Safety, Tolerability, Efficacy, and Pharmacokinetics of JBT-101 in Systemic Sclerosis

Part A of the study is an interventional, double-blind, randomized, placebo-control design
will be used to test safety, tolerability, pharmacokinetics, and efficacy of JBT-101 in
subjects ≥ 18 and ≤ 70 years of age with active diffuse cutaneous systemic sclerosis. The
screening period is up to 28 days, with 84 days treatment period and 28 days follow-up off
active treatment.

Part B of the study is an interventional, open-label design will be used. All subjects who
complete dosing in Part A without permanent discontinuation of study drug and who pass repeat
safety screening will be eligible for enrollment. The screening period is up to 28 days, with
a 364 day treatment period and 28 day follow up after last dose of JBT-101.

Inclusion Criteria:

Part A

- Diffuse cutaneous systemic sclerosis

- Have skin thickening from SSc in a body area suitable for repeat biopsy

- Disease duration ≤ 3 years from the first non-Raynaud's phenomenon or >3 years and ≤ 6
years from the first non-Raynaud's phenomenon and high sensitivity C-reactive protein
> 3 mg/L, high sensitivity interleukin-6 > 5 pg/mL, or increase in mRSS ≥ 5 points
over the last 6 months with total RSS ≥ 12.

- Stable treatment for SSc for at least 28 days before Visit 1

Part B

•Completion of dosing in Part A without permanent discontinuation of study product because
of safety or tolerability reasons.

Exclusion Criteria (Part A and B):

- Severe or unstable systemic sclerosis

- Significant diseases or conditions other than systemic sclerosis that may influence
response to the study product or safety;

- Any one of the following values for laboratory tests at Screening:

1. A positive pregnancy test (or at Visit 1);

2. Hemoglobin < 10 g/dL

3. Neutrophils < 1.0 x 10^9/L

4. Platelets < 75 x 10^9/L

5. Creatinine clearance < 50 ml/min according to modified Cockcroft-Gault equation

6. Serum transaminases > 2.0 x upper normal limit

7. Total bilirubin ≥ 1.5 x upper limit of normal

- Any other condition that, in the opinion of the Principal Investigator, is clinically
significant and may put the subject at greater safety risk, influence response to
study product, or interfere with study assessments.