Vitamin D3 in Systemic Lupus Erythematosus

Systemic Lupus Erythematosus (SLE) is an autoimmune disease characterized by the production
of autoantibodies with subsequent immune complex deposition and tissue inflammation. The
role of interferon (IFN) alpha in the development of SLE has been repeatedly documented.
Vitamin D deficiency is common among lupus patients. Vitamin D is recognized as a regulator
of immune response. This study will explore the impact of vitamin D3 supplementation on IFN
alpha expression in SLE patients.

The study will last approximately 12 weeks and consist of three treatment groups: 1.)
Participants will receive vitamin D3 2000 IU daily 2.) Participants will receive vitamin D3
4000 IU daily 3.) Participants will receive a vitamin D3 placebo daily. There will be four
study visits for each participant. Visits will occur at screening, study entry, and Weeks 6
and 12. Physical examination, vital signs, and blood and urine tests will occur at all
visits. For females of childbearing potential, a pregnancy test will be performed at
screening and Week 6.

Inclusion Criteria:

- Diagnosis of SLE by American College of Rheumatology (ACR) criteria

- Serum 25-OH vitamin D level of 20 ng/mL or less

- Stable disease at screening, defined as a modified Safety of Estrogens in Lupus
Erythematosus National Assessment SLE Disease Activity Index (SELENA-SLEDAI) of 4 or
less

- Interferon (IFN) signature present. More information about this criterion can be
found in the protocol

- Positive anti-double-stranded (anti-ds) DNA antibody blood test at screening

- If on corticosteroids, the dose must be less than 20 mg per day and stable for 4
weeks prior to screening and at study entry

- If on immunosuppressive or immunomodulatory medication such as azathioprine,
methotrexate, leflunomide, mycophenolate, or hydroxychloroquine, the dose must be
stable for 3 months prior to screening and at study entry

- If receiving a multivitamin or a vitamin D supplement, the dose of vitamin D must be
800 IU daily or less and stable for the 3 months prior to screening and at study
entry

- Agree to use effective contraceptive methods for the duration of the study

Exclusion Criteria:

- Unwilling to stop using drugs or substances that may interfere with fat absorption

- Hypercalcemia

- Hypercalciuria

- History of hyperparathyroidism

- History of kidney stones

- History of cancer, except cervical carcinoma in situ and resected basal and squamous
cell carcinomas of the skin

- Known history of chronic viral infections, including human immunodeficiency virus
(HIV), Hepatitis B, and Hepatitis C

- Known active tuberculosis

- Any British Isles Lupus Assessment Group (BILAG) A or B manifestation with the
exception of a BILAG B mucocutaneous manifestation

- Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) liver function
tests greater than or equal to two times the upper limit of normal

- Dialysis or serum creatinine greater than 1.5 mg/dL

- Expectation by the investigator to increase corticosteroid or immunosuppressive or
immunomodulatory medication dose at screening, study entry, or over the course of the
study

- Treatment with cyclophosphamide within 3 months of screening

- Treatment with rituximab within 12 months of screening

- Other investigational drug and or treatment during the 4 weeks or seven half lives of
the other investigational drug prior to study entry

- Drug or alcohol abuse within 6 months prior to study entry

- Treatment with digoxin

- Treatment with teriparatide

- Any condition that, in the opinion of the investigator, would jeopardize the
subject's safety following exposure to the study drug

- Pregnant or breastfeeding