenyl acetic acid mustard was assesed at Cycle 1-Day 4 and Cycle 3-Day 57. Blood samples were collected at Cycle 1-Day 1, Cycle 1-Day 4, and Cycle 3-Day 57. In each sampling, blood samples were collected at pre-dose, and 15 min, 30 min, 1 hr, 1.5 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, and 10 hr.

Plasma clearance is defined as the plasma volume which is totally cleared of drug per unit of time. Blood samples were collected at Cycle 1-Day1 (pre-dose, end of infusion, 10 min, 1hr, 2 hr, 24 hr, 72 hr, 120 hr).

Area under the concentration time curve over the dosing interval (AUC[0-tau]) is a measure of drug exposure over time. AUC(0-tau) is defined as the area under the drug plasma/serum concentration-time curve from dosing to time tau, where tau is the length of the dosing interval of the drug. For ofatumumab it was assesed at Cycle 1-Day 1 and Cycle 3-Day 57. Samples were collected at Cycle 1-Day 1 (pre-dose, end of infusion, 10 min, 1 hr, 2 hr, 24 hr, 72 hr, 120 hr) and Cycle 3-Day 57 (pre-dose, end of infusion, 10 min, 1 hr, 2 hr, 24 hr, 72 hr, 120 hr, 168 hr).

Area under the concentration time curve over the dosing interval (AUC[0-tau]) is a measure of drug exposure over time. AUC(0-tau) is defined as the area under the drug plasma/serum concentration-time curve from dosing to time tau, where tau is the length of the dosing interval of the drug. It was assesed at 1st (Cycle 1-Day 1), 4th (Cycle 1-Day 4), and 15th (Cycle 3-Day 57) chlorambucil administration. In each sampling, blood samples were collected at pre-dose, and 15 min, 30 min, 1 hr, 1.5 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, and 10 hr.

Area under the concentration time curve over the dosing interval (AUC[0-tau]) is a measure of drug exposure over time. AUC(0-tau) is defined as the area under the drug plasma/serum concentration-time curve from dosing to time tau, where tau is the length of the dosing interval of the drug. It was assesed at 1st (Cycle 1-Day 1), 4th (Cycle 1-Day 4), and 15th (Cycle 3-Day 57) chlorambucil administration. In each sampling, blood samples were collected at pre-dose, and 15 min, 30 min, 1 hr, 1.5 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, and 10 hr.

The total AUC or AUC0-infinity is the area under the curve from time 0 extrapolated to infinite time. It was assesed on Cycle 1-Day 1. The samples were collected at Cycle 1-Day1 (pre-dose, end of infusion, 10 min, 1hr, 2 hr, 24 hr, 72 hr, 120 hr).

The total AUC or AUC0-infinity is the area under the curve from time 0 extrapolated to infinite time. It was assesed at Cycle 1-Day 1, Cycle 1-Day 4, and Cycle 3-Day 57. In each sampling, blood samples were collected at pre-dose, and 15 min, 30 min, 1 hr, 1.5 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, and 10 hr.

The total AUC or AUC(0-infinity) is the area under the curve from time 0 extrapolated to infinite time. It was assesed at Cycle 1-Day 1, Cycle 1-Day 4, and Cycle 3-Day 57. In each sampling, blood samples were collected at pre-dose, and 15 min, 30 min, 1 hr, 1.5 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, and 10 hr.

Volume of distribution at steady state (Vss) is defined as the distribution of a drug between plasma and the rest of the body at steady state. Samples were collected at Cycle 1-Day1 (pre-dose, end of infusion, 10 min, 1hr, 2 hr, 24 hr, 72 hr, 120 hr).

t1/2 is the time required for the plasma concentration of ofatumumab to decrease by half. Samples were collected at Cycle 1-Day 1 (pre-dose, end of infusion, 10 min, 1hr, 2 hr, 24 hr, 72 hr, 120 hr) and Cycle 3-Day 57 (pre-dose, end of infusion, 10 min, 1 hr, 2 hr, 24 hr, 72 hr, 120 hr, 168 hr).

t1/2 is the time required for the serum concentration of chlorambucil to decrease by half. Blood samples for serum concentration of chlorambucil was collected at Cycle 1-Day 1, Cycle 1-Day 4, and Cycle 3-Day 57. In each sampling, blood samples were collected at pre-dose, and 15 min, 30 min, 1 hr, 1.5 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, and 10 hr.

t1/2 is the time required for the plasma/serum concentration of phenylacetic acid mustard to decrease by half. Blood samples for serum concentration of phenylacetic acid mustard was collected at Cycle 1-Day 1, Cycle 1-Day 4, and Cycle 3-Day 57. In each sampling, blood samples were collected at pre-dose, and 15 min, 30 min, 1 hr, 1.5 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, and 10 hr.

Tmax is the time required for reaching maximum concentration of drug (Cmax). Samples were collected at Cycle 1-Day 1 (pre-dose, end of infusion, 10 min, 1hr, 2 hr, 24 hr, 72 hr, 120 hr) and Cycle 3-Day 57 (pre-dose, end of infusion, 10 min, 1 hr, 2 hr, 24 hr, 72 hr, 120 hr, 168 hr).

Tmax is the time required for reaching maximum concentration of drug (Cmax). Blood samples were collected at Cycle 1-Day 1, Cycle 1-Day 4, and Cycle 3-Day 57. In each sampling, blood samples were collected at pre-dose, and 15 min, 30 min, 1 hr, 1.5 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, and 10 hr.

Tmax is the time required for reaching maximum concentration of drug (Cmax). Blood samples were collected at Cycle 1-Day 1, Cycle 1-Day 4, and Cycle 3-Day 57. In each sampling, blood samples were collected at pre-dose, and 15 min, 30 min, 1 hr, 1.5 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, and 10 hr.

MRTinf is the average amount of time that ofatumumab spends in the body. Samples were collected at Cycle 1-Day 1 (pre-dose, end of infusion, 10 min, 1hr, 2 hr, 24 hr, 72 hr, 120 hr).

MRTinf is the average amount of time that chlorambucil spends in the body. Blood samples were collected at Cycle 1-Day 1, Cycle 1-Day 4, and Cycle 3-Day 57. In each sampling, blood samples were collected at pre-dose, and 15 min, 30 min, 1 hr, 1.5 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, and 10 hr.

MRTinf is the average amount of time that phenyl acetic acid mustard spends in the body. Blood samples were collected at Cycle 1-Day 1, Cycle 1-Day 4, and Cycle 3-Day 57. In each sampling, blood samples were collected at pre-dose, and 15 min, 30 min, 1 hr, 1.5 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, and 10 hr.

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. Samples were collected at Cycle 1-Day 1 (pre-dose, end of infusion, 10 min, 1hr, 2 hr, 24 hr, 72 hr, 120 hr).

CL/F is defined as the apparent total clearance of the drug from plasma after oral administration of chlorambucil. It was assessed at Cycle 1-Day 1, Cycle 1-Day 4, and Cycle 3-Day 57. In each sampling, blood samples were collected at pre-dose, and 15 min, 30 min, 1 hr, 1.5 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, and 10 hr.

Vz/F of chlorambucil is defined as the apparent volume of distribution during terminal phase after non-intravenous (oral) administration of chlorambucil. It was assessed at Cycle 1-Day 1, Cycle 1-Day 4, and Cycle 3-Day 57. In each sampling, blood samples were collected at pre-dose, and 15 min, 30 min, 1 hr, 1.5 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, and 10 hr.

%AUC_extrap is defined as the area under the plasma concentration-time curve extrapolated from time t to infinity as a percentage of total AUC. Samples were collected at Cycle 1-Day 1 (pre-dose, end of infusion, 10 min, 1 hr, 2 hr, 24 hr, 72 hr, 120 hr).

%AUC_extrap is defined as the area under the plasma concentration-time curve extrapolated from time t to infinity as a percentage of total AUC. It was assessed at Cycle 1-Day 1, Cycle 1-Day 4, and Cycle 3-Day 57. In each sampling, blood samples were collected at pre-dose, and 15 min, 30 min, 1 hr, 1.5 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, and 10 hr.

%AUC_extrap is defined as the area under the plasma concentration-time curve extrapolated from time t to infinity as a percentage of total AUC. It was assessed at Cycle 1-Day 1, Cycle 1-Day 4, and Cycle 3-Day 57. In each sampling, blood samples were collected at pre-dose, and 15 min, 30 min, 1 hr, 1.5 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, and 10 hr.

AUC (0-t) represents the area under the concentration curve of ofatumumab in plasma from 0 to time t hours. AUC (0-t) was assessed at 168 hours and 672 hours post-dose.

AUC (0-t) represents the area under the concentration curve of chlorambucil in serum from 0 to time t hours. AUC (0-t) was assessed at 6 hours and 24 hours.

AUC (0-t) represents the area under the concentration curve of phenyl acetic acid mustard in serum from 0 to time t hours. AUC (0-t) was assessed at 6 hours and 24 hours.

Cmax/D is defined as the maximum plasma concentration (Cmax) per unit dose. It was assessed at Cycle 1-Day 1, Cycle 1-Day 4 and Cycle 3-Day 57. In each sampling, blood samples were collected at pre-dose, and 15 min, 30 min, 1 hr, 1.5 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, and 10 hr.

Cmax/D is defined as the maximum plasma concentration (Cmax) per unit dose. It was assessed at Cycle 1-Day 1, Cycle 1-Day 4, and Cycle 3-Day 57. In each sampling, blood samples were collected at pre-dose, and 15 min, 30 min, 1 hr, 1.5 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, and 10 hr.

Dose adjusted AUC for the indicated time points were assessed at Cycle 1-Day 1, Cycle 1-Day 4, and Cycle 3-Day 57. In each sampling, blood samples were collected at pre-dose, and 15 min, 30 min, 1 hr, 1.5 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, and 10 hr.

Dose adjusted AUC for the indicated time points were assessed at Cycle 1-Day 1, Cycle 1-Day 4, and Cycle 3-Day 57. In each sampling, blood samples were collected at pre-dose, and 15 min, 30 min, 1 hr, 1.5 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, and 10 hr.