ORKA-001 Achieves Deepening Skin Clearance Through Week 28 in Plaque Psoriasis

Oruka Therapeutics announced positive week 28 results from the ongoing phase 2a EVERLAST-A trial evaluating ORKA-001 in patients with moderate to severe plaque psoriasis, with skin clearance responses continuing to deepen months after patients received their last dose.¹

At week 28, 71.4% (45/63) of patients treated with ORKA-001 achieved complete skin clearance, as measured by a 100% improvement in Psoriasis Area and Severity Index (PASI 100). Additionally, 87.3% (55/63) achieved PASI 90, while Investigator Global Assessment (IGA) 0/1 responses were maintained at 84.1% (53/63).¹

Notably, patients in the active treatment arm received 600 mg of ORKA-001 only at weeks 0 and 4, meaning the week 28 findings were observed approximately 6 months after their last dose.

Responses Continued to Deepen Without Additional Dosing

EVERLAST-A is a randomized, double-blind, placebo-controlled phase 2a trial evaluating the safety, efficacy, and pharmacokinetics of ORKA-001, a half-life extended interleukin (IL)-23p19 monoclonal antibody, in adults with moderate to severe plaque psoriasis.

The trial enrolled 84 patients across 26 sites in the US and Canada. Participants were randomized 3:1 to receive 600 mg of ORKA-001 at weeks 0 and 4 or matching placebo. Patients initially assigned to placebo subsequently crossed over to receive ORKA-001 at weeks 16 and 20. The study will continue through week 52 to assess durability of response, maintenance dosing, and longer-term safety.¹

Previously reported week 16 results showed that 63.5% (40/63) of patients receiving ORKA-001 achieved PASI 100, meeting the study's primary endpoint. By week 28, the PASI 100 response rate had increased to 71.4%, while PASI 90 reached 87.3%.¹

“The depth of clearance seen at Week 28, achieved without any dosing beyond Week 4, is remarkable,” Bruce Strober, MD, PhD, clinical professor of dermatology at Yale University School of Medicine and lead investigator for EVERLAST-A, said in a statement. “To see PASI 100 rates continue to climb over time speaks to the potential of this molecule.”¹

Crossover Patients Show Similar Response Pattern

Patients initially randomized to placebo also demonstrated clinical responses after crossing over to ORKA-001 at week 16.

At week 28, corresponding to 12 weeks after initiating ORKA-001, 40.0% (8/20) of crossover patients achieved PASI 100. At the equivalent time point, 42.9% (27/63) of patients originally randomized to ORKA-001 had achieved PASI 100.^1

The findings provide additional support for the treatment effect observed in the original active-treatment group while the continued improvement among patients treated at weeks 0 and 4 provides preliminary evidence regarding the durability of response with ORKA-001.

Safety Findings Through Week 28

ORKA-001 maintained a favorable safety and tolerability profile through week 28, with findings consistent with the established IL-23p19 inhibitor class, according to Oruka.¹

Between weeks 16 and 28, the only treatment-emergent adverse event reported in at least 5% of patients receiving ORKA-001 was upper respiratory tract infection, which occurred in 8% (7/83) of patients.

Two serious adverse events were reported: a tibial fracture and prostate adenocarcinoma in a patient who had elevated prostate-specific antigen at baseline. Neither event was considered related to ORKA-001. No injection-site reactions were reported, and the company reported no observed impact of anti-drug antibodies on safety, efficacy, or pharmacokinetics.¹

Longer-Term Data Expected Later This Year

Oruka is developing ORKA-001 with the goal of providing durable disease control with substantially less frequent dosing. The investigational therapy's extended half-life and targeting of IL-23p19 are intended to potentially enable maintenance dosing as infrequently as once or twice annually.¹

The company plans to report longer-term EVERLAST-A results, including week 52 efficacy data for all patients, in December 2026. Results from the phase 2b EVERLAST-B trial are also expected during the fourth quarter of 2026.¹

The forthcoming results will provide additional evidence regarding whether the deep responses observed through week 28 can be maintained over longer follow-up and with an infrequent maintenance-dosing strategy.

References

1. Oruka Therapeutics. Oruka Therapeutics announces positive week 28 data for ORKA-001 from the ongoing EVERLAST-A trial showing deepening of responses without additional dosing. Published September 23, 2026.
2. Oruka Therapeutics. Oruka Therapeutics announces positive week 16 data for ORKA-001 from the ongoing EVERLAST-A phase 2a trial in moderate-to-severe plaque psoriasis. Published April 27, 2026.