Guselkumab in Crohn’s Disease: Inflammatory Bowel Diseases | September 2026

What Did the Study Find?

Five-year results from the GALAXI-1 long-term extension evaluated the durability of guselkumab, an IL-23p19 inhibitor, through week 240.

Among 87 patients remaining on treatment, 97.7% achieved clinical remission at 5 years.

Endoscopic response was maintained in 71.3%, with 51.7% achieving endoscopic remission.

Benefits remained evident in patients with previous biologic exposure.

Using the more conservative nonresponder-imputation analysis, clinical remission was 46.0% in the original efficacy population.

No new long-term safety signals emerged through 5 years.

The very high as-observed response rates should be interpreted in the context of treatment continuation and survivor bias.

Why Does It Matter?

As IL-23 therapies move earlier in Crohn’s disease management, clinicians need evidence that efficacy is durable—not simply effective during induction.

GastroAGI Takeaway

Guselkumab demonstrates reassuring long-term durability, including meaningful endoscopic benefit through 5 years. However, the 98% observed clinical remission rate reflects selected patients remaining on therapy; the 46% nonresponder-imputation rate provides important context. These data strengthen long-term confidence in guselkumab but should not be used for cross-trial superiority comparisons.