Sonelokimab for psoriatic arthritis: 24-week results from the phase II ARGO trial

The ARGO trial (NCT05640245) is a phase II, global, double-blind, placebo-controlled study evaluating sonelokimab, a novel interleukin-17A- and -17F-inhibiting nanobody, in patients with psoriatic arthritis. The trial met its primary endpoint, achieving American College of Rheumatology (ACR) 50 response at Week 12 with sonelokimab vs placebo. 

During the European Alliance of Associations for Rheumatology (EULAR) 2025 Congress, Iain McInnes presented the 24-week results from the ARGO trial. A total of 207 patients were randomized. At 12 weeks, patients on placebo switched to sonelokimab 120 mg without induction, and those with <20% improvement in Swollen Joint Count and Tender Joint Count were reassigned treatment. Multidomain endpoints included minimal disease activity rates and composite ACR70 + Psoriasis Area and Severity Index 100.

Key learnings

At Week 24, up to 62% achieved MDA with sonelokimab. Pooled data showed ≥50% MDA rates in key subgroups – females (51.6%), weight ≥100 kg (52.6%), hsCRP >ULN (56.4%), and ≥3% BSA (55.3%) – and ≥40% in those with more severe disease (PASI ≥10: 40.0%; DAPSA >28: 41.0%).

Sonelokimab achieved composite ACR70 + PASI100 in 48% of patients, demonstrating concurrent efficacy on high hurdle joint and skin outcomes. Individually, ACR70 and PASI100 were achieved by 42% and 63% of patients, respectively, with consistent responses across key subgroups and disease severity.

The treatment was well tolerated, with no unexpected safety signals. No cases of IBD, MACE, depression, or SIB occurred. Mild/moderate oral candidiasis was reported in 4 cases (2%).

Sonelokimab demonstrated strong efficacy in joint and skin endpoints across key patient subgroups, with a favorable safety profile. Two phase III studies (IZAR-1: NCT06641076 and IZAR-2: NCT06641089) are underway to further assess its therapeutic potential in PsA.