An AE was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. 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 81 months for Tofacitinib 5 mg BID group and up to 85 months for Tofacitinib 10 mg BID group that were absent before treatment or that worsened relative to pretreatment state. AEs included both serious and all non-serious AEs.

Serious infections were treated infections that required parenteral antimicrobial therapy or hospitalization for treatment or; met other criteria that required the infection to be classified as a serious adverse event (SAE). 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 81 months for Tofacitinib 5 mg BID group and up to 85 months for Tofacitinib 10 mg BID group that were absent before treatment or that worsened relative to pretreatment state.

Laboratory abnormalities: Hemoglobin, hematocrit, RBC: \<0.8\* LLN; reticulocytes (absolute \[Abs\], %): \<0.5\* LLN, \>1.5\* ULN; MCV, MCH: \<0.9\* LLN, \>1.1\* ULN; platelets:\<0.5\* LLN, \>1.75\* ULN; WBC:\<0.6\* LLN,\>1.5\* ULN; lymphocytes (Abs, %), total neutrophils (Abs,%):\<0.8\* LLN, \>1.2\* ULN; Basophils (Abs,%),eosinophils(Abs, %),monocytes(Abs, %):\>1.2\* ULN; total bilirubin,direct bilirubin,indirect bilirubin:\>1.5\* ULN; AST,ALT,gamma GT, LDH,ALP: \>3.0\* ULN; total protein,albumin: \<0.8\* LLN,\>1.2\* ULN: BUN,creatinine: \>1.3\* ULN;uric acid:\>1.2\* ULN; cholesterol,triglycerides: \>1.3\* ULN; cholesterol (HDL: \<0.8\* LLN; LDL: \>1.2\* ULN); sodium: \<0.95\* LLN, \>1.05\* ULN; potassium, chloride, calcium, bicarbonate: \<0.9\* LLN, \>1.1\* ULN; glucose: \<0.6\* LLN; creatine kinase \>2.0\* ULN; urine specific gravity: \<1.003; urine pH: \<4.5; urine (glucose,protein,blood,nitrite,leukocyte,esterase): \>=1; Urine (RBC,WBC): \>=20; urine epithelial cells:\>=6; urine (casts,granular casts,hyaline casts): \>1; urine bacteria:\>20.

Vital sign abnormalities included greater than or equal to (\>=) 30 millimeter of mercury \[mmHg\] increase in systolic blood pressure (BP), \>=30 mmHg decrease in systolic BP, Systolic BP (less than \[\<\] 90 mmHg), \>=20 mmHg increase in diastolic BP, \>=20 mmHg decrease in diastolic BP, diastolic BP (\<50 mmHg), pulse rate (\<40 beats per minute \[BPM\]), pulse rate (greater than \[\>\] 120 BPM).

Physical examinations included weight, general appearance, head, ears, eyes, nose, mouth, throat, thyroid, skin (presence of rash), lungs (auscultation), heart (auscultation for presence of murmurs, gallops, rubs, peripheral edema), abdominal (palpation and auscultation), perianal, musculoskeletal, extremities, neurologic (mental status, gait, reflexes, motor and sensory function, coordination) and lymph nodes. Clinically significant changes were judged by the investigator.

ECG abnormalities criteria: maximum PR interval (\>=300 millisecond); maximum QRS complex (\>=200 millisecond); and maximum QT interval (\>=500 millisecond).

Incidence rates for adjudicated cardiovascular (major adverse cardiovascular event \[MACE\]), malignancy (non-melanoma skin cancer \[NMSC\], malignancies excluding NMSC, opportunistic infections (OIs) (both herpes zoster and non herpes zoster OIs) and thromboembolic (venous thromboembolism) safety events were analyzed. This outcome measure was measured in participants with events per 100 participants-years (pt with events/100 pts-yrs).

Remission in participants was defined by a total mayo score of 2 points or lower, with no individual subscore exceeding 1 point and a rectal bleeding subscore of 0. Mayo score was an instrument designed to measure disease activity of ulcerative colitis (UC). It consisted of 4 subscores: stool frequency, rectal bleeding, findings of centrally read flexible sigmoidoscopy and physician global assessment (PGA), each subscore graded from 0 to 3 with higher scores indicating higher disease severity. These subscores were summed up to give a total score range of 0 to 12 where higher score indicating higher disease severity.