The purpose of this study is to assess the pharmacokinetics, safety and tolerability of PF-04965842 after single dose and once-daily multiple-doses in Chinese healthy participants.

This is a Phase 1, open-label, single-arm, single- and multiple-dose study to assess the pharmacokinetics, safety and tolerability of PF-04965842 in Chinese healthy participants.

Inclusion Criteria:

• Body mass index (BMI) of 19 to 26 kg/m2; and a total body weight >50 kg.
• Participants who are willing and able to comply with all scheduled visits, treatment plan, laboratory tests, lifestyle considerations, and other study procedures.

Exclusion Criteria:

• Evidence or clinically significant hematological, renal, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic (including alcoholic liver disease, nonalcoholic steatohepatitis (NASH), autoimmune hepatitis, and hereditary liver diseases), psychiatric, neurological, 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).
• History of human immunodeficiency virus (HIV) infection, hepatitis B, or hepatitis C; positive testing for HIV, hepatitis B surface antigen (HBsAg), hepatitis C antibody (HCVAb) and serological reaction of syphilis. As an exception, a positive hepatitis B surface antibody (HBsAb) finding as a result of participant vaccination is permissible.
• Evidence or history of clinically significant dermatological condition (eg, contact dermatitis or psoriasis) or visible rash present during physical examination.
• History of tuberculosis (TB) or active or latent or inadequately treated infection, positive QuantiFERON- TB Gold test or positive chest radiographs for active tuberculosis infection.
• Any history of chronic infections, any history of recurrent infections, any history of latent infections, or any acute infection within 2 weeks of baseline.
• History of disseminated herpes zoster, or disseminated herpes simplex, or recurrent localized dermatomal herpes zoster.
• Have any malignancies or have a history of malignancies with the exception of adequately treated or excised non-metastatic basal cell or squamous cell cancer of the skin, or cervical carcinoma in situ.
• A positive urine drug test.
• Screening sitting blood pressure (BP) >=140 mm Hg (systolic) or >=90 mm Hg (diastolic), following at least 5 minutes of supine rest. If BP is >=140 mm Hg (systolic) or >=90 mm Hg (diastolic), the BP should be repeated 2 more times and the average of the 3 BP values should be used to determine the participant's eligibility.
• Participants with ANY of the following abnormalities in clinical laboratory tests at screening, as assessed by the study-specific laboratory and confirmed by a single repeat test, if deemed necessary: Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) level >=1.5 × upper limit of normal (ULN); Total bilirubin level >1 × ULN; participants with a history of Gilbert's syndrome may have direct bilirubin measured and would be eligible for this study provided the direct bilirubin level is <=1 × ULN.

Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical\_trials/trial\_data\_and\_results/data\_requests.