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Evevident
Original paper
2010NEJMGastroenterology/Hepatology

SONIC

Infliximab, azathioprine, or combination therapy for Crohn's disease

RCTInflammatory bowel disease

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Overview

Combination infliximab plus azathioprine induced more steroid-free remission in Crohn disease.

Clinical takeaway

SONIC established the efficacy of early biologic-based therapy and combination therapy in biologic- and immunomodulator-naive Crohn disease.

Key result

Steroid-free remission at week 26 was highest with infliximab plus azathioprine.

Practice impact

Biologic therapy moved earlier for moderate-severe Crohn disease, with combination therapy considered in selected patients.

Evidence

Study design

Randomized double-blind trial.

Enrollment

508

Follow-up

Primary outcome at week 26.

Geography

Multinational

Clinical question

In Crohn disease naive to immunomodulators and biologics, is infliximab, azathioprine, or combination therapy most effective?

Population

  • Adults with moderate-to-severe Crohn disease naive to immunomodulators and biologic therapy.

Intervention

Infliximab plus azathioprine, or infliximab alone.

Comparator

Azathioprine alone and active treatment comparisons.

Primary outcome

Corticosteroid-free clinical remission at week 26.

Combination infliximab plus azathioprine produced the highest steroid-free remission rate.

Absolute remission rate / 56.8

Key results

  • Steroid-free remission at week 26: 56.8% combination vs 44.4% infliximab vs 30.0% azathioprine.
  • Mucosal healing was more common with infliximab-containing regimens.
  • Serious infection rates were similar in the trial but immunosuppression risks remain important.

Harms

  • Combination immunosuppression can increase infection and malignancy concerns.
  • Thiopurine toxicity requires TPMT/NUDT15 and lab monitoring in modern practice.

Clinical Use

When to cite

  • When explaining infliximab and combination therapy evidence in Crohn disease.

Practice impact

  • Shifted moderate-severe Crohn disease toward earlier biologic therapy and selected combination therapy.

Applicability

  • Biologic- and immunomodulator-naive patients with moderate-to-severe Crohn disease.

Limitations

  • Does not answer every modern biologic or small-molecule sequencing question.
  • Risk-benefit differs by age, EBV status, malignancy risk, and infection risk.

Common misinterpretations

  • Combination therapy is not mandatory for every Crohn patient; selection and monitoring matter.

Citation

Colombel JF, Sandborn WJ, Reinisch W, et al. Infliximab, azathioprine, or combination therapy for Crohn's disease. N Engl J Med. 2010;362(15):1383-1395. doi:10.1056/NEJMoa0904492