Sonelokimab, an IL-17A/IL-17F-inhibiting nanobody for active psoriatic arthritis: a randomized, placebo-controlled phase 2 trial.

Psoriatic arthritis (PsA) is a progressive, multidomain and interleukin-17 (IL-17)-linked disease that results in substantial quality-of-life deficits. Thereby, we conducted a phase 2 randomized, double-blind, placebo (PBO)-controlled trial of sonelokimab (SLK), a nanobody that binds with a similarly high affinity to IL-17A and IL-17F, inhibiting all dimers. Overall, 207 patients with active PsA were randomized to SLK 120-mg or 60-mg every 4 weeks (Q4W; both with induction (WI)), or to 60-mg Q4W with no induction, PBO or adalimumab (reference arm). The primary endpoint of American College of Rheumatology (ACR) 50 at week 12 was met for SLK 60-mg and 120-mg WI (60-mg WI = 46.3% (19/41; odds ratio (OR) = 3.6; 95% confidence interval (CI) = 1.3-9.9; P < 0.05); 120-mg WI = 46.5% (20/43; OR = 4.0; 95% CI = 1.4-11.3; P < 0.01) versus PBO = 20.0% (8/40)). SLK resulted in significant benefits across the key secondary endpoints of ACR20 (60-mg WI = 78.0% (32/41; P < 0.001) and 120-mg WI = 72.1% (31/43; P = 0.002) versus PBO = 37.5% (15/40)) and Psoriasis Area and Severity Index (PASI) 90 at week 12 (60-mg WI = 76.9% (20/26; P < 0.001) and 120-mg WI = 59.3% (16/27; P = 0.003) versus PBO = 15.4% (4/26)). Robust responses were observed among patients randomized to SLK at week 24 for the high-threshold composite endpoints of ACR70 + PASI 100 (exploratory) and minimal disease activity (secondary), achieved by up to 48% (13/27; 120-mg WI) and 61% (25/41; 60-mg WI), respectively. SLK was well-tolerated; the most common treatment-emergent adverse events were nasopharyngitis (60 mg = 6.1%; 120 mg = 5.2%), upper respiratory tract infection (60 mg = 6.1%; 120 mg = 4.1%), injection-site erythema (60 mg = 3.7%; 120 mg = 3.1%) and headache (60 mg = 2.4%; 120 mg = 4.1%). Four cases of mild to moderate oral candidiasis occurred (60 mg = 2.4%; 120 mg = 2.1%). Overall, SLK delivered substantial improvements in the signs and symptoms of PsA across various outcomes and domains. ClinicalTrials.gov registration: NCT05640245 .