Belimumab and Rituximab Combination Therapy for the Treatment of Diffuse Cutaneous Systemic Sclerosis

Inclusion Criteria: 1. Age greater than or equal to eighteen years and less than or equal to 80. 2. Classification of systemic sclerosis (SSc), as defined using the 2013 American College of Rheumatology/European Union League Against Rheumatism classification of SSc. 3. Diagnosis of dcSSc, as defined by LeRoy and Medsger. 4. Disease duration of less than or equal to 3 years as defined by the date of onset of the first non-Raynaud's symptom. 5. A modified Rodnan Skin Score (mRSS) of \> 14 Exclusion Criteria: 1. Inability to render informed consent in accordance with institutional guidelines. 2. Disease duration of greater than 3 years. 3. Patients with mixed connective tissue disease or "overlap" unless the dominant features of the illness are diffuse systemic sclerosis. 4. Limited scleroderma. 5. Systemic sclerosis-like illness associated with environmental or ingested agents such as toxic rapeseed oil, vinyl chloride, or bleomycin. 6. The use of other anti-fibrotic agents including colchicine, D-penicillamine, or tyrosine kinase inhibitors (nilotinib, imatinib, dasatinib) in the month prior to enrollment. 7. Use in the prior month of corticosteroids at doses exceeding the equivalent of prednisone 10 mg daily. Use of corticosteroid at \< 10 mg of prednisone can continue during the course of the study. 8. Concurrent serious medical condition which in the opinion of the investigator makes the patient inappropriate for this study such as uncontrollable CHF, arrhythmia, severe pulmonary or systemic hypertension, severe GI involvement, hepatic impairment, serum creatinine of greater than 2.0, active infection, severe diabetes, unstable atherosclerotic cardiovascular disease, malignancy, HIV, or severe peripheral vascular disease. 9. A positive pregnancy test at entry into this study. Men and women with reproductive potential will be required to use effective means of contraception through the course of the study, such as (1) surgical sterilization (such as a tubal ligation or hysterectomy), (2) double-barrier methods (such as a condom and occlusive cap (diaphragm or cervical/vault caps) plus spermicidal agent (foam/gel/film/cream/suppository)(3) an intrauterine device (IUD) or intrauterine system (IUS) (4) estrogenic vaginal ring (5) percutaneous contraceptive patches, or (6) implants of levonorgestrel or etonogestrel. Approved hormonal contraceptives (such as birth control pills, patches, implants or injections) may interact with and reduce the effectiveness of MMF so women receiving MMF who are using oral contraceptives for birth control should employ an additional method (e.g. barrier method). Contraceptive measures such as Plan B (TM), sold for emergency use after unprotected sex, are not acceptable methods for routine use. 10. Women not willing to use effective birth control for the duration of the study 11. Breastfeeding. 12. Participation in another clinical research study involving the evaluation of another investigational drug within ninety days of entry into this study. 13. The presence of severe lung disease as defined by a diffusion capacity of less than 30% of predicted or requiring supplemental oxygen and forced vital capacity (FVC) of less than 45% of predicted. 14. Grade 3 hypogammaglobulinemia 15. Have a significant IgG deficiency (IgG level \< 400 mg/dL) 16. Have an IgA deficiency (IgA level \< 10 mg/dL) 17. Have a historically positive HIV test or test positive at screening for HIV 18. Neutrophils \<1.5X10E9/L 19. Hepatitis status: 1. Serologic evidence of current or past Hepatitis B (HB) infection based on the results of testing for HBsAg and HBcAb as follows: 1\. Patients positive for HBsAg or HBcAb are excluded b) Positive test for Hepatitis C antibody 20. Known active bacterial, viral, fungal, mycobacterial, or other infection or any major episode of infection requiring hospitalization or treatment with IV antibiotics within 4 weeks of screening, or oral antibiotics within 2 weeks prior to screening 21. Infection history: 1. Currently on any suppressive therapy for a chronic infection (such as tuberculosis, pneumocystis, cytomegalovirus, herpes simplex virus, herpes zoster and atypical mycobacteria) 2. Hospitalization for treatment of infection within 60 days of Day 0. 3. Use of parenteral (IV or IM) antibiotics (antibacterials, antivirals, anti-fungals, or anti-parasitic agents) within 60 days of Day 0 22. Suppressive therapy for a chronic infection (such as tuberculosis, pneumocystis, cytomegalovirus, herpes zoster and atypical mycobacteria) 23. Any other disease, metabolic dysfunction, physical examination finding, or clinical laboratory finding giving reasonable suspicion of a disease or condition that contraindicates the use of an investigational drug or that may affect the interpretation of the results or render the patient at high risk from treatment complications 24. Prior use of Belimumab, Rituximab, or other B-Cell depleting therapies ever 25. The use of other biologics including TNF inhibitors, abatacept, or tocilizumab within the washout period below for each particular drug: Tocilizumab - 1 month for patients on 2mg/kg or 4 mg/kg. 2 months for patients on 8mg/kg. Cyclophosphamide (oral or IV) - 3 months. Abatacept - 2.5 months. TNF Inhibitors : Etanercept - 1 mo, Infliximab - 2 mo, Adalimumab - 2.5 mo. Any biologic investigational agent (e.g., abetimus sodium, anti CD40L antibody, BG9588/ IDEC 131) - 365 days prior to belimumab. Any non-biologic investigational agent - 30 days prior to belimumab. 26\. Have evidence of serious suicide risk including any history of suicidal behavior in the last 6 months and/or any suicidal ideation in the last 2 months or who in the investigator's judgment, pose a significant suicide risk. 27\. Current drug or alcohol abuse or dependence, or a history of drug or alcohol abuse or dependence within 364 days prior to Day 0. 28\. History of an anaphylactic reaction to parenteral administration of contrast agents, human or murine proteins or monoclonal antibodies 29. Live vaccines within 30 days prior to baseline 30. Have a history of malignant neoplasm within the last 5 years with the exception of basal cell or squamous cell carcinoma of the skin treated with local resection only or carcinoma in situ of the uterine cervix treated locally and with no evidence of metastatic disease for 3 years 31. Have a history of a primary immunodeficiency 32. Have any other clinically significant abnormal laboratory value in the opinion of the investigator 33. Have any intercurrent significant medical or psychiatric illness that the investigator considers would make the candidate unsuitable for the study 34. Non English speakers