An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE was considered treatment emergent if the event had start date on or after the first dosing date of this study.

An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An SAE was any untoward medical occurrence that at any dose: resulted in death; required inpatient hospitalization or prolongation of existing hospitalization; was life-threatening; resulted in persistent disability/incapacity; was a congenital anomaly/birth defect; other important medical events. AEs leading to discontinuation included participants who had an AE record that indicated that the AE caused the participant to be discontinued from the study or that action taken with study treatment was drug withdrawn.

Vital signs including blood pressure included systolic blood pressure (SBP) \[Millimeters of mercury, mmHg\]) and diastolic blood pressure (DBP) and pulse rate \[beats per minute (bpm)\] were measured using an automated device in a sitting position after at least 5 minutes of rest for the participant in a quiet setting without distractions. Criteria for vital sign abnormalities included: SBP\<90mmHg, DBP\<50 mmHg and pulse rate\<40mmHg.

Criteria for laboratory abnormalities included:Hemoglobin, Hematocrit, Erythrocytes (\<0.8\*LLN); Ery. Volume, Hemoglobin,Mean Corpuscular HGB Concentration \<0.8\*LLN or \>1.5\*LLN;Reticulocytes, Leukocytes, Lymphocytes, Neutrophils, Neutrophils, Basophils, Eosinophils, Monocytes (\>1.2\*ULN), Prothrombin Time(\>1.1\*ULN).Clinical Chemistry: Bilirubin, Direct Bilirubin, Indirect Bilirubin (1.5\*ULN), Aspartate Aminotransferase, Alanine Aminotransferase, Gamma Glutamyl Transferase, Alkaline Phosphatase (\>3.0\*ULN); Albumin, Urate (\<0.8\*LLN and \>1.2\*ULN; Urea Nitrogen,Creatinine Cholesterol \>1.3\*ULN; Cholesterol \<0.8\*LLN or \>1.2\*LLN, Triglycerides,Potassium,Calcium \< 0.9x LLN \& \> 1.1x ULN; Bicarbonate, Glucose, Creatine Kinase. Urinalysis: Glucose, Ketones, Protein, Hemoglobin, Urobilinogen, Bilirubin, Nitrite \>=1; Leukocyte Erythrocytes, Leukocytes \>=20; Epithelial Cells\>=6, Hyaline Cast\>1; Bacteria\>20. Number of participants with any laboratory abnormality meeting specified criteria is included.

Booster response to tetanus toxoid was defined as: \>=4-fold rise in anti-tetanus toxoid immunoglobulin G (IgG) antibody concentration at Month 1 if the pre-vaccination concentration was \<=2.7 International Units per milliliter (IU/mL); OR \>=2-fold rise in anti-tetanus toxoid IgG antibody concentration if the pre-vaccination concentration was \>2.7 IU/mL. Two-sided 95% confidence interval (CI) was based on Clopper-Pearson exact method.

SALT is a quantitative assessment of AA severity based on the scalp hair loss. The SALT score can vary from 0 (normal) to 100 (severe), with higher scores representing increased severity of disease. In this outcome measure, percentage of participants with SALT score less than or equal to (\<=) 20 at week 24 were reported.

SALT is a quantitative assessment of alopecia areata (AA) severity based on the scalp hair loss. Score range: 0-100%. Higher score indicates more severe disease. Change from baseline is defined as the baseline value minus the value at a specific visit. Positive change from baseline signifies an improvement. Baseline is defined as the last measurement prior to first dosing (Day 1).

An AE (non-serious and serious) was any untoward medical occurrence in a participant who received study treatment without regard to possibility of causal relationship. Any such events with initial onset or increasing in severity after the first dose of study treatment were counted as treatment-emergent Adverse Event (TEAE). Treatment-related TEAE were determined by investigators. Arms end with "withdrawal Segment" and "retreatment segment" described the same population while in different treatment segment .The reason why count on PF-06700841 differ by 1 participant is that 1 responder directly entered the retreatment segment and skipped the withdrawal segment.

An AE (non-serious and serious) was any untoward medical occurrence in a participant who received study treatment without regard to possibility of causal relationship. Any such events with initial onset or increasing in severity after the first dose of study treatment were counted as treatment-emergent Adverse Event (TEAE). Treatment-related TEAE were determined by investigators.

Following laboratory parameters were assessed against pre-defined abnormality criteria: hematology(Hemoglobin, Hematocrit, RBC count, Reticulocyte count, Platelet count, WBC count with differential, Total neutrophils, Eosinophils, Monocytes, Basophils, Lymphocytes); serum chemistry (BUN and Creatinine, Cystatin C, Creatine Phosphokinase, Glucose , Na+, K+, Cl ,Ca++, Total CO2, AST, ALT, Total Indirect \& Direct Bilirubin, Alkaline phosphatase, Uric acid, Albumin,Total protein, Fasting lipid Profile Panel; urinalysis(pH, Glucose, Protein, Nitrites, Leukocyte esterase, Microscopy culture);Other(HIV, HBsAg, HBcAb, HepB reflex (HbsAB), if applicable, HCVAb, Serum pregnancy test, Urine pregnancy test, FSH, QFT G or other IGRA, or PPD, EBV, CMV, HSV1, HSV2, VZV, Skin swab for herpetiform rash, Skin swab for potential drug related rash).Retest/discontinuation criteria are defined in Protocol Appendix 6.1 and 6.2 respectively.

Following laboratory parameters were assessed against pre-defined abnormality criteria: hematology(Hemoglobin, Hematocrit, RBC count, Reticulocyte count, Platelet count, WBC count with differential, Total neutrophils, Eosinophils, Monocytes, Basophils, Lymphocytes); serum chemistry (BUN and Creatinine, Cystatin C, Creatine Phosphokinase, Glucose , Na+, K+, Cl ,Ca++, Total CO2, AST, ALT, Total Indirect \& Direct Bilirubin, Alkaline phosphatase, Uric acid, Albumin,Total protein, Fasting lipid Profile Panel; urinalysis(pH, Glucose, Protein, Nitrites, Leukocyte esterase, Microscopy culture);Other(HIV, HBsAg, HBcAb, HepB reflex (HbsAB), if applicable, HCVAb, Serum pregnancy test, Urine pregnancy test, FSH, QFT G or other IGRA, or PPD, EBV, CMV, HSV1, HSV2, VZV, Skin swab for herpetiform rash, Skin swab for potential drug related rash).Retest/discontinuation criteria are defined in Protocol Appendix 6.1 and 6.2 respectively.