A late breaking poster at ACR Convergence reveals phase 3 trial data show icotrokinra significantly improved joint and skin symptoms in biologic-naive patients with psoriatic arthritis, with benefits continuing through 24 weeks.
An investigational oral IL-23 receptor inhibitor has significantly improved joint and skin symptoms in patients with active psoriatic arthritis, raising the prospect of a new once-daily treatment option.
Results from the phase 3 ICONIC-PsA 1 trial, presented as a late breaking poster at ACR Convergence 2026 in Orlando, showed that icotrokinra 200mg achieved significantly higher American College of Rheumatology 20% improvement (ACR20) response rates than placebo at week 16, with improvements continuing through week 24.
The findings were reported by an international research team including Australian rheumatologist Professor Peter Nash from Griffith University, alongside investigators from Japan, the US, Canada, and the UK.
The study also found that doubling the dose to 400mg provided no additional clinical benefit, suggesting the lower dose may be sufficient to achieve meaningful improvements in both joint and skin disease.
The randomised, double-blind, placebo-controlled trial enrolled 552 biologic-naive adults with active psoriatic arthritis, including patients previously or currently treated with conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) or apremilast.
Participants were randomised to receive once daily icotrokinra 200mg (n=153), icotrokinra 400mg (n=154), placebo (n=154), or ustekinumab (n=91).
At week 16, 58% of patients receiving icotrokinra 200mg achieved an ACR20 response, compared with 41% in the placebo group, representing a treatment difference of 17.7 percentage points (95% CI 7.1-28.3). The higher dose achieved an ACR20 response rate of 60%, reinforcing the absence of a clear dose-response advantage above 200mg.
More stringent measures of joint improvement also favoured icotrokinra.
An ACR50 response was achieved by 29% of patients receiving 200mg compared with 16% receiving placebo, a difference of 13.4 percentage points.
ACR70 responses were achieved by 13% and 5% of patients, respectively, representing an eight-percentage-point difference.
Joint responses continued to improve between weeks 16 and 24. By week 24, ACR20 response rates had increased to 69% in the 200mg group and 60% in the 400mg group, while ACR50 responses reached 38% and 33%, respectively.
The treatment also demonstrated substantial benefits for patients with concomitant psoriasis.
Among participants with at least 3% body surface area involvement and a baseline Investigator’s Global Assessment (IGA) score of at least two, 57% of those receiving either icotrokinra dose achieved clear or almost clear skin, with at least a two-grade improvement, at week 16. This compared with 14% of placebo recipients.
By week 24, IGA 0/1 response rates had increased to 64% with icotrokinra 200mg and 66% with 400mg.
Patients receiving icotrokinra 200mg also experienced greater improvements in physical function, measured using the Health Assessment Questionnaire Disability Index (HAQ-DI). At week 16, the least-squares mean difference from placebo was -0.10 (95% CI -0.2 to 0.0).
Safety findings through week 24 were generally consistent across treatment groups, with no new safety signals identified.
During the initial 16-week placebo-controlled period, adverse events were reported in 44% of patients receiving icotrokinra 200mg, 52% receiving 400mg and 41% receiving placebo.
Serious adverse events occurred in 1%, 3% and 2% of patients, respectively, while adverse events leading to treatment discontinuation were uncommon across all three groups.
Infections were reported in 21% of the 200mg group, 27% of the 400mg group and 24% of placebo recipients during the placebo-controlled period.
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Nasopharyngitis and upper respiratory tract infections were among the most frequently reported adverse events.
The researchers concluded that once daily icotrokinra 200mg produced significant improvements in both joint and skin manifestations of psoriatic arthritis, with continued benefits through week 24 and no apparent additional efficacy from the higher dose.
The trial included an ustekinumab reference arm, but it was not powered for formal statistical comparisons between icotrokinra and the active comparator.
Longer-term follow-up is continuing as part of the ICONIC-PsA clinical development program, which includes a second phase 3 study enrolling biologic-experienced and biologic-naive patients.
Icotrokinra is a first-in-class targeted oral peptide that selectively blocks the IL-23 receptor, inhibiting signalling through a pathway implicated in psoriatic inflammation.
Unlike existing injectable biologic therapies targeting the IL-23 pathway, icotrokinra is administered orally, potentially offering an alternative for patients who prefer tablets over injections.
The drug is already approved for moderate-to-severe plaque psoriasis in the US but remains under investigation for psoriatic arthritis.
In Australia it is currently under evaluation by the Therapeutic Goods Administration (TGA) as a new medicine (Application Type A) after an application by Janssen-Cilag Pty Ltd for the treatment of moderate-to-severe plaque psoriasis.
The TGA’s Advisory Committee on Medicines (ACM) discussed and provided advice on the application in October 2026, however the treatment is yet to received final approval.
