Risankizumab Mechanism of Action: How Risankizumab Works | Elicit
Risankizumab Mechanism of Action
How Risankizumab (Skyrizi) Works: Binds the IL-23 p19 subunit to inhibit IL-23 receptor interaction and downstream signaling.
Last updated: March 2026
Quick Summary
Risankizumab (Skyrizi) is a high-affinity neutralizing anti–interleukin-23 (IL-23) monoclonal antibody used for inflammatory diseases including plaque psoriasis, psoriatic arthritis, and Crohn’s disease. It binds the IL-23 p19 subunit and inhibits IL-23 from interacting with its receptor, blocking downstream signaling associated with inflammatory pathways.
Properties
| Details | Information |
|---|---|
| Generic Name | Risankizumab |
| Brand Names | Skyrizi |
| Drug Class | Interleukin-23 antagonist (anti–IL-23 monoclonal antibody) |
| Primary Target | Interleukin-23 subunit alpha (IL23A) (p19 subunit) |
| Approved Indications | Moderate-to-severe plaque psoriasis in adults, active psoriatic arthritis (PsA) in adults, moderately to severely active Crohn's disease in adults, moderately to severely active ulcerative colitis in adults |
| Key Effect | Neutralizes IL-23 by binding the p19 subunit, preventing IL-23 receptor interaction and subsequent inflammatory signaling |
Development History
Risankizumab was developed through a collaboration between Boehringer Ingelheim and AbbVie. The antibody selectively binds the p19 subunit of interleukin-23, blocking IL-23 from interacting with its receptor and downstream signaling. This selectivity differentiates it from ustekinumab, which neutralizes both IL-23 and IL-12 by targeting the shared p40 subunit. Risankizumab was designed to preserve IL-12-dependent immune surveillance while achieving a complete blockade of the IL-23/Th17 inflammatory pathway.
The pivotal program supporting the FDA approval comprised four phase 3 trials in moderate-to-severe plaque psoriasis: UltIMMa-1, UltIMMa-2, IMMhance, and IMMvent. Risankizumab received initial U.S. approval in April 2019 under the brand name Skyrizi.
Detailed Mechanism of Action
Following subcutaneous administration, risankizumab is absorbed into the circulation. As an IgG1 monoclonal antibody, it exhibits a two-compartment model without evidence of accumulation.
IL-23 p19 binding and selective blockade: Risankizumab targets the p19 subunit of IL-23, inhibiting receptor interaction and preventing downstream signaling initiation. The antibody shows no binding to the shared IL-12/23 p40 subunit, allowing IL-12–driven Th1 responses to remain intact.
Receptor blockade and JAK–STAT cascade interruption: Engagement of the IL-23 receptor normally triggers JAK2 and TYK2 activation, leading to phosphorylation of STAT3 and STAT4. By preventing receptor assembly, risankizumab blocks IL-23–dependent cell signaling and the release of proinflammatory cytokines.
Th17-axis gene expression: Downstream of JAK–STAT disruption, risankizumab suppresses Th17-linked programs in affected tissues, leading to reductions in IL-17 production by stimulated Th17 lymphocytes.
Clinical Relevance
Approved Indications
- Moderate-to-Severe Plaque Psoriasis (Adults): Achieved PASI 90 at week 16 in 75.3% versus placebo.
- Active Psoriatic Arthritis in Adults: ACR20 responses of 57.3% versus placebo.
- Moderately to Severely Active Crohn's Disease (Adults): CDAI clinical remission rates higher than placebo.
- Moderately to Severely Active Ulcerative Colitis (Adults): Clinical remission rates higher than placebo.
Key Drug Interactions
- No clinically significant CYP450 interactions: No significant changes in exposure of common CYP substrates.
- Live vaccines: Avoid during treatment.
Special Populations
- Tuberculosis (TB) screening: Evaluate for TB infection prior.
- Infections: May increase the risk of infections; should not initiate treatment if active infection is present.
Emerging Indications
Immunology
- Hidradenitis Suppurativa: Phase 2 study terminated early based on high placebo response.
- Atopic Dermatitis: Phase 2 study terminated with no statistically significant difference versus placebo.
Gastroenterology / Hepatology
- Ulcerative Colitis: FDA approved in 2024 following clinical trials showing efficacy.
Clinical Trials of Risankizumab
| Trial Name | Phase | N Enrolled | Indication | Key Result | Status |
|---|---|---|---|---|---|
| AFFIRM | Phase 3 | 289 | Moderate-to-severely active Crohn's disease | CDAI clinical remission was 55% with risankizumab vs 30% with placebo | Active, Not Recruiting |
| KEEPsAKE 1 | Phase 3 | 964 | Active psoriatic arthritis with inadequate response | At week 24, ACR20 was achieved by 57.3% with risankizumab vs 33.5% with placebo | Ongoing |
| COMMAND | Phase 3 | 754 | Moderately to severely active ulcerative colitis | At week 52, clinical remission was 40.2% with risankizumab vs 25.1% with placebo | Completed |
Open Research Questions
- How does risankizumab selectively modulate pathogenic versus non-pathogenic tissue-resident memory T cell subsets?
- What is the optimal dosing strategy for risankizumab in Crohn's disease?
- To what extent do molecular differences between IL-23 p19 inhibitors translate into clinically meaningful distinctions?