TLL-018 in Patients With Moderate to Severe Active Rheumatoid Arthritis With Inadequate Response or Intolerance to csDMARDs

The study will consist of a 35-day screening period, a 12-week randomized, double-blind, parallel-group, placebo-controlled treatment period (Period 1: primary efficacy observation period), a 12-week open-label treatment period with TLL-018 (Period 2: extension observation period), and a 14-day safety follow-up period. Approximately 90 study participants will be randomized at a 2:1 ratio to the TLL-018 20 mg group (treatment group, 60 participants, administered twice daily \[BID\]) or the placebo group (placebo group, 30 participants, administered twice daily \[BID\]). Treatment group: TLL-018 20 mg BID in Period 1 → TLL-018 20 mg BID in Period 2 Placebo group: Placebo BID in Period 1 → TLL-018 20 mg BID in Period 2