Oruka Therapeutics Inc. (NASDAQ: ORKA) on Wednesday reported week-28 efficacy and safety results from its EVERLAST-A Phase 2a trial of ORKA-001, an IL-23p19 monoclonal antibody engineered for extended half-life, in patients with moderate-to-severe plaque psoriasis.
The trial enrolled 84 patients across 26 sites in the United States and Canada, randomized 3:1 to receive either 600 mg of ORKA-001 or matching placebo at weeks 0 and 4. At week 28, 71.4% of patients in the main treatment arm achieved PASI 100 — full clearance — up from 63.5% at week 16, measured six months after the final dose. PASI 90 was reached by 87.3% of patients, and 84.1% achieved an IGA 0/1 response.
In the placebo-crossover cohort, patients initially assigned to placebo who switched to ORKA-001 at week 16 showed 40.0% achieving PASI 100 by week 28, compared with 42.9% of patients in the active arm at the equivalent timepoint.
Safety data through weeks 16 to 28 showed upper respiratory tract infection as the only treatment-emergent adverse event occurring in at least 5% of patients, affecting 8% of those receiving ORKA-001. Two serious adverse events — a tibial fracture and prostate adenocarcinoma in a patient with elevated baseline PSA — were not deemed drug-related. No injection-site reactions were reported, and the company said no impact of anti-drug antibodies on safety, efficacy, or pharmacokinetics has been observed.
Week 52 efficacy data for all patients is planned for release in December 2026. The company is also conducting the EVERLAST-B Phase 2b trial, with 16-week data expected in the fourth quarter of 2026. The EVERLAST-A study continues through week 52 to evaluate durability of response, maintenance dosing, and long-term safety.
