A PHASE 1, RANDOMIZED, MULTI-CENTER, DOUBLE-BLIND, SPONSOR OPEN, PLACEBO-CONTROLLED, SINGLE AND MULTIPLE DOSE-ESCALATION STUDY TO EVALUATE THE SAFETY, TOLERABILITY, PHARMACOKINETICS AND PHARMACODYNAMICS OF PF-06835375 IN SUBJECTS WITH SEROPOSITIVE SYSTEMIC LUPUS ERYTHEMATOSUS OR RHEUMATOID ARTHRITIS

Number of Participants With Treatment-Emergent Adverse Events (TEAEs) by Severity

Time Frame: From the first dose of study treatment up to 7-14 days after end of study criteria met (maximum duration for end of study criteria met: Day 225 for Part A, Day 281 for Part B)

An AE was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. Treatment-related AE was any untoward medical occurrence attributed to study drug in a participant who received study drug. Relatedness to study drug was assessed by the investigator. Treatment-emergent were events between first dose of study drug and up to approximately Week 40 that were absent before treatment or that worsened relative to pretreatment state. AEs are classified according to the severity in 3 categories a) mild - AEs does not interfere with participant's usual function b) moderate - AEs interferes to some extent with participant's usual function c) severe - AEs interferes significantly with participant's usual function.

Number of Participants With Permanent Discontinuation Due to TEAEs

Time Frame: From the first dose of study treatment up to 7-14 days after end of study criteria met (maximum duration for end of study criteria met: Day 225 for Part A, Day 281 for Part B)

An AE was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. Treatment-emergent were events between first dose of study drug and up to approximately Week 40 that were absent before treatment or that worsened relative to pretreatment state.

Number of Participants With Post-Baseline Vital Signs Data Meeting Categorical Summarization Criteria

Time Frame: From baseline up to end of study criteria met (maximum duration for end of study criteria met: Day 225 for Part A, Day 281 for Part B)

Criteria for abnormality in vital signs: supine pulse rate \<40 beats per minute (bpm) or \>120 bpm; standing pulse rate \<40 bpm or \>120 bpm; sitting systolic blood pressure (BP) \<90 mmHg, maximum increase or decrease from baseline of \>=30 mmHg; sitting diastolic BP \<50 mmHg, maximum increase or decrease from baseline of \>=20 mmHg. Baseline was defined as the last pre-dose measurement in Day 1. Only those categories in which at least 1 participant had data were reported.

Number of Participants With All-Causality and Treatment-Related Infections and Infestations

Time Frame: From the first dose of study treatment up to 7-14 days after end of study criteria met (maximum duration for end of study criteria met: Day 225 for Part A, Day 281 for Part B)

An AE was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. Treatment-related AE was any untoward medical occurrence attributed to study drug in a participant who received study drug. Relatedness to study drug was assessed by the investigator. The incidence of AEs by system organ class "infections and infestations" was reported here.

Number of Participants With Dose-Limiting Toxicity (DLT)

Time Frame: From the first dose of study treatment up to 7-14 days after end of study criteria met (maximum duration for end of study criteria met: Day 225 for Part A, Day 281 for Part B)

DLT was defined as any of the following events meeting the criteria: (1) \>=2 participants within a dose cohort developed Common Terminology Criteria for Adverse Events (CTCAE) v4.0 Grade 3 adverse event considered to be serious in the same organ system or 1 participant developed a CTCAE v4.0 Grade 4 or higher SAE considered related to study drug; (2) 50% or more participants within a dose cohort experienced a CTCAE v4.0 Grade 3 or higher infusion reaction; (3) a confirmed or probable case of Progressive Multifocal Leukoencephalopathy was observed; (4) the mean exposure for the treatment group reached or exceeded the exposure stopping limit of Cav of 261 mg/mL, or, based on the observed data, the group mean Cav of the next planned dose was projected to exceed the exposure stopping limit. Cav = average serum concentration.

Number of Participants With All-Causality and Treatment-Related TEAEs

Time Frame: From the first dose of study treatment up to 7-14 days after end of study criteria met (maximum duration for end of study criteria met: Day 225 for Part A, Day 281 for Part B)

An AE was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. Treatment-related AE was any untoward medical occurrence attributed to study drug in a participant who received study drug. Relatedness to study drug was assessed by the investigator. A serious adverse event (SAE) was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. Treatment-emergent were events between first dose of study drug and up to approximately Week 40 that were absent before treatment or that worsened relative to pretreatment state.

Number of Participants With Clinically Significant Laboratory Abnormalities in Hematology, Chemistry, and Urinalysis

Time Frame: From baseline up to end of study criteria met (maximum duration for end of study criteria met: Day 225 for Part A, Day 281 for Part B)

Hematology included hemoglobin, hematocrit, red blood cell, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, platelet and white blood cell count, total neutrophils, eosinophils, monocytes, basophils and lymphocytes. Chemistry included blood urea nitrogen, creatinine, glucose, calcium, sodium, potassium, chloride, bicarbonate, aspartate aminotransferase, alanine aminotransferase, total bilirubin, alkaline phosphatase, uric acid, albumin, total protein and creatine kinase. Urinalysis included pH, glucose, protein, blood, ketones, nitrites, leukocyte esterase, urobilinogen, urine bilirubin, microscopy and creatinine. Clinical significance was judged by the investigator and those met the criteria of AE are listed here. Clinically significant laboratory abnormalities reported for at least 1 participant in the whole study are presented here. Baseline was the last pre-dose measurement (first treatment for MAD cohorts).

Number of Participants With Post-Baseline Electrocardiogram (ECG) Data Meeting Categorical Summarization Criteria

Time Frame: From baseline up to end of study criteria met (maximum duration for end of study criteria met: Day 225 for Part A, Day 281 for Part B)

ECG abnormalities criteria included: 1) maximum QTc interval (ms): 450\<= QTc \<480, 480\<= QTc \<500, and QTc \>=500; QTc maximum increase from baseline (ms): 30\<= change \<60, and change \>=60; 2) maximum PR interval (ms): \>=300; PR increase from baseline (ms): baseline \>200 with 25% increase at maximum, baseline \<=200 with 50% increase at maximum; 3) maximum QRS (ms): \>=140; QRS increase from baseline (ms) \>=50%. QTcF indicates QT interval corrected using the Fridericia's formula. QTcB indicates QT interval corrected using the Bazett's formula. Baseline was defined as the average of the triplicate pre-dose recordings at Day 1. Only those categories in which at least 1 participant had data were reported.