USTAPPerianal CD · Induction and maintenance
Ustekinumab for fistulising perianal Crohn's disease: a randomised placebo-controlled trial from the GETAID
Wils P, et al.
Gut 2026 · PMID 42498622 (PubMed, opens in a new tab) · doi 10.1136/gutjnl-2026-339158 (full paper, opens in a new tab)
| Outcome | Ustekinumab | Placebo | Estimate (confidence interval) | P |
|---|---|---|---|---|
| Combined remission, Primary endpoint (primary) | 62% | 25% | 5.1 (95% CI 1.07–24.4) | |
| Clinical remission, No drainage | 62.5% | 31% | 3.75 (95% CI 0.84–16.8) | |
| Radiological remission, No abscess over 2 cm on MRI | 87.5% | 75% | 2.7 (95% CI 0.34–21.1) |
With 16 patients per arm every interval is wide and neither component alone was significant. Radiological remission reached 75% even with placebo, after standardised surgical management.
Source: Wils 2026, abstract (16 patients per arm; 69% had previous anti-TNF failure). Percentages and odds ratios as printed.
Structured abstract
BackgroundFistulising perianal Crohn's disease is debilitating, yet few randomised trials have studied it. USTAP was a placebo-controlled trial of ustekinumab designed specifically for perianal fistulas, after surgical management.
MethodsDouble-blind, multicentre, randomised, placebo-controlled trial (GETAID; 10 French centres), with an open-label phase after week 12. 32 patients. Primary endpoint: Combined clinical remission (no drainage from all external openings) and radiological remission (no abscess larger than 2 cm on blinded central MRI) at week 12.
ResultsPrimary result. 62% with ustekinumab vs 25% with placebo; OR 5.1 (95% CI 1.07–24.4).
Take-homeIn a small trial, ustekinumab after surgical drainage improved short-term combined clinical and MRI remission of perianal fistulas, but the effect was uncertain by week 48.
| Patients | 32 |
|---|---|
| Population | Adults with Crohn's disease and active draining perianal fistulas, after standardised surgical management. 69% had previous anti-TNF failure. |
| Comparison | Ustekinumab (6 mg/kg IV, 90 mg SC at week 8, then every 8 weeks) vs placebo |
| Drugs | ustekinumab |
| Classes | Anti-IL-12/23 |
| Published | Wils P, et al. Gut 2026 (published online ahead of print). |
Key points
- Clinical remission at week 12: 62.5% vs 31% (OR 3.75, 95% CI 0.84–16.8).
- Radiological remission at week 12: 87.5% vs 75% (OR 2.7, 95% CI 0.34–21.1).
- Nine placebo patients switched to ustekinumab in the open-label phase; at week 48, combined remission was 50% in the original placebo arm and 31% in the ustekinumab arm.
- Designed specifically for perianal fistulas, with 16 patients per arm.
Limitations
- Very small (32 patients), with wide confidence intervals.
- Short primary endpoint (week 12); crossover and dose intensification after week 12 make the week 48 results hard to interpret.
- Single country.
Commentary
Most evidence for biologics in perianal Crohn’s disease comes from anti-TNF trials. USTAP adds randomised placebo-controlled evidence for ustekinumab in a trial designed specifically for perianal fistulas, and supports it as an option, especially after anti-TNF failure. Surgical drainage and setons first remain essential.
Journal club
Design
Double-blind, multicentre, randomised, placebo-controlled trial (GETAID; 10 French centres), with an open-label phase after week 12. 32 patients.
Primary result. 62% with ustekinumab vs 25% with placebo; OR 5.1 (95% CI 1.07–24.4).
Validity and applicability
- Very small (32 patients), with wide confidence intervals.
- Short primary endpoint (week 12); crossover and dose intensification after week 12 make the week 48 results hard to interpret.
- Single country.
Where it sits now
In a small trial, ustekinumab after surgical drainage improved short-term combined clinical and MRI remission of perianal fistulas, but the effect was uncertain by week 48.
Questions for discussion
- With 16 patients per arm, the odds ratio's 95% CI ran from 1.07 to 24.4. How would you describe the size of the benefit to a patient?
- Radiological remission was 75% even with placebo. What does this say about the contribution of surgical drainage and setons?
- At week 48, combined remission was 50% in the original placebo arm and 31% with ustekinumab. How do crossover and intensification make later results hard to read?