Combination of Osimertinib and Anlotinib May Overcome the Resistance Mediated by in cis EGFR T790M-C797S in NSCLC: A Case Report

Allelic Context of EGFR C797X-Mutant Lung Cancer Defines Four Subtypes With Heterogeneous Genomic Landscape and Distinct Clinical Outcomes

INTRODUCTION

EGFR C797X (C797S or C797G) mutation is the most frequent on-target mechanism of resistance to osimertinib. The hypothesis that the allelic context of C797X/T790M has implications for treatment is on the basis of sporadic reports and needs validation with larger cohorts.

METHODS

We identified patients with EGFR C797X-mutant NSCLC from nine centers who progressed on osimertinib, all analyzed in a single laboratory through next-generation sequencing. We analyzed genomic profiles and assessed associations between clinical outcomes and C797X status.

RESULTS

A total of 365 EGFR C797X-mutant cases were categorized into four subtypes on the basis of allelic context: in cis (75.3%), in trans (6.4%), cis&trans (10.4%), and C797X-only (7.9%). Genomically, the cis&trans subtype displayed the highest frequency of concurrent alterations at osimertinib resistance sites (21.1%), while the in cis subtype had the lowest (8.4%). Clinically, cis&trans patients exhibited the worst progression-free survival (PFS) on both previous (median 7.7 mo) and subsequent treatment (median 1.0 mo) and overall survival (median 3.9 mo). In subsequent treatments, in cis patients exhibited superior PFS with combined brigatinib and cetuximab (median 11.0 mo) compared with other regimens (p = 0.005), while in trans patients exhibited variable outcomes with combined first or second- and third-generation EGFR inhibitor (PFS range: 0.7-8.1 mo, median 2.6 mo). Notably, subtype switching was observed after subsequent treatments, predominantly toward the in cis subtype.

CONCLUSIONS

Allelic context could define four EGFR C797X-mutant NSCLC subtypes with heterogeneous genetic landscapes and distinct clinical outcomes. Subsequent treatments further complicate the scenario through subtype switching.

20 years since the approval of first EGFR-TKI, gefitinib: Insight and foresight

Epidermal growth factor receptor (EGFR) actively involves in modulation of various cancer progression related mechanisms including angiogenesis, differentiation and migration. Therefore, targeting EGFR has surfaced as a prominent approach for the treatment of several types of cancers, including non-small cell lung cancer (NSCLC), pancreatic cancer, glioblastoma. Various first, second and third generation of EGFR tyrosine kinase inhibitors (EGFR-TKIs) have demonstrated effectiveness as an anti-cancer therapeutics. However, rapid development of drug resistance and mutations still remains a major challenge for the EGFR-TKIs therapy. Overcoming from intrinsic and acquired resistance caused by EGFR mutations warrants the further exploration of alternative strategies and discovery of novel inhibitors. In this review, we delve into the breakthrough discoveries have been made in previous 20 years, and discuss the currently ongoing efforts aimed to circumvent the chemo-resistance. We also highlight the new challenges, limitations and future directions for the development of improved therapeutic approaches such as fourth-generation EGFR-TKIs, peptides, nanobodies, PROTACs etc.

Efficacy and safety of osimertinib plus anlotinib in advanced non-small-cell lung cancer patients after drug resistance

OBJECTIVE

To retrospectively analyze the efficacy and safety of osimertinib combined with anlotinib in the treatment of advanced non-small-cell lung cancer (NSCLC) after drug resistance, and to explore the related factors affecting the efficacy.

METHODS

The clinical data of 34 patients with advanced NSCLC who received osimertinib combined with anlotinib as three or more lines of treatment in the Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College from June 2019 to March 2022 were collected, and the therapeutic efficacy and safety were analyzed.

RESULTS

A total of 34 advanced NSCLC patients met the inclusion criteria. The objective response rate was 20.6%, the disease response rate was 88.2%, the median overall survival was 19.0 months, and the median progression-free survival was 6.0 months. The common adverse events were mainly grade 1-2, and only three cases (11.1%) of adverse events were grade 3, including hypertension, proteinuria, and vomiting. No grade 4 or above adverse events were observed. Multivariate Cox regression analysis showed that the Eastern Cooperative Oncology Group Performance Status score and bone metastasis were independent prognostic factors for osimertinib combined with anlotinib as three or more lines of treatment in advanced NSCLC.

CONCLUSIONS

Osimertinib combined with anlotinib as three or more lines of treatment in advanced NSCLC was effective and adverse events were tolerable.

Therapeutic strategies for EGFR-mutated non-small cell lung cancer patients with osimertinib resistance

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are the preferential options for advanced non-small cell lung cancer (NSCLC) patients harboring EGFR mutations. Osimertinib is a potent irreversible third-generation EGFR-TKI targeting EGFR mutations but has little effect on wild-type EGFR. In view of its remarkable efficacy and manageable safety, osimertinib was recommended as the standard first-line treatment for advanced or metastatic NSCLC patients with EGFR mutations. However, as the other EGFR-TKIs, osimertinib will inevitably develop acquired resistance, which limits its efficacy on the treatment of EGFR-mutated NSCLC patients. The etiology of triggering osimertinib resistance is complex including EGFR-dependent and EGFR-independent pathways, and different therapeutic strategies for the NSCLC patients with osimertinib resistance have been developed. Herein, we comprehensively summarized the resistance mechanisms of osimertinib and discuss in detail the potential therapeutic strategies for EGFR-mutated NSCLC patients suffering osimertinib resistance for the sake of the improvement of survival and further achievement of precise medicine.

Two case reports of non-small cell lung cancer patients harboring acquired EGFR T790M-cis-C797S benefit from immune checkpoint inhibitor combined with platinum-based doublet chemotherapy

Background

Acquired resistance is inevitable in non-small cell lung cancer (NSCLC) patients treated with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs). The emergence of EGFR exon 20 C797S is one of the major resistance mechanisms to osimertinib as a third-generation EGFR-TKI. To date, there is no standard of care for NSCLC patients after acquiring EGFR C797S. Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of various types of cancers in the last decade. Whether NSCLC patients with acquired EGFR C797S could benefit from ICIs remains elusive.

Case Description

Herein, we reported two cases of EGFR-mutant NSCLC patients who acquired a tertiary EGFR mutation C797S benefited from ICIs. A 28-year-old woman presented with anepithymia and nausea. Chest computed tomography (CT) revealed a mass in the right lung. She was diagnosed with stage IV lung adenocarcinoma (LUAD) with EGFR exon 19 deletion (19del) based on imaging and next-generation sequencing (NGS) findings. She received icotinib followed by osimertinib, then acquired EGFR T790M-cis-C797S. She had low tumor mutation burden (TMB) and achieved partial response (PR) to a programmed cell death-1 (PD-1) inhibitor sintilimab combined with platinum-based doublet chemotherapy as late-line treatment lasting more than 5 months. A 66-year-old man complained with chest tightness, hemoptysis, and back pain. CT scans revealed a mass in the right lung and metastases to the bilateral lungs, liver, adrenal gland, mediastinal lymph nodes, and bone. He was also diagnosed with EGFR 19del-positive LUAD and treated with icotinib followed by osimertinib. He also acquired EGFR T790M-cis-C797S. The patient had low TMB also and benefited from a PD-1 inhibitor camrelizumab combined with platinum-based doublet chemotherapy as late-line treatment with a progression-free survival (PFS) of 8 months. Two cases had no treatment-related adverse events leading to discontinuation of PD-1 inhibitors.

Conclusions

Our study provides the first clinical evidence that ICIs combined with platinum-based doublet chemotherapy may be effective treatment options for overcoming resistance mediated by EGFR T790M-cis-C797S. Clinical trials are needed to evaluate the efficacy and safety of PD-1 inhibitors in the treatment of NSCLC patients harboring EGFR T790M-cis-C797S.

Clinical outcomes and safety of osimertinib plus anlotinib for patients with previously treated EGFR T790M-positive NSCLC: A retrospective study

WHAT IS KNOWN AND OBJECTIVE

Although osimertinib achieved convincing efficacy for patients with EGFR T790M-positive non-small-cell lung cancer (NSCLC) as second-line treatment in the AURA3 clinical trials, patients developed drug resistance ultimately. Therefore, the present study was to investigate the clinical outcome and safety of osimertinib plus anlotinib for patients with previously treated EGFR T790M-positive NSCLC.

METHODS

Designed as a retrospective study, this study consecutively included a total of 33 patients with advanced NSCLC who possessed a EGFR T790M-positive mutation and progressed after the first-line therapy. Eligible patients were treated with osimertinib plus anlotinib. Baseline characteristics of the patients were collected during hospitalization. Efficacy of the combination regimen was assessed with the change of target lesion using imaging evidence according to RECIST 1.1 criteria, and all the patients were followed up regularly. Adverse reactions were collected and documented during the treatment. Univariate analysis according to baseline characteristic subgroups was performed using log-rank test, and multivariate analysis was carried out by Cox regression analysis.

RESULTS AND DISCUSSION

The best overall response of the patients during osimertinib and anlotinib combination indicated that complete response was found in one patient, partial response was observed in 26 patients, stable disease was noted in 5 patients and progressive disease was reported in one patient. Therefore, objective response rate (ORR) of the combination regimen was 81.8% (95%CI: 64.5%-93.0%), and disease control rate (DCR) was 97.0% (95%CI: 84.2%-99.9%). Furthermore, the median progression-free survival (PFS) of the 33 patients with NSCLC was 15.5 months (95%CI: 6.19-24.81). In addition, the median overall survival (OS) of the 33 patients with NSCLC was 23.8 months (95% CI: 17.67-29.93). Safety profile suggested that the most common adverse reactions of the patients with NSCLC who received anlotinib plus osimertinib were hypertension (63.6%), fatigue (57.6%), diarrhoea (48.5%%), dermal toxicity (39.4%) and proteinuria (33.3%). Interestingly, multivariate Cox regression analysis for PFS demonstrated that ECOG performance status was an independent factor to predict the PFS of the combination regimen.

WHAT IS NEW AND CONCLUSION

Osimertinib plus anlotinib regimen preliminarily exhibited encouraging clinical outcomes and acceptable safety profile for patients with previously treated EGFR T790M-positive NSCLC numerically. This conclusion should be validated in prospective clinical trials.

Resistance mechanisms to osimertinib and emerging therapeutic strategies in nonsmall cell lung cancer

PURPOSE OF REVIEW

This review aims to introduce the resistance mechanisms to osimertinib, discuss the therapeutic strategies, and make clinical updates in overcoming resistance to osimertinib.

RECENT FINDINGS

Osimertinib has shown favorable efficacy on second-line and first-line treatments in EGFR-mutant advanced nonsmall cell lung cancer (NSCLC). However, the presence of primary and acquired resistance to osimertinib restricts its clinical benefits. The primary resistance mainly consists of BIM deletion polymorphism and EGFR exon 20 insertions. Meanwhile, the heterogeneous mechanisms of acquired resistance include EGFR-dependent (on-target) and EGFR-independent (off-target) mechanisms. EGFR C797S mutation, MET amplification, HER2 amplification, and small cell lung cancer transformation were identified as frequent resistance mechanisms. Recently, more novel mechanisms, including rare EGFR point mutations and oncogenic fusions, were reported. With the results of completed and on-going clinical trials, the emerging therapeutic strategies of postosimertinib progression are summarized.

SUMMARY

The resistance mechanisms to osimertinib are heterogeneous and gradually perfected. The combination of osimertinib with bypass targeted therapy and other therapeutic approaches emerge as promising strategies.