A Study to Evaluate the Long-Term Safety and Efficacy of GDC-0853 in Participants With Moderate to Severe Rheumatoid Arthritis Enrolled in Study GA29350 (NCT02833350)

Inclusion Criteria:

- Completion of treatment as specified in Study GA29350, including completion of the Day
84 study visit assessments

- Acceptable safety and tolerability during Study GA29350 as determined by the
investigator or Medical Monitor

- Have not received any prohibited medications in Study GA29350

- While taking methotrexate, must be willing to receive oral folic acid (at least 5
milligrams per week [mg/week])

- If receiving oral corticosteroids (less than or equal to [ [mg/day] prednisone or equivalent) and/or non-steroidal anti-inflammatory drugs, doses
have remained stable for the duration of Study GA29350

Exclusion Criteria:

- Met protocol defined treatment stopping criteria during Study GA29350

- Treatment with any investigational agent (i.e., other than study drug) or
live/attenuated vaccine or any other prohibited medication during Study GA29350 or
since the last administration of study drug in Study GA29350

- In the opinion of the investigator, any new (since initially enrolling in the Phase II
Study GA29350), significant, uncontrolled comorbidity that would increase the risk to
the participant in Study GA30067

- Pregnant or lactating, or intending to become pregnant during the study

- Participants who experienced a de novo or reactivated serious viral infection such as
hepatitis B virus (HBV), hepatitis C virus (HCV), or human immunodeficiency virus
(HIV) during the Phase II Study GA29350

- Any major episode of infection requiring hospitalization or treatment with intravenous
antibiotics during the Phase II Study GA29350

- Participants who developed a malignancy during the Phase II Study GA29350

- 12-lead electrocardiogram (ECG) on Day 84 in Study GA29350 that demonstrates
clinically relevant abnormalities that may affect participant safety or interpretation
of study results

- Current treatment with medications that are well known to prolong the QT interval