Q&A: Zasocitinib Response in the Scalp, Nails, Palms and Soles

Takeda has reported site-specific responses among patients with psoriasis in the scalp, nails, palms and soles with zasocitinib, an investigational once-daily oral tyrosine kinase 2 (TYK2) inhibitor, in 2 phase 3 trials.¹

LATITUDE PsO 3001 and 3002 enrolled 693 and 1,108 adults with moderate-to-severe plaque psoriasis and compared zasocitinib with placebo and apremilast.¹ The US Food and Drug Administration (FDA) has accepted the New Drug Application under Priority Review, with a target action date slated for the first quarter of 2027, Takeda announced in September 2026.¹

At Week 16, 77% of those in 3001 and 74% in 3002 attained scalp-specific Physician Global Assessment (ssPGA) scores of 0 or 1, compared with 7% and 13% with placebo (P < .001).¹˒² The Nail Psoriasis Severity Index (NAPSI) least-squares mean shift from the point of baseline was -7.1 in 3001 and -8.6 in 3002 (P < .001 vs placebo).¹˒² Hands and/or feet Physician Global Assessment (hfPGA) scores of 0 or 1 occurred in 71% and 69% with zasocitinib, compared with 22% and 10% with placebo, in a secondary endpoint not controlled for multiplicity.¹

In 3002, 17% of patients reached Psoriasis Area and Severity Index 75 (PASI 75) at week 4 with zasocitinib, compared with 4% with placebo (P < .001).¹ Takeda also reported skin clearance increasing through weeks 24 and 52, with no new safety signals.¹ The open-label LATITUDE PsO 3003 study, which enrolled about 2,100 participants, is evaluating long-term safety, tolerability and efficacy.¹

Raj Chovatiya, MD, PhD, a board-certified dermatologist and associate professor at Rosalind Franklin University Chicago Medical School, also founded and directs the Center for Medical Dermatology + Immunology Research in Chicago. In the following Q&A interview discussion, Chovatiya shares his perspective on special site involvement, speed of response and once-daily dosing with zasocitinib:

HCPLive: Why are the scalp, nails, palms and soles particularly challenging areas from both a treatment and cosmetic perspective?

Raj Chovatiya, MD, PhD: In psoriasis, we talk about special sites, and what really makes them special is, number one, they seem to potentially be slightly more difficult in terms of drug penetration. So we've always wondered if you had the right type of targeting agent, could you potentially hit better efficacy? And two, individuals who may have involvement of these areas can have relatively limited extent, but they oftentimes feel the same degree of burden as somebody who might have more traditional plaque psoriasis from head to toe.

If you think about your scalp being a part of the head and neck region that you have to go about every single day, talking to folks, having people looking at you, when you think about your hands, shaking hands, going out there doing your work and day-to-day functioning, thinking about your nails, even thinking about the genital region as well, all of these are special in the sense that they're often associated with undue burden for our patients. So it's particularly exciting, beyond some of the top-line data we've seen, that zasocitinib can result in a high degree of clearance in these areas too. And I think the scientific question that's very interesting is, now with more and more small-molecule options coming about in psoriasis, might there be a pathogenic reason why we see efficacy there compared to biologic therapies?

That question isn't really known, but we wonder if there's going to be a root reason why we could potentially have better effect there, or even a target standpoint. One of the theoretical ideas with TYK2 inhibition has been, given its role in other elements of the immune system signaling pathway, could it potentially result in some different degrees of clearance in some of these sites too? And I think that's really what the next generation of research is setting us up for, as long as we have newer therapeutic options.

HCPLive: With about 70% of patients achieving clear or almost clear skin at week 16, how quickly might patients see a visible difference?

Raj Chovatiya, MD, PhD: One of the nice things about the data cuts we've seen from zasocitinib so far is that it definitely doesn't appear to be slow. I think our patients are going to start seeing meaningful differences pretty early, and it seems like many of these results also continue to improve, potentially even beyond the primary period of our examination as we enter longer phases of this study. Compared to the way we've felt about oral therapies prior, and particularly in the case of our more first-generation TYK2 inhibitors, I think we're going to be able to have a reasonable discussion and balance of speed, effectiveness, as well as long-term effectiveness and durability overall.

HCPLive: How might a once-daily oral option like zasocitinib change the conversation around managing visible psoriasis?

Raj Chovatiya, MD, PhD: I think if somebody can get over the idea of having to use something beyond a cream, then a once-daily option you can take orally resonates with the way we've all thought about medications all of our lives. Whether you think about antibiotics or analgesics or cold medication, they're all essentially once-daily medications that you take for varying degrees of time. In this case, this one would be more of a chronic medication. But I think the idea of something you just have to take once a day as a pill continues to be an important piece in the psyche of just human beings when thinking about medications overall.

Editor's Note: This transcript has been edited for grammar and clarity using artificial intelligence tools.

References

1. Takeda Pharmaceutical Company Limited. U.S. FDA accepts new drug application under priority review for Takeda's zasocitinib in moderate-to-severe plaque psoriasis, with potential to redefine oral treatment expectations. Published September 14, 2026. Accessed September 21, 2026. https://www.takeda.com/newsroom/newsreleases/2026/fda-priority-review-zasocitinib-psoriasis/.

2. Armstrong AW, et al. Zasocitinib, a once-daily oral TYK2 inhibitor, demonstrates efficacy at high impact sites in adults with moderate-to-severe plaque psoriasis: results from two randomized phase 3 trials (LATITUDE-PsO-3001 and 3002). Presented at: 2026 American Academy of Dermatology Innovation Academy; July 16, 2026; New York, NY.