I believe the FDA approving a first biologic agent for polymyalgia rheumatica is the start of something big.
Last week, the FDA approved sarilumab, a fully human monoclonal antibody that inhibits binding of IL-6 to its α receptor, for the treatment of glucocorticoid-resistant polymyalgia rheumatica (PMR).
For patients living with this chronic rheumatic disease and ardent PMR researchers like me, the magnitude of this development cannot be understated.
Among inflammatory autoimmune rheumatic diseases, PMR has an incidence second only to rheumatoid arthritis (RA) in terms of its lifetime risk. Despite this, efforts to modernise its treatment have been few.
While conditions such as RA, psoriatic arthritis and, more recently, PMR’s close cousin giant cell arteritis have benefitted from a steroid-sparing therapeutic paradigm and the advent of biologic medications, PMR patients have been left to languish on prednisolone monotherapy and suffer its many adverse consequences. But, hopefully, not for much longer.
Based on results from the pivotal SAPHYR study, presented by Dr Robert Spiera at ACR Convergence 2022, the FDA has accepted that sarilumab (Kevzara, Sanofi) demonstrated sufficient efficacy and safety to justify its use in PMR among patients with an insufficient response to glucocorticoid therapy.
This phase III randomised controlled trial notably found a highly statistically significant result (p=0.0193), based upon 28.3% of participants receiving fortnightly sarilumab in combination with a 12-week prednisolone taper achieving the lofty endpoint of sustained clinical remission, compared with only 10.3% in the placebo with 52-week prednisolone taper group.
“Sustained clinical remission” was defined as achievement of disease remission by week 12, absence of flare from week 12 to 52, sustained reduction in CRP from week 12 to 52, and no rescue therapy from week 12 to 52.
A profound steroid-sparing effect was additionally documented in the treatment arm, along with substantive improvement in the patient-reported SF-36 for both physical and mental function.
So as modern imaging has permitted us new appreciation of PMR’s underlying pathology, it seems novel approaches to therapy will begin to illuminate the profound morbidity, both disease- and treatment-related, that typically characterises this rheumatic condition.
Approval of a biologic medication underscores the legitimacy of PMR as a distinct entity, with patients that are equally deserving of the latest in rheumatology care.
Today, I look to a future in PMR management that is far brighter thanks to the knowledge that evidence finally exists for a treatment other than glucocorticoid therapy.
Dr Claire Owen is a Rheumatologist and Department Deputy Director at Austin Health in Melbourne. Her PhD investigated the role of imaging, specifically whole-body PET/CT, in PMR, and she additionally serves as Co-Chair of the international OMERACT PMR Working Group.
