This study includes a 35-day screening period; a 24-week randomized, double-blind, parallel-group, placebo-controlled treatment period (Period 1); a 52-week open label long-term extension period (Period 2); and a 28 to 35-day follow-up period (FU).
Participants who meet eligibility criteria will be randomized in a 1:1 ratio to two treatment groups:
Group 1: LNK01001 12 mg BID (Day 1 to Week 24)， LNK01001 12 mg BID (Week 24 and thereafter)
Group 2: Placebo (Day 1 to Week 24)， LNK01001 12 mg BID (Week 24 and thereafter)
Participants who complete the Week 24 visit (end of Period 1) will enter the extension portion of the study, Period 2, and continue to receive LNK01001 12 mg BID treatment. Starting at Week 12, rescue therapy is allowed if there's less than 20% improvement in both swollen joint count (SJC) and tender joint count (TJC) compared to Baseline. Starting at Week 24, initiation of or change in corticosteroids, non-steroidal anti-inflammatory drugs (NSAIDs), acetaminophen, or adding or increasing doses in up to 2 csDMARDs (concomitant use of up to 2 csDMARDs except the combination of methotrexate and leflunomide) is allowed.
