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Immune checkpoint inhibitor (ICI) treatment has become an important therapeutic option for various cancer types. Although the treatment is effective, ICI can overstimulate the patient's immune system, leading to potentially severe immune-related adverse events (irAEs), including hepatitis, colitis, pneumonitis and myocarditis. The initial mainstay of treatments includes the administration of corticosteroids. There is little evidence how to treat steroid-resistant (sr) irAEs. It is mainly based on small case series or single case reports. This systematic review summarizes available evidence about sr-irAEs. We conducted a systematic literature search in PubMed. Additionally, we included European Society for Medical Oncology, Society for Immunotherapy of Cancer, National Comprehensive Cancer Network and American Society of Clinical Oncology Guidelines for irAEs in our assessment. The study population of all selected publications had to include patients with cancer who developed hepatitis, colitis, pneumonitis or myocarditis during or after an immunotherapy treatment and for whom corticosteroid therapy was not sufficient. Our literature search was not restricted to any specific cancer diagnosis. Case reports were also included. There is limited data regarding life-threatening sr-irAEs of colon/liver/lung/heart and the majority of publications are single case reports. Most publications investigated sr colitis (n=26), followed by hepatitis (n=21), pneumonitis (n=17) and myocarditis (n=15). There is most data for mycophenolate mofetil (MMF) to treat sr hepatitis and for infliximab, followed by vedolizumab, to treat sr colitis. Regarding sr pneumonitis there is most data for MMF and intravenous immunoglobulins (IVIG) while data regarding infliximab are conflicting. In sr myocarditis, most evidence is available for the use of abatacept or anti-thymocyte globulin (ATG) (both with or without MMF) or ruxolitinib with abatacept. This review highlights the need for prompt recognition and treatment of sr hepatitis, colitis, pneumonitis and myocarditis. Guideline recommendations for sr situations are not defined precisely. Based on our search, we recommend-as first line treatment-(1) MMF for sr hepatitis, (2) infliximab for sr colitis, followed by vedolizumab, (3) MMF and IVIG for sr pneumonitis and (4) abatacept or ATG (both with or without MMF) or ruxolitinib with abatacept for sr myocarditis. These additional immunosuppressive agents should be initiated promptly if there is no sufficient response to corticosteroids within 3 days., Competing Interests: Competing interests: ED: None. TW: None. DK: Received consulting/advisor fees from AstraZeneca, Amgen, Sanofi, Merck Sharp & Drohne, MSD and support for attending meetings and/or travel from Amgen, Roche, Sanofi. AZ: Received consulting/advisor fees from Bristol-Myers Squibb, Merck Sharp & Dohme, Hoffmann–La Roche, NBE Therapeutics, Secarna, ACM Pharma, and Hookipa, and maintains further non-commercial research agreements with Secarna, Roche, Vectorbiopharma, T3 Pharma and Bright Peak Therapeutics. HL: Received travel grants and consultant fees from BMS, Alector, and MSD; received research support from BMS, Novartis, GlycoEra and Palleon Pharmaceuticals. JN: Received consulting/advisor fees from AstraZeneca, Bristol-Myers Squibb, Roche/Genentech, Arcus Biosciences, NGM Pharmaceuticals, Bayer, Regeneron, Takeda, Pfizer, Elevation Oncology, AbbVie, Kaleido Biosciences, Daiichi Sankyo. JN: Received research support from AstraZeneca, Bristol-Myers Squibb, Roche/Genentech, Arcus Biosciences and Mirati. LC: Research funding from Bristol-Myers Squibb., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Immune checkpoint inhibitors (ICIs) have improved survival and are increasingly used for non-small cell lung cancer. However, use may be limited by immune-related adverse events such as checkpoint-inhibitor pneumonitis (CIP). Literature estimates for CIP incidence are inconsistent. Real-world adherence to guidelines, clinical course, and healthcare utilization in the treatment of CIP has not been described in large cohorts., Methods: A combined claims and electronic health record database (TriNetX) was used to identify 13,113 patients with lung cancer treated with programmed cell death receptor/ligand 1 (PD-1/PD-L1) inhibitors, and a propensity score-matched control cohort treated with chemotherapy or targeted therapies. The attributable risk of CIP was calculated in the first 12 months after therapy by comparing the incidence of diagnosis codes for pneumonitis/pneumonia between cohorts. Cases of CIP, identified by the most specific code for drug-induced respiratory conditions, were further analyzed for medication usage, rates of diagnostic bronchoscopy, ICI discontinuation rates, and usage of hospital services compared with patients receiving PD-1/PD-L1 inhibitors who did not develop CIP., Results: The attributable risk of pneumonitis to PD-1/PD-L1 inhibitors was 2.49% (95% CI, 1.50% to 3.47%). Median time to onset in the CIP subcohort was 3.9 months (IQR, 2.1-7.3 months). Steroid and antibiotic use increased dramatically after a pneumonitis diagnosis, and 70.2% of patients permanently discontinued ICI therapy. Compared with controls, patients with CIP had more than a threefold increased risk of needing critical care (relative risk 3.59, 95% CI, 2.31 to 5.57) and an increased risk of mortality (HR 2.34, 95% CI, 1.47 to 3.71)., Conclusions: In a large claims-based analysis, PD-1/PD-L1 inhibitors increase the risk of pneumonitis in patients with lung cancer by 2.49%. Cases of CIP are associated with high healthcare utilization, discontinuation of ICIs, and mortality., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Trastuzumab deruxtecan (T-DXd; DS-8201) is an antibody-drug conjugate targeting human epidermal growth factor receptor 2. Interstitial lung disease (ILD)/pneumonitis is an adverse event associated with T-DXd; in most cases, it is low grade (grade ≤ 2) and can be treated effectively but may develop to be fatal in some instances. It is important to increase patient and provider understanding of T-DXd-related ILD/pneumonitis to improve patient outcomes. Drug-related ILD/pneumonitis is a diagnosis of exclusion; other possible causes of lung injury/imaging findings must be ruled out for an accurate diagnosis. Symptoms can be nonspecific, and identifying early symptoms is challenging; therefore, diagnosis is often delayed. We reviewed characteristics of patients who developed T-DXd-related ILD/pneumonitis and its patterns, produced multidisciplinary guidelines on diagnosis and management, and described areas for future investigation. Ongoing studies are collecting data on T-DXd-related ILD/pneumonitis to further our understanding of its clinical patterns and mechanisms. SEARCH STRATEGY AND SELECTION CRITERIA: References were identified based on the guidelines used by the authors in treating interstitial lung disease and pneumonitis. Searches of the authors' own files were also completed. A search of PubMed with the search terms (trastuzumab deruxtecan) AND (interstitial lung disease) AND (guidelines) was conducted on November 1, 2021, with no restrictions based on publication date, and the two articles yielded by the search were included., (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Introduction: Immune-mediated adverse events (imAEs), including all-cause immune-mediated pneumonitis, were reported in approximately 25% of patients in the placebo-controlled, phase III PACIFIC trial of durvalumab monotherapy (for up to 12 months) in patients with unresectable, stage III NSCLC and no disease progression after concurrent chemoradiotherapy; only 3.4% of patients experienced grade 3/4 imAEs. With broad application of the PACIFIC regimen (consolidation durvalumab after chemoradiotherapy), now standard-of-care in this setting, there is a need to better characterize the occurrence of imAEs with this regimen., Methods: We performed descriptive, post-hoc, exploratory analyses to characterize the occurrence of imAEs (pneumonitis and non-pneumonitis) in PACIFIC in terms of: incidence, severity, and timing; clinical management and outcomes; and associations between the occurrence of imAEs and (1) all-cause AEs and (2) baseline patient, disease, and treatment characteristics., Results: Any-grade immune-mediated pneumonitis (9.4%) and non-pneumonitis imAEs (10.7%) occurred infrequently and were more common with durvalumab versus placebo. Grade 3/4 immune-mediated pneumonitis (1.9%) and non-pneumonitis imAEs (1.7%) were uncommon with durvalumab, as were fatal imAEs (0.8%; all pneumonitis). The most common non-pneumonitis imAEs with durvalumab were thyroid disorders, dermatitis/rash, and diarrhea/colitis. Dermatitis/rash had the shortest time to onset (from durvalumab initiation), followed by pneumonitis; dermatitis/rash had the longest time to resolution, followed by thyroid disorders. Most patients with immune-mediated pneumonitis (78.4%) and non-pneumonitis imAEs (56.3%) had these events occur ≤ 3 months after initiating durvalumab. ImAEs were well managed with administration of systemic corticosteroids, administration of endocrine replacement therapy, and interruption/discontinuation of durvalumab. Time elapsed from completion of prior radiotherapy to trial randomization (<14 vs. ≥ 14 days) did not impact either incidence or severity of imAEs. Durvalumab had a manageable safety profile broadly irrespective of whether patients experienced imAEs., Conclusion: The risk of imAEs should not deter use of the PACIFIC regimen in eligible patients, as these events are generally well managed through appropriate clinical intervention., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Patients with non-small cell lung cancer may develop pneumonitis after thoracic radiotherapy (RT) and immune checkpoint inhibitors (ICIs). We hypothesized that distinct morphologic features are associated with different pneumonitis etiologies., Materials and Methods: We systematically compared computed tomography (CT) features of RT- versus ICI-pneumonitis. Clinical and imaging features were tested for association with pneumonitis severity. Lastly, we constructed an exploratory radiomics-based machine learning (ML) model to discern pneumonitis etiology., Results: Between 2009 and 2019, 82 patients developed pneumonitis: 29 after thoracic RT, 23 after ICI, and 30 after RT + ICI. Fifty patients had grade 2 pneumonitis, 22 grade 3, and 7 grade 4. ICI-pneumonitis was more likely bilateral (65% vs. 28%; p = .01) and involved more lobes (66% vs. 45% involving at least three lobes) and was less likely to have sharp border (17% vs. 59%; p = .004) compared with RT-pneumonitis. Pneumonitis morphology after RT + ICI was heterogeneous, with 47% bilateral, 37% involving at least three lobes, and 40% sharp borders. Among all patients, risk factors for severe pneumonitis included poor performance status, smoking history, worse lung function, and bilateral and multifocal involvement on CT. An ML model based on seven radiomic features alone could distinguish ICI- from RT-pneumonitis with an area under the receiver-operating curve of 0.76 and identified the predominant etiology after RT + ICI concordant with multidisciplinary consensus., Conclusion: RT- and ICI-pneumonitis exhibit distinct spatial features on CT. Bilateral and multifocal lung involvement is associated with severe pneumonitis. Integrating these morphologic features in the clinical management of patients who develop pneumonitis after RT and ICIs may improve treatment decision-making., Implications for Practice: Patients with non-small cell lung cancer often receive thoracic radiation and immune checkpoint inhibitors (ICIs), both of which can cause pneumonitis. This study identified similarities and differences in pneumonitis morphology on computed tomography (CT) scans among pneumonitis due to radiotherapy (RT) alone, ICI alone, and the combination of both. Patients who have bilateral CT changes involving at least three lobes are more likely to have ICI-pneumonitis, whereas those with unilateral CT changes with sharp borders are more likely to have radiation pneumonitis. After RT and/or ICI, severe pneumonitis is associated with bilateral and multifocal CT changes. These results can help guide clinicians in triaging patients who develop pneumonitis after radiation and during ICI treatment., (© 2021 The Authors. The Oncologist published by Wiley Periodicals LLC on behalf of AlphaMed Press.)

Background: Immune-checkpoint inhibitor (ICI)-pneumonitis that does not improve or resolve with corticosteroids and requires additional immunosuppression is termed steroid-refractory ICI-pneumonitis. Herein, we report the clinical features, management and outcomes for patients treated with intravenous immunoglobulin (IVIG), infliximab, or the combination of IVIG and infliximab for steroid-refractory ICI-pneumonitis., Methods: Patients with steroid-refractory ICI-pneumonitis were identified between January 2011 and January 2020 at a tertiary academic center. ICI-pneumonitis was defined as clinical or radiographic lung inflammation without an alternative diagnosis, confirmed by a multidisciplinary team. Steroid-refractory ICI-pneumonitis was defined as lack of clinical improvement after high-dose corticosteroids for 48 hours, necessitating additional immunosuppression. Serial clinical, radiologic (CT imaging), and functional features (level-of-care, oxygen requirement) were collected preadditional and postadditional immunosuppression., Results: Of 65 patients with ICI-pneumonitis, 18.5% (12/65) had steroid-refractory ICI-pneumonitis. Mean age at diagnosis of ICI-pneumonitis was 66.8 years (range: 35-85), 50% patients were male, and the majority had lung carcinoma (75%). Steroid-refractory ICI-pneumonitis occurred after a mean of 5 ICI doses from PD-(L)1 start (range: 3-12 doses). The most common radiologic pattern was diffuse alveolar damage (DAD: 50%, 6/12). After corticosteroid failure, patients were treated with: IVIG (n=7), infliximab (n=2), or combination IVIG and infliximab (n=3); 11/12 (91.7%) required ICU-level care and 8/12 (75%) died of steroid-refractory ICI-pneumonitis or infectious complications (IVIG alone=3/7, 42.9%; infliximab alone=2/2, 100%; IVIG + infliximab=3/3, 100%). All five patients treated with infliximab (5/5; 100%) died from steroid-refractory ICI-pneumonitis or infectious complications. Mechanical ventilation was required in 53% of patients treated with infliximab alone, 80% of those treated with IVIG + infliximab, and 25.5% of those treated with IVIG alone., Conclusions: Steroid-refractory ICI-pneumonitis constituted 18.5% of referrals for multidisciplinary irAE care. Steroid-refractory ICI-pnuemonitis occurred early in patients' treatment courses, and most commonly exhibited a DAD radiographic pattern. Patients treated with IVIG alone demonstrated an improvement in both level-of-care and oxygenation requirements and had fewer fatalities (43%) from steroid-refractory ICI-pneumonitis when compared to treatment with infliximab (100% mortality)., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Importance: The spectrum of individual immune-related adverse events (irAEs) from anti-programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PD-L1) immune checkpoint inhibitors (ICIs) has been reported widely, and their development is associated with improved patient survival across tumor types. The spectrum and impact on survival for patients with non-small cell lung cancer (NSCLC) who develop multisystem irAEs from ICIs, has not been described., Objective: To characterize multisystem irAEs, their association with survival, and risk factors for multisystem irAE development., Design, Setting, and Participants: This retrospective cohort study carried out in 5 academic institutions worldwide included 623 patients with stage III/IV NSCLC, treated with anti-PD-(L)1 ICIs alone or in combination with another anticancer agent between January 2007 and January 2019., Exposures: Anti-PD-(L)1 monotherapy or combinations., Main Outcomes and Measures: Multisystem irAEs were characterized by combinations of individual irAEs or organ system involved, separated by ICI-monotherapy or combinations. Median progression-free (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method. Differences in PFS and OS between irAE groups were assessed by multivariable models. Risk for multisystem irAE was estimated as odds ratios by multivariable logistic regression., Results: The 623 patients included in the study were mostly men (60%, n = 375) and White (77%, n = 480). The median (range) age was 66 (58-73) years, and 148 patients (24%) developed a single irAE, whereas 58 (9.3%) developed multisystem irAEs. The most common multisystem irAE patterns in patients receiving anti-PD-(L)1 monotherapy were pneumonitis thyroiditis (n = 7, 14%), hepatitis thyroiditis (n = 5, 10%), dermatitis pneumonitis (n = 5, 10%), and dermatitis thyroiditis (n = 4, 8%). Favorable Eastern Cooperative Oncology Group (ECOG) performance status (PS) (ECOG PS = 0/1 vs 2; adjusted odds ratio [aOR], 0.27; 95% CI, 0.08-0.94; P = .04) and longer ICI duration (aOR, 1.02; 95% CI, 1.01-1.03; P < .001) were independent risk factors for development of multisystem irAEs. Patients with 1 irAE and multisystem irAEs demonstrated incrementally improved OS (adjusted hazard ratios [aHRs], 0.86; 95% CI, 0.66-1.12; P = .26; and aHR, 0.57; 95% CI, 0.38-0.85; P = . 005, respectively) and PFS (aHR, 0.68; 95% CI, 0.55-0.85; P = .001; and aHR, 0.39; 95% CI, 0.28-0.55; P < .001, respectively) vs patients with no irAEs, in multivariable models adjusting for ICI duration., Conclusions and Relevance: In this multicenter cohort study, development of multisystem irAEs was associated with improved survival in patients with advanced NSCLC treated with ICIs.

Approximately one third of patients with non-small-cell lung cancer (NSCLC) present with stage III or locally advanced NSCLC. These patients have historically been managed with chemoradiotherapy. However, outcomes for these patients remain poor, with a 5-year survival rate between 15% and 32%. Immune checkpoint inhibitors have revolutionized the treatment of patients with NSCLC. One such agent, durvalumab, a selective high-affinity human immunoglobulin G1 monoclonal antibody that blocks programmed cell death ligand 1 binding to programmed cell death protein 1 and cluster of differentiation 80, was recently approved in the consolidation setting after completion of definitive platinum-based chemoradiotherapy and has become the current standard of care for patients with stage III locally advanced NSCLC. Immune checkpoint blockade is associated with increased risk of immunotherapy-related adverse events, which can be managed most effectively when detected early, ideally in the context of a multidisciplinary approach. Pneumonitis represents the potentially most severe and life-threatening of all reported immunotherapy-related adverse events, but it is further complicated in the context of recent prior therapies also known to cause pulmonary toxicity, such as radiotherapy. However, there are major gaps in our ability to identify immunotherapy-related pneumonitis and distinguish it from radiation pneumonitis. This review aims to define the key steps in the detection, diagnosis, and treatment of immunotherapy-related pneumonitis., (Copyright © 2020 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Pneumonitis from immune checkpoint inhibitors (ICI) is a potentially fatal immune-related adverse event (irAE) from antiprogrammed death 1/programmed death ligand 1 immunotherapy. Most cases of ICI pneumonitis improve or resolve with 4-6 weeks of corticosteroid therapy. Herein, we report the incidence, clinicopathological features and management of patients with non-small cell lung cancer (NSCLC) and melanoma who developed chronic ICI pneumonitis that warrants ≥12 weeks of immunosuppression., Methods: Patients with ICI pneumonitis were identified from institutional databases of ICI-treated patients with advanced melanoma and NSCLC between January 2011 and July 2018. ICI pneumonitis was defined as clinical/radiographic evidence of lung inflammation without alternative diagnoses, adjudicated by a multidisciplinary team. Chronic ICI pneumonitis was defined as pneumonitis that persists or worsens with steroid tapering, and necessitates ≥12 weeks of immunosuppression, after ICI discontinuation. Serial chest CT was used to assess radiological features, and tumor response by Response EvaluationCriteria for Solid Tumors V.1.1. Bronchoalveolar lavage fluid (BALF) samples were assessed by cell differential. Lung biopsy samples were evaluated by H&E staining and multiplex immunofluorescence (mIF), where available., Results: Among 299 patients, 44 developed ICI pneumonitis (NSCLC: 5/205; melanoma: 1/94), and of these, 6 experienced chronic ICI pneumonitis. The overall incidence of chronic ICI pneumonitis was thus 2%. Of those who developed chronic ICI pneumonitis: the majority had NSCLC (5/6), all sustained disease control from ICIs, and none had other concurrent irAEs. Timing of chronic ICI pneumonitis development was variable (range: 0-50 months), and occurred at a median of 12 months post ICI start. Recrudescence of ICI pneumonitis occurred at a median of 6 weeks after initial steroid start (range: 3-12 weeks), with all patients requiring steroid reintroduction when tapered to ≤10 mg prednisone/equivalent. The median total duration of steroids was 37 weeks (range: 16-43+weeks). Re-emergence of radiographic ICI pneumonitis occurred in the same locations on chest CT, in most cases (5/6). All patients who developed chronic ICI pneumonitis had BALF lymphocytosis on cell differential and organising pneumonia on lung biopsy at initial ICI pneumonitis presentation, with persistent BALF lymphocytosis and brisk CD8+ infiltration on mIF at pneumonitis re-emergence during steroid taper., Conclusions: A subset of patients who develop pneumonitis from ICIs will develop chronic ICI pneumonitis, that warrants long-term immunosuppression of ≥12 weeks, and has distinct clinicopathological features., Competing Interests: Competing interests: JN: research funding: AstraZeneca, Merck, Consulting/Advisory Board: AstraZeneca, Merck, Bristol-Myers Squibb, Honoraria: AstraZeneca, Merck, Bristol-Myers Squibb. EL: research funding: Bristol-Myers Squibb, Merck, Regeneron, Consulting/Advisory Board: Bristol-Myers Squibb, Merck, Novartis, EMD Serono, Array BioPharma, MacroGenics, Sanofi. PMF: research funding: AstraZeneca, Bristol-Myers Squibb, Corvus, Kyowa, Novartis, Consulting/Advisory Board: AstraZeneca, Bristol-Myers Squibb, Janssen, Merck, Novartis, Lilly, Boehringer. LBY: research funding: Rocket Medical, Consulting/Advisory Board: Boston Scientific. HL: Consulting/Advisory Board: Boston Scientific; DFK/Advisory Board: Consulting: Boston Scientific. JT: research funding: Bristol-Myers Squibb, Consulting/Advisory Board: Bristol-Myers Squibb, Merck, AstraZeneca. JRB: research funding: Bristol-Myers Squibb, Consulting/Advisory Board: Bristol-Myers Squibb, Merck, AstraZeneca, and Genentech, and reports receiving commercial., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Immune-related (IR)-pneumonitis is a rare and potentially fatal toxicity of anti-PD(L)1 immunotherapy. Expert guidelines for the diagnosis and management of IR-pneumonitis include multidisciplinary input from medical oncology, pulmonary medicine, infectious disease, and radiology specialists. Severe acute respiratory syndrome coronavirus 2 is a recently recognized respiratory virus that is responsible for causing the COVID-19 global pandemic. Symptoms and imaging findings from IR-pneumonitis and COVID-19 pneumonia can be similar, and early COVID-19 viral testing may yield false negative results, complicating the diagnosis and management of both entities. Herein, we present a set of multidisciplinary consensus recommendations for the diagnosis and management of IR-pneumonitis in the setting of COVID-19 including: (1) isolation procedures, (2) recommended imaging and interpretation, (3) adaptations to invasive testing, (4) adaptations to the management of IR-pneumonitis, (5) immunosuppression for steroid-refractory IR-pneumonitis, and (6) management of suspected concurrent IR-pneumonitis and COVID-19 infection. There is an emerging need for the adaptation of expert guidelines for IR-pneumonitis in the setting of the global COVID-19 pandemic. We propose a multidisciplinary consensus on this topic, in this position paper., Competing Interests: Competing interests: JN: research funding: Merck, AstraZeneca; consulting/advisory board: Bristol-Myers Squibb, AstraZeneca, Roche/Genentech; honoraria: Bristol-Myers Squibb, Merck, AstraZeneca. DBJ: advisory boards/consulting: Array Biopharma, BMS, Jansen, Merck, Novartis; research funding: BMS, Incyte. JRB: advisory boards/consulting: Amgen, BMS, Genentech/Roche, Eli Lilly, GlaxoSmithKline, Merck, Sanofi; research funding: AstraZeneca, BMS, Genentech/Roche, Merck, RAPT Therapeutics Inc., Revolution Medicines; data and safety monitoring board/committees: GlaxoSmithKline, Sanofi. MN: advisory boards/consulting: Daiichi Sankyo, AstraZeneca; research funding: Merck, Canon Medical Systems, AstraZeneca, Daiichi Sankyo; honorarium: Roche. PMF: advisory boards/consulting: Abbvie, AstraZeneca, BMS; research funding: AstraZeneca, BMS, Kyowa, Novartis, Corvus., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Purpose of Review: Checkpoint inhibitor pneumonitis (CIP) is a toxicity of immune checkpoint blockade (ICB) that can be highly morbid and at times fatal. Here, we review the proposed biologic mechanisms of CIP, epidemiology and risk factors for CIP development, diagnostic work-up and management strategies for CIP, and future directions of CIP research., Recent Findings: CIP incidence appears to be greater in real-world populations and may continue to rise as FDA approvals for ICB continue to expand to multiple malignancies. Multiple retrospective studies and case series have identified potential risk factors for CIP. Several society guidelines have helped to unify the classification of CIP severity and standardize treatment approaches but significant gaps remain, including formal validated diagnostic criteria for CIP. While significant strides have been made in enhancing the knowledge and management of CIP, ongoing research is needed to continue to advance our understanding of the biologic underpinnings of CIP, as well as optimize diagnostic and management strategies for this potentially devastating toxicity.

Rationale: Immune checkpoint inhibitors (ICIs) have revolutionized cancer care but are associated with unique adverse events, including potentially life-threatening pneumonitis. The diagnosis of ICI-pneumonitis is increasing; however, the biological mechanisms, clinical and radiologic features, and the diagnosis and management have not been well defined. Objectives: To summarize evidence, identify knowledge and research gaps, and prioritize topics and propose methods for future research on ICI-pneumonitis. Methods: A multidisciplinary group of international clinical researchers reviewed available data on ICI-pneumonitis to develop and refine research questions pertaining to ICI-pneumonitis. Results: This statement identifies gaps in knowledge and develops potential research questions to further expand knowledge regarding risk, biologic mechanisms, clinical and radiologic presentation, and management of ICI-pneumonitis. Conclusions: Gaps in knowledge of the basic biological mechanisms of ICI-pneumonitis, coupled with a precipitous increase in the use of ICIs alone or combined with other therapies, highlight the importance in triaging research priorities for ICI-pneumonitis.

Background: Checkpoint inhibitor pneumonitis (CIP) is a highly morbid complication of immune checkpoint immunotherapy (ICI), one which precludes the continuation of ICI. Yet, the mechanistic underpinnings of CIP are unknown., Methods: To better understand the mechanism of lung injury in CIP, we prospectively collected bronchoalveolar lavage (BAL) samples in ICI-treated patients with (n=12) and without CIP (n=6), prior to initiation of first-line therapy for CIP (high dose corticosteroids. We analyzed BAL immune cell populations using a combination of traditional multicolor flow cytometry gating, unsupervised clustering analysis and BAL supernatant cytokine measurements., Results: We found increased BAL lymphocytosis, predominantly CD4+ T cells, in CIP. Specifically, we observed increased numbers of BAL central memory T-cells (Tcm), evidence of Type I polarization, and decreased expression of CTLA-4 and PD-1 in BAL Tregs, suggesting both activation of pro-inflammatory subsets and an attenuated suppressive phenotype. CIP BAL myeloid immune populations displayed enhanced expression of IL-1β and decreased expression of counter-regulatory IL-1RA. We observed increased levels of T cell chemoattractants in the BAL supernatant, consistent with our pro-inflammatory, lymphocytic cellular landscape., Conclusion: We observe several immune cell subpopulations that are dysregulated in CIP, which may represent possible targets that could lead to therapeutics for this morbid immune related adverse event.

Purpose: To investigate the relationship between radiotherapy (RT), in particular chest RT, and development of immune-related (IR) pneumonitis in non-small-cell lung cancer (NSCLC) patients treated with anti-programmed cell death 1 (PD-1)/programmed death ligand 1 (PD-L1)., Patients and Methods: Between June 2011 and July 2017, NSCLC patients treated with anti-PD-1/PD-L1 at a tertiary-care academic cancer center were identified. Patient, treatment, prior RT (intent, technique, timing, courses), and IR pneumonitis details were collected. Treating investigators diagnosed IR pneumonitis clinically. Diagnostic IR pneumonitis scans were overlaid with available chest RT plans to describe IR pneumonitis in relation to prior chest RT. We evaluated associations between patient, treatment, RT details, and development of IR pneumonitis by Fisher exact and Wilcoxon rank-sum tests., Results: Of the 188 NSCLC patients we identified, median follow-up was 6.78 (range, 0.30-79.3) months and median age 66 (range, 39-91) years; 54% (n = 102) were male; and 42% (n = 79) had stage I-III NSCLC at initial diagnosis. Patients received anti-PD-1/PD-L1 monotherapy (n = 127, 68%) or PD-1/PD-L1-based combinations (n = 61, 32%). In the entire cohort, 70% (132/188) received any RT, 53% (100/188) chest RT, and 37% (70/188) curative-intent chest RT. Any grade IR pneumonitis occurred in 19% (36/188; 95% confidence interval, 13.8-25.6). Of those who developed IR pneumonitis and received chest RT (n = 19), patients were more likely to have received curative-intent versus palliative-intent chest RT (17/19, 89%, vs. 2/19, 11%; P = .051). Predominant IR pneumonitis appearances were ground-glass opacities outside high-dose chest RT regions., Conclusion: No RT parameter was significantly associated with IR pneumonitis. On subset analysis of patients who developed IR pneumonitis and who had received prior chest RT, IR pneumonitis was more common in patients who received curative-intent chest RT. Attention should be paid to NSCLC patients receiving curative-intent RT followed by anti-PD-1/PD-L1 agents., (Copyright © 2019 Elsevier Inc. All rights reserved.)

With increasing use of immune checkpoint inhibitors (ICIs) for advanced NSCLC, there is increasing recognition of immune-related adverse events associated with ICI use. We recently reported increased incidence of checkpoint inhibitor pneumonitis (CIP) in ICI-treated NSCLC patients. Since development of immune-related adverse events in other organ systems has been associated with either no change or even improvement in tumor response/cancer outcomes, we sought to better understand the impact of CIP development on overall survival in ICI-treated NSCLC patients. Using baseline and follow-up data collected on a cohort of 205 ICI-treated NSCLC patients, we used a multi-state modeling approach to understand the effect of developing CIP on the risk of death. We observed time-dependent changes in risk of developing and recovery from CIP, with an increased risk of both developing and recovering from CIP in the first year after initiating ICI. We found that developing CIP independently increased the risk of transitioning to death in both adjusted and unadjusted models. In the multivariate model, we found that the increase in mortality associated with CIP was only seen in patients with adenocarcinoma tumor histology. Collectively, these findings suggest that in NSCLC, development of CIP worsens survival in patients receiving immunotherapy., (Copyright © 2018 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.)

Checkpoint inhibitor pneumonitis (CIP) is an immune-related adverse event that can occur after initiation of anti-programmed death 1/programmed death ligand 1 immune checkpoint inhibitor (ICI) therapy for the treatment of multiple malignancies, including NSCLC. However, the incidence of CIP has not been previously examined in a population that included both trial-enrolled and non-trial-enrolled patients with advanced NSCLC. Furthermore, risk factors and other clinical characteristics associated with CIP severity are not known. In this study, we retrospectively examined clinical characteristics, incidence, and risk factors for CIP in a cohort of 205 patients with NSCLC, all of whom received anti-programmed death 1/programmed death ligand 1 ICIs. Our results demonstrate a higher incidence of CIP (19%) than previously reported in clinical trials (3%-5%). Our data also suggest that tumor histologic type may be a risk factor for CIP development. We observed a wide range of time to onset of CIP (median 82 days), with high morbidity and mortality associated with higher-grade CIP regardless of degree of immunosuppression. Our data provide new insight into the epidemiology and clinical characteristics of CIP. Further studies are needed to increase CIP pharmacovigilance, improve risk stratification, and refine diagnostic algorithms for the diagnosis and management of this potential life-threatening complication of ICI therapy., (Copyright © 2018 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.)

Immune checkpoint inhibitors (ICIs) are newer, immunotherapy-based drugs that have been shown to improve survival in advanced non-small cell lung cancer (NSCLC). Unlike traditional chemotherapeutic agents, ICIs work by boosting the body's natural tumor killing response. However, this unique mechanism of action has also led to the recognition of class-specific side effects. Labeled immune-related adverse events, these toxicities can affect multiple organ systems including the lungs. Immune-mediated lung injury because of ICI use, termed checkpoint inhibitor pneumonitis (CIP), occurs in about 3% to 5% of patients receiving ICIs; however, the real-world incidence of this entity may be higher, especially now that ICIs are being used in nonclinical trial settings. In this review, we briefly introduce the biology of ICIs and the indications for ICI use in NSCLC and then discuss the epidemiology and clinical and radiologic manifestations of CIP. Next, we discuss management strategies for CIP, including the current consensus on management of steroid-refractory CIP. Given the nascent nature of this field, we highlight areas of uncertainty and emerging research questions in the burgeoning field of checkpoint inhibitor pulmonary toxicity., (Copyright © 2018 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

Pneumonitis is defined as a focal or diffuse inflammation of the lung parenchyma, and is a known, potentially fatal toxicity of anti-programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) immune checkpoint inhibitors. Herein we discuss two patients who developed pneumonitis secondary to anti-PD-1/PD-L1 immune checkpoint inhibitor therapy and illustrate a stepwise approach to the diagnostic evaluation and management of anti-PD-1/PD-L1-related pneumonitis. In the majority of patients who develop this toxicity, pneumonitis appears to clinically resolve with corticosteroid therapy alone; however, a subset of patients require additional immunosuppressive medications. Patients who clinically improve with steroid treatment must be monitored closely in the outpatient setting. If pneumonitis management results in complete clinical and radiologic resolution, patients may be able to restart their immune checkpoint inhibitor therapy. It is currently unclear which population of patients is more susceptible to developing higher-grade or steroid-refractory pneumonitis.

Purpose Pneumonitis is an uncommon but potentially fatal toxicity of anti-programmed death-1 (PD-1)/programmed death ligand 1 (PD-L1) monoclonal antibodies (mAbs). Clinical, radiologic, and pathologic features are poorly described. Methods Patients who received anti-PD-1/PD-L1 monotherapy or in combination with anti-cytotoxic T-cell lymphocyte-4 mAb were identified at two institutions (Memorial Sloan Kettering Cancer Center: advanced solid cancers, 2009 to 2014, and Melanoma Institute of Australia: melanomas only, 2013 to 2015). Pneumonitis was diagnosed by the treating investigator; cases with confirmed malignant lung infiltration or infection were excluded. Clinical, radiologic, and pathologic features of pneumonitis were collected. Associations among pneumonitis incidence, therapy received, and underlying malignancy were examined with Fisher's exact test as were associations between pneumonitis features and outcomes. Results Of 915 patients who received anti-PD-1/PD-L1 mAbs, pneumonitis developed in 43 (5%; 95% CI, 3% to 6%; Memorial Sloan Kettering Cancer Center, 27 of 578 [5%]; Melanoma Institute of Australia, 16 of 337 [5%]). Time to onset of pneumonitis ranged from 9 days to 19.2 months. The incidence of pneumonitis was higher with combination immunotherapy versus monotherapy (19 of 199 [10%] v 24 of 716 [3%]; P < .01). Incidence was similar in patients with melanoma and non-small-cell lung cancer (overall, 26 of 532 [5%] v nine of 209 [4%]; monotherapy, 15 of 417 v five of 152 [ P = 1.0]; combination, 11 of 115 v four of 57 [ P = .78]). Seventy-two percent (31 of 43) of cases were grade 1 to 2, and 86% (37 of 43) improved/resolved with drug holding/immunosuppression. Five patients worsened clinically and died during the course of pneumonitis treatment; proximal cause of death was pneumonitis (n = 1), infection related to immunosuppression (n = 3), or progressive cancer (n = 1). Radiologic and pathologic features of pneumonitis were diverse. Conclusion Pneumonitis associated with anti-PD-1/PD-L1 mAbs is a toxicity of variable onset and clinical, radiologic, and pathologic appearances. It is more common when anti-PD-1/PD-L1 mAbs are combined with anti-cytotoxic T-cell lymphocyte-4 mAb. Most events are low grade and improve/resolve with drug holding/immunosuppression. Rarely, pneumonitis worsens despite immunosuppression, and may result in infection and/or death.

This commentary outlines the strategy employed by a multidisciplinary immune‐related toxicity team to evaluate patients who may be at high risk for the development of immune‐related toxicity, in particular, those with preexisting lung conditions and subsequent immune‐related pneumonitis. [ABSTRACT FROM AUTHOR]