There is now an alternative to prednisone that was recently FDA approved for the treatment of PMR. It is a biologic called Kevzara (sarilumab).
https://www.pharmacytimes.com/view/fda-approves-sarilumab-for-adults-with-polymyalgia-rheumatica
I don't have any personal experience with Kevzara. My rheumatologist was running out of options for my long term PMR. The side effects of my 12 years on prednisone were taking a toll on me.

Other medications used as steroid sparing medications like methotrexate and leflunomide didn't work very well for me. My rheumatologist tried me on Actemra (tocilizumab) 4 years ago and it worked well. After more than 12 years of prednisone daily in excess of 10 mg, I am finally off prednisone. I'm still on Actemra so I'm not medication free. My rheumatologist thinks I'm better off on Acterma instead of prednisone. I would wholeheartedly agree!

The mechanism of action of Kevzara and Actemra is basically the same. Both biologics are IL-6 receptor blockers. IL-6 related inflammation is implicated in PMR and GCA.
https://www.pmrandil6.com/il-6-and-pmr/.