To compare the effect of RAYOS® versus immediate-release (IR) prednisone on fatigue as measured by Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F).

Inclusion Criteria:

1. Provide written informed consent agreeing to all study procedures, before any study-specific procedures are done.

2. Males or non-pregnant females, aged 18 years or older

3. Diagnosis of SLE by either the American College of Rheumatology (ACR) or Systemic Lupus International Collaborating Clinics Classification (SLICC) criteria

4. Fatigue measured by FACIT-F ≤30.

5. On a stable regimen of IR prednisone (5 to 15 mg/day) for a period of at least 30 days prior to Screening, expected to remain stable for the next 6 months.

6. On a stable SLE treatment regimen for a period of at least 30 days prior to Screening, and expected to remain stable for the next 6 months. Any of the following medications are permitted if stable for at least 30 days prior to Screening and expected to remain stable for the next 6 months:

   • Hydroxychloroquine or equivalent anti-malarial
   • Other immunosuppressive or immunomodulatory agents including methotrexate, azathioprine, leflunomide, mycophenolate (including mycophenolate sodium or mycophenylate mofetil at no more than 2 grams/day), belimumab, cyclophosphamide, calcineurin inhibitors (e.g. tacrolimus, cyclosporine)

7. Entry of daily ePRO data on 11 of 14 days during the baseline period, and completion of at least 6 out of the 8 weekly ePRO questionnaires during the baseline period

8. Willing and able to perform and comply with all study procedures, including taking pills daily as prescribed, completing the ePROs on the smart phone, wearing the smart watch day and night, bringing the smartphone on all activities away from home (e.g., walks, errands, visiting, shopping, traveling), keeping the smartphone and smartwatch charged daily, carefully using the smartphone and smartwatch as clinical tools and keeping them secure from others, and attending monthly clinic visits as scheduled

9. Females of childbearing potential must be currently using a highly effective method of contraception that may include, but is not limited to, abstinence, sex only with persons of the same sex, monogamous relationship with vasectomized partner, hysterectomy, bilateral tubal ligation, licensed hormonal methods, intrauterine device, or use of a spermicide combined with a barrier method (e.g., condom, diaphragm) for 30 days before and 90 days after receiving the study drug

Exclusion Criteria:

1. Previously taken any of the following medications:

   • RAYOS®
   • Rituximab within 6 months prior to Screening
   • Any investigational therapy within 3 months or 5 half-lives of the agent prior to Screening

2. History of noncompliance with taking pills as prescribed.

3. Rapidly progressive neurologic disease

4. Rapidly progressive renal disease (defined by proteinuria >6 g/24 hours or equivalent using spot urine protein to creatinine ratio, or serum creatinine >2.5 mg/dL)

5. Diagnosis of fibromyalgia

6. Any of the following clinical laboratory abnormalities:

   • Hemoglobin <8.0 mg/dL
   • Platelet count <50,000/mm3
   • White blood count (WBC) ≤ 2000/mm3; may be 1999-1000/mm3 if stable and related to SLE
   • Absolute neutrophil count (ANC) ≤1000/mm3; may be 500-999/mm3 if stable and related to SLE
   • Aspartate transaminase (AST) or alanine transaminase (ALT) ≥3× upper limit of normal (ULN) unless related to SLE
   • Calculated creatinine clearance ≤25 mL/min per 1.73 m2 (by Cockcroft-Gault equation)

7. Grade 3 or greater laboratory abnormality based on the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE; Appendix 3) except for the following that are allowed:

   • Activated partial thromboplastin time (PTT) > >2.5× ULN due to lupus anticoagulant and not related to liver disease or anti-coagulant therapy
   • Hypoalbuminemia <2 g/dL due to chronic lupus nephritis, and not related to liver disease
   • Gamma glutamyl transferase (GGT) <20× ULN due to lupus hepatitis, and not related to alcoholic liver disease, uncontrolled diabetes, or viral hepatitis. If present, any abnormalities in the ALT and/or AST must be ≤5× ULN

8. Pregnant or nursing, or females not using effective contraception

9. Current drug or alcohol abuse or dependence, or a history of drug or alcohol abuse or dependence within 1 year prior to Screening

10. Clinical evidence of significant unstable or uncontrolled acute or chronic diseases not caused by SLE (e.g., diabetes, cardiovascular, pulmonary, hematologic, gastrointestinal, neurological, or infectious) which, in the opinion of the Investigator, could confound the results of the study or put the subject at undue risk