Oruka Therapeutics Falls 5% Despite Positive Phase 2a Psoriasis Drug Data

Shares of Oruka Therapeutics, Inc. (NASDAQ: ORKA) fell 5% in Wednesday morning trading, even after the company announced positive Week 28 data from its Phase 2a trial for ORKA-001, an investigational treatment for moderate-to-severe plaque psoriasis.

Trial Results Show Improved Efficacy

Oruka reported that its drug candidate, a half-life extended IL-23p19 monoclonal antibody, demonstrated continued improvement in efficacy six months after the last dose was administered. The update from the EVERLAST-A study showed increasing rates of skin clearance over time.

Key efficacy endpoints at Week 28 included:

• PASI 100 response (complete skin clearance) was achieved by 71.4% of patients, an increase from 63.5% at Week 16.
• PASI 90 response (90% skin clearance) was achieved by 87.3% of patients.

The EVERLAST-A trial enrolled 84 patients who were randomized to receive either 600 mg of ORKA-001 or a placebo at Week 0 and Week 4.

Market Reaction and Outlook

Ad

The stock's decline despite the strong clinical results may suggest a "sell-the-news" reaction from investors, where positive expectations were already factored into the share price ahead of the announcement. The market will now likely turn its focus to upcoming catalysts for the drug program.

Oruka stated it plans to share 52-week data from the EVERLAST-A trial in December 2026. The company also anticipates releasing data from its larger EVERLAST-B Phase 2b trial during the fourth quarter of 2026.

Safety Profile Remains Favorable

Oruka confirmed that ORKA-001 maintained a favorable safety profile through Week 28, consistent with the established profile of the IL-23p19 inhibitor class. Between weeks 16 and 28, the only treatment-emergent adverse event reported in 5% or more of patients was upper respiratory tract infection (8%).

Two serious adverse events were reported during the trial, but investigators deemed neither to be related to the study drug. The company also noted that patients who initially received a placebo and later crossed over to receive ORKA-001 demonstrated similar response patterns to those who received the drug from the start.