Giant cell arteritis (GCA) and Takayasu arteritis (TAK) are the two main large 
vessel vasculitides. They share some similarities regarding their clinical, 
radiological and histological presentations but some pathogenic processes in GCA 
and TAK are activated differently, thus explaining their different sensitivity 
to biological therapies. The treatment of GCA and TAK essentially relies on 
glucocorticoids. However, thanks to major progress in our understanding of their 
pathogenesis, the role of biological therapies in the treatment of these two 
vasculitides is expanding, especially in relapsing or refractory diseases. In 
this review, the efficacy, the safety and the limits of the main biological 
therapies ever tested in GCA and TAK are discussed. Briefly, anti TNF-α agents 
appear to be effective in treating TAK but not GCA. Recent randomized 
placebo-controlled trials have reported on the efficacy and safety of abatacept 
and mostly tocilizumab in inducing and maintaining remission of GCA. Abatacept 
was not effective in TAK and robust data are still lacking to draw any 
conclusions concerning the use of tocilizumab in TAK. Furthermore, ustekinumab 
appears promising in relapsing/refractory GCA whereas rituximab has been 
reported to be effective in only a few cases of refractory TAK patients. If a 
biological therapy is indicated, and in light of the data discussed in this 
review, the first choice would be tocilizumab in GCA and anti-TNF-α agents 
(mainly infliximab) in TAK.