Table of Contents

• Overview of the clinical trial program
• Trials in plaque psoriasis
• Trials in psoriatic arthritis
• Trials in ulcerative colitis and Crohn’s disease
• Trials in vitiligo and hidradenitis suppurativa
• Main endpoints and what they mean
• Who can join these studies

Overview of the clinical trial program

Clinical trials of Zasocitinib are studying several diseases, mainly moderate-to-severe plaque psoriasis and psoriatic arthritis, with additional studies in ulcerative colitis, Crohn’s disease, non-segmental vitiligo, and hidradenitis suppurativa.^{[1][2][3][4][5][6][7][8][9][10][11][12][13]}

Most of the studies are Phase 3 trials, while some are Phase 2 or Phase 2b trials.^{[1][2][3][4][5][6][7][8][9][10][11][12][13]}

These trials are designed to measure both efficacy and safety, and several also look at tolerability, long-term follow-up, or comparison with placebo or another treatment.^{[1][2][3][4][5][6][7][8][9][10][11][12][13]}

Trials in plaque psoriasis

Several studies are focused on moderate-to-severe plaque psoriasis, which is a long-term skin disease that causes thick, scaly plaques.^{[1][2][4][5][13]}

One Phase 3 study is an open-label, multicenter trial looking at the long-term safety, tolerability, and efficacy of Zasocitinib in people with moderate-to-severe plaque psoriasis.^[1]

Two completed Phase 3 studies compared Zasocitinib with placebo over 16 weeks and measured skin improvement using sPGA 0/1 response and PASI-75 at Week 16.^[2][5]

Another completed Phase 3 study compared Zasocitinib with deucravacitinib and measured PASI-100, which means complete skin clearance on the score used in the study.^[4]

A pediatric Phase 3 study includes adolescents and children with plaque psoriasis and has two parts: one part checks skin improvement at Week 16, and another part measures pharmacokinetics, which means how the body handles the study drug, in younger children.^[12]

Trials in psoriatic arthritis

Zasocitinib is also being studied in psoriatic arthritis, a disease that causes joint inflammation in people who may also have psoriasis.^[3][6][13]

Two Phase 3 studies are evaluating whether Zasocitinib improves joint symptoms in adults with active psoriatic arthritis, including people with or without prior biologic DMARD exposure, which means previous use of advanced immune-targeting medicines.^[3][6][13]

The main endpoint in these arthritis trials is ACR20 at Week 16, which means a 20% improvement in arthritis signs and symptoms.^[3][6]

One of these studies is a long-term extension trial that follows adults over time to check continued safety, tolerability, and efficacy.^[13]

Trials in ulcerative colitis and Crohn’s disease

Some studies are testing Zasocitinib in ulcerative colitis and Crohn’s disease, which are inflammatory bowel diseases that affect the digestive tract.^[5][8][9]

A Phase 2 study in moderately to severely active ulcerative colitis is measuring clinical remission at Week 12 using the modified Mayo score, stool frequency, rectal bleeding, and endoscopy findings.^[5]

A Phase 2b study in moderately to severely active Crohn’s disease is measuring endoscopic response at Week 12, based on improvement in the Simple Endoscopic Score for Crohn’s Disease.^[8]

A Phase 2 continuation study is following people with ulcerative colitis or Crohn’s disease who met response criteria at Week 52 in the parent trials, and it tracks long-term safety, lab changes, vital signs, and special safety events for up to 108 weeks.^[9]

Trials in vitiligo and hidradenitis suppurativa

Zasocitinib is also being studied in non-segmental vitiligo, a condition that causes patchy loss of skin color.^[10]

This Phase 2 study in adults measures the proportion of participants who achieve at least 75% improvement in F-VASI at Week 24, which is a score used to track facial skin color improvement.^[10]

Another Phase 2 study is testing Zasocitinib in moderate to severe hidradenitis suppurativa, a painful inflammatory skin condition with abscesses and nodules.^[11]

The main endpoint in that study is HiSCR75 at Week 16, which means at least a 75% drop in abscess and inflammatory nodule count without more abscesses or draining tunnels.^[11]

Main endpoints and what they mean

The trials use different endpoints, but most are designed to measure how much the disease improves after treatment with Zasocitinib.^{[1][2][3][4][5][8][10][11]}

• sPGA 0/1: a skin score showing clear or almost clear skin, with at least a 2-point improvement from the start of the study.^[2][5][12]

• PASI-75: at least 75% improvement in psoriasis severity from baseline.^[2][5][12]

• PASI-100: complete improvement in the psoriasis score used in the study.^[4]

• ACR20: a 20% improvement in arthritis symptoms and signs.^[3][6]

• Clinical remission: very low or absent disease activity in ulcerative colitis at the time measured in the study.^[5]

• Endoscopic response: improvement seen on a camera test inside the bowel.^[8]

• HiSCR75: major improvement in hidradenitis suppurativa with fewer abscesses and inflammatory nodules.^[11]

• PK or pharmacokinetics: how the body absorbs, moves, and removes the study drug.^[12]

Who can join these studies

The target groups vary by trial, but most studies include people with active, moderate to severe disease who still need treatment options.^{[1][2][3][5][8][10][11]}

Some trials are for adults only, such as the psoriatic arthritis, ulcerative colitis, Crohn’s disease, vitiligo, and hidradenitis suppurativa studies.^{[3][5][8][9][10][11][13]}

The pediatric psoriasis study includes adolescents aged 12 to less than 18 years, and it plans to include children aged 4 to less than 12 years in a later part of the protocol.^[12]

Several trials also compare Zasocitinib with placebo, which helps researchers see whether the study drug works better than no active treatment.^{[2][4][5][8][10][11]}