5-ASA use questioned after escalating IBD treatment

IBD

By Mardi Chapman

25 Aug 2021

The value of continuing 5-aminosalicylic acid treatment is being questioned after a study found little apparent benefit in patients who started anti-TNF and immunosuppressive therapies.

Most patients with IBD still receive at least one dispensation of 5-aminosalicylic acid (5-ASA) but their use is dropping, particularly in Crohn’s disease, a Canadian study has shown.

A retrospective cohort study of over 8,000 patients in the University of Manitoba IBD Epidemiology Database found 85% of ulcerative colitis patients and 68% of Crohn’s disease were still on 5-ASA treatment.

However the most common pattern of 5-ASA use was intermittent (65%) and only 17% of patients had persistent use. Of all 5-ASA starts, only 25% were continued longer than 20 months.

The study, published in AP&T, found 5-ASA use was significantly reduced in later eras of the study period – from before 1996 to 2018.

It found that after anti-TNF initiation, 61% of patients continued 5-ASA for a median 9.3 months.

“There was a similar distribution of 5-ASA continuers vs discontinuers between UC and CD, by age at anti-TNF initiation, by sex and by disease duration,” the study authors said.

After immunomodulator initiation, 62% of patients continued 5-ASA for a median of 14 months.

“After immunomodulator or anti-TNF initiation, there was no difference in either UC or CD for negative outcomes (hospitalisation,] surgery, corticosteroid starts, colorectal cancers or drug-related adverse events) between those who continued 5-ASA versus those who discontinued.”

“Once an anti-TNF or immunomodulator is initiated, continuation of 5-ASA seems to add no benefit.”

The findings suggested that clinicians have not been heeding recent guidelines to avoid 5-ASA use in CD.

“This could be secondary to a failure to pay attention to national or international guidelines, or that despite guidelines clinicians consider 5-ASA to have a role in CD,” they said.

Among the total IBD population, 5-ASA use was 59% oral, 3% rectal and 14% combination.

Commenting on the study, Associate Professor Miles Sparrow told the limbic he was a little surprised by how low the 5-ASA use was in ulcerative colitis.

“Only 17% persistence is surprising. It would be higher than that here. In ulcerative colitis, when we use them we use them persistently. It would still be at least 50% of UC patients who continue on 5-ASAs at this stage, although that number is gradually reducing.”

“This reflects I think Northern American practice where they are stopping them a lot quicker than we are.”

He said an issue with 5-ASAs was that they are not cheap, so some decisions were based just around economics.

Associate Professor Sparrow, Clinical Head of IBD at Alfred Health, said reduction in use of 5-ASA in Crohn’s disease over time was very appropriate and should be zero.

“Certainly in Crohn’s disease, 5-ASA shouldn’t be used but they often still are. A positive thing to highlight out of this would be that there is absolutely no need for them in CD when you escalate.”

He said there was no logic in using 5-ASAs just because they were safe when they don’t work, are expensive, and there were now better therapies.

Associate Professor Sparrow noted the 3% rate of rectal use was lower than it should be for ulcerative colitis and lower than in Australia.

“I’d like to think for ulcerative colitis, the rate of rectal use is higher than that. My guess is it would be 10-15% here.”

An Invited Editorial in the journal said whether to ‘stop or continue’ 5-ASA should be discussed on a case-by-case basis.

“The answer is difficult and can be certainly yes for efficacy, but is not so clear regarding the impact of longstanding 5-ASA exposure on colon dysplasia.”

“Altogether, we consider it premature to recommend stopping 5-ASA when escalating IBD treatment with immunosuppressive and anti-TNF agents,” it concluded.

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