Pharmacological Treatments Available for Immune-Checkpoint-Inhibitor-Induced Colitis

An updated review on immune checkpoint inhibitor-induced colitis: epidemiology, pathogenesis, treatment strategies, and the role of traditional Chinese medicine

Immune checkpoint inhibitor-induced colitis (irColitis) is a common and severe adverse reaction to immune checkpoint inhibitors (ICIs), significantly impacting the treatment outcomes and quality of life of cancer patients. Epidemiological studies indicate that the incidence of irColitis is associated with factors such as the type of ICIs, the patient's gender, age, and medical history. Although the exact pathophysiology remains unclear, irColitis is thought to be related to immune system activation and dysregulation, gut microbiota imbalance, and impaired epithelial barrier function. This review summarized the epidemiology, clinical presentation, diagnostic criteria, and pathogenesis of irColitis. Additionally, the standard and novel therapeutic strategies of irColitis, including corticosteroids, biologics, and gut microbiota interventions, more importantly the potential and application of Traditional Chinese Medicine (TCM). Future researches call for deeper mechanistic investigations, the development of biomarkers, and reveal the integration of TCM therapies within individual immunotherapy frameworks.

Treatment of immune checkpoint inhibitor-related colitis: a narrative review

Background and Objective

Cancer is one of the most difficult diseases facing modern medicine, and increasing amounts of research and clinical treatments are being applied to the treatment of cancer. Immunotherapy, particularly immune checkpoint inhibitor (ICI) therapy, has revolutionized the treatment and overall survival of patients with several different types of cancer. Approximately one-third of patients treated with ICIs may experience immune-related adverse events (irAEs). Immune checkpoint inhibitor-associated colitis (ICIC) is the most common irAE with an incidence of approximately 8-10%, ICIC usually presents as watery or bloody diarrhea, and if the symptoms are severe, ICI treatment must be interrupted or even terminated. This review summarizes the epidemiology, pathogenesis, clinical characteristics, and therapies of ICIC, focusing on the use of biologics, in order to propose treatment options in different situations to control immune checkpoint inhibitor-related colitis as soon as possible.

Methods

To find relevant articles for this narrative review paper, a combination of keywords such as immune checkpoint inhibitor-related colitis, corticosteroids, biologics were searched for in PubMed databases.

Key Content and Findings

The pathogenesis of ICIC is complex and primarily involves antitumor effects and indirect damage to colonic tissues, as well as the activation of specific proinflammatory pathways. Corticosteroids (CSs) are the first line of treatment for ICIC, but steroid-refractory or steroid-resistant cases often occur. Patients with irAE colitis respond favorably to biologics, and patients with CS-resistant/refractory enterocolitis can benefit from the early use of biologics.

Conclusions

Biologics are currently recommended for the treatment of ICIC but are usually used as a supplement after the failure of first-line CS therapy. Patients with irAE colitis respond favorably to biologics, and patients with CS-resistant/refractory enterocolitis can benefit from the early use of biologics. Biologics (alone or in combination with CS) should be considered as an early therapy option for high-risk patients rather than just an escalation after a failure to respond to CS.

Enterocolitis and other immunotherapy and targeted therapy-related gastrointestinal manifestations: A review for gastroenterologist

New oncologic treatments, particularly immunotherapy (IT), have revolutionized the treatment of advanced-stage malignant tumors. Immune checkpoint inhibitors are the main form of IT and act by increasing T cell activity and the organism's immune response against neoplastic cells. Targeted therapy is another form of IT that acts by inhibiting oncogenes or inflammation signaling and tumor angiogenesis pathways. However, these mechanisms of tumor destruction can interfere with the host's immune self-tolerance or with the mechanisms of epithelial tissue repair and predispose to immune system-mediated adverse events that can affect multiple organs, including the digestive tract. The gastrointestinal manifestations of damage caused by IT can range from low-grade mucositis to ulceration, and in some cases, necrosis and perforation. Any part of the gastrointestinal tract can be affected, but there is greater involvement of the small bowel and colon, with a pattern similar to that seen in inflammatory bowel disease. The most common clinical manifestation is chronic diarrhea. The differential diagnosis includes enteropathogenic infections, especially those caused by opportunistic microorganisms; adverse drug reactions; and other inflammatory and malabsorption disorders. Treatment is guided by damage severity. Mild cases can be treated with antidiarrheals and rehydration in the outpatient setting; moderate cases with hospitalization, systemic steroids, and temporary suspension of IT; and severe cases with immunosuppressants or biologic agents and definitive suspension of IT.

Colon Adenoma After Diagnosis of Immune Checkpoint Inhibitor-mediated Colitis

Purpose: While the occurrence of colitis during immune checkpoint inhibitor (ICI) treatment is recognized as a sign of robust immune activation and correlates with better oncological outcomes, the long-term impact of ICI-mediated colitis on the colonic mucosa has not been studied. We thus aim to describe the colonoscopy and histology findings in patients at a follow-up time of ≥ 6 months post initial colitis event. Methods: This retrospective analysis included adult cancer patients diagnosed with ICI colitis at a tertiary cancer center between October 2013 and June 2020. The study group included patients diagnosed with immune mediated colitis who had also undergone a follow up colonoscopy or flex sigmoidoscopy. The control group was patients exposed to ICI without immune mediated colitis. We reported patients' colitis clinical course, treatment, outcomes, and endoscopic and histologic features at diagnosis and at follow-up time of ≥ 6 months. Results: Total 39 patients met the study criteria, with 82% being male, and 35.8% having melanoma. Most patients received a combination of CTLA-4 and PD-1/L1 inhibitors (82%). On initial endoscopic evaluation, inflammation without ulceration was reported in 76.9% of patients and active inflammation on histologic examination in 79.3% of patients. Most patients (79.4%) received corticosteroids, and 56.4% received add-on selective immunosuppressive therapy. Four patients received fecal microbiota transplantation. On follow-up, new incidence of colonic polyps was reported in 51.2% of patients, including adenomas in 33.3% among the colitis patients with median follow up duration of 12 months. The incidence of adenoma polyps 12 months after the colitis event was significantly higher compared to the control group without colitis based on the time-to-event analysis (p=0.041). Conclusion: At a median follow up of 12 months after their initial colitis diagnosis, 51.2% of the patients had new incidence of colonic polyps, including a third with adenoma, at a significantly higher incidence than the control group without colitis. Studies with larger sample sizes are needed to further define the long-term impact of colitis and its treatments on colon health and to refine recommendations for surveillance of colonic adenomas and colorectal cancer.

Check this out: treatment paradigms in immune-checkpoint inhibitor colitis

PURPOSE OF REVIEW

Immune checkpoint inhibitors (ICI) have become a pillar of cancer therapy for many people around the world. However, up to two-thirds of all patients undergoing ICI therapy will have immune-related adverse events (irAEs), including immune-checkpoint inhibitor colitis (ICIC). This review summarizes the most valuable and currently available information about the mechanism, diagnosis, and management of ICIC.

RECENT FINDINGS

Recent findings include several developments on the leading theories for the mechanisms of ICIC such as the role of the gut microbiome. New emerging therapy strategies include tocilizumab, ustekinumab, mycophenolate mofetil, and calcineurin inhibitors.

SUMMARY

The occurrence of irAEs remains a limiting factor for the use of immunotherapy in cancer treatment. Prompt diagnosis of ICIC with endoscopy and histologic confirmation can lead to early utilization of known effective treatments such as corticosteroids, infliximab, vedolizumab, and other emerging therapy strategies. We summarize the key points of this review article in our abstract video, Supplemental Digital Content 1, http://links.lww.com/COG/A44.

Multiple White Plaques in the Esophagus: A Possible Case of Esophageal Mucosal Alteration Associated With Immune-Related Adverse Events of Immune Checkpoint Inhibitors

We report two cases of multiple white plaques in the esophagus that emerged after the administration of immune checkpoint inhibitors. Both patients developed enterocolitis as immune-related adverse events associated with immune checkpoint inhibitors. Esophagogastroduodenoscopy revealed duodenal involvement and multiple white plaques in the esophagus. A biopsy of the esophagus showed predominant CD3⁺ lymphocyte infiltration, suggesting that esophageal mucosal alterations were associated with immune-related adverse events. In addition, histopathology showed keratinized stratified squamous epithelium in the first case while increased inflammatory cell infiltration in the intraepithelial and subepithelial layers was observed in the second case. These data suggest a different pathogenesis of the multiple esophageal white plaques between the two cases. Although further investigation is needed to elucidate the significance of these observations, recognition of the esophageal plaques may be important for prompt diagnosis of immune-related adverse events when associated with immune checkpoint inhibitors.

Cryobiopsy for pneumonitis diagnosis in NSCLC immunotherapy

Nowadays immunotherapy is considered the tip of the arrow as treatment for non-small cell lung cancer for inoperable patients. Programmed death-ligand 1 is considered a valuable marker for the success of immunotherapy. The higher the score ≥50% the more successful the treatment will be. However; previous studies have presented favorable data even for those patients where the programmed death-ligand 1 was ≤50% or even 0%, therefore it can be administered as first line treatment in these patients with the addition of chemotherapy or radiotherapy. Other treatment modalities are tested as surrogates like gene therapy with immunotherapy to improve the results in patients with programmed death-ligand 1 was ≤50% or even 0%. The main issue for these patients is an adverse effect pneumonitis, in case we will present the valuable method of lung parenchyma sampling with cryobiopsy for early diagnosis of immunotherapy induced pneumonitis.