Immune microenvironment features and efficacy of PD-1/PD-L1 blockade in non-small cell lung cancer patients with EGFR or HER2 exon 20 insertions

Background

Insertions in exon 20 (Ex20ins) of epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) are relatively insensitive to first‐ and second‐generation EGFR‐tyrosine kinase inhibitors (TKIs) in non‐small cell lung cancer (NSCLC). This study aimed to investigate the immune microenvironment features and efficacy of PD‐1/PD‐L1 blockade of NSCLC with EGFR and HER2 Ex20ins.

Methods

Clinical characteristics, coexisting mutations, and outcomes to EGFR‐TKIs and immune checkpoint blockade were reviewed for NSCLC patients with exon 20 mutations of EGFR or HER2. Data obtained included the molecular spectrum (extended genotyping for mutations in 324 cancer‐related genes), as well as tumor mutational burden (TMB), PD‐L1 protein expression, and the abundance of CD4+ and CD8+ tumor‐infiltrating lymphocytes (TILs).

Results

A total of 1270 NSCLC patients were identified. Of these, 504 (39.7%) cases had EGFR mutations and 6.9% (35/504) of them had EGFR Ex20ins. Meanwhile, 21 (1.7%) cases with HER2 Ex20ins were detected. Comprehensive genomic profiling identified A767_V769dup variant (25.0%) was the most common type in tumors with EGFR Ex20ins. Co‐occurring mutations were not uncommon including TP53 (45%), PIK3CA (20%), CDKN2A (10%), and EGFR amplification (20%). The average TMB was 3.3 mutations/megabase. PD‐L1 expression in patients with EGFR Ex20ins was significantly higher than for those with HER2 mutations (48.6% vs. 19.0%, P = 0.027). High TMB and PD‐L1 expression was independently associated with significantly poor prognosis (P = 0.025, P = 0.045, respectively) while there was no association between CD4+/CD8+ TILs and prognosis in EGFR or HER2 mutant NSCLC. Finally, patients harboring EGFR Ex20ins seemed to be sensitive to PD‐1/PD‐L1 blockage whereas it showed limited efficacy in patients with HER2 Ex20ins.

Conclusions

NSCLC patients with EGFR/HER2 Ex20ins had similar genomic characteristics and distinct immune features. Patients with EGFR Ex20ins had significantly higher PD‐L1 expression than those with HER2 mutations, which may be the potential reason for the different responses to PD‐1/PD‐L1 blockage.

Lung adenocarcinoma harboring rare epidermal growth factor receptor L858R and V834L mutations treated with icotinib: A case report

BACKGROUND

Epidermal growth factor receptor (EGFR) tyrosine-kinase inhibitors are widely used for the treatment of non-small-cell lung cancer with EGFR mutations. However, patients with rare, even compound EGFR mutations have different responses to EGFR-tyrosine-kinase inhibitors, which bring uncertainty to clinical treatment.

CASE SUMMARY

A 45-year-old female patient presented with a 3-mo history of cough and white sputum without chest pain. Chest computed tomography revealed lung space-occupying lesions and multiple lymphadenectasis. Bronchoscopy and pathology suggested lung adenocarcinoma. Compound variation of EGFR gene (exon 21 L858R/V834L) was detected in both tissue and circulating tumor deoxyribonucleic acid samples. As a result of next-generation sequencing and her family’s wishes, the patient was given oral treatment with icotinib hydrochloride (125 mg/d, tid) from March 21, 2019 and has achieved stable disease for the last 1 year.

CONCLUSION

Non-small cell lung adenocarcinoma with EGFR L858R/V834L was treated successfully with icotinib, and it may be a new medication treatment option.

First-line afatinib for the treatment of EGFR mutation-positive non-small-cell lung cancer in the 'real-world' clinical setting

Afatinib is an ErbB family blocker that is approved for the treatment of epidermal growth factor receptor (EGFR) mutation-positive non-small-cell lung cancer (NSCLC). Pivotal randomized clinical studies demonstrated that afatinib significantly prolonged progression-free survival compared with platinum-based chemotherapy (LUX-Lung 3, LUX-Lung 6), and with gefitinib (LUX-Lung 7), with manageable side effects. However, these results were derived from controlled studies conducted in selected patients and are not necessarily representative of real-world use of afatinib. To gain a broader understanding of the effectiveness and safety of first-line afatinib, we have undertaken a literature review of real-world studies that have assessed its use in a variety of patient populations. We focused on patients with uncommon EGFR mutations, brain metastases, or those of advanced age, as these patients are often excluded from clinical studies but are regularly seen in routine clinical practice. The available real-world studies suggest that afatinib has clinical activity, and is tolerable, in diverse patient populations in an everyday clinical practice setting. Moreover, consistent with LUX-Lung 7, several real-world comparative studies indicate that afatinib might confer better efficacy than first-generation EGFR tyrosine kinase inhibitors. Tolerability-guided dose adjustment, undertaken in 21-68% of patients in clinical practice, did not appear to reduce the efficacy of afatinib. Taken together, these findings provide further support for the use of afatinib as a treatment option in patients with EGFR mutation-positive NSCLC.