LFD-200

This is a double-blind, randomized, placebo- and active-controlled study investigating the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of subcutaneous (SC) doses of LFD-200. The study design includes: a single ascending dose (SAD) study in up to 66 adult healthy participants (HPs) to investigate the effects of a single SC dose, with a 30-day follow-up; a multiple ascending dose (MAD) study in up to 40 HPs to assess up to 4 weekly SC doses, with a 30-day follow-up after the last dose; and a MAD study in up to 70 participants with moderate to severe rheumatoid arthritis (RA) to evaluate up to 13 weekly SC doses, with a 30-day follow-up after the last dose.