INCB047986 in Rheumatoid Arthritis

This will be a double-blind, placebo-controlled study with 4 parallel treatment groups.
Subjects will be screened for up to 28 days before study drug administration to ensure that
all eligibility criteria are met. On Day 1, subjects will be randomized to 1 of 4 dose
groups of 15 subjects each (INCB047986 4 mg, 8 mg, 12 mg, or placebo QD). Study drug will
be self administered on Days 1 through 28. A follow-up telephone call to the subject to
assess safety will occur at Day 42. A final safety and efficacy evaluation will be
performed at the Day 58 visit.

Inclusion Criteria:

- Men or women aged 18 to 75 years, inclusive.

- Body mass index between 18 and 40 kg/m^2, inclusive.

- Subjects must have a diagnosis of rheumatoid arthritis (RA) of at least 6 months'
duration at the time of screening and must satisfy the ACR/European League Against
Rheumatism (EULAR) 2010 Classification Criteria (Appendix B).

- Subjects must have active moderate to severe RA as determined by the following:

- ≥ 6 tender joints (28 joint count),

- ≥ 4 swollen joints (28 joint count), and

- CRP level ≥ 6 mg/L.

- Subjects must have a negative tuberculosis (TB) test (QuantiFERON®-TB Gold test or
purified protein derivative (PPD)) at screening.

Exclusion Criteria:

- Current or recent history of severe and/or progressive uncontrolled renal, hepatic,
hematologic, gastrointestinal, pulmonary, cardiac, neurological, or cerebral disease.

- Current or recent history (< 30 days before screening and/or < 45 days before
randomization) of a clinically meaningful bacterial, fungal, parasitic, or
mycobacterial infection.

- Onset of RA before the age of 16 years.

- History of known or currently suspected inflammatory disease other than RA

- Current regimen of prednisone or equivalent with an average daily dose of > 10 mg or
having been treated with a stable daily dose ≤ 10 mg for < 6 weeks.

- Previous treatment with at Janus kinase (JAK) inhibitor.

- Significant impairment of bone marrow function present at screening

- Receipt of any live vaccine within 2 months before screening or anticipated need for
a live vaccine within the 2 months after last dose of study drug.