Dupixent
Dupilumab, brand name Dupixent, is a human IgG4 monoclonal antibody that was initially approved by the FDA in March of 2017. The initial approval was for the treatment of atopic dermatitis for patients with moderate-to-severe disease that is not adequately controlled with topical prescription therapies. Since its initial approval, it has been approved to be used in patients aged 6-11 years with atopic dermatitis as well as for the treatment of moderate-to-severe asthma for patients 12 years or older with an eosinophilic phenotype or who require an oral corticosteroid in their treatment.
Atopic dermatitis is a chronic skin condition that is characterized by a disturbed skin barrier and immune-mediated responses to environmental antigens. Th2 cytokines, interleukin-4 and interleukin-14, have been believed to play a role in the disease of atopic dermatitis but the clinical effect of blocking these interleukins had not been tested until the introduction of dupilumab. Dupilumab blocks signaling from both interleukins and shows positive response in atopic dermatitis patients. In addition, blockage of these Th2 interleukins showed efficacy in patients with moderate-to-severe asthma identifying that the blockage could aid in other Th2 related disease states. In a pivotal study for the approval of dupilumab in atopic dermatitis, the treatment was studied in two, 4-week monotherapy trials, a 12-week monotherapy trial, and a 4-week combination trial with topical glucocorticoids. Across all four studies, a positive correlation was found highlighting the significance of Th2 cytokines in the pathophysiology of atopic dermatitis. The blockade of these interleukins provided a reduction in skin lesions, as well as a decrease in pruritus which is a major complaint in patients with atopic dermatitis. Within the study groups, it was noted that the patients receiving placebo had higher rates of skin infection, indicating dupilumab aids in improving the skin barrier function.
As previously mentioned, Th2 cytokines play a role in the pathogenesis of asthma. Asthma presents in different phenotypes, meaning that the pathological process that produces asthma can slightly vary among patients. The inflammatory processes with these specific cytokines are present in about half of patients who are living with asthma. Despite several types of treatments on the market, 10-20% of patients with this diagnosis are not adequately controlled. The Th2 cytokines that are present in patients with atopic dermatitis are also present in patients with asthma but are signaled through different receptors. In one study, dupilumab was able to reduce asthma-exacerbation events by 87% compared to placebo.3. Dupilumab shows positive objective and subjective endpoints when it was added to previous mainstay therapies such as inhaled glucocorticoids and long-acting beta agonists. Compared to other monoclonal antibodies studied in asthma patients, such as lebrikizumab and tralokinumab, dupilumab also targets interleukin-4 and provides a reduction in asthma symptoms, beta-agonist drug use, and an increase in quality of life. These other treatments only improved lung function. Dupilumab is still in the pipeline to expand its indications to different age groups within its currently approved indications as well as a brand-new indication for the treatment of patients with peanut or grass allergies.
References:
1. Beck LA, Thaçi D, Hamilton JD, et al. Dupilumab treatment in adults with moderate-to-severe atopic dermatitis. N Engl J Med. 2014;371(2):130-139. doi:10.1056/NEJMoa1314768
2. Barry K, Gorelik D. Dupilumab (Dupixent) for Asthma. Am Fam Physician. 2020;101(4):244-245.
3. Wenzel S, Ford L, Pearlman D, et al. Dupilumab in persistent asthma with elevated eosinophil levels. N Engl J Med. 2013;368(26):2455-2466. doi:10.1056/NEJMoa1304048
While eosinophilic esophagitis was originally considered one of the defining characteristics of GERD, it has since been identified that the esophagus, typically free of eosinophils, possesses immunological activity which can attract eosinophils in response to various triggers. When the presence of eosinophils in the GI tract is confined to the esophagus, presents with distinctive symptoms, and other potential causes of esophageal eosinophilia have been excluded, it is termed eosinophilic esophagitis (EoE). EoE is defined as “a chronic, immune/antigen-mediated, esophageal disease characterized clinically by symptoms related to esophageal dysfunction and histologically by eosinophil-predominant inflammation.”
The presence of EoE has been identified across various regions across the world, including in North and South America, Europe, Asia and Australia. Initially, early reports of EoE showed patients presenting with multiple esophageal rings, often attributed to GERD, as aforementioned. However, since then, further studies have presented uncertainty regarding this association, especially because several patients would not respond to anti-GERD therapy or exhibit objective, clinical reflux evidence on 24-hour pH studies. In terms of demographics, EoE is mostly predominant in males in their 20s to 30s. Even amongst children, males have been found to be more commonly affected by this condition. While specific risk factors for the development of EoE are still poorly understood, studies suggest that some of the possible risk factors include smoking, NSAID use, antibiotic exposure and breastfeeding. EoE is classified into three different subtypes, each with its own unique characteristics:
EoEe1: Mild, characterized by a normal appearance of the esophagus and subtle changes in the histology and endoscopy of the tissue.
EoEe2: Inflammatory subtype, indicated by high levels of inflammatory cytokine expression with steroid-responsive genes but phenotype resistant to steroid treatment.
EoEe3: Presence of fibrosis and stenosis of the esophagus, marked by the most severe endoscopic and histological features.
In terms of how EoE clinically manifests, it is varied by age. While in adults and teenages, EoE will often present with dysphagia and food impaction, in younger children, it is commonly manifested by abdominal pain, difficulty in feeding and symptoms of gastroesophageal reflux. In general, however, common symptoms of EoE include but are not limited to dysphagia, food impaction, chest pain that may or may not respond to antacids and upper abdominal pain. Diagnosis of EoE is reliant on the presence of symptoms aforementioned, endoscopic findings and histological evidence. EoE should be suspected in patients with frequent symptoms of esophageal dysfunction in addition to prior medical conditions such as asthma, eczema, hay fever or immediate reactions to certain foods. In terms of diagnostic criteria, there are three primary requirements that must be met in order to make the diagnosis:
Symptoms indicative of esophageal dysfunction
Eosinophil-predominant inflammation or esophageal biopsy consisting of a peak value (at least 60 eosinophils per mm^2)
Exclusion of other possible causes
An example of a medication that is indicated for the treatment of EoE is Dupilumab, more commonly known as its brand name, Dupixent. Dupixent is an IL-4 and IL-13 antagonist, which inhibits cytokine-induced inflammatory responses, including the release of proinflammatory cytokines, chemokines, and IgE. Dupixent is currently approved by the FDA for adult and pediatric patients who are at least 1 year of age and who weigh at least 15 kg. Other approved indications for Dupixent also include moderate to severe eosinophilic asthma, atopic dermatitis, prurigo nodularis and rhinosinusitis.
Approval of Dupixent for the treatment of EoE was based on a three-part, randomized clinical trial in which patients at least 12 years of age were randomized in a 1:1 ratio to receive either subcutaneous Dupixent at a weekly dose of 300 mg or placebo (Part A), or in a 1:1:1 ratio to receive Dupixent either weekly or every 2 weeks or weekly placebo (Part B). Once both part A and B were completed, eligible patients who completed part A received a dose of Dupixent 300 mg weekly for up to week 52 (Part A-C group). However, the patients who were from Part B proceeding to Part C (Part B-C group) is still ongoing. The two primary endpoints that were assessed in week 24 of the trial were histologic remission, indicated by no greater than 6 eosinophils per high-power field, and a reduction from the baseline in the Dysphagia Symptom Questionnaire (DSQ). When assessed in week 24, Part A showed histologic remission in about 60% of patients who received weekly Dupixent versus only 5% in those who received the placebo (P<0.001). In Part B of the trial, about 60% of those who received Dupixent every 2 weeks achieved histological remission, whereas about 59% and 6% of patients that received Dupixent weekly or placebo achieved histologic remission, respectively. In terms of the patients who proceeded from Part A to Part C (Group A-C), the results were consistent with those from Part A. About 56% of patients in Group A-C had achieved histologic remission by week 52 and about 82% presented with less than 15 eosinophils per high-power field. In terms of the DSQ score for Part A, which was another primary endpoint, the reduction from baseline to week 24 in the Dupixent group was larger than the reduction seen by the placebo group (-21.92 points versus -9.6 points respectively). Furthermore, the DSQ reduction for Part B was also consistent with these results, demonstrating a -23.78 point change in the Dupixent group versus a -13.86 point change in the placebo group.
Based upon these results, it can be concluded that Dupilumab, better known as Dupixent, resulted in enhanced outcomes and diminished symptoms of eosinophilic esophagitis in both adults and adolescents. Throughout the treatment period, the most common adverse effects experienced by the participants were injection site reactions, however it is important to note that this side effect did not lead to discontinuation in both the Dupixent and placebo groups.
Resources:
Bonis P, Gupta S. Clinical manifestations and diagnosis of eosinophilic esophagitis (EoE). UpToDate . September 15, 2023. Accessed April 16, 2024. https://www-uptodate-com.jerome.stjohns.edu/contents/clinical-manifestations-and-diagnosis-of-eosinophilic-esophagitis-eoe?search=eosinophilic+esophagitis&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1#H582285.
Dupilumab (Lexi-Drugs). Lexicomp. Accessed April 16, 2024. https://online-lexi-com.jerome.stjohns.edu/lco/action/doc/retrieve/docid/patch_f/6452231?cesid=9IZ4inzSPvG&searchUrl=%2Flco%2Faction%2Fsearch%3Fq%3Ddupilumab%26t%3Dname%26acs%3Dtrue%26acq%3Ddupi#.
Dellon ES, Rothenberg ME, Collins MH, et al. Dupilumab in Adults and Adolescents with Eosinophilic Esophagitis. N Engl J Med. 2022;387(25):2317-2330. doi:10.1056/NEJMoa2205982
Bonis P, Gupta S. Treatment of eosinophilic esophagitis (EoE). UpToDate. March 13, 2024. Accessed April 16, 2024. https://www-uptodate-com.jerome.stjohns.edu/contents/treatment-of-eosinophilic-esophagitis-eoe?search=eosinophilic+esophagitis+treatment&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1#H352392936.