Dipyridamole Assessment for Flare Reduction in Systemic Lupus Erythematosus (SLE)

T cells in systemic lupus erythematosus (SLE) express an abnormal phenotype characterized by
increased effector functions and deficient regulatory responses. Dipyridamole, a
phosphodiesterase inhibitor extensively used in combination with low dose aspirin in
secondary stroke prevention, has been proposed as a specific T cell directed treatment for
SLE. Dipyridamole inhibits the calcium/calcineurin/NF-AT pathway in SLE T cells in vitro and
abrogates expression of cytokines and costimulatory molecules, eventually also affecting B
cell responses. Dipyridamole delays the emergence of lupus related pathology in lupus prone
mice, but has not yet been studied in humans with SLE. The investigators aim to investigate
the efficacy of dipyridamole in the prevention of flares in SLE patients after withdrawal of
background immunosuppressive medications. The investigators will additionally evaluate the
safety and tolerability of dipyridamole and its impact on quality of life measures in this
population. Furthermore, the effect of dipyridamole on T and B cell biomarkers will be
examined.

Inclusion Criteria:

- Patients with SLE meeting the 1997 ACR Classification Criteria

- Evidence of positive ANA or anti-dsDNA within one year of screening

- SLEDAI ≥4 or ≥1 BILAG A or B at screening, despite standard of care

Exclusion Criteria:

- Leukopenia (WBC <2.000/mm3) or lymhopenia (lymphocytes < 300/mm3)

- AST or ALT >3 times above normal cut off values

- Acute lupus nephritis defined as class II, IV or V nephritis diagnosed within 6
months or prot/creat > 1.5 gm/gm due to active lupus or in process of receiving
induction therapy for nephritis

- Active CNS lupus affecting mental status

- Pregnancy or breast feeding

- Current requirement for anticoagulation

- Contraindication to aspirin or dipyridamole, including history of recent or severe GI
bleeding, hemoglobin <9 mg/dL, platelet count of <30,000 /mm3 or unstable platelet
count

- Any other medical condition, whether or not related to lupus which, in the opinion of
the investigator would render the patient inappropriate or too unstable to complete
the study protocol

- Inability or unwillingness to understand and/or sign informed consent