The purpose of the study is to determine the safety, tolerability, and pharmacokinetics of PIT565, in participants with rheumatoid arthritis (RA).

This is an open-label, uncontrolled study in participants with RA. PIT565 will be administered subcutaneously. The objective of the study is to assess the safety of PIT565 in participants with RA.

Inclusion Criteria:

• Signed informed consent must be obtained prior to participation in the study. Male and female patients, aged 18 to 75 years at screening, diagnosed with RA according to the 2010 ACR/EULAR or 1987 ACR classification at least 12 weeks prior to screening.
• Immunization (primary or from vaccinations) against pneumococcus, influenza, meningococcus and COVID-19 infection at least 2 weeks prior to the first dosing. Local guidelines should be followed to determine requirement for vaccination (or booster), as well as the type and schedule of vaccination.

Exclusion Criteria:

• Any of the following cardiac conditions

1. Unstable angina, myocardial infarction, coronary artery bypass graft (CABG), or stroke within 6 months prior to screening
2. Clinically significant and/or uncontrolled heart disease such as congestive heart failure requiring treatment (NYHA Grade ≥ 2) or uncontrolled hypertension
3. Concomitant clinically significant cardiac arrhythmias, e.g., sustained ventricular tachycardia, and clinically significant second or third degree atrioventricular block without a pacemaker
4. History of familial long QT syndrome or known family history of Torsades-de- Pointes
5. Resting QTcF ≥ 450 msec (male) or ≥ 460 msec (female) at screening
6. Use of agents known to prolong the QT interval unless they can be permanently discontinued for the duration of the study.

Other protocol-defined inclusion/exclusion criteria may apply.