Lessons for clinicians
The National Comprehensive Cancer Network, the Society for Immunotherapy of Cancer, and the European Society of Medical Oncology have all published guidelines and recommendations for immunosuppression for steroid-refractory adverse events from ICIs.
Unfortunately, there is little experience with steroid-unresponsive ICI-related pneumonitis. The ideal sequence, dose, and duration of additional immune modulator therapy for ICI-related pneumonitis are unclear and may differ from the approaches to other immune-related toxicities.
This is important because, as suggested in an editorial by Margaret Gatti-Mays, MD, and James L. Gulley, MD, PhD, it is likely that ICI-related pneumonitis will be seen more in routine practice than in clinical trial populations. In addition, across all tumor types, ICI-related pneumonitis is the most common cause of ICI-associated death from toxicity.
The retrospective studies from Johns Hopkins and Memorial Sloan Kettering constitute the largest published experience with ICI-related pneumonitis and yield important clinical insights.
Uniform definitions of potentially important patient subgroups (e.g., steroid refractory vs. steroid resistant) are needed. The steroid-refractory and steroid-resistant subgroups have distinctly different clinical features and outcomes. Uniformity in the subgroup definitions would be a useful starting point from both clinical and research perspectives.
Preferred treatment choices need to be tested systematically in multi-institutional studies. Any potential impact of treatment for ICI-related pneumonitis on antitumor immune control should be identified.
Endpoints of interest need to be defined and measured prospectively. All-cause mortality after 90 days is important, but, as the authors of both reviews noted, there are vitally important narratives and differences in functionality that are completely concealed by restricting the focus to mortality.
Potential causal relationships with antecedent exposure to tobacco, radiation, intrathoracic tumor burden, or other factors need to be defined.
Clinicians need predictive biomarkers for ICI-related pneumonitis (e.g., in peripheral blood, pulmonary function testing, or bronchoscopy specimens). At-risk patients may benefit from early intervention.
The limitations of single-institution record reviews in guiding real-world patient management notwithstanding, these reviews illustrate the value of registries and prospective studies to guide the path forward. Taking these next steps will ensure for our patients that the success of immune-targeted therapy against their cancer never becomes a Pyrrhic victory.
The Johns Hopkins investigators and the editorialists reported having no disclosures. The Memorial Sloan Kettering investigators disclosed relationships with Targeted Oncology, Merck, Array BioPharma, Novartis, and many other companies.
Dr. Lyss was a community-based medical oncologist and clinical researcher for more than 35 years before his recent retirement. His clinical and research interests were focused on breast and lung cancers, as well as expanding clinical trial access to medically underserved populations. He is based in St. Louis. He has no conflicts of interest.