This phase 1a and 1b study is designed to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics, immunogenicity, and preliminary efficacy of NTR-1011 in healthy adults and in adult patients with systemic lupus erythematosus and rheumatoid arthritis. The main goals of this study are to determine the safety profile of NTR-1011 across subcutaneous and intravenous dose levels, understand how the drug behaves in the body, characterize its biological activity through relevant pharmacodynamic markers, assess the potential for immune responses to treatment, and explore early signals of clinical benefit in autoimmune disease settings.

This is a randomized, double blind, placebo controlled study that begins with a single ascending dose evaluation in healthy volunteers followed by a multiple dose assessment in patients. The design is intended to define the highest safe and well tolerated dose, establish a robust PK and PD baseline, and generate initial patient level evidence to support dose selection and advancement into subsequent clinical development.

1. Healthy males and females between 18 and 55 years of age.
2. Body mass index between 17.0 and 30.0 kg/m2.
3. Healthy with no clinically significant findings, as determined by medical evaluation (medical history, physical examination, vital signs, 12-lead electrocardiogram (ECG), and clinical laboratory evaluations) at Screening Visit.
4. Participant voluntarily agrees to participate in this study and signs an Ethics Committee (EC) approved informed consent form (ICF) prior to performing any of the Screening Visit procedures.
5. Participant can understand and is willing to comply with all study requirements, and willing to follow the instructions of the study staff.

Exclusion Criteria:

1. Pregnancy, nursing, and/or breastfeeding.
2. The participant has used an investigational drug within 30 days (or 5 half-lives whichever is longer) before the first dose of the study intervention.

2. Has received any prescription or nonprescription over the counter (except occasional use of acetaminophen, paracetamol, or ibuprofen prior to dosing) medication during the last 14 days. Occasional use is defined at the Investigator's discretion.

3. Has a positive urine test for drugs of abuse, or cotinine at the Screening Visit, regular consumption of alcohol within 6 months before screening or use of illicit substances within 3 months before the Screening Visit.

4. Has a positive test for hepatitis B surface antigen, hepatitis C virus and/or human immunodeficiency virus (HIV).

5. Donation or loss of blood or plasma within 4 weeks before initial dosing.

No value outside of this trial