Oruka Therapeutics Announces Positive Week 28 Data for ORKA-001 from the Ongoing EVERLAST-A Trial Showing Deepening of Responses Without Additional Dosing

Phase 2a psoriasis data show deepening PASI responses through Week 28 after only two induction doses, with longer-term readouts expected in late 2026.

Rhea-AI Summary

Oruka Therapeutics (ORKA) reported positive Week 28 data from the EVERLAST-A Phase 2a trial of ORKA-001 in moderate-to-severe plaque psoriasis.

Among patients initially randomized to ORKA-001, PASI 100 response rates increased from 63.5% at Week 16 to 71.4% (45/63) at Week 28, and PASI 90 rose to 87.3% (55/63), six months after the last dose at Week 4. IGA 0/1 responses were maintained at 84.1% (53/63). Patients who started on placebo and crossed over to ORKA-001 at Week 16 achieved PASI 100 in 40.0% (8/20) by Week 28, similar to the 42.9% (27/63) rate in the active arm at the same timepoint post‑dosing.

Between Weeks 16–28, upper respiratory tract infection was the only treatment-emergent adverse event occurring in ≥5% of patients, seen in 8% (7/83). Two serious adverse events were reported, neither considered drug related, and there were no injection site reactions. Oruka expects 52‑week EVERLAST-A data in December 2026 and 16‑week EVERLAST-B Phase 2b data in 4Q 2026.

Positive

• PASI 100 71.4% (45/63) at Week 28 after last dose at Week 4
• PASI 90 87.3% (55/63) at Week 28 in ORKA-001 arm
• IGA 0/1 responses maintained at 84.1% (53/63) at Week 28
• Placebo crossover arm reached 40.0% PASI 100 (8/20) by Week 28
• Only ≥5% treatment-emergent AE between Weeks 16–28 was URTI in 8% (7/83)
• No injection site reactions and no observed anti-drug antibody impact through Week 28

Negative

• None.

Market Context

Aug 10's update reported Week 16 PASI 100 in 63.5% (40/63), establishing a same-trial benchmark for ...

Analysis

Aug 10's update reported Week 16 PASI 100 in 63.5% (40/63), establishing a same-trial benchmark for this Week 28 readout; that earlier company update also contained financial and pipeline items, so its 6.4% move cannot be attributed solely to the trial.

Key Figures

PASI 100 response: 71.4% (45 of 63) PASI 90 response: 87.3% (55 of 63) IGA 0/1 response: 84.1% (53 of 63) +5 more

PASI 100 response

71.4% (45 of 63)

Week 28

PASI 90 response

87.3% (55 of 63)

Week 28

IGA 0/1 response

84.1% (53 of 63)

Week 28

Crossover-arm PASI 100 response

40.0% (8 of 20) vs. 42.9% (27 of 63)

Week 28, 12 weeks after crossover dosing; placebo crossover and initial active arms

Upper respiratory tract infection

8% (7 of 83 patients)

Only treatment-emergent adverse event occurring in at least 5% of ORKA-001 patients between Weeks 16 and 28

Serious adverse events

2 events

Neither event was deemed drug related

Study enrollment

84 patients

EVERLAST-A randomized 3:1 to ORKA-001 or placebo

ORKA-001 dosing

600 mg at Week 0 and Week 4

Initial active-arm dosing

Historical Context

2 past events · Latest: Aug 10

2 events

1. Aug 10

   Clinical update

   24h Move

   +6.4%

   Prior EVERLAST-A results included Week 16 PASI 100 in 63.5% of treated participants

2. May 13

   Clinical update

   24h Move

   +1.1%

   EVERLAST-A Week 16 results reported 63.5% PASI 100 with tolerability similar to placebo

24h Move is the share-price change in the day after each event; other market factors may also have contributed.

Key Terms

pasi 100, pharmacokinetics, monoclonal antibody, anti-drug antibodies, +1 more

5 terms

pasi 100 medical

"PASI 100 response rates increased to 71.4%"

PASI 100 is a clinical-trial measure meaning a patient’s psoriasis has cleared completely, showing a 100% improvement on the Psoriasis Area and Severity Index. Think of it like a before-and-after photo where all visible signs of the condition are gone. For investors, PASI 100 signals a therapy’s top-level effectiveness claim, which can drive regulatory approval prospects, market adoption and a product’s commercial value.

pharmacokinetics medical

"evaluating the safety, efficacy, and pharmacokinetics of ORKA-001"

Pharmacokinetics is the study of how a substance, such as a drug or chemical, moves through and is processed by the body over time. It tracks how it is absorbed, distributed, broken down, and eventually eliminated. For investors, understanding pharmacokinetics helps gauge the effectiveness, safety, and potential risks of new medications or treatments, which can influence a company’s success and valuation in the healthcare industry.

monoclonal antibody medical

"a novel half-life extended IL-23p19 monoclonal antibody"

A monoclonal antibody is a laboratory-made protein designed to recognize and attach to a specific target in the body, such as a disease-causing substance or cell. It functions like a highly precise lock-and-key tool, helping to treat or detect illnesses. For investors, companies developing monoclonal antibodies can represent promising opportunities in the healthcare sector, especially as these treatments often address unmet medical needs.

anti-drug antibodies medical

"No impact of anti-drug antibodies on safety, efficacy, or PK"

Anti-drug antibodies are immune system proteins that form in patients in response to a biological therapy, such as a therapeutic protein or antibody, and can bind to the medicine. They matter to investors because they can reduce or eliminate a drug’s effectiveness, create safety problems, force higher dosing or additional testing, and influence regulatory approval and commercial success — like delivery guards accidentally intercepting and stopping a needed package.

placebo-controlled medical

"a randomized, double-blind, placebo-controlled Phase 2a trial"

"Placebo-controlled" describes a testing method where one group receives the actual treatment or intervention, while another group receives a harmless, inactive version called a placebo. This approach helps determine whether the real treatment has genuine effects beyond psychological expectations. For investors, understanding this ensures confidence that reported benefits are real and not influenced by bias or false perceptions.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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PASI 100 increased to 71.4% and PASI 90 increased to 87.3%, despite no dosing after Week 4

Placebo crossover patients reached PASI 100 and PASI 90 rates similar to those initially dosed with ORKA-001

ORKA-001 maintained a favorable safety and tolerability profile through Week 28

52-week EVERLAST-A data for all patients expected in December 2026

16-week EVERLAST-B data expected in 4Q 2026

MENLO PARK, Calif., Sept. 23, 2026 (GLOBE NEWSWIRE) -- Oruka Therapeutics, Inc. (“Oruka”) (Nasdaq: ORKA), a clinical-stage biotechnology company developing novel biologics designed to set a new standard for the treatment of chronic skin diseases including plaque psoriasis (PsO) and hidradenitis suppurativa (HS), today announced positive Week 28 results from its EVERLAST-A Phase 2a trial of ORKA-001, a novel half-life extended IL-23p19 monoclonal antibody, in moderate-to-severe plaque psoriasis.

“These Week 28 results, with responses continuing to deepen months after the last dose, point to the incredible potential of ORKA-001,” said Joana Goncalves, MBChB, Chief Medical Officer of Oruka. “With over 70% of patients achieving completely clear skin after just two induction doses and a safety profile consistent with the IL-23 class, ORKA-001 has the potential to redefine the standard of care for psoriasis. We look forward to sharing the full 52-week data later this year.”

“The depth of clearance seen at Week 28, achieved without any dosing beyond Week 4, is remarkable,” said Bruce Strober, MD, PhD, Clinical Professor of Dermatology at Yale University School of Medicine and lead investigator for EVERLAST-A. “To see PASI 100 rates continue to climb over time speaks to the potential of this molecule. The emerging profile of ORKA-001 could offer patients substantial disease control along with very infrequent dosing.”

EVERLAST-A is a randomized, double-blind, placebo-controlled Phase 2a trial evaluating the safety, efficacy, and pharmacokinetics of ORKA-001 in patients with moderate-to-severe plaque psoriasis. The study is being conducted across 26 sites in the United States and Canada and enrolled 84 patients randomized 3:1 to receive 600 mg of ORKA-001 at Week 0 and 4 or matching placebo. Patients who initially received placebo received 600 mg of ORKA-001 at Week 16 and 20. The study continues through Week 52 to assess durability of response, maintenance dosing, and long-term safety.

Efficacy

As previously reported, 63.5% of patients (40 of 63) treated with ORKA-001 achieved the primary endpoint of PASI 100 at Week 16. Clinical responses continued to deepen through Week 28, six months after the last dose of ORKA-001. PASI 100 response rates increased to 71.4% (45 of 63) and PASI 90 response rates increased to 87.3% (55 of 63) at Week 28. IGA 0/1 response rates were maintained at 84.1% (53 of 63).

Patients who initially received placebo and crossed over blinded to ORKA-001 at Week 16 demonstrated a similar pattern of clinical response to those initially receiving ORKA-001. In this dosing arm, 40.0% (8 of 20) achieved PASI 100 at Week 28 (12 weeks after dosing) compared to 42.9% (27 of 63) of patients in the active arm at the equivalent timepoint.

Safety

ORKA-001 continues to be well tolerated, with a safety profile consistent with the IL-23p19 class. Between Weeks 16-28, the only treatment-emergent adverse event in ≥5% of patients receiving ORKA-001 was upper respiratory tract infection, occurring in 8% (7 of 83) of patients. Two patients experienced serious adverse events, neither deemed drug related: one tibial fracture and one case of prostate adenocarcinoma in a patient with elevated prostate-specific antigen (PSA) at baseline. There continue to be no injection site reactions. No impact of anti-drug antibodies on safety, efficacy, or PK has been observed.

Upcoming Milestones for ORKA-001 

Oruka plans to share longer-term data from EVERLAST-A, including efficacy at Week 52 for all patients, in December 2026. The Company also continues to advance the EVERLAST-B Phase 2b trial of ORKA-001, with data expected during the fourth quarter of 2026. 

About Oruka Therapeutics

Oruka Therapeutics is developing novel biologics designed to set a new standard for the treatment of chronic skin diseases. Oruka’s mission is to offer patients suffering from inflammatory diseases like plaque psoriasis and hidradenitis suppurativa the greatest possible freedom from their condition by achieving high rates of disease clearance with dosing as infrequently as once or twice a year. For more information, visit www.orukatx.com and follow Oruka on LinkedIn. 

Forward Looking Statements

Certain statements in this press release, other than statements of historical fact, are "forward-looking statements" within the meaning of the federal securities laws, including the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. These forward-looking statements include, but are not limited to, statements regarding: the potential therapeutic benefits, efficacy, safety, tolerability, durability of response and dosing profile of ORKA-001; the potential for ORKA-001 to provide durable disease control with infrequent dosing; the planned conduct, progress, timing and results of the EVERLAST-A and EVERLAST-B trials; and the anticipated timing of clinical data readouts. These forward-looking statements are based on Oruka’s current expectations and beliefs concerning future developments and their potential effects. There can be no assurance that future developments affecting Oruka will be those that have been anticipated. These forward-looking statements involve a number of risks, uncertainties (some of which are beyond Oruka’s control) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. These risks and uncertainties include, but are not limited to, those uncertainties and factors described under the heading "Risk Factors" and "Cautionary Note Regarding Forward-Looking Statements" in Oruka’s most recent filings with the Securities and Exchange Commission (SEC), including its Annual Report on Form 10-K and Quarterly Reports on Form 10-Q. Should one or more of these risks or uncertainties materialize, or should any of Oruka’s assumptions prove incorrect, actual results may vary in material respects from those projected in these forward-looking statements. Nothing in this press release should be regarded as a representation by any person that the forward-looking statements set forth therein will be achieved or that any of the contemplated results of such forward-looking statements will be achieved. You should not place undue reliance on forward-looking statements in this press release, which speak only as of the date they are made and are qualified in their entirety by reference to the cautionary statements herein and in Oruka’s SEC filings. Oruka does not undertake or accept any duty to make any updates or revisions to any forward-looking statements except as required by applicable law. 

Investor Contact:

Alan Lada
(650)-606-7911
alan.lada@orukatx.com

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What is the EVERLAST-A trial design and dosing regimen for ORKA-001?

EVERLAST-A is a randomized, double-blind, placebo-controlled Phase 2a trial in moderate-to-severe plaque psoriasis conducted at 26 sites in the United States and Canada. Eighty-four patients were enrolled and randomized 3:1 to receive either 600 mg of ORKA-001 at Week 0 and Week 4 or matching placebo. Patients who initially received placebo crossed over, still blinded, to 600 mg ORKA-001 at Week 16 and Week 20. The study continues through Week 52 to assess durability of response, maintenance dosing, and long-term safety.

How many patients have been evaluated in EVERLAST-A so far?

The EVERLAST-A trial enrolled 84 patients with moderate-to-severe plaque psoriasis. At Week 28, efficacy data for PASI and IGA responses were reported for 63 patients in the initial ORKA-001 arm and 20 patients in the initial placebo crossover arm. Safety data between Weeks 16–28 were reported for 83 patients receiving ORKA-001.

What specific safety findings were observed between Weeks 16 and 28?

Between Weeks 16–28, the only treatment-emergent adverse event occurring in ≥5% of patients receiving ORKA-001 was upper respiratory tract infection, reported in 8% (7/83) of patients. Two serious adverse events were observed, a tibial fracture and a case of prostate adenocarcinoma in a patient with elevated PSA at baseline, and both were reported as not drug related. There were no injection site reactions, and no impact of anti-drug antibodies on safety, efficacy, or pharmacokinetics was observed.

What upcoming clinical milestones has Oruka outlined for ORKA-001?

Oruka plans to share 52-week EVERLAST-A data, including efficacy results for all patients, in December 2026. In addition, the company is advancing the EVERLAST-B Phase 2b trial of ORKA-001, with 16-week data expected during the fourth quarter of 2026.