Mepolizumab As a Steroid-sparing Treatment Option in the Churg Strauss Syndrome

Specific Aims:

• Document the safety of mepolizumab therapy in patients with CSS.
• Demonstrate the steroid sparing effect of mepolizumab therapy by decreasing corticosteroid dosage while using this anti-IL5 therapy.
• Demonstrate the efficacy of anti-IL5 therapy in improving the signs and symptoms of CSS by:

• Measuring serum markers of CSS disease activity, including: peripheral eosinophilia, erythrocyte sedimentation rate, anti- neutrophil cytoplasmic antigen, C-reactive protein and IgE levels.
• Assessing the activity level of vasculitis via the Birmingham Vasculitis Activity Score
• Evaluating asthmatic response via serial peak flow and FEV1 measurements as well as asthma symptom scores using the Juniper scale.
• Assessing changes in novel parameters such as fractional excretion of nitric oxide and IL-5 levels.

Inclusion criteria

• Age >18 years old
• Diagnosis of Churg Strauss Syndrome
• Maintained on stable corticosteroid dose of at least prednisone 10mg daily (or equivalent) prior to enrollment in study
• If on cyclophosphamide, azathioprine or methotrexate, must be on a stable dose and be able to maintain that dose for the duration of the study

Exclusion criteria

• Hypereosinophilic Syndrome
• Wegener's Granulomatosis
• Malignancy
• Parasitic Disease
• Pregnant or nursing
• If female and of child-bearing potential, must have negative pregnancy test prior to each infusion of study medication and must adhere to acceptable method of contraception (with <1% failure rate)
• Any other medical illness that precludes study involvement