Safety, Tolerability, and Efficacy of GS-9876 in Participants With Active Rheumatoid Arthritis on Background Therapy With Methotrexate

Key Inclusion Criteria:

• Active RA disease as defined by: a tender joint count (TJC) of ≥ 6 (out of 68), aswollen joint count (SJC) of ≥ 6 (out of 66) at screening and Day 1

• Inadequate response to treatment with oral or parenteral methotrexate (MTX) 7.5 to 25mg/week continuously for at least 12 weeks

• No evidence of active or latent tuberculosis

Key Exclusion Criteria:

• Prior treatment with B-cell depleting agents (eg, rituximab), unless more than 6months prior to the first dose of study drug and documented return of CD19+ cells atscreening

• Prior treatment with any commercially available or investigational spleen tyrosinekinase (SYK) inhibitor

• Concurrent treatment with any other conventional synthetic DMARD (csDMARD) other thanMTX and/or hydroxychloroquine (HCQ) (prior csDMARD treatment allowed if appropriatewash out as defined in the protocol)

• Concurrent treatment with any biological disease modifying anti-rheumatic drug (bDMARD)(prior bDMARD treatment allowed if appropriate wash out as defined in theprotocol). Prior failure to treatment with bDMARDs is not an exclusion criterion. Note: Other protocol defined Inclusion/ Exclusion criteria may apply.