Researchers
have identified differences in the composition and the function of the gut
microbiome between patients for whom treatment with a monclonal antibody-based
drug was effective in inducing remission of inflammatory bowel disease symptoms
and those for whom it was not.
Inflammatory
bowel diseases like Crohn's disease and ulcerative colitis are autoimmune
disorders in which the immune system turns on the body's own tissues, in this
case the gastrointestinal tract. Traditional therapies include anti-inflammatory
and immunosuppressive drugs, but the biologic drugs introduced in recent years
more precisely target specific aspects of the immune response and have had
superior results in many but not all patients with IBD or other autoimmune
conditions.
Previous
efforts to determine which patients might respond to particular biologic drugs
based on their symptoms and on gene expression in the affected tissues have had
only modest success. Since considerable recent research has found that the gut
microbiome has an important role in several immune system disorders, the
research team investigated whether it might also determine response to biologic
treatment for IBD.
The
study enrolled 85 patients -- 43 with ulcerative colitis and 42 with Crohn's
disease -- who initiated treatment with vedolizumab (Entyvio), a
monoclonal-antibody-based biologic that prevents white blood cells from
migrating to inflammatory intestinal tissue. Stool samples taken before
vedolizumab treatment and 14, 30 and 54 weeks into treatment were analyzed both
for the composition of the microbial population and for functional qualities,
based on expression patterns of microbial genes.
Participants
who met criteria for remission of IBD symptoms at 14 weeks were found to have a
more diverse pretreatment microbial population -- with a greater abundance of
potentially anti-inflammatory species -- than did participants not achieving
remission. Even more striking were differences in microbial functional patterns
between those who did and did not achieve remission -- both before treatment
and 14 weeks into treatment. For those who were in remission at 14 weeks,
microbial changes observed at that point persisted for at least a year,
indicated that early changes could identify patients likely to achieve and
maintain response to treatment.
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Posted by Dr. Tim Sandle