Bioequivalence Study of PF-06651600 Capsules Relative to Tablets and Estimation of Food Effect on Capsules.

Inclusion Criteria: * Male and female participants who are healthy as determined by medical evaluation including a detailed medical history, complete physical examination, which includes BP and pulse rate measurement, clinical laboratory tests, and cardiac evaluation (including ECG). * BMI of 17.5 to 30.5 kg/m2; and a total body weight \>50 kg (110 lb). Exclusion Criteria: * Evidence or history of clinically significant hematological, renal, endocrine (including diabetes), pulmonary, gastrointestinal, cardiovascular (including hypertension and congestive heart failure), hepatic, psychiatric, neurological, dermatological, or allergic disease (including drug allergies, but excluding untreated, asymptomatic, seasonal allergies at the time of dosing). * Any condition possibly affecting drug absorption (eg, gastrectomy, cholecystectomy). * Known immunodeficiency disorder, including positive serology for human immunodeficiency virus (HIV) at screening, or a first degree relative with a hereditary immunodeficiency. Participants with any of the following acute or chronic infections or infection history: * Any infection requiring treatment within 2 weeks prior to the dosing visit. * Any infection requiring hospitalization or parenteral antimicrobial therapy within 60 days of the first dose of study intervention. * Any infection judged to be an opportunistic infection or clinically significant by the investigator, within the past 6 months of the first dose of study intervention. * Known active or history of recurrent bacterial, viral, fungal, mycobacterial or other infections. * History of recurrent (more than one episode of) localized dermatomal herpes zoster, or history of disseminated (single episode) herpes simplex or disseminated herpes zoster.