Treatment of Pan-Ulcerative Colitis with Infliximab and Azathioprine

Introduction to Treatment

The American Gastroenterological Association recommends the treatment plan of Inflectra (infliximab-abda) 10mg/kg IV every 8 weeks combined with Imuran (azathioprine) 125mg daily as medically necessary and standard of care for patients with pan-ulcerative colitis who have achieved deep histologic remission on this regimen 1, 2

Anti-TNF therapy is strongly recommended for patients with ulcerative colitis who fail to respond to conventional therapy, with strong recommendation and high-quality evidence supporting its use for inducing and maintaining complete corticosteroid-free remission 3
Combination therapy with infliximab plus azathioprine is superior to monotherapy in patients with moderate-to-severe ulcerative colitis, with significantly higher remission rates (40% vs 22%) at week 16 compared to infliximab alone 2
Deep histologic remission achieved by patients represents an optimal treatment outcome that reduces long-term complications, including dysplasia and colorectal cancer risk, making continuation medically necessary to maintain this disease control 1, 2

The 2020 American Gastroenterological Association guidelines provide a strong recommendation with moderate-quality evidence for using infliximab in moderate-to-severe ulcerative colitis for both induction and maintenance of remission 1, 4
The 2019 British Society of Gastroenterology guidelines confirm infliximab's role in ulcerative colitis management, with clinical remission rates of 30% for 5mg/kg sustained to week 54, and corticosteroid-free remission rates of 22% 2
The 2015 Toronto Consensus guidelines strongly recommend anti-TNF therapy combined with a thiopurine rather than monotherapy to induce complete remission (strong recommendation, moderate-quality evidence for azathioprine) 3

Combination therapy decreases immunogenicity, which is particularly relevant for patients with documented history of immunogenicity 5
The UC SUCCESS study demonstrated that patients receiving infliximab plus azathioprine had significantly higher remission rates (40%) compared to infliximab alone (22%) 2
Combination therapy is an independent predictor for sustained clinical response (hazard ratio 3.98, 95% CI 1.73-9.14) in retrospective studies 5

The 2019 British Society of Gastroenterology guidelines state that patients responding to infliximab induction should continue anti-TNF therapy to maintain complete remission (strong recommendation) 2
Mesalamine maintenance treatment should be continued long-term as it may reduce colorectal cancer risk 5