Combination treatment of inflammatory bowel disease: Present status and future perspectives

The treatment of patients with inflammatory bowel disease (IBD), especially those with severe or refractory disease, represents an important challenge for the clinical gastroenterologist. It seems to be no exaggeration to say that in these patients, not only the scientific background of the gastroenterologist is tested, but also the abundance of "gifts" that he should possess (insight, intuition, determination, ability to take initiative, etc.) for the successful outcome of the treatment. In daily clinical practice, depending on the severity of the attack, IBD is treated with one or a combination of two or more pharmaceutical agents. These combinations include not only the first-line drugs (e.g., mesalazine, corticosteroids, antibiotics, etc) but also second- and third-line drugs (immunosuppressants and biologic agents). It is a fact that despite the significant therapeutic advances there is still a significant percentage of patients who do not satisfactorily respond to the treatment applied. Therefore, a part of these patients are going to surgery. In recent years, several small-size clinical studies, reviews, and case reports have been published combining not only biological agents with other drugs (e.g., immunosuppressants or corticosteroids) but also the combination of two biological agents simultaneously, especially in severe cases. In our opinion, it is at least a strange (and largely unexplained) fact that we often use combinations of drugs in a given patient although studies comparing the simultaneous administration of two or more drugs with monotherapy are very few. As mentioned above, there is a timid tendency in the literature to combine two biological agents in severe cases unresponsive to the applied treatment or patients with severe extraintestinal manifestations. The appropriate dosage, the duration of the administration, the suitable timing for checking the clinical and laboratory outcome, as well as the treatment side-effects, should be the subject of intense clinical research shortly. In this editorial, we attempt to summarize the existing data regarding the already applied combination therapies and to humbly formulate thoughts and suggestions for the future application of the combination treatment of biological agents in a well-defined category of patients. We suggest that the application of biomarkers and artificial intelligence could help in establishing new forms of treatment using the available modern drugs in patients with IBD resistant to treatment.