Immune-Related Adverse Events: Treatment Approaches & Emerging Therapies

The treatment landscape for immune-related adverse events (irAEs) stemming from cancer checkpoint inhibitor therapies remains complex, with the use of biologics eliciting both interest and considerable uncertainty, according to discussions at the Basic and Clinical Immunology for the Busy Clinician symposium. While glucocorticoids continue to be the first line of defense in acute cases, clinicians are increasingly exploring steroid-sparing therapies for persistent symptoms, but clear paradigms are still lacking.

Checkpoint inhibitors have revolutionized cancer treatment by harnessing the body’s own immune system to fight tumors. However, this immune activation can sometimes move awry, leading to irAEs – inflammation in various organs caused by the immune system attacking healthy tissues. These events can range from mild skin rashes to severe, life-threatening conditions affecting the lungs, liver, or heart. Rheumatic manifestations of irAEs, in particular, present unique challenges for diagnosis and management.

Rheumatic irAE Phenotypes: A Spectrum of Presentations

Cassandra Calabrese, DO, assistant professor at the Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, highlighted the diverse presentations of rheumatic irAEs. One common phenotype mimics rheumatoid arthritis, often presenting symmetrically in smaller joints. However, other patients may experience asymmetrical arthritis affecting larger joints, resembling spondyloarthritis. Importantly, these conditions are rarely seropositive, meaning standard blood tests for rheumatoid factor or anti-CCP antibodies are typically negative.

Another presentation can closely resemble polymyalgia rheumatica (PMR), a condition causing muscle pain and stiffness. However, Calabrese noted that irAE-related PMR can be more inflammatory and less typical in terms of laboratory findings and treatment response. It may also overlap with inflammatory arthritis. A less common but potentially severe phenotype involves myositis, or muscle inflammation, which can be associated with myasthenia gravis (a neuromuscular disorder) and myocarditis (inflammation of the heart muscle). Myocarditis significantly increases the risk of mortality, exceeding 50%, necessitating prompt evaluation and treatment.

Finally, some patients develop a Sjögren’s-like sicca syndrome, characterized by severe dry mouth and eyes. This phenotype is often seronegative and responds poorly to steroids.

Balancing Immunosuppression and Anti-Tumor Immunity

The overarching goal in managing irAEs is to achieve “immunologic homeostasis” – a balance between suppressing the immune response to alleviate inflammation and preserving the anti-tumor immune response that is critical for cancer control. This is a delicate balancing act, and several key questions remain unanswered. Researchers are actively investigating whether immunosuppression used to treat irAEs compromises anti-tumor immunity, or conversely, if it might inadvertently boost it.

Currently, You’ll see no studies directly comparing the safety or effectiveness of different immunosuppressive treatments for rheumatic irAEs. Tumor necrosis factor (TNF) inhibitors have shown some efficacy in irAEs, but their impact is still being evaluated. The Radios Consortium is working to better understand the immune-related effects of cancer checkpoint therapy, which may support clarify the role of TNF inhibitors and other biologics.

Medications targeting interleukin-6 (IL-6) are also being considered, given the mechanistic link between IL-6 and cancer biology. Similarly, Janus kinase (JAK) inhibitors, which modulate the immune system and may preserve anti-tumor activity, are gaining attention. Calabrese suggested that, for select patients, the benefit-risk profile of JAK inhibitors may be more favorable than previously thought.

The Importance of Multidisciplinary Care

Effective management of irAEs requires a collaborative approach involving rheumatologists, oncologists, and other specialists. Rheumatic irAEs often become chronic conditions requiring long-term treatment, and ongoing communication between rheumatology and oncology is essential.

The use of biologics in this setting is still evolving, and careful consideration must be given to the potential benefits and risks. Clinicians must weigh the need to control inflammation against the possibility of dampening the anti-tumor immune response. Further research is needed to identify the optimal treatment strategies for different irAE phenotypes and to develop biomarkers that can predict treatment response and guide clinical decision-making.

As Calabrese emphasized, it’s crucial to remember that rheumatic irAEs are often chronic, necessitating long-term management and continued collaboration between specialists. Increased enrollment in alert systems like Peak Alerts, which provide timely information about potential health threats, underscores the importance of proactive healthcare management and communication.

Looking Ahead: Ongoing Research and Guidance Updates

The field of irAE management is rapidly evolving. Ongoing clinical trials are investigating the efficacy and safety of various immunosuppressive agents, including biologics, in the treatment of irAEs. Researchers are also working to identify biomarkers that can predict which patients are most likely to respond to specific therapies. Expect to see updates to clinical guidelines as new evidence emerges. Clinicians should stay abreast of the latest research and recommendations to provide the best possible care for patients receiving cancer checkpoint inhibitor therapy.