The Psoriasis Drug That Could Require Just One or Two Shots a Year

A new psoriasis drug matched the best skin clearance rate in its class — 63.5 percent PASI 100 at Week 16, the same rate as Bimzelx — while potentially requiring only one or two clinic injections per year instead of six or more, and the reason it can do that stems from a structural change that makes the drug linger in the bloodstream roughly three times longer than its predecessors.

ORKA-001, an experimental therapy from Oruka Therapeutics, hit that 63.5 percent PASI 100 rate in a 63-patient Phase 2a trial, according to the company's announcement. PASI 100 — a perfect score on the Psoriasis Area and Severity Index, the gold standard endpoint in dermatology trials — means complete or near-complete skin clearance. That matches what Bimzelx, an IL-23p19 inhibitor from Belgian pharma UCB, achieved in its own Phase 3 program.

The difference is the injection schedule. Bimzelx requires a clinic visit every eight weeks, or roughly six times a year. ORKA-001 may require one or two annual clinic visits, based on pharmacokinetic modeling that has yet to be tested in a Phase 3 maintenance period where patients go months without re-dosing.

The mechanism behind that potential asymmetry is half-life engineering. ORKA-001 was designed to hit the same inflammatory target as Skyrizi, AbbVie's psoriasis and Crohn's disease drug, with similar strength but a modified structure that keeps circulating drug levels high for about 100 days rather than the roughly 30-day half-life typical of existing drugs in this class, according to the company's Phase 1 pharmacokinetic data. Phase 1 data showed drug concentrations remained above therapeutic thresholds for an entire year after a single dose, which is the basis for the proposed once-yearly schedule.

The Phase 2a trial enrolled 84 patients randomized 3-to-1 to receive ORKA-001 or placebo, according to the trial data. Beyond PASI 100, 83 percent of participants hit PASI 90 — at least 90 percent skin clearance — and 84 percent achieved an Investigator's Global Assessment score of zero or one, meaning clear or nearly clear skin.

"If this type of efficacy and safety profile could be available with dosing once to twice per year, it would represent a major step forward for the field," said Dr. Bruce Strober, a dermatologist at Yale School of Medicine who consults for multiple IL-23 inhibitor makers including some Oruka competitors. "I could envision this being the preferred product for any patient with moderate-to-severe psoriasis."

That endorsement comes with a significant caveat. The 63.5 percent PASI 100 rate comes from a Phase 2a in 63 patients with a Week 16 primary endpoint. The once-yearly dosing claim rests on Phase 1 pharmacokinetic modeling, not yet demonstrated in a Phase 2 or Phase 3 maintenance period. Durability data — what happens when patients go extended periods without re-dosing — are expected from the ongoing EVERLAST trial in the second half of 2026. Anti-drug antibodies, which can develop in broader populations and alter how a drug circulates, have not yet been characterized in a study large enough to detect meaningful rates. The FDA has not approved ORKA-001.

The market is large and competitive. Bimzelx posted PASI 100 rates of roughly 62 to 64 percent at Week 16 in its Phase 3 program, according to the published trial data. Skyrizi, the market leader, achieves PASI 100 in roughly a third of patients at the same timepoint, according to Phase 3 data. Skyrizi generated $11.7 billion in global sales in 2024, according to AbbVie's full-year results. Oruka's differentiation is not efficacy — it is convenience. If the pharmacokinetic profile holds in Phase 3, the asymmetry in injection burden could shift patient and prescriber preferences in a market where quarterly clinic visits are the standard of care.

ORKA-001 is Oruka's most advanced pipeline candidate out of five programs. The Menlo Park, California biotech filed its investigational new drug application in 2024 and entered Phase 2a within two years, backed by investors venBio Partners and Sofinnova Investments.

What Oruka may have found is a way to make an old target do something new: one injection that lasts a year instead of six that have to be scheduled. Whether that holds up in Phase 3 is the next two years of clinical trials.