Successful afatinib rechallenge in a patient with non-small cell lung cancer harboring EGFR G719C and S768I mutations

An epidermal growth factor receptor compound mutation of L858R with S768I in advanced non-small-cell lung cancer: a case report

BACKGROUND

In the current treatment landscape for non-small cell lung cancers, epidermal growth factor receptor-tyrosine kinase inhibitors have emerged as a well-established treatment option for patients with advanced or metastatic disease. This is particularly true for those with commonly occurring epidermal growth factor receptor mutations. However, the therapeutic efficacy of these agents for so-called rare epidermal growth factor receptor mutations, and in particular those characterized by a high degree of complexity, such as double mutations, remains a subject of clinical uncertainty.

CASE PRESENTATION

In this context, we present the case of a 64-year-old man of Moroccan descent, a lifelong non-smoker, diagnosed with metastatic non-small cell lung cancer characterized by a complex epidermal growth factor receptor mutation encompassing L858R and S768I. The patient subsequently underwent afatinib-based treatment, showing notable clinical results. These included a remarkable overall survival of 51 months, with a median progression-free survival of more than 39 months.

CONCLUSIONS

This case report is a compelling testimony to the evolving therapeutic landscape of non-small cell lung cancers, providing valuable insight into the potential therapeutic efficacy of epidermal growth factor receptor-tyrosine kinase inhibitors in the realm of rare and complex epidermal growth factor receptor mutations.

A rare case of double primary lung adenocarcinomas with uncommon complex EGFR G719X and S768I mutations and pleomorphic carcinoma

Epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI)-targeted therapy has emerged as a viable treatment for patients with advanced non-small cell lung cancer with common EGFR mutations. The uncommon G719X and S768I mutations can co-occur as complex mutations in the same tumor. Here we report a case of a 72-year-old male patient with double lung carcinoma, with G719X and S768I complex mutations detected in the right upper lung lobe along with brain metastases. Osimertinib (80 mg/day) was administered as the first-line treatment, and a reduction in the right lobe tumor and brain lesions was achieved. However, the left upper lung lobe mass remained unchanged; histopathological examination via a lobectomy revealed pleomorphic carcinoma. Thus, the patient was diagnosed with multiple primary lung cancers. In conclusion, osimertinib is a viable treatment option for lung cancer with rare EGFR G719X and S768I complex mutations.

Toward the next generation EGFR inhibitors: an overview of osimertinib resistance mediated by EGFR mutations in non-small cell lung cancer

Epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) is currently the standard first-line therapy for EGFR-mutated advanced non-small cell lung cancer (NSCLC). The life quality and survival of this subgroup of patients were constantly improving owing to the continuous iteration and optimization of EGFR-TKI. Osimertinib, an oral, third-generation, irreversible EGFR-TKI, was initially approved for the treatment of NSCLC patients carrying EGFR T790M mutations, and has currently become the dominant first-line targeted therapy for most EGFR mutant lung cancer. Unfortunately, resistance to osimertinib inevitably develops during the treatment and therefore limits its long-term effectiveness. For both fundamental and clinical researchers, it stands for a major challenge to reveal the mechanism, and a dire need to develop novel therapeutics to overcome the resistance. In this article, we focus on the acquired resistance to osimertinib caused by EGFR mutations which account for approximately 1/3 of all reported resistance mechanisms. We also review the proposed therapeutic strategies for each type of mutation conferring resistance to osimertinib and give an outlook to the development of the next generation EGFR inhibitors. Video Abstract.

Dacomitinib for Advanced Non-small Cell Lung Cancer Patients Harboring Major Uncommon EGFR Alterations: A Dual-Center, Single-Arm, Ambispective Cohort Study in China

Objective: Dacomitinib has been approved for non-small-cell lung cancer (NSCLC) patients harboring classical epidermal growth factor receptor (EGFR) mutations; however, clinical evidence of its activity on major uncommon EGFR mutations is currently limited.

Materials and methods: This was a dual-center, single-arm, ambispective cohort study in China. Patients with histologically confirmed metastatic or recurrent NSCLC harboring major uncommon EGFR mutations were eligible for the study. The objective response rate and disease control rate were determined by RECIST 1.1 every 1–2 months. Adverse events were assessed by CTCAE 5.0.

Results: In total, 32 NSCLC patients were enrolled between July 2020 and January 2022, and 18 (56.3%) patients received dacomitinib as first-line therapy. Median age was 64 years, and 20 (62.5%) were female. The mutations identified were G719X (n = 24; 75%), followed by L861X (n = 10; 31.3%), and S768I (n = 8; 25%). In the first-line setting, 72.2% of patients (13/18) had a confirmed partial response and 100% (18/18) had disease control, and the median progression-free survival (PFS) and overall survival (OS) were unreached. In the whole cohort, 56.3% of patients (18/32) had a confirmed partial response and 90.6% (29/32) had disease control, and the median PFS was 10.3 months (95% confidence interval, 6.1–14.5) and the median OS was 36.5 months. Except for one case not available for brain re-evaluation, control of the intracranial metastases was observed in 13 patients (13/14, 92.9%). No grade 4–5 adverse events (AEs) occurred, but all patients had grade 1–2 AEs, and 12.5% (4/32) patients required a dosage reduction due to intolerable AEs.

Conclusions: Dacomitinib demonstrated favorable activity with manageable toxicity in patients with NSCLC harboring major uncommon EGFR mutations.

Preclinical assessment of combination therapy of EGFR tyrosine kinase inhibitors in a highly heterogeneous tumor model

The development of tyrosine kinase inhibitors (TKIs) has improved the treatment of non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations. The current research priority is to provide viable treatments for patients who have drug-resistant EGFR mutations. We evaluated the drug sensitivity of various EGFR mutants to monotherapies and combination therapies of EGFR-TKIs. In vitro, the transforming potential and drug sensitivity of 357 EGFR variants were assessed. In vivo, we tested the sensitivity of EGFR variants to different regimens of EGFR-TKIs by examining changes in the proportion of each variant within the tumor. Out of 357 variants thoroughly examined for transforming activities, 144 (40.3%) and 282 (79.0%) transformed 3T3 and Ba/F3 cells, respectively. Among the latter variants, 50 (17.7%) were found to be resistant or only partly resistant to osimertinib or afatinib. Four of 25 afatinib-resistant variants (16%) were sensitive to osimertinib, whereas 25 of 46 osimertinib-resistant variants (54.3%) were sensitive to afatinib. Despite the lack of a synergistic impact, TKI combination treatment effectively reduced in vivo the heterogeneous tumors composed of 3T3 cells with different EGFR variants. Regimens starting with afatinib and subsequently switched to osimertinib suppressed tumor development more efficiently than the opposite combination. Combination EGFR-TKI treatment may decrease tumor growth and prevent the development of resistant variants. This work created an experimental model of a heterogeneous tumor to find the best combination therapy regimen and proposes a basic notion of EGFR-TKI combination therapy to enhance the prognosis of NSCLC patients.