The study was terminated due to extensive Covid-19 delay.

This is a Phase 1 non-randomized, open-label, parallel cohort study of PF-06651600 in subjects with severe renal impairment and subjects without renal impairment (Part 1) and in subjects with mild and moderate renal impairment (Part 2).

This is a Phase 1 non-randomized, open-label, parallel cohort, multi-site study to investigate the effect of renal impairment on the pharmacokinetics, safety and tolerability of PF-06651600 after multiple oral doses of 50 mg daily. Subjects will be selected and categorized into normal renal function or renal impairment groups based on their estimated glomerular filtration rate. Part 1: A total of approximately 16 subjects will be enrolled; approximately 8 subjects with severe renal impairment and approximately 8 with normal renal function. After statistical evaluation of results from Part 1, Part 2 may be conducted with approximately 8 subjects each with moderate and mild renal impairment. The total duration of participation from Screening visit to Day 11 will be a maximum of 39 days and from Screening visit to Follow-up/Contact Visit will a maximum of 73 days.

Inclusion Criteria:

• Body mass index (BMI) of >/= 17.5 to </= 40.0 kg/m2; and a total body weight > 50 kg (110 lb)

Additional inclusion criteria for subjects with renal impairment:

• Meet the following eGFR criteria during the screening period based upon MDRD equation:
• Severe renal impairment: eGFR <30 mL/min but not requiring hemodialysis
• Moderate renal impairment (Part 2 only): eGFR >/=30 mL/min and <60 mL/min
• Mild renal impairment (Part 2 only): eGFR between 60 and 89 mL/min
• Any form of renal impairment except acute nephritic syndrome (subjects with history of previous nephritic syndrome but in remission can be included)
• Stable drug regimen

Exclusion Criteria:

• Females of child-bearing potential must use an accepted, highly effective contraceptive method
• Renal transplant recipients
• Urinary incontinence without catheterization
• Subjects with clinically significant infections within the past 6 months prior to first dose of study drug, evidence of active or chronic infection requiring oral treatment within 4 weeks prior, history of disseminated herpes simplex or recurrent or disseminated herpes zoster
• Subjects with malignancy or with a history of malignancy, with the exception of adequately treated or excised non-metastatic basal cell or squamous cell cancer of skin or cervical carcinoma in situ
• HIV, Hepatitis B, or Hepatitis C infection

Additional exclusion criteria for subjects with renal impairment:

• Subjects requiring hemodialysis and peritoneal dialysis
• Screening BP >/=180 mmHg (systolic) or >/=110 mmHg (diastolic)
• Screening 12-lead ECG demonstrating QTcF >470 msec

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.

The baseline analysis population included all participants enrolled in the study.

From Screening (Day -28) through and including up to 35 calendar days after the last administration of investigational product, assessed up to 74 days.

Serious adverse events (SAEs) and non-serious AEs were recorded on the CRF. SAEs were also reported on the Clinical Trial (CT) SAE report form to Pfizer Safety within 24 hours of awareness.

Since the study was terminated, the results of this study was not complete and the interpretation of the study results was limited.