There is good information about GCA including info on prednisone and Actemra treatments and how they work differently on the Vasculitis Foundation website. They also have info on building your medical team including rheumatologist, neurologist and ophthalmologist.
I primarily see a rheumatologist for my GCA treatment. The prednisone is important but has many side effects. Per my rheumatologist Actemra helps me get off prednisone sooner and significantly reduce the amount of prednisone needed over the course of my treatment than Prednisone alone.