Lung adenocarcinoma with ERBB2 exon 20 insertions: Comutations and immunogenomic features related to chemoimmunotherapy

BACKGROUND

The genomic mutation and immune feature landscape of ERBB2 exon 20 insertion (ERBB2-ex20ins)-driven non-small cell lung cancer and the features associated with the response to chemoimmunotherapy are currently unknown.

METHODS

The genomic landscape of ERBB2-ex20ins lung adenocarcinoma (LUAD) patients was characterized by next-generation sequencing (NGS) of 1021 cancer genes. The clinical outcomes of chemoimmunotherapy were evaluated among 13 patients with stage IV ERBB2-ex20ins LUAD, and potential biomarkers of the response to chemoimmunotherapy were explored using NGS and T cell receptor sequencing.

RESULTS

Among 8247 LUAD patients, 207 (2.5%) had ERBB2-ex20ins, of whom 181 (87.4%) harbored more than one comutation. The most common comutations were in TP53. Patients with ERBB2-ex20ins had a low tumor mutational burden (TMB; median, 4.2 mutations/Mb), and most (66.7%) were PD-L1 negative. Thirteen of the 207 patients received chemoimmunotherapy, for whom the objective response rate, disease control rate, and median progression-free survival were 31%, 77%, and 8.0 months, respectively. Responders exhibited a higher TMB and a trend toward lower clonality in tumors compared with nonresponders (p = 0.0067 and p = 0.085, respectively). A high TMB combined with mutations in DNA damage repair pathways and SWI/SNF chromatin remodeling complexes was associated with a benefit from chemoimmunotherapy.

CONCLUSIONS

The efficacy and outcome of chemoimmunotherapy were encouraging among ERBB2-ex20ins LUAD patients, who were characterized by low TMB and negative PD-L1 expression. The combination of TMB and comutations is a potential biomarker to identify patients who will benefit from chemoimmunotherapy.

Durable response to immunotherapy plus chemotherapy in a patient with untreated, brain-metastatic, EGFR exon 20 insertion mutation lung adenocarcinoma: A case report

RATIONAL

Epidermal growth factor receptor (EGFR) 20 exon insertion is the second most common EGFR aberrations in non-small cell lung cancer (NSCLC). Despite some novel EGFR inhibitors, clinically obtainable management for this subset of patients remains an unmet need. there are no previous reports of upfront combination therapy with immunotherapy and chemotherapy for lung adenocarcinoma with brain metastasis harboring EGFR 20 insertion.

PATIENT CONCERNS

A 56-year-old man who sought care for dry cough was diagnosed with lung adenocarcinoma with brain metastases indicating a poor prognosis.

DIAGNOSIS

Next-generation sequencing of lung biopsied tissue revealed an EGFR exon 20 in-frame insertion (P772_H773insYNP+H773Y).

INTERVENTIONS

The patient started treatment of pemetrexed and carboplatin plus programmed cell death-1 inhibitor sintilimab in November 2019.

OUTCOMES

The patient achieved partial responses both intra- and extra-cranially. After 6 cycles of treatment, the patient accepted sintilimab plus pemetrexed every 3 weeks as maintenance therapy, which was well-tolerated without any toxicity and is still ongoing after 18 months since initiation of 1st-line treatment.

LESSONS

This is the first case report of the clinical benefit of upfront immune checkpoint inhibitors (ICIs) plus chemotherapy for a brain metastatic NSCLC patient harboring EGFR exon 20 insertion mutation. Further study is needed to validate the predictor involved in responders to ICIs-based therapy with EGFR mutations.