Clinical Characteristics and Outcomes in Immune Checkpoint Inhibitor Therapy-Associated Myocarditis

Immune Checkpoint Inhibitor-Associated Myocarditis: A Literature Review

Recently in the field of oncology, immune checkpoint inhibitors (ICI) are being increasingly utilized both in clinical trials and in clinical practice. It is a form of biological therapy that targets tumors by activating the immune system, which in turn eliminates proliferating cancer cells. These have numerous immune-related adverse events (irAEs), one of which is myocarditis, which has high rates of mortality. This article was a narrative review of myocarditis related to ICI use.  Studies from the PubMed, Cochrane, and American Society of Clinical Oncology (ASCO) databases were used in writing this review. The databases were searched for original publications for adverse effects related to ICI use and myocarditis specifically. There are numerous published instances of cancer immunotherapy causing myocarditis. ICI therapy has numerous benefits, as it upregulates the immune system to target cancer cells, utilizing the body's own defense mechanisms to target proliferating cells. Myocarditis is a serious side effect, however. Therefore, on balance, these monotherapies are worth using. While this literature review primarily identifies cross-reaction as the main mechanism of myocarditis, there are other possible mechanisms. One proposed mechanism involves a shared antigen between the myocardial tissue and the tumor. This mechanism is called molecular mimicry, where the monoclonal antibody attacks both the myocardial tissue and the tumor cell. Management of ICI-induced myocarditis has not been studied by randomized controlled trials or prospective studies, but based on previous case reports and case series it is mostly treated with steroids initially. An ICI rechallenge after temporary discontinuation appears conceivable in many cases, especially given its therapeutic effects, but only limited data are available on the safety of a rechallenge after an irAE. The lack of RCTs regarding rechallenge with an ICI after irAE, more so specifically about myocarditis, along with the overall results and the complexity involved in such cases once again emphasize the need to make decisions on an individual basis by a multidisciplinary expert working group. At the same time, the focus should also be on publishing more data as the need will grow along with the indications for ICI therapies.

Plasma exchange plus glucocorticoids in the treatment of immune checkpoint inhibitor-induced myocarditis: A case series and review

Immune checkpoint inhibitors (ICIs), including antiprogrammed cell-death (PD)-1/anti-PD-ligand (PDL-1) monoclonal antibodies, are effective at improving the prognosis of patients with cancer. Among immune-related adverse events, myocarditis associated with anti-PD-1/anti-PD-L1 antibodies is rare but lacks effective treatment and mortality is very high. In this study, the authors extracted data from the previous 8 years from electronic medical records housed in the hospital information system to identify patients hospitalized with myocarditis putatively caused by anti-PD-1/anti-PD-L1 tumor therapy. Clinical data from these patients are reported. Four patients who developed myocarditis after undergoing treatment with anti-PD-1/anti-PD-L1 antibodies for malignant tumors, all of whom responded favorably to therapy consisting of plasma exchange and glucocorticoids for myocarditis, and all patients improved and were discharged from hospital. Plasma exchange plus systemic glucocorticoids may be effective for treating anti-PD-1/anti-PD-L1 antibody-induced myocarditis in patients with cancer.

A Systematic Review of Myocarditis Induced by Immune Checkpoint Inhibitors: How Concerning Is the Most Common Cardiotoxicity of Immune Checkpoint Inhibitors?

Novel cancer therapies have revolutionized the management of various cancers. An immune checkpoint inhibitor (ICI) is one of these antitumor medications. ICIs, which are immune therapies, enhance the immune system's capacity to fight cancer cells. Based on the receptors that they inhibit, such as PD-1, PD-L1, and CTLA-4, ICIs are subdivided. Although this class of drugs is extremely beneficial for cancer patients, their adverse effects can be fatal. Multiple organs, such as the cardiovascular system, may be impacted by immune-related adverse effects (irAEs). These cardiotoxic irAEs can occur at a rate of up to 1% and can be fatal. Myocarditis is the most prevalent of all cardiotoxicities. The purpose of this systematic review is to assess the seriousness of myocarditis, the most prevalent cardiotoxicity of ICIs, and the importance of screening. We chose studies based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 criteria. Therefore, from 2018 to 2023, we gathered articles from databases such as PubMed, ScienceDirect, Web of Science, the Cochrane Library, and Google Scholar. Of the 665 studies identified based on various screening methods and quality assessment tools, 13 were selected for inclusion in the study. This study shows that although the risk of myocarditis in ICI therapy is low and the majority of cases are asymptomatic or mild, some cases can be deadly and disastrous, and physicians should be aware that if myocarditis is suspected based on clinical symptoms, troponin, electrocardiogram, and echocardiogram, treatment should be initiated accordingly.

Integrated Single-Cell and RNA Sequencing Analysis Identifies Key Immune Cell and Dendritic Cells Associated Genes Participated in Myocarditis

Myocarditis is a complex disease characterized by myocardial inflammatory cell infiltration. The purpose of our study was to investigate the gene and single-cell signature to explore the involvement of immune cells in myocarditis. Gene expressions merged from GSE35182 and GSE35182 datasets were subjected to differential expression gene (DEG) analysis and PPI network construction. The correlation analysis of DEGs with immune cell infiltration was performed. Single-cell RNA sequencing (scRNA-seq) was downloaded from GSE174458. A total of 58 DEGs were identified, including 51 DEGs upregulated and 7 DEGs downregulated in the myocarditis group compared with the control group. GO and KEGG enrichment analyses revealed that myocarditis triggered DEGs mainly involved in immune-related processes and pathways. PPI network analysis identified 20 central hub genes. Occurrence of myocarditis induced significant enrichment of conventional dendritic cell 2 (cDC2), plasmacytoid DC, and plasma cell in myocardial tissue. Mmp12, Gpnmb, and Atp6v0d2 expressions were positively correlated with cDC abundance, of which only Mmp1 and Gpnmb were shared with hub gene list. A total of 20972 cells in scRNA-seq yielded 26 cell clusters and annotated 9 cell types, including fibroblasts, neutrophils, stromal cells, monocytes, basophils, B cells, natural killer T cells, innate lymphoid cells, and T cells, and only proportion of natural killer T cells and monocytes were higher in the myocarditis than in control. Monocytes annotated 3 subclusters including DC, macrophage, and monocytes. Hub genes of Ctss, Mpeg1, Cybb, H2-Ab1, Ly86, CD74, and Lgals3 were highly expressed in monocytes cluster. Among DC-correlated DEGs, Mmp12 was mainly expressed in monocyte cluster, and Gpnmb was mainly expressed in fibroblast cluster, whereas Atp6v0d2 expression has a weaker signal and weaker cell preference. In conclusion, DC infiltration and its associated pivotal genes may be responsible for progression of myocarditis. Our study expands and provides novel information on the immune cell engagement of myocarditis.

Adverse Events and Tolerability of Combined Durvalumab and Tremelimumab versus Durvalumab Alone in Solid Cancers: A Systematic Review and Meta-Analysis

Background: Recently, the combination of durvalumab and tremelimumab, two immune checkpoint inhibitors, for the treatment of different types of cancers has been considered; however, its overall effects, including its safety, are still unclear and need to be further investigated. Objectives: The aim of the present systematic review and meta-analysis was to investigate the safety and tolerability of this combination of drugs. Methods: A systematic review of the literature, based on the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement, was conducted by employing online electronic databases and the American Society of Clinical Oncology (ASCO) Meeting Library. The selection of eligible publications was made following a staged screening and selection process. The software RevMan 5.4 was used to run the quantitative analysis and forest plots, while the Cochrane tool was employed for risk of bias assessment. Results: From the retrieved 157 results, 9 randomized controlled trials involving 3060 patients were included. By comparing the combination of durvalumab and tremelimumab vs. durvalumab monotherapy, it was observed that: adverse events (AEs) ≥ Grade 3 incidence was 32.6% (536/1646) vs. 23.8% (336/1414) (Z = 2.80; p = 0.005; risk ratio (RR) = 1.44), reduced appetite incidence was 10.8% (154/1427) vs. 8.3% (108/1305) (Z = 2.26; p = 0.02; RR = 1.31), diarrhea was reported in 15.6% (229/1473) vs. 8.1% (110/1352) (Z = 5.90; p < 0.00001; RR = 1.91), rash incidence was equal to 11.1% (160/1441) vs. 6.5% (86/1320) (Z = 4.35; p <0.0001; RR = 1.75), pruritis was 13.6% (201/1473) vs. 7.7% (104/1352) (Z = 5.35; p < 0.00001; RR = 1.83), fever was 10.5% (42/399) vs. 6.6% (22/330) (Z = 2.27; p = 0.02; RR = 1.77), discontinuation rate was 18% (91/504) vs. 3% (36/434) (Z = 4.78; p < 0.00001; RR = 2.41), and death rate was 2.6% (13/504) vs. 0.7% (3/434) (Z = 1.90; p = 0.06; RR = 2.77). Conclusions: It was observed that the combined (durvalumab and tremelimumab) vs. monotherapy (durvalumab) is associated with a higher risk of treatment discontinuation, mortality, fever, diarrhea, rash, pruritis, and reduced appetite. This information is relevant and should be disclosed, especially to patients that are currently enrolled in clinical trials considering this combined therapy.