Oruka raises efficacy expectations for long-acting IL-23 inhibitors

The current standard of care in moderate-to-severe psoriasis consists of biologics targeting the IL-23 and IL-17 pathways, but many patients still have residual disease, experience treatment fatigue from lifelong injectable therapy, or relapse rapidly after withdrawal; the field views the next frontier not in incremental efficacy gains but in optimizing dosing strategies to reduce treatment burden and extend drug-free remission, with high-dose, extended half-life IL-23 inhibitors potentially achieving deeper and more sustained disease control through durable suppression of pathogenic tissue-resident memory T cells . Oruka's ORKA-001 embodies this approach: a next-generation extended half-life IL-23p19 monoclonal antibody engineered with Fc modifications to markedly prolong systemic exposure, with Phase 1 data showing a terminal half-life of approximately 100 days—more than three times that of risankizumab—sustained pharmacodynamic suppression of IL-23 signaling, and a favorable safety profile . ORKA-001 binds a similar epitope as risankizumab with comparable potency .

The news is the company's second Phase II psoriasis readout: in the EVERLAST-B trial, 61% of patients in the highest dose group achieved complete skin clearance (PASI 100) at week 16, and 86% in the same group achieved at least a PASI 90 improvement, driving one of the week's largest clinical data-related stock gains. EVERLAST-B is evaluating three induction dose levels: 37.5 mg at Week 0, 300 mg at Weeks 0 and 4, and 600 mg at Weeks 0 and 4 , with PASI 100 at Week 16 as the primary endpoint; at Week 28, patients achieving PASI 100 will be re-randomized 1:1 into a maintenance period . The trial corresponds to the randomized, double-blind Phase II dose-ranging study NCT07290569 with 160 planned participants in the registry, whose primary endpoint is the proportion of participants achieving 100% reduction in PASI score at Week 16 .

This readout reinforced the prospect that long-acting IL-23 inhibition can deliver higher skin clearance rates with less frequent dosing. Whereas Phase 1 only characterized pharmacokinetics and safety, the Phase II data provide pivotal proof of concept for the core question of whether a high-dose, long-acting strategy can support sparse dosing. The company has already initiated an open-label extension study, NCT07449702, with once-yearly high-dose, once-yearly low-dose, and twice-yearly arms, planning to enroll 240 participants with safety as the primary endpoint through Week 144, starting in February 2026 with primary completion expected in May 2030 . This design points directly toward once-yearly dosing and long-term drug-free remission, consistent with the view in a concurrent review that high-dose IL-23 inhibitors could challenge the paradigm of lifelong continuous therapy .

Not yet disclosed: full safety data across EVERLAST-B dose groups, efficacy numbers for the placebo and lower-dose groups, and durability results from the Week 28 re-randomized maintenance period. Upcoming milestones include long-term follow-up readouts from extension study NCT07449702 (primary completion expected May 2030) and primary completion of dose-ranging study NCT07290569 in June 2027 .