Treatment of steroid-resistant checkpoint inhibitor pneumonitis with pirfenidone: A case report

Clinical management of checkpoint inhibitor pneumonitis: Focus, challenges, and future directions

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment landscape for various malignancies by demonstrating exceptional antitumor effects and significant improvement in patient survival. Despite their overt therapeutic advantages, ICIs also induce immune-related adverse events (irAEs). Of these, checkpoint inhibitor pneumonitis (CIP) represents a prominent manifestation of pulmonary toxicity following ICI therapy, with incidence rates ranging from 2.7 % to 20.0 %. Notably, a substantial proportion of CIP cases show severe manifestations, often leading to life-threatening complications, which emphasizes its clinical significance. Understanding the risk factors and potential pathogenetic mechanisms of CIP, combined with vigilant monitoring during immunotherapy, is pivotal for early detection and management of this condition. Proactive strategies for the timely identification, accurate diagnosis, and effective management of CIP are essential to optimize patient outcomes. However, several challenges persist in CIP management, including management of severe and refractory cases, determining the timing of ICI rechallenge after CIP, management of long-term chronic CIP, and mitigating secondary infections. In order to manage this potentially life-threatening irAE effectively, it is urgent to establish multi-disciplinary treatment (MDT) management, precision CIP management, and practical surveillance systems for CIP monitoring, diagnosis, and management and to call for prospective multi-center clinical trials.

Risk Factors for Refractory Immune Checkpoint Inhibitor-related Pneumonitis in Patients With Lung Cancer

Checkpoint inhibitor-related pneumonitis (CIP) is one of the most important immune checkpoint inhibitors side effects, and it is rare but fatal. Identifying patients at risk of refractory CIP before the start of CIP therapy is important for controlling CIP. We retrospectively analyzed the clinical data of 60 patients with lung cancer who developed CIP. Refractory CIP was defined as CIP with poor response to corticosteroid treatment, including CIP not relieved with corticosteroid administration or CIP recurrence during the corticosteroid tapering period. We analyzed clinical characteristics, peripheral blood biomarkers, treatment, and outcomes in nonrefractory and refractory CIP. Risk factors associated with refractory CIP were assessed. Among 60 patients with CIP, 16 (26.7%) had refractory CIP. The median onset time for patients with nonrefractory and those with refractory CIP was 16.57 (interquartile range [IQR], 6.82-28.14) weeks and 7.43 (IQR, 2.71-19.1) weeks, respectively. The level of lactate dehydrogenase (LDH) was significantly higher in the refractory CIP group at baseline (255 [222, 418] vs. 216 [183, 252], P =0.031) and at CIP onset (321.5 [216.75, 487.5] vs. 219 [198. 241], P =0.019). An LDH level >320 U/L at CIP onset was an independent risk factor of refractory CIP (odds ratio [OR], 8.889; 95% confidence interval [CI]: 1.294-61.058; P =0.026). The incidence of refractory CIP is high among patients with CIP. An increased LDH level at CIP onset is independently associated with refractory CIP. Monitoring LDH levels during immune checkpoint inhibitors treatment is recommended.

Proposed clinical phases for the improvement of personalized treatment of checkpoint inhibitor-related pneumonitis

Background

Checkpoint inhibitor-related pneumonitis (CIP) is a lethal immune-related adverse event. However, the development process of CIP, which may provide insight into more effective management, has not been extensively examined.

Methods

We conducted a multicenter retrospective analysis of 56 patients who developed CIP. Clinical characteristics, radiological features, histologic features, and laboratory tests were analyzed. After a comprehensive analysis, we proposed acute, subacute, and chronic phases of CIP and summarized each phase's characteristics.

Results

There were 51 patients in the acute phase, 22 in the subacute phase, and 11 in the chronic phase. The median interval time from the beginning of CIP to the different phases was calculated (acute phase: ≤4.9 weeks; subacute phase: 4.9~13.1 weeks; and chronic phase: ≥13.1 weeks). The symptoms relieved from the acute phase to the chronic phase, and the CIP grade and Performance Status score decreased (P<0.05). The main change in radiologic features was the absorption of the lesions, and 3 (3/11) patients in the chronic phase had persistent traction bronchiectasis. For histologic features, most patients had acute fibrinous pneumonitis in the acute phase (5/8), and most had organizing pneumonia in the subacute phase (5/6). Other histologic changes advanced over time, with the lesions entering a state of fibrosis. Moreover, the levels of interleukin-6, interleukin-10 and high-sensitivity C-reactive protein (hsCRP) increased in the acute phase and decreased as CIP progressed (IL-6: 17.9 vs. 9.8 vs. 5.7, P=0.018; IL-10: 4.6 vs 3.0 vs. 2.0, P=0.041; hsCRP: 88.2 vs. 19.4 vs. 14.4, P=0.005).

Conclusions

The general development process of CIP can be divided into acute, subacute, and chronic phases, upon which a better management strategy might be based devised.

Treatment of steroid-resistant checkpoint inhibitor pneumonitis with pirfenidone: A case report

With the increased use of immune checkpoint inhibitors (ICIs) in lung cancer, which are of great benefit to patients, more and more immune-related adverse events (irAEs) are being reported. Checkpoint inhibitor pneumonitis (CIP) is one of the most challenging adverse events, which pose a huge challenge to clinical diagnosis and treatment, and its incidence in the real world is greatly underestimated. Currently, the treatment of CIP mainly depends on the use of glucocorticoids. As for steroid-resistant CIP, there is no unified standardized treatment strategy. Herein, we report a case of steroid-resistant CIP induced by pembrolizumab in a patient with advanced non-small cell lung cancer (NSCLC), in which their symptoms were successfully controlled with pirfenidone.