Adding or switching biologics is a common practice in the treatment of patients with inflammatory bowel disease (IBD), but there is a dearth of clinical data on whether patients should receive their first or second biologic as monotherapy or combined with immunomodulatory therapies. It’s a clinical conundrum made more difficult by the increasing number of biologics and drugs available to treat IBD, and the fact that some first-line biologics may fail because of immune responses.
The authors of a new review by Roni Aoun, MD, published in the Journal of Clinical Gastroenterology sought to provide some much-needed advice on these issues, surveying the literature that does exist in order to offer evidence-based recommendations for how and when biologics should be used.
A confusing array of therapeutic choices
The review arrives at a moment when IBD treatments have hit a therapeutic plateau, producing remission rates of only around 30%-35%, despite new treatments and mechanisms of action. “That’s just not where we want to be [so] there’s a lot of interest in how we can make our therapies better,” said David Rubin, MD, a professor of medicine and the codirector of the Digestive Diseases Center at the University of Chicago, and the chair of the scientific advisory committee for the Crohn’s & Colitis Foundation.
Dr. Rubin, who did not participate in authoring the review, added that the field also faces questions of what patients should receive after their first has either failed to work entirely or the initial response has waned.
“Understanding sequencing is important,” he said. “The best way to assess that right now has been through claims data, which are notoriously missing important information like [disease activity].”
The landmark SONIC and SUCCESS studies concluded that combining antibodies with immunomodulatory drugs was the best approach, but times have changed since these results were published. One recent study showed that the patient’s HLA subtype can be associated with anti–tumor necrosis factor (TNF) immune responses.
“We now know that you can be much more specific and precise about this. You can predict the likelihood someone’s going to have antidrug antibodies against an anti-TNF [agent],” said Dr. Rubin.
Factors that go into the decision of whether or not to prescribe an immunomodulator include the class of biologic, whether it is a first or second biologic, the presence or absence of antidrug antibodies, patient preference, and any comorbid conditions.
Anti-TNF agents often lose efficacy, with one study finding an average 41% loss of response to certolizumab, 33% to infliximab, and 30% to adalimumab. Another problem is posed by the intrinsic risk of immunogenicity with biologics, with rates reported to be as high as 65.3% for infliximab and 38% for adalimumab.
Immunogenicity to one anti-TNF agent often predicts immunogenicity to other anti-TNF biologics. Some data suggest that, in patients who produced antibodies to an initial anti-TNF agent, combination therapy can provide benefit with a second anti-TNF biologic. However, there are some scenarios that call for monotherapy, such as when a patient can’t take immunomodulators or when over-suppression could be risky. According to Dr. Aoun and colleagues, limited data and lessons from clinical practice suggest that monotherapy anti-TNF biologics with proactive therapeutic drug monitoring is a reasonable approach in these cases. Monitoring may also reduce the risk of immunogenicity.