**5. Treatment of eosinophilic granulomatosis with polyangiitis**

#### **5.1 Conventional therapeutic regimen**

Like other AAV, corticosteroids are the treatment's cornerstone for GEPA. Depending on the severity of the presentation, high-dose corticosteroids are oftenly *Current Treatment of ANCA Vasculitis DOI: http://dx.doi.org/10.5772/intechopen.110375*

initiated with pulses of methylprednisolone (15 mg/kg). It is recommended for a minimum period of 4 weeks followed by a taper. This helps to control asthma, general signs and hypereosinophilia [32]**.** Corticosteroids are prescribed alone or combined with an immunosuppressant after evaluation of the clinical presentation by the FFS.


#### **5.2 Therapeutic alternatives**

There have been very few randomized controlled trials conducted to date in EGPA. Rituximab is not yet validated as an alternative to cyclophosphamide in GEPA. Due to the rarity of this disease compared to other AAV, a small number of therapeutic trials have been reported in the literature with conflicting results. Some studies confirm the efficiency of this biomedicine especially in case of relapse [35–38] and particularly in patients with a positive vasculitis/anti-MPO profile [39]**.** Nevertheless, in addition to infectious complications, rituximab has been incriminated in the occurrence of severe bronchospasm secondary to a hypersensitivity reaction [39]**.**

Recently, interleukin-5 inhibitors have been introduced into the GEPA therapeutic regimen. Mepolizumab is a humanized monoclonal antibody against interleukin-5. It has been approved for use in severe eosinophilic asthma. In refractory forms of GEPA, it was effective in remission induction and maintenance due to its immunosuppressive properties [40, 41]. A recent international randomized, controlled and double-blind study compared the effect of mepolizumab versus placebo in refractory GEPA treated with corticosteroids combined or not with immunosuppressive treatment. Long-term remission of GEPA was noted in the group using mepolizumab [42]**.**

Anti-IgE drugs such as omalizumab have been used during severe allergic asthma. For GEPA, the results of the use of this biomedicine are variable and contradictory. As previously described, omalizumab has been incriminated as an unmasking factor for underlying vasculitis [43]**.** Other studies suggest its efficacy during GEPA especially for pulmonary relapses but also as a cortisone-sparing agent [44, 45]. In conclusion, further data are needed before omalizumab can be recommended or contraindicated in the treatment of GEPA [36]**.**

### **6. Treatment of microscopic polyangiitis**

Management of MPA is based on remission induction therapy and remission maintenance therapy. For non-renal forms with an FFS equal to zero, corticosteroids are used alone as a first-line treatment to induce remission. An immunosuppressant will be associated in case of non-response, relapse or dependence on corticosteroids

but also in case of extension to a systemic form with involvement of other organs (cardiac, renal, CNS …). However, high-dose corticosteroids associated with rituximab or cyclophosphamide are recommended for severe forms of MPA with a life-threatening outcome [22]. Azathioprine and methotrexate have been validated as remission maintenance treatments [31]**.** By extrapolation of their efficacy in good pasture's syndrome, plasma exchange is indicated in fulminant forms of MPA with severe renal involvement and/or alveolar hemorrhage. Currently, rituximab is also recommended for remission induction in case of refractory disease [28]**.**
