Pharmacokinetic endpoint: Area under the concentration-time curve from time 0 (immediately predose on Day 1) to last quantifiable concentration (AUC0-t). Geometric means by treatment (Pharmacokinetic Analysis Set).

Pharmacokinetic Analysis Set. (AUC(0-t) could not be determined for 15 participants in the SAIT101 arm, 23 participants in the MabThera arm and 17 in the Rituxan arm as the Week 24 sample was either collected post-dose (i.e. not evaluable), was out of the collection window or was missing.

Pharmacokinetic endpoint: Area Under the Plasma Concentration from time 0 to infinity (AUC0-∞ (infinity). Calculated by linear up/log down trapezoidal summation and extrapolated to infinity by addition of the last quantifiable concentration divided by the elimination rate constant: AUC(0-last) + C(last)/λz.

Pharmacokinetic Analysis Set. AUC0-∞ could not be calculated for 1 participant in the SAIT101 arm, 2 participants in the MabThera arm and 2 participants in the Rituxan arm as either the terminal phase was undetermined, the samples were missing or the Regulatory Scientific Quality (RSQ) was <0.800.

Pharmacokinetic endpoint: Area Under the Concentration verses time from time 0 to Day 15 prior to infusion (AUC0-D15) calculated by linear up/log down trapezoidal summation. Actual time/concentration on Day 15 was used for the calculation of this parameter unless the parameter was derived by interpolation.

Pharmacokinetic Analysis Set. AUC0-D15 could not be determined for 3 participants in the SAIT101 arm, 5 participants in the MabThera arm and 10 participants in the Rituxan arm as either the 336-hours blood sample was collected <312 hours or samples were missing.

Pharmacokinetic endpoint: Maximum Plasma Concentration (Cmax) after Day 15 infusion (Dose 2)

Pharmacokinetic Analysis Set.

Pharmacokinetic endpoint: Trough concentration (Ctrough) before the second infusion on Day 15 (Dose 2). Trough (pre-dose) concentration prior to second infusion on Day 15 obtained directly from the observed concentration versus time data.

Pharmacokinetic Analysis Set. Ctrough could not be determined for 11 participants in the SAIT101 arm, 12 participants in the MabThera arm and 16 participants in the Rituxan arm as samples were collected outside of a 312 to 360 hour window.

Disease Activity Score 28 C-reactive protein score (DAS28-CRP) at Week 24 (Full Analysis Set). CRP samples were collected at Baseline and Weeks 8, 16 and 24. DAS28-CRP was calculated using the following equation: [0.56*Square Root (SQRT) (tender 28 joint count)+0.28*SQRT(swollen 28 joint count)+0.36*ln(CRP+1)]*1.10+1.15.

Total DAS28-CRP scores were calculates and range from 2.0 (minimum) to 10 (maximum). Lower scores represent a better patient outcome. Disease remission is considered achieved if the score is between 0 and <2.6. Low disease activity corresponds to 2.6 to <3.2. Moderate activity is between 3.2 & ≤5.1, while high activity is above 5.1.

Full Analysis Set

Pharmacokinetic endpoint: Area under the concentration time curve week 2 to week 24 (AUC(w2-24) calculated by linear up/log down trapezoidal summation.

Pharmacokinetic Analysis Set. AUC0-w24 could not be determined for 30 participants in the SAIT101 arm, 32 participants in the MabThera arm and 28 participants either in the Rituxan arm as either there was no concentration at the start and/or end time, the Week 24 sample was out of window or samples were missing.

Pharmacokinetic endpoint: Area under the concentration time curve Day 0 to Week 12 calculated by linear up/log down trapezoidal summation.

Pharmacokinetic Analysis Set. AUC0-w12 could not be determined for 1 participant in the SAIT101 arm, 4 participants in the MabThera arm and 1 participant in the Rituxan arm because samples were missing

Pharmacokinetic endpoint: Maximum plasma concentration over the first dosing interval obtained directly from the observed concentration versus time data.

Pharmacokinetic Analysis Set. Tmax (dose 1) could not be determined for 1 participant in the SAIT101 arm, 1 patient in the MabThera arm and 2 participants in the Rituxan arm as samples were missing or set to missing due to initial or embedded Below the Limit of Quantification (BLQ)..

Time of maximum concentration postinfusion over the second dosing interval, obtained directly from the observed concentration versus time data.

Pharmacokinetic Analysis Set

Pharmacokinetic endpoint: Apparent terminal rate constant (λz) determined by linear regression of the terminal points of the log-linear concentration-time curve. Best fit method followed by visual assessment was used to identify the terminal linear phase of the concentration-time profile. A minimum of 3 data points was used for determination.

Pharmacokinetic Analysis Set. λz could not be determined for 1 participant in the SAIT101 arm, 2 participants in the MabThera arm and 1 participant in the Rituxan arm as either the terminal phase was undetermined or the Regulatory Scientific Quality (RSQ) was <0.800.

Pharmacokinetic endpoint: Systemic clearance (CL) over the first dosing period calculated as dose (first + second dose) divided by AUC(0-∞).

Pharmacokinetic Analysis Set. CL could not be determined for 1 participant in the SAIT101 arm, 2 participants in the MabThera arm and 2 participants in the Rituxan arm as either the terminal phase was undetermined or the Regulatory Scientific Quality (RSQ) was <0.800.

Pharmacokinetic endpoint: Volume of distribution (VD) over the first dosing period calculated as dose (first + second dose) divided by [λz AUC(0-∞)]

Pharmacokinetic Analysis Set. VD could not be determined for 1 participant in the SAIT101 arm, 2 participants in the MabThera arm and 2 participants in the Rituxan arm as either the terminal phase was undetermined or the Regulatory Scientific Quality was <0.800.

Pharmacokinetic endpoint: Terminal half-life determined as ln2/λz.

Pharmacokinetic Analysis Set. T1/2 could not be determined for 1 participant in the SAIT101 arm, 2 participants in the MabThera arm and 1 participant in the Rituxan arm as either the terminal was undetermined or the Regulatory Scientific Quality was <0.800.

Disease Activity Score 28-C-Reactive Protein (DAS28-CRP) samples taken at Baseline and Weeks 8, 16, 24, 36 and 52. DAS28-CRP was calculated using the following equation: [0.56*Square Root (SQRT) (tender 28 joint count)+0.28*SQRT(swollen 28 joint count)+0.36*ln(CRP+1)]*1.10+1.15.

Total DAS28-CRP scores are presented and range from 2.0 (minimum) to 10 (maximum). Lower scores represent a better patient outcome. Disease remission is considered achieved if the score is between 0 and <2.6. Low disease activity corresponds to 2.6 to <3.2. Moderate activity is between 3.2 & ≤5.1, while high activity is above 5.1.

Full Analysis Set (analyses are reported in terms of the arm that the patient was initially randomised into. In the Rituxan arm only, patients eligible for treatment in Part B underwent a second randomisation to receive either Rituxan or SAIT101 and are reported in the Rituxan arm according to their initial randomisation).

American Collage of Rheumatology (ACR) 20% response criteria (ACR20) response rates were assessed at Baseline and Weeks 8, 16, 24, 36 and 52.

An ACR20 response is defined as both improvement of 20% in the number of tender and number of swollen joints, and a 20% improvement in three of the following five criteria: patient global assessment, physician global assessment, functional ability measure [Health Assessment Questionnaire (HAQ)], visual analogue pain scale, and erythrocyte sedimentation rate or C-reactive protein (CRP).

Full Analysis Set (analyses are reported in terms of the arm that the patient was initially randomised into. In the Rituxan arm only, patients eligible for treatment in Part B underwent a second randomisation to receive either Rituxan or SAIT101 and are reported in the Rituxan arm according to their initial randomisation).

Efficacy endpoint: American Collage of Rheumatology 50% response criteria (ACR50) response rates and American Collage of Rheumatology 70% response criteria (ACR70) at weeks 8, 16, 24, 36 and 52.

An ACR50 response is defined as both improvement of 50% in the number of tender and number of swollen joints, and a 50% improvement in three of the following five criteria: patient global assessment, physician global assessment, functional ability measure [Health Assessment Questionnaire (HAQ)], visual analogue pain scale, and erythrocyte sedimentation rate or C-reactive protein (CRP).

An ACR70 response is defined as both improvement of 70% in the number of tender and number of swollen joints, and a 70% improvement in three of the following five criteria: patient global assessment, physician global assessment, functional ability measure [Health Assessment Questionnaire (HAQ)], visual analogue pain scale, and erythrocyte sedimentation rate or C-reactive protein (CRP).

Full Analysis Set (analyses are reported in terms of the arm that the patient was initially randomised into. In the Rituxan arm only, patients eligible for treatment in Part B underwent a second randomisation to receive either Rituxan or SAIT101 and are reported in the Rituxan arm according to their initial randomisation).

Efficacy endpoint: Individual components of the ACR improvement criteria on Day 1 and at weeks 8, 16, 24, 36 and 52: Swollen Joint Count (SJC) and tender joint count (TJC) (the 66/68 joint count system). SJC and TJC assess the level of skeletal disease involvement. The 66/68 Joint Count evaluates 66 joints for swelling and 68 joints for tenderness.

Full Analysis Set (analyses are reported in terms of the arm that the patient was initially randomised into. In the Rituxan arm only, patients eligible for treatment in Part B underwent a second randomisation to receive either Rituxan or SAIT101 and are reported in the Rituxan arm according to their initial randomisation).

Efficacy endpoint: Individual Components of the ACR Improvement Criteria on Day 1 and at Weeks 8, 16, 24, 36 and 52: Physicians global assessment of disease activity (assessed on 1 to 100 mm Visual Analog Scale [VAS]). Where 0 = no disease activity and 100 = maximum disease activity.

Full Analysis Set (analyses are reported in terms of the arm that the patient was initially randomised into. In the Rituxan arm only, patients eligible for treatment in Part B underwent a second randomisation to receive either Rituxan or SAIT101 and are reported in the Rituxan arm according to their initial randomisation).

Participants assessment of pain (assessed on 1 to 100 mm Visual Analog Scale [VAS]). Participants assessment of pain (assessed on 1 to 100 mm Visual Analog Scale [VAS]) where 0 = no pain and 100 = severe pain.

Full Analysis Set (analyses are reported in terms of the arm that the patient was initially randomised into. In the Rituxan arm only, patients eligible for treatment in Part B underwent a second randomisation to receive either Rituxan or SAIT101 and are reported in the Rituxan arm according to their initial randomisation).

Efficacy endpoint: Individual Components of the ACR Improvement Criteria on Day 1 and at Weeks 8, 16, 24, 36 and 52: Participants global assessment of disease activity (assessed on 1 to 100 mm visual analogue scale [VAS]). Patients rate how their Rheumatoid Arthritis has affected them, where 0 = very well and 100 = very poor.

Full Analysis Set (analyses are reported in terms of the arm that the patient was initially randomised into. In the Rituxan arm only, patients eligible for treatment in Part B underwent a second randomisation to receive either Rituxan or SAIT101 and are reported in the Rituxan arm according to their initial randomisation).

the Health Assessment Questionnaire-Disability Index (HAQ-DI) contains 20 questions split into 8 categories (dressing & grooming, arising, eating, walking, hygiene, reach, grip & activities). Scores were: 0 = Without ANY Difficulty; 1 = With SOME Difficulty; 2 = With MUCH Difficulty; 3 = UNABLE to Do. Total scores were calculated as the summed category scores divided by the number of categories.

Total HAQ-DI scores are presented which range from 0 to 3. Higher scores represent a worse outcome. Scores of 0 to 1 represent mild to moderate difficulty, 1 to 2 moderate disability, and 2 to 3 severe to very severe disability.

Full Analysis Set (analyses are reported in terms of the arm that the patient was initially randomised into. In the Rituxan arm only, patients eligible for treatment in Part B underwent a second randomisation to receive either Rituxan or SAIT101 and are reported in the Rituxan arm according to their initial randomisation).

C-reactive protein (CRP) level (Mg/L). CRP is a marker for inflammation. a normal reading is <3 Mg/L. Higher values indicate disease related inflammation and increased cardiovascular risk.

CRP levels between 3 Mg/L and 10 Mg/L are mildly elevated. Levels between 10 Mg/L and 100 Mg/L are moderately elevated and CRP levels above 100 Mg/L are severely elevated.

Full Analysis Set (analyses are reported in terms of the arm that the patient was initially randomised into. In the Rituxan arm only, patients eligible for treatment in Part B underwent a second randomisation to receive either Rituxan or SAIT101 and are reported in the Rituxan arm according to their initial randomisation).

Disease Activity Score 28- Erythrocyte Sedimentation Rate (DAS28-ESR) consisted of tender joint counts (TJC), swollen joint counts (SJC) & erythrocyte sedimentation rate (ESR). The formula is: [0.56*SQRT(tender 28 joint count)+0.28*SQRT(swollen 28 joint count)+0.7*ln(ESR)]+0.014*patient global health assessment.

Total DAS28-ESR scores are presented. Total scores range from 2 (minimum) to 10 (maximum). A lower score represents a better patient outcome. A DAS28-ESR of greater than 5.1 implies active disease, less than 3.2 low disease activity, and less than 2.6 remission.

Full Analysis Set (analyses are reported in terms of the arm that the patient was initially randomised into. In the Rituxan arm only, patients eligible for treatment in Part B underwent a second randomisation to receive either Rituxan or SAIT101 and are reported in the Rituxan arm according to their initial randomisation).

Efficacy endpoint: number of participants with a major clinical response defined as a continuous ACR70 from Baseline (Day 1) for at least 24 weeks.

ACR70 is a measure based on American College of Rheumatology criteria of at least a 70% improvement in the number of tender and swollen joints, and a 70% improvement in at least 3 of the following: the patient's global assessment of disease status; the patient's assessment of pain; the patient's assessment of function measured using the Stanford Health Assessment Questionnaire the physician's global assessment of disease status; serum C-reactive protein levels.

Full Analysis Set (analyses are reported in terms of the arm that the patient was initially randomised into. In the Rituxan arm only, patients eligible for treatment in Part B underwent a second randomisation to receive either Rituxan or SAIT101 and are reported in the Rituxan arm according to their initial randomisation).

Number if Participants with a Clinical Remission Response (CRR) defined by the Simplified Disease Activity Index (SDAI) <3.3 at weeks 8, 16, 24, 36 and 52 (EOS).

Full Analysis Set (analyses are reported in terms of the arm that the patient was initially randomised into. In the Rituxan arm only, patients eligible for treatment in Part B underwent a second randomisation to receive either Rituxan or SAIT101 and are reported in the Rituxan arm according to their initial randomisation).

Efficacy endpoint: Proportion of participants with European League Against Rheumatism (EULAR) response (defined as good response, moderate response or no response) at weeks 8, 16, 24 36 and 52 (EOS). EULAR (European League Against Rheumatism) response was classified using the individual amount of change in the DAS28-CRP score. The DAS28-CRP was classified into 3 categories: low disease activity (<= 3.2), moderate disease activity (> 3.2 and <= 5.1) and high disease activity (> 5.1). Good response was defined as >1.2 improvement in the DAS28-CRP from baseline with low disease activity.

Full Analysis Set (analyses are reported in terms of the arm that the patient was initially randomised into. In the Rituxan arm only, patients eligible for treatment in Part B underwent a second randomisation to receive either Rituxan or SAIT101 and are reported in the Rituxan arm according to their initial randomisation).

Change from baseline (Day 1) in immunoglobulin G (IgG), Immunoglobulin M (IgM) and Immunoglobulin A (IgA) levels (mg/dL) at Week 8, 16, 24 36 and 52 (End of study)

Pharmacodynamic Analysis Set (analyses are reported in terms of the arm that the patient was initially randomised into. In the Rituxan arm only, patients eligible for treatment in Part B underwent a second randomisation to receive either Rituxan or SAIT101 and are reported in the Rituxan arm according to their initial randomisation).

Pharmacodynamic endpoint: proportion of participants (n) with depletion of CD19+ B-cell count up to week 24 (Pharmacodynamic analysis set).

Pharmacokinetic data set

Time needed to CD19+ B-cell depletion in Part A (calculated as the first time CD19+ B-cell count below 20/µL minus time of first dosing in days).

Pharmacodynamic Analysis Set. Two participants in the SAIT101 arm, 3 participants in the MabThera arm and 3 participants in the Rituxan arm were excluded from the analysis either as they had a depleted C-cell count at baseline and / or if the Week 24 assessment was missing.

Duration of CD19+ B-cell depletion (only participants that returned to non-depletion at or before week 24 were included)

Pharmacodynamic Analysis Set.Pharmacodynamic Analysis Set. Fifty seven participants in the SAIT101 arm, 70 participants in the MabThera arm and 72 participants in the Rituxan arm were excluded from the analysis either as they had a depleted C-cell count at baseline or if the Week 24 assessment was missing.

Number of participants with CD19+ B-cell count recover versus baseline. Incidence of B-Cell recovery was defined as either CD19+ B-cell counts retuned to baseline or the lower limit or normal of 110 cells/µL at week 24).

Pharmacodynamic Analysis Set

Area under the concentration time curve of CD19 B-cell count change at Day 15 (AUEC0-d15) and week 24 (AUEC0-w24) based on change from baseline and percent of baseline values

Pharmacodynamic Analysis Set. AUC0-d15 could not be determined for 23 participants in the SAIT101 arm, 20 participants in the MabThera arm and 20 participants in the Rituxan arm as either the baseline data was missing and /or there was a missing b-cell could at the last timepoint.

Pharmacodynamic endpoint: Descriptive statistics (mean [SD]) of the change from baseline in CD19+ B-cell count during the study period (Day 15 [AUEC(0-d15] and Week 24 [AUEC(0-w24])

Pharmacodynamic Analysis Set. participants in the SAIT101 arm, Twenty three participants in the MabThera arm, 20 participants in the MabThera and 20 participants in the Rituxan arm were excluded from the analysis either as they had a depleted C-cell count at baseline and / or the Week 24 assessment was missing.

Pharmacodynamic endpoint: Change from baseline (Day 1) in C-reactive protein (CRP) levels (mg/dL) at weeks 8, 16, 24, 36 and 52 (EOS)

Pharmacodynamic Analysis Set