Summary
Polymyalgia rheumatica (PMR) often relapses when the glucocorticoid (GC) dose is reduced.
Traditionally, methotrexate (MTX) is then used as a GC-sparing measure.
Sarilumab, which like tocilizumab blocks the alpha chain of the IL-6 receptor, has been investigated in phase 3 trials for the treatment of both giant cell arteritis (GCA) and PMR.
While the RZA study was unable to recruit as desired in the context of Covid, it was possible to achieve significantly better remission maintenance and a reduction in the GC dose in recurrent PMR

Patients were randomized 1:1 and treated with sarilumab 200mg (2-weekly) or placebo for 52 weeks.
In the sarilumab arm, prednisone (PDN) was discontinued within 12 weeks; in the placebo arm, prednisone was reduced over 52 weeks.
The primary end point was a stable remission from week 12 to week 52 (defined as symptom-free, normalized CRP and adherence to the prescribed GC reduction).

118 patients were included.
Sustained remission was achieved in 28% with sarilumab and in 10% in the placebo arm (difference 18%, p=0.02).
The cumulative PDN dose was 777mg in the sarilumab arm and 2044mg in the placebo arm.
More adverse events were seen in the sarilumab arm, such as neutropenia in 15% versus 0%.

In summary, the data should provide good support for reimbursement applications for sarilumab in the context of recurrent PMR with impending severe GC side effects.

References
[1] Robert F Spiera, Sebastian Unizony, Kenneth J Warrington, et al.
SAPHYR Investigators.
Sarilumab for Relapse of Polymyalgia Rheumatica during Glucocorticoid Taper.
N Engl J Med. 2023 Oct 5;389(14):1263-1272.
doi: 10.1056/NEJMoa2303452.

Written by
Prof. Dr. med. Peter M. Villiger
Monbijou Medical Center
Monbijoustrasse 10, 3011 Berne
October 2023