BIOLOGICS IN INFLAMMATORY BOWEL DISEASE: WHO, WHEN, HOW LONG? POSSIBLE SIDE EFFECTS AND THEIR MANAGEMENT

With the worsening environmental conditions, the increasing reliance on processed foods in dietary habits, and the added stress factor, inflammatory bowel disease (IBD) is becoming increasingly prevalent year after year. The limited effectiveness of conventional medications (aminosalicylates, steroids, and immunosuppressants) often left patients with this disease, especially Crohn’s disease patients, with the need for surgery. The introduction of biological drugs in the last 20 years has revolutionized IBD treatment. As a concrete result of this change, the percentage of patients requiring surgery has decreased significantly. Based on current evidence, initiating treatment with the most effective agent is the most recommended approach in patient management, especially in patients with Crohn’s disease. The classification of drugs developed to address the underlying mechanisms of disease development and eliminate these steps was written by Dr. Cem Aygün. Dr. Veysel Tahan and colleagues comprehensively discussed when patients should receive biological therapy. Anti-tumor necrosis factors (anti-TNFs) were the first biological agents discovered, and the initial experiences with patients also relate to the use of these agents. Dr. Yusuf Erzin et al. explained the use of anti-TNF in ulcerative colitis, while Dr. Ahmet Dobrucalı et al. discussed the use of the same agents (anti-TNF) in Crohn’s disease. Dr. Harleen Chela et al. provided detailed information on the use of other agents. A significant issue in IBD is also managing extraintestinal manifestations in patients. Arthritis, in particular, is a common finding, and complaints related to almost every organ system can arise during the course of the disease. Dr. İbrahim Hatemi et al. discussed the management of extraintestinal manifestations with biological agents. Although the introduction of biological drugs has reduced the need for surgery in IBD, surgical treatment is still among the treatment options in both ulcerative colitis and Crohn’s disease. Dr. Hülya Över Hamzaoğlu wrote about the treatment approach in postoperative patients. The use of these agents during pregnancy and lactation was written by Dr. Ömer Şentürk. Dr. Tolga Konduk reported on the combined use of biological and non-biological drugs. The idea of intermittent use of biological drugs, proposed to reduce their potential side effects, was discussed by Dr. Ebubekir Dağlılar et al. based on existing evidence. Monitoring serum drug levels and detecting antibodies against the drug can determine the treatment strategy in treated patients. For this purpose, these tests can be performed either regularly (proactively) or when a problem arises (reactively). Dr. Öykü Tayfur Yürekli explained which of these two approaches is more appropriate based on the evidence. In addition to the beneficial effects they produce in treatment, the potential side effects of these drugs constitute their limitations. Undoubtedly, drug side effects are an undesirable part of treatments. These side effects are not only specific to biological agents but concern all drugs used in the treatment. Dr. Arif Mansur Coşar discussed biological agents, infection risks, and their management; Dr. İsmail Hakkı Kalkan discussed the malignant potential of these drugs and their prevention; and Dr. Emel Ahıshalı et al. addressed these two non-complication side effects. Another factor limiting the use of biological drugs, like their side effects, is their cost. The development of equivalent drugs (bioequivalents, biosimilars) has been an important step in reducing the cost of drugs. The use of biosimilars in IBD was written by Dr. Uğur Korkmaz. While the increasing number of newly discovered biologics offers significant treatment opportunities for physicians, they also make drug selection increasingly difficult and bring with them new potential side effects. In this context, newly developed drugs were explained in detail by Prof. Dr. Hale Akpınar. Despite the use of each agent alone, the desired response is not obtained in a group of patients, leading to new treatment approaches. In this context, the combination of biological drugs is one of the most important issues of recent times. This topic was comprehensively addressed by Dr. Ömer Şentürk. For how long should biologic drugs be used in patients who respond to treatment? In other words, can these drugs be discontinued? This issue was discussed by Dr. Orhan Kocaman in the light of current data. When using biological drugs, do the drugs pose a risk for surgery when patients have surgical needs, or do they contribute to the development of surgical complications? This topic was explained by Dr. Melih Özel. Finally, the treatment of IBD in the pediatric age group with biological agents was comprehensively evaluated by Dr. Ayşen Uncuoğlu et al. In conclusion, this comprehensive book addresses all the problems that any physician practicing in IBD treatment might encounter, along with suggested solutions. Many thanks to everyone involved. Prof. Dr. Ömer ŞENTÜRK Bahçeşehir University, Medical Park Göztepe Hospital, Department of Gastroenterology, İstanbul, Türkiye