The Pediatric Lupus Nephritis Mycophenolate Mofetil (PLUMM) Study

Inclusion

1. Male or female aged 8 to < 21 years;

2. Must meet Classification Criteria for SLE as per the criteria of the AmericanCollege of Rheumatology (ACR)/ European League Against Rheumatism

3. Newly diagnosed with proliferative LN as per the International Society ofNephrology/Renal Pathology Society4 based on kidney biopsy done within 90 days priorto enrollment into the study; Subjects may have been previously diagnosed with other Classes of LN. For studyinclusion, the kidney biopsy must be newly interpreted as one of the followingclasses: Class 3, Class 3/5, Class 4, or Class 4/5.

4. Treatment of LN with twice daily MMF as per the decision of the treating physician. The subject will have taken MMF as prescribed by their treating physician for aminimum of 4 days (or 8 doses).

5. Subject tolerates MMF as per the treating physician's opinion;

6. Able to swallow MMF tablets and capsules;

7. If subject is treated with belimumab, must be IV or SQ;

8. Subjects who are willing and able to comply with scheduled visits, treatment plan,laboratory tests, and other study procedures;

9. Evidence of a personally signed and dated Informed Consent document and Assentdocument (as appropriate) indicating that the subject and a legally acceptablerepresentative/ parent(s)/legal guardian has been informed of all pertinent aspectsof the study.

10. Parent or legal guardian must have a smart phone available and able to support thePLUMM smart phone application.

11. Must be able to complete study questionnaires in English or Spanish.

Exclusion Criteria:

1. Perceived or stated inability to adhere to the study protocol;

2. Hypersensitivity to MMF or any component of the drug product;

3. Presence of features (from SLE or other chronic disease) that a-priori suggest thatthe subject benefits from other therapies than that suggested or allowable by thestudy protocol; These disease features include but are not limited to severe,progressive, or uncontrolled hepatic, hematologic, gastrointestinal, metabolic,endocrine, pulmonary, cardiac or neurologic disease.

4. History of other kidney disease besides LN or prior to the diagnosis of SLE;

5. Need for renal replacement therapy within 2 weeks from Baseline Subjects can haverequired short-term renal replacement therapy prior to Baseline, for example due topreceding acute kidney injury.

6. Infections:

7. Untreated latent or active tuberculosis (TB);

8. Chronic infections requiring treatment;

9. A subject known to be infected with Human Immunodeficiency Virus (HIV),Hepatitis B;

10. Diagnosis of any infection requiring hospitalization, parenteral antimicrobialtherapy or judged to be opportunistic by the investigator within 4 weeks priorto Baseline visit;

11. Any treated infections within 2 weeks of Baseline visit;

12. History of infected joint prosthesis with prosthesis still in situ;

13. Blood dyscrasias, including:

14. Hemoglobin <8.5 g/dL or Hematocrit <22%;

15. White Blood Cell count <2.6 x 109/L;

16. Neutrophil count <1.2 x 109/L;

17. Platelet count <100 x 109/L;

18. Lymphocyte count <0.5 x 109/L.

19. Estimated glomerular filtration rate [GFR] <40 mL/min/1.73 m2 calculated using themodified Schwartz equation5 (see Appendix 4);

20. Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) >1.5 times theupper limit of normal;

21. Vaccinated or exposed to a live or attenuated vaccine within the 4 weeks prior toBaseline visit;

22. History or current symptoms suggestive of lymphoproliferative disorders (e.g.,Epstein Barr Virus [EBV] related lymphoproliferative disorder, lymphoma, leukemia,myeloproliferative disorders, or multiple myeloma);

23. Current malignancy or history of any malignancy with the exception of adequatetreated or excised basal cell or squamous cell or cervical cancer in situ;

24. Recent (within 4 weeks prior to Baseline visit) significant trauma or major surgery;

25. Herbal supplements with pharmaceutical properties must be discontinued at least 1week prior to Baseline visit, unless there are sufficient data available regardingthe duration of an herbal medication's pharmacokinetic and pharmacodynamic effectsto allow a shorter or longer washout to be specified (e.g., 5 half-lives).

26. Oral or intravenous cyclophosphamide must be discontinued 12 weeks prior to Baselinevisit

27. Rituximab or other selective B lymphocyte depleting agents: Must be discontinued for 6 months prior to Baseline visit or CD19/20+ counts must be normal by FACS analysis;

28. Use of prohibited prescription medication as listed in Appendix 3 within thespecified time frame prior to Baseline visit

29. Participation in other studies involving investigational drug(s) within 4 weeks or 5half-lives (whichever is longer) prior to Baseline visit and/or during studyparticipation; Exposure to investigational biologics should be discussed with theSponsor.

30. Pregnant female subjects; breastfeeding female subjects; male subjects with partnerscurrently pregnant; male subjects able to father children and female subjects ofchildbearing potential who are unwilling or unable to use two highly effectivemethods of contraception or are abstinent for the duration of the study;

31. Other severe acute or chronic medical or psychiatric condition or laboratoryabnormality that may increase the risk associated with study participation orinvestigational product administration or may interfere with the interpretation ofstudy results and, in the judgment of the investigator, would make the subjectinappropriate for entry into this study.