Genomic Landscape of Primary Resistance to Osimertinib Among Hispanic Patients with EGFR-Mutant Non-Small Cell Lung Cancer (NSCLC): Results of an Observational Longitudinal Cohort Study

A meta-analysis of liquid biopsy versus tumor histology for detecting EGFR mutations in non-small cell lung cancer

OBJECTIVE

To assess the consistency of liquid biopsy and histologic analysis for detecting epidermal growth factor receptor (EGFR) gene mutations in patients with advanced non-small cell lung cancer (NSCLC).

METHODS

The PubMed, Cochrane Library, and CNKI et al. databases were searched to collect studies comparing liquid biopsy and histopathologic specimens. The EGFR mutation status was extracted from the studies, and meta-analysis was carried out using Stata 12.0 software.

RESULTS

We included 22 studies of 3359 NSCLC patients. In the meta-analysis, eight papers with a sample size of size <150 had an OR of 45, indicating that liquid biopsy had high sensitivity for detecting EGFR mutations. In addition, seven papers with a sample size ≥150, with an OR of 70, reported that liquid biopsy was highly susceptible to detecting EGFR mutations. The pooled diagnostic effect size of 6 for literature that included the T790M mutation was smaller than that of 69 for literature that did not include the T790M mutation, and I2 >50 %, showing that literature that did not include the T790M mutation was more heterogeneous. The combined diagnostic effect size of 34 in the exon 19 group was smaller than that in the group with no exon 19, with an I2>50 %. There was substantial heterogeneity in both the exon 19 group and the non-exon 19 group. The group with the L858R mutation had a greater diagnostic effect size of 28, lower I2, and less heterogeneity than the group without the L858R mutation. The exon 21 group had a larger pooled diagnostic effect size of 66, a smaller I2, and less heterogeneity than the group without exon 21.

CONCLUSION

Liquid biopsy and histologic analysis have high concordance for detecting EGFR mutations in NSCLC. Liquid biopsy can provide an alternative technology for individualized treatment and monitoring of minimal residual disease (MRD) in advanced NSCLC patients with EGFR tyrosine kinase inhibitor-sensitive and drug resistance (T790M) mutations.

Liquid biopsy for the management of NSCLC patients under osimertinib treatment

Therapeutic management of NSCLC patients is quite challenging as they are mainly diagnosed at a late stage of disease, and they present a high heterogeneous molecular profile. Osimertinib changed the paradigm shift in treatment of EGFR mutant NSCLC patients achieving significantly better clinical outcomes. To date, osimertinib is successfully administered not only as first- or second-line treatment, but also as adjuvant treatment while its efficacy is currently investigated during neoadjuvant treatment or in stage III, unresectable EGFR mutant NSCLC patients. However, resistance to osimertinib may occur due to clonal evolution, under the pressure of the targeted therapy. The utilization of liquid biopsy as a minimally invasive tool provides insight into molecular heterogeneity of tumor clonal evolution and potent resistance mechanisms which may help to develop more suitable therapeutic approaches. Longitudinal monitoring of NSCLC patients through ctDNA or CTC analysis could reveal valuable information about clinical outcomes during osimertinib treatment. Therefore, several guidelines suggest that liquid biopsy in addition to tissue biopsy should be considered as a standard of care in the advanced NSCLC setting. This practice could significantly increase the number of NSCLC patients that will eventually benefit from targeted therapies, such as EGFR TKIs.

Epidemiological characteristics and therapeutic advances of EGFR exon 20 insertion mutations in non-small cell lung cancer

The third most prevalent type of epidermal growth factor receptor (EGFR) mutation, EGFR exon 20 insertions (EGFRex20ins), involves 2%-12% of all cases of EGFR-positive non-small cell lung cancer (NSCLC). Approximately 90% of the mutations occur within the loop structure region, and the most frequently reported subtypes are A767_V769dup and S768_D770dup, which together account for almost 50% of instances. Apart from the unique subtype of A763_Y764insFQEA, NSCLCs with EGFRex20ins are resistant to approved EGFR tyrosine kinase inhibitors (TKIs) and are also insensitive to chemotherapy or immunotherapy. A new modality of treatment for NSCLC patients with EGFRx20ins has been established with the approval of mobocertinib and amivantamab. There are also numerous novel targeted treatments for NSCLC with EGFRex20ins in development, which are anticipated to improve this patient population's survival even further. This review provides a reference for the clinical management of these patients by summarizing the most recent epidemiological, and clinicopathological characteristics, diagnostic techniques, and therapeutic advances of EGFRex20ins in NSCLC.

Intrinsic Resistance to Osimertinib in EGFR Mutated NSCLC Cell Lines Induced by Alteration in Cell-Cycle Regulators

BACKGROUND

Cell-cycle regulators are mutated in approximately 40% of all cancer types and have already been linked to worse outcomes in non-small cell lung cancer adenocarcinomas treated with osimertinib. However, their exact role in osimertinib resistance has not been elucidated.

OBJECTIVE

In this study, we aimed to evaluate how the CDK4/6-Rb axis may affect the sensitivity to osimertinib.

METHODS

We genetically increased the level of CCND1 (Cyclin D1) and reduced the levels of CDKN2A (p16) in two different adenocarcinoma cell lines, PC9 and HCC827. We also retrospectively evaluated the outcome of patients with epidermal growth factor receptor-mutated advanced non-small cell lung cancer depending on their level of Cyclin D1 and p16.

RESULTS

The modified clones showed higher proliferative capacity, modifications in cell-cycle phases, and higher migratory capacity than the parental cells. Cyclin D1-overexpressing clones were highly resistant to acute osimertinib treatment. CDKN2A knockdown conferred intrinsic resistance as well, although a longer time was required for adaption to the drug. In both cases, the resistant phenotype was epidermal growth factor receptor independent and associated with a higher level of Rb phosphorylation, which was unaffected by osimertinib treatment. Blocking the phosphorylation of Rb using abemaciclib, a CDK4/6 inhibitor, exerted an additive effect with osimertinib, increasing sensitivity to this drug and reverting the intrinsic resistant phenotype. In a group of 32 patients with epidermal growth factor receptor-mutated advanced non-small cell lung cancer, assessed for Cyclin D1 and p16 expression, we found that the p16-deleted group presented a lower overall response rate compared with the control group.

CONCLUSIONS

We conclude that perturbation in cell-cycle regulators leads to intrinsic osimertinib resistance and worse patient outcomes.

Prevalence of oncogenic driver mutations in Hispanics/Latin patients with lung cancer. A systematic review and meta-analysis

INTRODUCTION

The frequency of actionable mutations varies between races, and Hispanic/Latino (H/L) people are a population with different proportions of ancestry. Our purpose was to establish prevalence of actionable mutations in the H/L population with NSCLC.

METHODS

EMBASE, LILACS, MEDLINE, and Virtual Health Library were searched for studies published up to April 2023 that evaluated the prevalence of ALK, BRAF, EGFR, HER-2, KRAS, MET, NTRK, RET, ROS1 in H/L patients. Meta-analyses were done to determine prevalence using a random effects model.

RESULTS

Fifty-five articles were included. EGFR and KRAS were the most prevalent genes with high heterogeneity across the countries. The overall mutation frequency for EGFR was 22%. The most frequent mutations in the EGFR gene were del19 (10%) and L858R (7%). The mean of KRAS mutation was a 14% prevalence. KRASG12C was the most frequent mutation with a 7% prevalence in an entire population. The overall frequency of ALK rearrangement was 5%. The mean frequency of ROS-1 rearrangement was 2%, and the frequencies of HER-2, MET, BRAF, RET, NTRK molecular alterations were 4%, 3%, 2%, 2%, and 1% respectively. Almost half of the cases were male, and 65.8% had a history of tobacco exposure. The most common clinical stage was IV.

CONCLUSIONS

The prevalence of driver mutations such as EGFR and KRAS in LA populations differs from what is reported in Asians and Europeans. In the present article, countries with a high proportion of Amerindian ancestry show a greater prevalence of EGFR in contrast to countries with a high proportion of Caucasians. Lack of information on some countries or studies with a small sample size affects the real prevalence data for the region.

Long-lasting benefit on multimodal treatment combining osimertinib and stereotaxic radiotherapy for metastatic non-small cell lung cancer with the EGFR exon 20 insertion 773-774 HVdelinsLM: a case report

A non-small-cell-lung-cancer patient with cerebral metastasis presenting an atypical exon 20 mutation in the EGFR gene had a long-lasting tumor cotrol on mulimodal treatment with osimertinib and stereotaxic radiotherapy on oligoprogressing lesions. Most exon-20 mutations are resistant to first, second and third generation EGFR-directed TKI. This case was discussed on our molecular tumour board. As the more specific exon-20 targeted therapies were not yet available and as sporadic short responses on the third generation EGFR-directed TKI, osimertinib had been described, the patient started osimertinib. She had a prolonged tumoral response on Osimertinib. The patient is still asymptomatic up to 32 months after initiating the medication. This case confirms that not all exon20 EGFR mutations are equal to osimertinib and that the localization of the exon 20 insertion mutation is probably important to consider when treating EGFR mutated NSCLC. The long-term clinical benefit can be maintained through stereotactic radiotherapy on focal progressive lesions.