Graham Heap, MBBS, PhD, Discusses Positive Phase 3 Results for Zasocitinib

Recent top-line results from 2 global phase 3 clinical trials evaluating the investigational oral tyrosine kinase 2 (TYK2) inhibitor zasocitinib suggest meaningful efficacy and a safety profile consistent with earlier studies in patients with moderate to severe plaque psoriasis. The findings were discussed in an interview with Dermatology Times by Graham Heap, MBBS, PhD, vice president and global program lead at Takeda.

According to Heap, both phase 3 studies met their co-primary endpoints, achieving Psoriasis Area and Severity Index (PASI) 75 and static Physician Global Assessment (sPGA) scores of 0 or 1 at week 16. In addition, all 44 prespecified secondary endpoints were met across the trials. These secondary measures included higher thresholds of skin clearance, such as PASI 90 and PASI 100, which are increasingly used to benchmark efficacy in contemporary psoriasis trials.

At week 16, approximately half of treated patients achieved PASI 90, reflecting near-complete skin clearance, while around 30% achieved PASI 100, indicating complete clearance. These results place zasocitinib within a competitive efficacy range among advanced systemic therapies, although cross-trial comparisons should be interpreted cautiously. Heap noted that further detailed data will be presented at upcoming medical congresses, allowing for a more granular assessment of outcomes across subgroups and endpoints.

From a safety perspective, the adverse events observed were described as consistent with prior studies and with the known TYK2 mechanism. The most frequently reported events included nasopharyngitis and acne, and no new safety signals were identified in the phase 3 program to date. Long-term safety remains an important consideration, and patients from the pivotal trials are continuing in an extension study designed to evaluate safety and durability of response over months to years.

Zasocitinib remains investigational, and regulatory submissions are planned for the first half of Takeda’s 2026 financial year. In parallel, additional data are anticipated from a head-to-head trial comparing zasocitinib with deucravacitinib, another oral TYK2 inhibitor, which may provide clinically relevant comparative insights.

Beyond plaque psoriasis, the zasocitinib development program includes phase 3 studies in psoriatic arthritis, as well as phase 2 trials in Crohn’s disease, vitiligo, and hidradenitis suppurativa. A pediatric psoriasis program is also planned to run alongside adult studies.

Heap emphasized that many patients continue to seek convenient, effective, and safe oral treatment options, particularly given that a substantial proportion of patients with moderate to severe psoriasis do not receive advanced therapies. While further peer-reviewed data and regulatory review are needed, the phase 3 results position zasocitinib as a potential future option within the expanding landscape of oral targeted therapies for immune-mediated skin disease.