Epidermal growth factor receptor tyrosine kinase inhibitors in advanced nonsmall cell lung cancer: what is the preferred first-line therapy?

Non-small cell lung cancer with synchronous brain metastases: Identification of prognostic factors in a retrospective multicenter study (HOT 1701)

Background

Non-small-cell lung cancer (NSCLC) is associated with a high incidence of brain metastasis (BM), and the prognosis of patients with NSCLC and BM is poor. This study aimed to identify the prognostic factors and elucidate the survival rates of Japanese patients with NSCLC and BM at initial diagnosis.

Methods

HOT 1701 is a retrospective multicenter study of patients with NSCLC and BM at initial diagnosis. The medical records of all consecutive patients diagnosed with advanced or recurrent NSCLC and BM at 14 institutions of the Hokkaido Lung Cancer Clinical Study Group Trial (HOT) in Japan were reviewed. The participants were categorized based on the presence or absence of driver mutations. The Kaplan-Meier method was used to estimate median overall survival (OS). Univariate and multivariate analyses were performed to identify prognostic factors in these patients.

Results

Among 566 patients with NSCLC and BM, the median OS was 11.8 months. Patients with driver mutations survived longer than those without driver mutations. The univariate and multivariate analyses revealed 6 independent prognostic factors: age ≥65 years, poor performance status, T factor, absence of driver gene mutations, presence of extracranial metastases, and number of BM. According to the prognostic score based on these 6 factors, the patients were stratified into 3 risk groups: low-, intermediate-, and high-risk, with median OS of 27.8, 12.2, and 2.8 months, respectively.

Conclusions

We developed a new prognostic model for patients with NSCLC and BM, which may help determine prognosis at diagnosis.

The D ~ Sense ex-vivo viability assay application in a patient with stage IV lung adenocarcinoma: a case report

BACKGROUND

The treatment resistance is a problem for lung cancer. In this study, we used a vitro tissue culturing system to select a new therapy strategy for a patient with tyrosine kinase inhibitors (TKIs) resistance.

CASE PRESENTATION

A 42-year-old male Asian patient was diagnosed with advanced lung adenocarcinoma harboring an exon 19 deletion in the epidermal growth factor receptor (EGFR) gene. The patient was treated with Gefitinib, resulting in an almost complete remission for over a year. The patient relapsed after 13 months treatment, and received four cycles of chemotherapy. At 20 months, the patient had developed multiple lung metastases and a solitary cerebellar metastasis. An EGFR T790M mutation was identified in the peripheral blood sample. Subsequent treatment with Osimertinib resulted in a complete response of the intracranial metastasis. By 33 months, the patient had developed a mediastinal tumor mass that responded well to local radiotherapy. By 39 months, an EGFR C797S cis-mutation had been identified and the patient was treated with Brigatinib and Cetuximab. By 44 months, the tumor cells from the pleural effusion had been tested for sensitivity against 30 targeted and cytostatic drugs using the D ~ Sense ex-vivo viability assay. The assay identified 8 drugs with moderate to high sensitivity. Combination therapy of Gemcitabin and Lobaplatin had resulted in disease stabilization.

CONCLUSIONS

The case showed that individualized treatment aided by D ~ Sense ex-vivo viability assay can be a viable option for patients with advanced lung adenocarcinoma with pleural effusions.

Immunotherapy for EGFR-mutant advanced non-small-cell lung cancer: Current status, possible mechanisms and application prospects

Immune checkpoint inhibitors (ICIs) are effective against advanced and even perioperative non-small-cell lung cancer (NSCLC) and result in durable clinical benefit, regardless of programmed death ligand-1 (PD-L1) expression status in cancer. Existing clinical evidence shows that the effect of immunotherapy in patients with EGFR-mutant NSCLC after the development of tyrosine kinase inhibitor (TKI) resistance is not satisfactory. However, compared with monotherapy, ICIs combined with chemotherapy can improve the efficacy. Encouragingly, compared with that of patients with sensitive mutations, the progression-free survival of patients with rare mutations who were treated with ICIs was increased. Adequately maximizing the efficacy of ICIs in EGFR-mutant NSCLC patients is worth exploring. In this review, we described preclinical and clinical studies of ICIs or combined therapy for EGFR-mutant NSCLC. We further focused on EGFR mutations and the cancer immune response, with particular attention given to the role of EGFR activation in the cancer-immunity cycle. The mechanisms for the natural resistance to ICIs were explored to identify corresponding countermeasures that made more EGFR-mutant NSCLC patients benefit from ICIs.

EGFR-mutant NSCLC: emerging novel drugs

PURPOSE OF REVIEW

Despite the significant advances in EGFR-mutant nonsmall cell lung cancer (NSCLC), some challenges remain. One of the permanent and inevitable issues is the emergence of acquired resistance. Therefore, blocking the activation of EGFR pathway and overcoming drug resistance with novel agents are still in high demand. Here, we review the development of novel drugs in EGFR-mutant, advanced NSCLC, including targeting EGFR exon 20 insertion (EGFR20ins), and novel role of epidermal growth factor receptor, tyrosine kinase inhibitor (EGFR-TKIs) in early-stage NSCLC.

RECENT FINDINGS

EGFR-TKIs as adjuvant therapy or neoadjuvant therapy in patients with early-stage NSCLC with EGFR-sensitizing mutations have shown promising efficacy. The resistance mechanisms of third-generation EGFR-TKIs can be divided into two types: EGFR dependent and EGFR independent. Several clinical trials have demonstrated that the addition of MET inhibitors to EGFR-TKIs was an effective option for patients who had acquired resistance to EGFR-TKIs caused by hepatocyte growth factor receptor gene (MET) amplification or overexpression. Novel compounds that selectively and potently inhibit EGFR20ins are being investigated in phase III studies.

SUMMARY

A better characterization and understanding of resistance mechanisms to first-line osimertinib and adjuvant osimertinib is helpful to guide further treatment.

Comparison of Biocartis IDYLLA ™ cartridge assay with Qiagen GeneReader NGS for detection of targetable mutations in EGFR, KRAS/NRAS, and BRAF genes

Lung and colorectal cancers (CRC) have two of the highest mortality rates among all cancer types, and their occurrence and the need for personalized diagnostics and subsequent therapy were not influenced by the COVID-19 pandemics. However, due to the disruption of established delivery chains, standard assays for in vitro diagnostics of those cancers were temporarily not available, forcing us to implement alternative testing methods that enabled at least basic therapy decision making. For this reason, we evaluated rapid testing on the Biocartis Idylla™ platform (Biocartis, Mechelen, Belgium) for four important genes commonly mutated in lung and colorectal cancers, namely EGFR, NRAS, KRAS, and BRAF. Clinical specimens from which the mutation status has previously been determined using Next Generation Sequencing (NGS), were retested to determine whether Idylla™ can offer accurate results. To compare the results, the sensitivity, specificity, positive predictive values (PPV) and negative predictive values (NPV) are calculated for each of the mutation types and then combined to determine the values of the Idylla™ system in total, while setting NGS as the gold-standard basis the assays were compared with. Idylla testing thereby displayed acceptable sensitivity and specificity and delivered reliable results for initial therapy decisions.

Metachronous Brain Metastasis in patients with EGFR-mutant NSCLC indicates a worse prognosis

Purpose: NSCLC patients with EGFR mutation were associated with high incidence of brain metastasis (BM). BM could be grouped by the time of occurrence, including synchronous BM at initial diagnosis and metachronous BM during disease course. The primary aim of the study was to investigate the survival of patients with metachronous BM.

Methods: A total of 99 EGFR-mutant advanced NSCLC patients in our institute between 2012 and 2018 were grouped into synchronous BM and metachronous BM. Comparisons of OS were performed based on BM status. The independent prognostic factors of OS were investigated, and extracranial and intracranial PFS were further analyzed.

Results: Patients with metachronous BM (mOS: 22.1 months) had poorer outcomes than synchronous BM (mOS: 30.3 months) (P=0.016). Moreover, multivariate analysis indicated that BM status (P=0.015), local therapy for BM (P=0.013) and subsequent treatment of Osimertinib (P=0.008) impact significantly on OS. Significantly, the proportion of local therapy for BM had no difference between patients with synchronous and metachronous BM. And patients with metachronous BM harbored a more favorable prognostic factor (higher proportion of subsequent Osimertinib treatment), but also harbored a poorer prognostic factor (metachronous BM), which confirmed BM status was the most significant prognostic factor of OS. At last, results of extracranial and intracranial PFS indicated that patients with metachronous BM tended to have a higher risk of intracranial disease progression.

Conclusions: Patients developing metachronous BM during EGFR-TKIs treatment have worse outcomes than synchronous BM. Our findings suggested that the patients with metachronous BM should receive more aggressive treatments.

Coiled-coil domain-containing 68 promotes non-small cell lung cancer cell proliferation in vitro

Coiled-coil domain-containing 68 (CCDC68) is a novel secretory protein that acts as a tumor suppressor gene in several types of malignant tumors. However, the role of CCDC68 in the development of lung cancer has not been extensively studied. In the present study, to explore the biological functions of CCDC68 in NSCLC, we performed cell proliferation, viability and apoptosis assays on human lung cancer cell lines upon CCDC68 gene silencing with short hairpin RNA. The results demonstrated that following knockdown of CCDC68 expression, cell proliferation was decreased and the apoptotic rates were increased in A549 and H1299 cells. The role and mechanism of CCDC68 in malignant tumors, particularly in lung cancer, should be further explored, and CCDC68 may serve as a novel target for treatment of lung cancer.

Deducing the Conformational Properties of a Tyrosine Kinase Inhibitor in Solution by Optical Spectroscopy and Computational Chemistry

Dacomitinib (PF-00299804) was recently approved by the Food and Drug Administration (FDA) as a tyrosine kinase inhibitor (TKI). Unfortunately, side effects and disease resistance eventually result from its use. Off-target effects in some kinase inhibitors have arisen from drug conformational plasticity; however, the conformational states of Dacomitinib in solution are presently unknown. To fill this gap, we have used computational chemistry to explore optimized molecular geometry, properties, and ultraviolet-visible (UV-Vis) absorption spectra of Dacomitinib in dimethyl sulfoxide (DMSO) solution. Potential energy scans led to the discovery of two planar and two twisted conformers of Dacomitinib. The simulated UV-Vis spectral signatures of the planar conformers reproduced the two experimental spectral bands at 275 and 343 nm in solution. It was further discovered that Dacomitinib forms conformers through its three flexible linkers of two C-NH-C bridges, which control the orientations of the 3-chloro-4-fluoroaniline ring (Ring C) and the quinazoline ring (Rings A and B) and the 4-piperidin-1-yl-buten-2-nal side chain, and one C-O-C local bridge which controls the methoxy group locally. When in isolation, these flexible linkers form close hexagon and pentagon loops through strong intramolecular hydrogen bonding so that the "planar" conformers Daco-P1 and Daco-P2 are more stable in isolation. Such flexibility of the ligand and its ability to dock and bind with protein also depend on their interaction with the environment, in addition to their energy and spectra in isolation. However, an accurate quantum mechanical study on drug/ligand conformers in isolation provides necessary reference information for the ability to form a complex with proteins.

Risk factors of metachronous brain metastasis in patients with EGFR-mutated advanced non-small cell lung cancer

Background

NSCLC patients with EGFR mutation were at a higher incidence of developing brain metastasis (BM). Patients with BM are associated with high mortality. Reducing BM incidence becomes increasingly significant for NSCLC patients to achieve prolonged survival. The aim of the study was to explore the possible risk factors of developing metachronous BM during EGFR-TKIs treatment, and to identify the potential candidates for prophylactic cranial irradiation (PCI) or the first-line Osimertinib treatment.

Methods

A total of 157 consecutive EGFR-mutated advanced NSCLC patients without BM at initial diagnosis in our institution from 2012 and 2018 were retrospectively reviewed. Comparisons of OS were performed based on BM status. The cumulative incidence of metachronous BM was calculated by the Kaplan-Meier method, and the independent risk factors of metachronous BM were investigated by multivariate analysis.

Results

Patients developing metachronous BM had worse survival (mOS: 22.1 months) than patients not-developing BM (mOS: 44.8 months). Moreover, the multivariate analysis indicated that age ≤ 49 years (P = 0.035), number of extracranial metastases (P = 0.013), and malignant pleural effusion (P = 0.002) were independent risk factors of metachronous BM. Furthermore, the 1-year actuarial incidence of developing metachronous BM in patients with no risk factor (n = 101), 1 risk factor (n = 46), and 2 risk factors (n = 10) were 7.01, 14.61, and 43.75%, respectively (P < 0.001).

Conclusions

Patients developing metachronous BM during EGFR-TKIs treatment have worse outcomes. Our results suggested that EGFR-mutated advanced NSCLC patients with ≥1 risk factors were candidates for PCI or the first-line Osimertinib treatment.

Anticancer potential of some imidazole and fused imidazole derivatives: exploring the mechanism via epidermal growth factor receptor (EGFR) inhibition

Imidazole-based epidermal growth factor receptor (EGFR) inhibitors were computationally designed and synthesized. All the compounds were assessed for their anti-proliferative activity against five cancer cell lines, viz., MDA-MB-231 (breast), T47D (breast) and MCF-7 (breast), A549 (lung) and HT-29 (colorectal). Compounds 2c and 2d emerged as better anticancer molecules with no toxicity towards normal cells. 2c and 2d inhibited EGFR enzymatic activity in vitro with IC₅₀ values of 617.33 ± 0.04 nM and 710 ± 0.05 nM, respectively. In order to further improve the potency, we explored an unoccupied area of the ATP binding domain of EGFR and analysed an in silico interaction model of 2c and 2d-EGFR complexes that guided and allowed substitution of the 4-fluorophenyl ring (2c and 2d) with 4-(4-methylpiperazinyl)-3-nitrophenyl at the N-9 position, resulting in compound 3c with a better binding score and potent EGFR inhibitory activity (IC₅₀: 236.38 ± 0.04 nM), which was comparable to the positive control erlotinib (239.91 ± 0.05 nM). 3c exhibited a great improvement in anticancer potency with inhibition of cell growth of all cancer cell lines at very low micromolar concentrations (IC₅₀ = 1.98 to 4.07 μM). Further investigation revealed that 3c also induced an increase in ROS levels in cancer cells in a mitochondrial-independent manner and halted the cell cycle at the sub-G₁ phase.

Plasma cell-free DNA methylation combined with tumor mutation detection in prognostic prediction of patients with non-small cell lung cancer (NSCLC)

BACKGROUND

Lung Cancer is one of the most common cancers with high degree of malignancy, is a devastating disease with a poor prognosis worldwide. prognostic prediction for patients with non small-cell lung cancer (NSCLC) is still challenge.

MATERIAL AND METHODS

The cohort consisted of 64 consecutive patients with NSCLC identified from June1, 2014, to June 30, 2018. Liquid biopsy samples were collected. Genomic mutation DNA was calculated by including all substitutions and indels over the entire somatic, coding, sequencing length. statistical evaluations were carried out using SPSS software.

RESULTS

Quantity of total ctDNA was successfully determined in all 64 patients from whom baseline circulating DNA was available. ctDNA concentration ranged from 4000 to 3,562,000 genome equivalents per milliliter. Treatments induced a significant decrease in cancer specific markers in most patients with response to treatments, while the methylated DNA demonstrated favorable prediction efficiency regardless of the response status. Patients with ctDNA mutation and methylated DNA decreasing have favorable overall survival (P < .05). combination of genetic and methylated DNA decreasing had high reliability in predicting overall survival of patients with NSCLC.

CONCLUSIONS

We have detected both tumor mutations and methylated DNA in plasma of patients with NSCLC. Combined genetic and methylated DNA decreasing after treatment was an independent risk factor for prognosis of patients with NSCLC. Meanwhile, it had favorable predict value and had potential to be defined as a novel biomarker for patients with NSCLC.

Mutational spectrum of acquired resistance to reversible versus irreversible EGFR tyrosine kinase inhibitors

Background

Over the past years, EGFR tyrosine kinase inhibitors (TKI) revolutionized treatment response. 1st-generation (reversible) EGFR TKI and later the 2nd –generation irreversible EGFR TKI Afatinib were aimed to improve treatment response. Nevertheless, diverse resistance mechanisms develop within the first year of therapy. Here, we evaluate the prevalence of acquired resistance mechanisms towards reversible and irreversible EGFR TKI.

Methods

Rebiopsies of patients after progression to EGFR TKI therapy (> 6 months) were targeted to histological and molecular analysis. Multiplexed targeted sequencing (NGS) was conducted to identify acquired resistance mutations (e.g. EGFR p.T790M). Further, Fluorescence in situ hybridisation (FISH) was applied to investigate the status of bypass mechanisms like, MET or HER2 amplification.

Results

One hundred twenty-three rebiopsy samples of patients that underwent first-line EGFR TKI therapy (PFS ≥6 months) were histologically and molecularly profiled upon clinical progression. The EGFR p.T790M mutation is the major mechanism of acquired resistance in patients treated with reversible as well as irreversible EGFR TKI. Nevertheless a statistically significant difference for the acquisition of T790M mutation has been identified: 45% of afatinib- vs 65% of reversible EGFR TKI treated patients developed a T790M mutation (p-value 0.02). Progression free survival (PFS) was comparable in patients treated with irreversible EGFR irrespective of the sensitising primary mutation or the acquisition of p.T790M.

Conclusions

The EGFR p.T790M mutation is the most prominent mechanism of resistance to reversible and irreversible EGFR TKI therapy. Nevertheless there is a statistically significant difference of p.T790M acquisition between the two types of TKI, which might be of importance for clinical therapy decision.

Risk factors of acquired T790M mutation in patients with epidermal growth factor receptor-mutated advanced non-small cell lung cancer

Background: It is still controversial to employ osimertinib as the first-line therapy for EGFR-mutated non-small cell lung cancer (NSCLC) patients in practice. The aim of the current study was to explore the risk factors of acquired T790M mutation during EGFR-TKIs therapy, and to identify the potential patients most likely to benefit from first-line osimertinib treatment. Methods: A total of 222 patients with EGFR-mutated (non-T790M) advanced NSCLC were analyzed. The progression-free survival (PFS), overall survival (OS), and cumulative incidence of acquired T790M mutation were calculated with the Kaplan-Meier method. The independent risk factors were investigated with the multivariate analysis. Results: A total of 70 patients acquired T790M mutation and were treated with osimertinib as a second-line treatment. These patients showed a significantly better OS (P=0.003) than those without T790M mutation. Multivariate analysis indicated that BMI ≤ 25 (P= 0.031), NSE > 17.9 ng/ml (P= 0.013) before treatment, and retroperitoneal lymph node (LN) metastasis (P= 0.002) were independent risk factors of acquired T790M mutation. At last, the actuarial risks of acquired T790M mutation at 1 year after EGFR-TKI treatment were 6.6% in patients with 0-1 risk factor and 31.5% in patients with 2-3 risk factors. Conclusions: Patients developing acquired T790M mutation during EGFR-TKI treatment had a better OS of osimertinib treatment. Lower BMI, higher NSE before treatment, and retroperitoneal LN metastasis are independent risk factors of acquired T790M mutation. Our study suggested that patients with 2-3 risk factors were highly recommended the first-line osimertinib treatment.

TP53 co-mutations in EGFR mutated patients in NSCLC stage IV: A strong predictive factor of ORR, PFS and OS in EGFR mt+ NSCLC

INTRODUCTION

The impact of TP53 co-mutations in EGFR mutated patients on PFS and OS is controversial. Different classifications of TP53 mutations with respect to functional and potential clinical impact have been published. Therefore, we retrospectively analyzed the impact of TP53 co-mutations on ORR, PFS and OS in a cohort of EGFR mutated NSCLC IV patients (UICC 7) using different classifications of TP53 mutations.

METHODS

75 EGFR mutated NSCLC IV patients homogeneously treated with 1st line EGFR TKI were analyzed for TP53 co-mutations. TP53 mutations were classified according to three different types of classifications. The endpoints ORR, PFS and OS were investigated.

RESULTS

TP53 co-mutations were found in 29/59 patients (49.2%). TP53 co-mutations were a statistically significant independent negative predictive factor for ORR, PFS and OS. TP53 co-mutations were associated with inferior mPFS and mOS: mPFS/mOS 12 vs. 18/24 vs. 42 months for non-disruptive/disruptive mutations vs. WT (p < 0.004)/(p < 0.009), 11 vs. 17/23 vs. 42 months for pathogenic vs. non-pathogenic/WT (p < 0.001)/(p < 0.001), and 7 vs. 12 vs. 18/12 vs. 28 vs. 42 months for exon 8 vs. non-exon 8 vs. WT (p < 0.001)/(p < 0.002).

CONCLUSIONS

TP53 co-mutations are frequent in EGFR mt+ NSCLC and have a strong negative impact on all clinical endpoints of TKI therapy.

Tyrosine Kinase Inhibitors for the Treatment of EGFR Mutation-Positive Non-Small-Cell Lung Cancer: A Clash of the Generations

The availability of 3 generations of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) with different pharmacologic characteristics and clinical profiles has provided oncologists with a potentially confusing choice for the treatment of EGFR mutation-positive non-small-cell lung cancer. Although recent head-to-head clinical trials have demonstrated improved efficacy with second-generation (ie, afatinib, dacomitinib) and third-generation (ie, osimertinib) TKIs compared with the first-generation TKIs (eg, erlotinib, gefitinib), acquired resistance has been inevitable, regardless of which agent has been chosen as first-line therapy. Thus, the potential availability of subsequent treatment options is an important consideration. Recent data have demonstrated that osimertinib confers an overall survival benefit compared with first-generation EGFR TKIs, and dacomitinib has shown an overall survival benefit compared with gefitinib in an exploratory analysis. However, the relative benefits of different sequential EGFR-TKI regimens, especially those involving second- and third-generation agents, have remained uncertain and require prospective evaluation. Few such data currently exist to inform treatment choices. In the present review, we examined the pharmacologic characteristics and current clinical data for EGFR TKIs, including emerging information on the molecular mechanisms of resistance across the different generations of TKIs. Given the uncertainties regarding the optimal treatment choice, we have focused on the factors that might help determine the treatment decisions, such as efficacy and safety in patient subgroups. We also discussed the emerging real-world data, which have provided some insights into the benefits of sequential regimens in everyday clinical practice.

[A Review of EGFR-TKIs Therapy of Non-small Cell Lung Cancer with Uncommon EGFR Mutations]

肺癌是目前最常见的癌症，也是导致癌症死亡的首要原因。非小细胞肺癌（non-small cell lung cancer, NSCLC）占85%以上，且高达50%的亚洲NSCLC患者携带表皮生长因子受体（epidermal growth factor receptor, EGFR）基因突变。研究证明，伴有EGFR突变的NSCLC患者接受表皮生长因子受体-酪氨酸激酶抑制剂（epidermal growth factor receptor-tyrosine kinase inhibitors, EGFR-TKIs）治疗能获得更好的生存结果。然而，因为EGFR罕见突变相对治疗效果较差，会对研究结果带来负面影响，所以大部分研究EGFR-TKIs疗效的临床试验都不包含罕见突变患者，另外EGFR罕见突变本身就少见，就导致临床试验中这部分患者数量较少。由于EGFR罕见突变样本量少且具有高度异质性，EGFR-TKIs对EGFR罕见突变患者的疗效仍然不清楚。本文就EGFR罕见突变与EGFR-TKIs的疗效关系进行综述，为携带EGFR罕见突变的NSCLC患者合理选择治疗方式提供指导和建议。

Intrinsic resistance to EGFR-Tyrosine Kinase Inhibitors in EGFR-Mutant Non-Small Cell Lung Cancer: Differences and Similarities with Acquired Resistance

Activating mutations in the epidermal growth factor receptor gene occur as early cancer-driving clonal events in a subset of patients with non-small cell lung cancer (NSCLC) and result in increased sensitivity to EGFR-tyrosine-kinase-inhibitors (EGFR-TKIs). Despite very frequent and often prolonged clinical response to EGFR-TKIs, virtually all advanced EGFR-mutated (EGFRM+) NSCLCs inevitably acquire resistance mechanisms and progress at some point during treatment. Additionally, 20-30% of patients do not respond or respond for a very short time (<3 months) because of intrinsic resistance. While several mechanisms of acquired EGFR-TKI-resistance have been determined by analyzing tumor specimens obtained at disease progression, the factors causing intrinsic TKI-resistance are less understood. However, recent comprehensive molecular-pathological profiling of advanced EGFRM+ NSCLC at baseline has illustrated the co-existence of multiple genetic, phenotypic, and functional mechanisms that may contribute to tumor progression and cause intrinsic TKI-resistance. Several of these mechanisms have been further corroborated by preclinical experiments. Intrinsic resistance can be caused by mechanisms inherent in EGFR or by EGFR-independent processes, including genetic, phenotypic or functional tumor changes. This comprehensive review describes the identified mechanisms connected with intrinsic EGFR-TKI-resistance and differences and similarities with acquired resistance and among clinically implemented EGFR-TKIs of different generations. Additionally, the review highlights the need for extensive pre-treatment molecular profiling of advanced NSCLC for identifying inherently TKI-resistant cases and designing potential combinatorial targeted strategies to treat them.

An endothelial growth factor receptor compound mutation of T790M substitution with exon 19 deletion in a previously untreated patient: a case report

BACKGROUND

Endothelial growth factor receptor (EGFR) mutations are an essential driver of personalized therapy for patients with lung cancer and are detected in approximately 15% of Caucasian and 50% of Asian patients. EGFR tyrosine kinase inhibitors have been developed and used for this set of patients. T790M mutation in exon 20 is usually associated with secondary resistance to EGFR tyrosine kinase inhibitors therapy but is also present in treatment-naïve patients. The frequency for baseline T790M mutation varies from 4 to 35% according to the detection method used. Newer techniques have yielded higher rates, but concerns about false-positive results have been raised. Compound mutations account for 4-14% of all EGFR-mutated tumors, with no studies yet to provide a frequency rate for T790M + 19 deletion association due to the small number of cases. However, there are reports that pretreatment T790M + L858R association is significantly more frequent compared to T790M + exon 19 deletion mutations. Diagnostic challenges, current knowledge on the subject, and therapeutic decisions are discussed.

CASE PRESENTATION

We present the case of a 43-year-old Hispanic woman, a treatment-naïve patient, with metastasized lung cancer adenocarcinoma harboring a T790M deletion along with the classic 19 mutation. The initial symptoms were monoparesis of her left leg, associated with hyperreflexia, and hypoesthesia. In the absence of third-generation tyrosine kinase inhibitors, a platinum-based therapy was initiated with no response and she died 4 months after diagnosis.

CONCLUSIONS

Osimertinib seems to be a suitable therapy for treatment-naïve patients with sensitizing and resistant compound EGFR mutations. More studies regarding the clinical characteristics of these patients and the appropriate management of this condition are needed to provide the highest standard of care.