I'm on straight Medicare and not an Advantage Plan but I had a similar issue losing my coverage for Kevzara when the drug company's patient assistance program kicked me off at the end of last year. My part D drug plan would not cover Kevzara. You could try to get on their program called Kevzara Connect or just get some advice from them. I ended up on Actemra infusions which are covered by Medicare with a GCA diagnosis. My primary diagnosis is PMR but I have some GCA symptoms so my doctor coded it "giant cell arteritis syndrome" and the infusions are covered. Some people on this list have gotten Actemra covered for PMR so it might be worth looking into.