IL-17 Inhibitors and IBD: What a 2.5x Risk Increase Means for Medical Affairs and Safety Teams

Key takeaways:

• New-onset IBD was rare in both cohorts; 1.07% of IL-17 inhibitor users and 0.45% of apremilast users. 

• IL-17 inhibitor use was associated with a 2.5-fold increase in new-onset IBD compared with apremilast, a finding detected across 26,432 propensity-matched patients. 

• The scale of the study allows for granular risk profiling: subgroup findings differentiate by drug, age, and disease type, giving medical affairs and safety teams the specificity needed to build targeted monitoring protocols and patient stratification frameworks. 

• For regulatory and safety teams, this is post-market evidence strengthens safety monitoring and can inform the prescribing guidance frameworks teams are actively building. 

IL-17 inhibitors have become a cornerstone of treatment for immune-mediated conditions including psoriasis and ankylosing spondylitis. They work. But as these therapies have moved from trial settings into widespread clinical use, safety monitoring is using real-world data (RWD) as a crucial task to ensure safety and effective medication use. 

An analysis by Alsakarneh et al. 2025 (Aliment Pharmacol Ther. 2025 Jul;62(1):72-76) using the TriNetX LIVE™ platform enables safety monitoring at a scale previously impossible. Among 26,432 propensity-matched patients, IL-17 inhibitor use was found to be associated with a 2.5-fold increase in new-onset inflammatory bowel disease (IBD) compared with apremilast. For medical affairs, regulatory, and safety teams managing IL-17 inhibitor portfolios, this is the kind of post-market finding that helps ensure safe and effective use of new therapies.

Why RWD Surfaces What Trials Miss

The study drew from electronic health record (EHR) data across U.S. healthcare organizations representing approximately 120 million patients. That breadth matters. IBD induction is a low-frequency event, the kind of potential safety outcome that requires a very large, longitudinal population to study with confidence. In the matched cohort, incident IBD was rare, occurring in 1.07% of IL-17 inhibitor users versus 0.45% of apremilast users, yielding an adjusted hazard ratio of 2.50. 

Clinical trials in psoriasis and ankylosing spondylitis are not designed to capture rare safety events. Their populations are controlled, their follow-up periods constrained, and patients with gastrointestinal (GI) risk factors are frequently excluded. The analysis reflects the patients actually receiving these therapies in practice, including those with comorbidity profiles and demographic characteristics that trials routinely screen out. 

The Risk Is Not Uniform

One of the most important dimensions of this finding is the granularity of the subgroup data. The IBD risk was not evenly distributed across diagnosis type, drug, age, or sex, and those distinctions matter for how teams respond. 

Crohn’s disease (CD) showed a stronger association than ulcerative colitis (UC), a differential that has implications for patient counseling and monitoring prioritization, particularly in gastroenterology referral pathways. 

Among the specific agents studied, secukinumab showed a statistically significant association with increased IBD risk. Ixekizumab did not reach statistical significance, a distinction that may inform formulary and portfolio decisions where both agents are active. 

Age emerged as a meaningful risk modifier. Adults over 60 exhibited the highest relative risk in the analysis. For medical affairs teams, this translates directly into patient selection and risk stratification frameworks: older patients initiating IL-17 inhibitor therapy warrant heightened vigilance for early GI symptoms. 

Both sexes showed increased risk, though the association for CD was stronger in men. 

Who Is at Highest Risk: A Quick Reference

For teams developing monitoring guidance or patient counseling materials, the subgroup profile emerging from this study points to a consistent picture. 

Patients at highest relative risk include adults over 60, patients with psoriasis or ankylosing spondylitis initiating secukinumab specifically, and male patients where CD risk is the primary concern. Early monitoring for GI symptoms, including fecal calprotectin measurement to detect bowel inflammation before diagnosis, is a clinically appropriate response the study’s authors highlight. 

What This Means Beyond the Exam Room

The clinical implications here are clear. But for life sciences teams, the strategic implications deserve equal attention. 

Post-market safety monitoring of this quality and scale is increasingly what regulators expect to see as part of ongoing pharmacovigilance. An analysis drawing on large representative populations and more than a decade of prescribing history is not an academic exercise. It is the kind of evidence that informs strengthens post-market safety monitoring and supports the prescribing guidance materials that medical affairs teams develop and maintain. 

For commercial and market access teams, the secukinumab versus ixekizumab distinction in this dataset is worth tracking closely. If the differentiation between agents holds and replicates in further analyses, it has potential formulary and positioning implications in a market where both agents compete for the same indicated populations. 

The finding also underscores a broader point about what real-world evidence (RWE) infrastructure makes possible. This finding existed in the data before this study was conducted. The question was always whether anyone had the network scale to surface it. 

The Full Picture

This IL-17 inhibitor analysis is one of five independent studies in TriNetX’s CSO Perspectives: Research Impact Report on IBD. The remaining four address treatment sequencing after TNFi failure, colorectal cancer risk following terminal ileum resection in CD, the safety and effectiveness of semaglutide in patients with IBD and obesity, and the relationship between acne, acne treatments, and IBD onset. 

 Together, they represent a cross-section of actively debated evidence gaps in IBD today, answered at a scale only population-level RWD can achieve. 

About Jeffrey Brown, PhD 

With more than 25 years of experience in research and consulting, Jeff is an internationally recognized expert in the use of RWD to support the evidentiary needs of regulatory agencies and medical product sponsors and an expert in the assessment of data quality of RWD resources.