INCB028050 Compared to Background Therapy in Patients With Active Rheumatoid Arthritis (RA) With Inadequate Response to Disease Modifying Anti-Rheumatic Drugs

Inclusion Criteria:

- Must have rheumatoid arthritis which has been inadequately controlled with at least
one DMARD

- For subjects receiving antimalarials, they must be treated with antimalarials for at
least 6 months and receiving a stable daily dose

- For subjects receiving sulfasalazine, they must be treated with Sulfasalazine (SSZ)
for at least 6 months and receiving a stable daily dose of no more than 3 grams per
day

- For subjects on methotrexate, they must be treated with methotrexate for at least 6
months, and receiving a stable weekly dose of methotrexate between 7.5 and 25 mg

- For subjects on leflunomide, they must be treated with leflunomide for at least 6
months, and receiving a stable dose of leflunomide between 10 to 20 mg

- For subjects receiving corticosteroids, they must be on a dose not to exceed 10 mg of
prednisone daily

- Active rheumatoid arthritis at the time of screening defined by the following: 6 or
more joints tender or painful on motion and 4 or more swollen joints and at least one
of the following two: Erythrocyte sedimentation rate (ESR) greater than or equal to 28
mm/hr or C-reactive protein (CRP) greater than or equal to 7 mg/liter

- Have evidence of lack of risk for tuberculosis

Exclusion Criteria:

- Current or recent viral, bacterial, fungal, parasitic or mycobacterial infection
requiring systemic therapy

- History of infected joint prosthesis

- Subjects who have a current or recent history of severe, progressive, uncontrolled
renal, hepatic, hematological, gastrointestinal, pulmonary, cardiac, neurological or
cerebral disease

- Subjects who have received treatment with the following drugs or drug classes within
the specified timeframe: prior treatment with rituximab within 12 months, prior
treatment with an oral Janus kinase (JAK) inhibitor, DMARDs or other anti-rheumatic
therapies not specified and allowed according to protocol, treatment with any
investigational medication within 12 weeks or 5 half-lives (whichever is longer), and
treatment with a biologic agent within 12 weeks prior to the first dose of study
medication

- Subjects with a past history of neutropenia, thrombocytopenia or anemia requiring
transfusion other than at the time of trauma or surgery, and subjects that meet
protocol specified laboratory measures