A biologic helped polymyalgia patients taper steroids in a phase 3 trial

Polymyalgia rheumatica is one of the more common inflammatory diseases of older adults, causing pain and stiffness in the shoulders and hips. Treatment has barely changed in decades: glucocorticoids such as prednisone work, but relapses are frequent and long steroid courses carry their own toll — bone loss, diabetes, infection [s1]. A phase 3 trial has now tested whether an interleukin-17A inhibitor already used in psoriasis can do better [s1].

What the trial did

REPLENISH enrolled patients with recently relapsed polymyalgia rheumatica and randomly assigned them 1:1:1 to secukinumab 300 mg (SEC-300), secukinumab 150 mg (SEC-150), or placebo, for 52 weeks [s1]. Everyone, including the placebo group, also received prednisone on a tapering schedule over 24 weeks — so the comparison is a steroid taper with the biologic against a steroid taper alone [s1].

A total of 381 patients were randomised, 127 to each group [s1]. The primary outcome was sustained remission at week 52: the absence of signs or symptoms attributable to polymyalgia rheumatica, with no new giant-cell arteritis requiring rescue treatment, maintained from week 12 through week 52 [s1]. That is a demanding definition. It is not a snapshot of feeling better at one visit but a requirement that remission hold across most of a year, and it explicitly counts a slide into giant-cell arteritis — a related large-vessel vasculitis that can share the same patient — as a failure [s1]. Two doses were tested so the trial could show not only whether the drug worked but whether the higher dose was needed [s1].

The trial was funded by Novartis, which markets secukinumab [s1]. That is the standard arrangement for a drug's pivotal trial, and it is the reason to read the endpoints and the safety data closely rather than the framing.

What it found

Secukinumab beat placebo on the primary endpoint. Sustained remission at 52 weeks was reached by 41.2% of patients in the SEC-300 group (95% CI, 32.8 to 49.7), 40.6% in the SEC-150 group (32.2 to 49.0), and 20.4% in the placebo group (13.6 to 27.2), with P<0.001 for each secukinumab dose versus placebo [s1].

The two doses performed almost identically — a useful finding, because if 150 mg works as well as 300 mg, the lower dose is the relevant one for cost and exposure [s1].

The steroid-sparing effect, the outcome that matters most for long-term harm, went in the same direction. The mean adjusted annual cumulative glucocorticoid dose was 1603.7 mg in the SEC-300 group, 1683.2 mg in the SEC-150 group, and 2093.0 mg in the placebo group [s1]. Patients on the biologic needed less steroid over the year.

Safety

Serious adverse events were similar across the three arms: 13.5% in the SEC-300 group, 15.9% in the SEC-150 group, and 14.2% in the placebo group [s1]. Nasopharyngitis, hypersensitivity reactions, urinary tract infections, fungal infections, and back pain were more common in the secukinumab groups than in the placebo group [s1] — a profile broadly consistent with what is already known about IL-17A inhibition.

What the numbers do and do not show

The honest way to read the headline result is that most patients did not reach sustained remission even on the drug: roughly 41% did, which means close to 60% did not [s1]. That is a real improvement over the 20.4% on a steroid taper alone, but it is a shift in the odds, not a cure, and the trial reports remission over one year rather than durability after the drug stops [s1].

Why a steroid-sparing option matters

The case for a drug like this rests less on the remission numbers than on the steroids it lets patients avoid. Glucocorticoids are the first-line treatment for polymyalgia rheumatica precisely because they work, but relapses and glucocorticoid-related toxic effects are common, which is the gap the trial's authors set out to address [s1]. A regimen that reaches remission in more patients while cutting the annual steroid dose from 2093.0 mg to about 1600 mg is aiming at that toll directly [s1]. Whether the reduction is large enough to translate into fewer fractures, infections, or cases of steroid-induced diabetes is a question this trial was not designed to answer.

The limits, stated plainly

This is a single manufacturer-funded trial over 52 weeks [s1]. It enrolled patients with recently relapsed disease, not everyone with polymyalgia rheumatica, so the population is selected toward those with a harder course [s1]. It does not report what happens after treatment ends, whether the benefit holds beyond a year, or how secukinumab compares with other steroid-sparing options rather than with placebo. Longer follow-up and independent replication would strengthen the case.

What to watch

Whether regulators treat the steroid-sparing data as sufficient for a polymyalgia rheumatica indication, and whether the near-identical performance of 150 mg and 300 mg shapes the dose that reaches patients [s1]. The trial is registered as REPLENISH [s2].

This article describes trial results, including doses and adverse events, for informational purposes only. It is not medical advice and not a recommendation about any medication.

Sources

• [s1] Stone JH, Buttgereit F, Saraux A, et al; REPLENISH Investigators. Phase 3 Trial of Secukinumab in Polymyalgia Rheumatica. New England Journal of Medicine, published online 2026 (created 2026-06-03).
• [s2] ClinicalTrials.gov. Study of Secukinumab Versus Placebo in Combination With a Glucocorticoid Taper in Polymyalgia Rheumatica (REPLENISH). NCT05767034, last update posted 2026-06-22.