Patients treated with nivolumab often experience its unique adverse events, called immune-related adverse events (irAEs). Regarding the mechanisms of immune-checkpoint inhibitors (ICIs), the occurrence of irAEs may also reflect antitumor responses. Here, we report the clinical correlation between irAEs and efficacy in NSCLC patients treated with nivolumab. Between December 2015 and February 2017, 38 advanced NSCLC patients were treated in our institution. All the patients were enrolled in our single-institutional, prospective, observational cohort study (UMIN000024414). IrAEs were defined as having a potential immunological basis that required more frequent monitoring and potential intervention. We divided the patients into two groups (irAEs group or no-irAEs group) and evaluated the objective response rate (ORR) and progression-free survival (PFS). The median age of the patients was 68.5 years (range 49-86 years); male/female ratio was 28/10; squamous/non-squamous cell carcinoma cases were 10/28; performance status was 0-1/2/3, 7/26/5. Among the overall population, ORR was 23.7% and median PFS was 91days. At the data cutoff, 14 irAEs were observed. The most common irAE was interstitial pneumonia (n=5). Other irAEs were hypothyroidism (n=4), hyperthyroidism, hypopituitarism, liver dysfunction, rash, and elevated thyroid stimulating hormone levels (n=1, each). Patients with irAEs had significantly higher ORRs compared with no-irAE patients (63.6% versus 7.4%, p <0.01). Similarly, the PFS among irAE patients was longer (median: not reached [95% confidence interval {CI}: 91days to not applicable]) than no-irAE patients (median 49days [95% CI: 36-127days], hazard ratio [HR] 0.10 [95% CI: 0.02-0.37, p<0.001]). Landmark analysis of patients who achieved PFS ≥60days demonstrated similar tendencies, but this was not significant (HR 0.28 [95% CI: 0.04-1.46], p=0.13). There was a correlation between irAE and efficacy in NSCLC patients treated with nivolumab.

Among metastatic non–small cell lung cancer (NSCLC), EGFR mutation is the second most frequent genetic driver. First-generation and second-generation epidermal growth factor receptor (EGFR)–tyrosine kinase inhibitors (TKIs) have shown favorable efficacy over cytotoxic chemotherapy in patients with NSCLC with EGFR mutation.^1,2 However, these patients ultimately experience disease progression within 10 to 13 months. Translational analyses revealed that about half of tumors acquired EGFR exon 20 T790M mutation as the most common mechanism of resistance.³

Immune‐related adverse events (irAEs) are often seen during immune‐checkpoint inhibitor (ICI) treatment of various malignancies. Endocrine irAEs including thyroid dysfunctions are the most common irAEs, but their biomarkers remain unclear. In order to identify individuals who are susceptible to thyroid irAE for earlier diagnosis and appropriate follow‐up, the current study is aimed to investigate biomarkers of thyroid irAE. Herein, patients with advanced malignant diseases who received ICIs treatment were prospectively studied. Clinical and laboratory examination, thyroid function, and autoantibodies were evaluated at baseline, and every 4 wk after first treatment with ICIs. Cytokines/chemokines were measured at baseline and at 4 wk. In vivo effects of ICIs on experimental autoimmune thyroiditis were evaluated. Twenty‐six patients with malignant diseases who received ICIs treatment were enrolled in the study. Patients were divided into two groups: those who developed thyroid irAE, and those without irAEs. Comparing the two groups, early increase (≤4 wk) in serum thyroglobulin (Tg) levels and thyroid autoantibodies was seen in thyroid irAE (P < .05). Notably, higher levels of serum IL‐1β, IL‐2, and GM‐CSF at baseline, and early decrease of IL‐8, G‐CSF, and MCP‐1 were significantly associated in the development of thyroid irAE (P < .05). In vivo effects of anti‐PD‐1 antibody on deterioration of mice experimental thyroiditis were seen. In conclusion, early change in Tg, thyroid autoimmunity, and cytokine levels might indicate development of thyroid irAE. Pre‐existing thyroid autoimmunity might be involved with the development of thyroid irAE. Potential application of these factors as surrogate biomarkers for tumor therapy was indicated.

Nivolumab, a first-in-class anti-programmed cell death-1 (anti-PD-1) antibody, has become the standard second-line treatment in patients with advanced non-small cell lung cancer (NSCLC). Nivolumab sometimes causes immune-related adverse events. Pneumonitis occurred in 3% of patients in the pivotal trial [1], but its nature had not been fully elucidated. Here, we present two cases of a unique pattern of nivolumab-related pneumonitis.

Background. Although predictive value of immune‐related adverse events (irAEs) induced by immune checkpoint inhibitors (ICIs) have been suggested by several studies, their assessments were insufficient because patients were categorized only by the occurrence of irAEs. It has not been elucidated whether irAEs also play a significant role even in responders. Materials and Methods. Between December 2015 and September 2018, 106 patients with advanced non‐small cell lung cancer treated with ICIs were enrolled in our prospective biomarker study. Twenty‐three of these were responders, defined as those with complete or partial response. We investigated the proportion of irAEs among overall and responders. For responders, progression‐free survival (PFS) and overall survival of ICIs were compared between those with and without irAEs. As an exploratory analysis, we measured 41 proteins from peripheral blood before and after ICI treatment. Results. The proportion of irAEs was significantly higher in responders than nonresponders (65.2% vs. 19.3%, p < .01). Among responders, clinical characteristics did not differ regardless of the occurrence of irAEs. However, there was a significant difference in PFS among responders (irAE group 19.1 months vs. non‐irAE group 5.6 months; hazard ratio: 0.30 [95% confidence interval: 0.10–0.85]; p = .02). Of 41 protein analyses, fibroblast growth factor‐2 at baseline and monocyte chemoattractant protein fold change showed significant differences between them (p < .04). Conclusion. Although this is a small sample–sized study, irAE might be a predictive factor of durable efficacy, even in patients who responded to ICIs. Investigation into the significance of irAEs in responders will contribute to the establishment of optimal administration of ICI. Implications for Practice. Although the predictive value of immune‐related adverse events (irAEs) induced by immune checkpoint inhibitors (ICIs) has been suggested by several studies, it has not been elucidated whether irAEs also play a significant role even in responders. This study showed that more than 60% of responders had irAEs. It demonstrated the strong correlation between irAEs and efficacy even in responders. Investigation into the significance of irAEs in responders will contribute to the establishment of optimal administration of ICI.

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are the first‐line treatment for patients with EGFR mutant non‐small‐cell lung cancer (NSCLC). However, most patients become resistant to these drugs, so their disease progresses. Osimertinib, a third‐generation EGFR‐TKI that can inhibit the kinase even when the common resistance‐conferring Thr790Met (T790M) mutation is present, is a promising therapeutic option for patients whose disease has progressed after first‐line EGFR‐TKI treatment. AURA3 was a randomized (2:1), open‐label, phase III study comparing the efficacy of osimertinib (80 mg/d) with platinum‐based therapy plus pemetrexed (500 mg/m²) in 419 patients with advanced NSCLC with the EGFR T790M mutation in whom disease had progressed after first‐line EGFR‐TKI treatment. This subanalysis evaluated the safety and efficacy of osimertinib specifically in 63 Japanese patients enrolled in AURA3. The primary end‐point was progression‐free survival (PFS) based on investigator assessment. Improvement in PFS was clinically meaningful in the osimertinib group (n = 41) vs the platinum‐pemetrexed group (n = 22; hazard ratio 0.27; 95% confidence interval, 0.13‐0.56). The median PFS was 12.5 and 4.3 months in the osimertinib and platinum‐pemetrexed groups, respectively. Grade ≥3 adverse events determined to be related to treatment occurred in 5 patients (12.2%) treated with osimertinib and 12 patients (54.5%) treated with platinum‐pemetrexed. The safety and efficacy results in this subanalysis are consistent with the results of the overall AURA3 study, and support the use of osimertinib in Japanese patients with EGFR T790M mutation‐positive NSCLC whose disease has progressed following first‐line EGFR‐TKI treatment. (ClinicalTrials.gov trial registration no. NCT02151981.)