A Study to Compare Subcutaneous Versus Intravenous MabThera (Rituximab) in Combination With Chemotherapy in Patients With Chronic Lymphocytic Leukemia

Ctrough is defined as the trough or minimum serum concentration. Pharmacokinetic parameters for rituximab were assessed during Cycles 5 (IV rituximab) and 6 (SC rituximab). Rituximab pharmacokinetic (PK) data from Part 1 were integrated into a population PK model using parametric, nonlinear, mixed-effects modelling. Rituximab IV 500 mg/m^2 administered once every 4 weeks was compared to fixed doses of rituximab SC between 1400 mg and 1870 mg. The dose selection was performed on Ctrough concentrations at Cycle 5 (pre-dose Cycle 6). A test of the probability of success was applied to each of the 100 replicates, and the percentage of replicates with a positive test corresponded to the probability of success of the trial.

Ctrough is defined as the trough or minimum serum concentration in a given cycle of treatment. The objective of Part 2 was to demonstrate the comparability of the observed Ctrough of rituximab SC 1600 mg and rituximab IV 500 mg/m2 at Cycle 5, as assessed by a non-inferiority test with a lower boundary of at least 0.8 for the 90% CI.

AUC values were calculated by numerical integration using the linear trapezoidal rule. AUC levels were analyzed using the model below: Ln(AUC) = μ + τi + BlTLij + εij wherein, Ln is the natural log, μ denotes the overall mean effect, τi the effect in each treatment group, BlTLij the tumor load at baseline for each patient and εij a random error variable with normal distribution and mean 0. The treatment effect therein was based on a contrast statement in the model to calculate 90 % confidence intervals for ln(AUC SC)- ln(AUC IV).

Cmax was obtained directly from the measured concentration-time curves. The concentration-time curve is the result of time points of blood sampling and its measured concentration of rituximab in the blood samplings.

Multiple blood samples were obtained at pre-dose, post-dose and on Days 2, 3, 8 ,15, 29 of Cycle 6 in Rituximab IV arm, and at pre-dose, and on Days 2, 3, 8 ,15, 29 of Cycle 6 in Rituximab SC arm and time to peak plasma concentration of rituximab was determined.

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

In part 1 of the trial, upon completion of dosing in cycle 6, participants and their treating nurses were asked whether they have a preference of dosing route, IV vs SC

Physicians and nurses who administered rituximab were asked to answer the following question: " If used in routine practice, on average, how much staff time could be saved with each administration of rituximab SC as compared to rituximab IV? (Please do not consider the time needed for the first IV administration, consider only the subsequent ones)". The number of nurses that responded for both the IV and SC arms was 70. The number of physicians that responded for the IV and SC arms were 78 and 81 respectively.

Physicians and nurses who administered rituximab were asked to answer the following question: "Which formulation of rituximab (SC or IV) do you think is more convenient?" with pre-specified responses as below. Percentage of participants with specified answers were reported. The number of nurses that responded for both the IV and SC arms was 70. The number of physicians that responded for the IV and SC arms were 78 and 81 respectively.

Blood samples for the assessment of antibodies against rituximab (HACAs) were drawn pre-dose at Cycle 5 and Cycle 6 in Part 1 and at each follow up visit until 24 months after the last dose.

In Part 2, samples for the HACA assay were collected at each treatment cycle prior to the administration of rituximab and at each follow-up visit until 24 months after the last dose of rituximab.

CD 19 is a surface antigen (protein) present on B-lymphocytes.

Total B-cell depletion (normal B-cell plus Malignant B-cell depletion) was defined for each individual participant when the sum of CD5-/CD19+ (normal B-cells) and CD5+/CD19+ (malignant B-cells) cell counts decreased below 80 cells/μL.

CD 19 is a surface antigen (protein) present on B-lymphocytes.

Total B-cell depletion (normal B-cell plus Malignant B-cell depletion) was defined for each individual participant when the sum of CD5-/CD19+ (normal B-cells) and CD5+/CD19+ (malignant B-cells) cell counts decreased below 80 cells/μL.