What is the recommended dose of ustekinumab (Stelara) for an adult patient with moderate to severe Crohn's disease?

Ustekinumab Dosing for Crohn's Disease

For adults with moderate to severe Crohn's disease, administer ustekinumab as a single weight-based intravenous induction dose (approximately 6 mg/kg), followed by 90 mg subcutaneous maintenance injections starting at week 8, then every 8 weeks thereafter. 1, 2

Induction Dosing

Weight-based IV induction regimen:

• ≤55 kg: 260 mg IV (2 vials)
• >55 to 85 kg: 390 mg IV (3 vials)
• >85 kg: 520 mg IV (4 vials)

2

This single intravenous dose is administered at week 0, with clinical response typically evident by week 6-8. 1, 3

Maintenance Dosing

Standard maintenance: 90 mg subcutaneously at week 8 (first maintenance dose), then every 8 weeks thereafter. 1, 2

The every-8-week dosing interval is preferred over every-12-week dosing based on superior efficacy data:

• Every 8 weeks: 53.1% achieved remission at week 44
• Every 12 weeks: 48.8% achieved remission at week 44
• Placebo: 35.9% remission

3

The British Society of Gastroenterology specifically notes that 8-weekly dosing achieved 43.8% remission versus 24% with placebo, with numerical benefits particularly evident in anti-TNF refractory populations. 4

Clinical Response Timeline

Symptom improvement occurs rapidly:

• Day 1: Stool frequency improvement significantly better than placebo
• Day 10: All patient-reported symptoms (stool frequency, abdominal pain, general well-being) significantly improved
• Week 3-16: Cumulative remission rates continue to increase after the week 8 subcutaneous dose
• Week 44: Up to 66.7% maintain clinical response with q8w dosing

5

Efficacy by Patient Population

Anti-TNF naïve patients (UNITI-2):

• Week 6 response: 55.5% with 6 mg/kg vs 28.7% placebo (p<0.001)
• Week 44 remission: Higher cumulative rates (23.0% at week 3 increasing to 55.5% at week 16)

3, 5

Anti-TNF failure patients (UNITI-1):

• Week 6 response: 33.7% with 6 mg/kg vs 21.5% placebo (p≤0.003)
• Week 44 remission: 41.1% vs 26.2% placebo
• Lower cumulative rates (12.9% at week 3 increasing to 24.1% at week 16)

6, 3, 5

Important Clinical Considerations

Do not delay the week 8 subcutaneous dose based on week 8 clinical status. Neither week 8 CDAI score change nor ustekinumab pharmacokinetics predict week 16 response—clinical outcomes continue improving through week 16 and beyond regardless of week 8 status. 5

Therapeutic drug monitoring: Trough concentrations ≥0.8 μg/mL (optimally up to 1.4 μg/mL) associate with higher rates of maintained clinical remission. Steady-state concentrations are reached by the second maintenance dose, with median trough levels approximately threefold higher with q8w versus q12w dosing. 7

Monotherapy is appropriate: No evidence supports routine combination with thiopurines or methotrexate—ustekinumab concentrations do not appear affected by concomitant immunomodulators. 6, 7

Comparative effectiveness: The 2024 ECCO guidelines note that ustekinumab and adalimumab demonstrate equal efficacy in biologic-naïve patients (57% vs 60% remission at week 16,64.9% vs 61.0% at week 52), though newer agents like risankizumab now receive stronger recommendations. 1

Safety Profile

Ustekinumab demonstrates favorable safety with low antibody formation rates (<5%). 6 Long-term safety through 96 weeks shows no dose-dependent increase in adverse events, with serious adverse event rates similar to placebo (18.82 vs 19.24 per 100 patient-years). 8 Avoid live vaccines during treatment. 6