Safety and Pharmacokinetics of LPX-TI641 in Rheumatoid Arthritis and Psoriatic Arthritis

This is an early-phase safety study of a new investigational drug called LPX-TI641 in patients with rheumatoid arthritis (RA) or psoriatic arthritis (PsA) — inflammatory joint diseases. The study focuses on understanding the drug's safety, tolerability, and how the body processes it. **You may be eligible if...** - You are 18 or older with a BMI between 18 and 35 - You have been diagnosed with rheumatoid arthritis (RA) meeting 2010 ACR/EULAR criteria for at least 3 months, with active disease (at least 6 tender and 6 swollen joints), OR you have psoriatic arthritis (PsA) with active skin and joint disease - Your disease remains active despite current treatment **You may NOT be eligible if...** - You have had a prior serious adverse reaction to a biologic therapy - You have significant infections, organ problems, or other conditions that could make the study unsafe - You do not meet the active disease criteria at both screening and enrollment Talk to your doctor to see if this trial is right for you.