Evidence-based best practices for EGFR T790M testing in lung cancer in Canada

Discovery of novel pyrazole based Urea/Thiourea derivatives as multiple targeting VEGFR-2, EGFRWT, EGFRT790M tyrosine kinases and COX-2 Inhibitors, with anti-cancer and anti-inflammatory activities

A novel series of pyrazole derivatives with urea/thiourea scaffolds 16a-l as hybrid sorafenib/erlotinib/celecoxib analogs was designed, synthesized and tested for its VEGFR-2, EGFRWT, EGFRT790M tyrosine kinases and COX-2, pro-inflammatory cytokines TNF-α and IL-6 inhibitory activities. All the tested compounds showed excellent COX-2 selectivity index in range of 18.04-47.87 compared to celecoxib (S.I. = 26.17) and TNF-α and IL-6 inhibitory activities (IC50 = 5.0-7.50, 6.23-8.93 respectively, compared to celecoxib IC50 = 8.40 and 8.50, respectively). Screening was carried out against 60 human cancer cell lines by National Cancer Institute (NCI), compounds 16a, 16c, 16d and 16 g were the most potent inhibitors with GI% ranges of 100 %, 99.63-87.02 %, 98.98-43.10 % and 98.68-23.62 % respectively, and with GI50 values of 1.76-15.50 µM, 1.60-5.38 µM, 1.68-7.39 µM and 1.81-11.0 µM respectively, in addition, of showing good safety profile against normal cell line (F180). Moreover, compounds 16a, 16c, 16d and 16 g had cell cycle arrest at G2/M phase with induced necrotic percentage compared to sorafenib of 2.06 %, 2.47 %, 1.57 %, 0.88 % and 1.83 % respectively. Amusingly, compounds 16a, 16c, 16d and 16 g inhibited VEGFR-2 with IC50 of 25 nM, 52 nM, 324 nM and 110 nM respectively, compared to sorafenib (IC50 = 85 nM), and had excellent EGFRWT and EGFRT790M kinase inhibitory activities (IC50 = 94 nM, 128 nM, 160 nM, 297 nM), (10 nM, 25 nM, 36 nM and 48 nM) respectively, compared to both erlotinib and osimertinib (IC50 = 114 nM, 56 nM) and (70 nM, 37 nM) respectively and showed (EGFRwt/EGFRT790M S.I.) of (range: 4.44-9.40) compared to erlotinib (2.03) and osmertinib (1.89).

Clinical Practice Guideline for Blood-based Circulating Tumor DNA Assays

Circulating tumor DNA (ctDNA) has emerged as a promising tool for various clinical applications, including early diagnosis, therapeutic target identification, treatment response monitoring, prognosis evaluation, and minimal residual disease detection. Consequently, ctDNA assays have been incorporated into clinical practice. In this review, we offer an in-depth exploration of the clinical implementation of ctDNA assays. Notably, we examined existing evidence related to pre-analytical procedures, analytical components in current technologies, and result interpretation and reporting processes. The primary objective of this guidelines is to provide recommendations for the clinical utilization of ctDNA assays.

Iodoquinazoline-derived VEGFR-2 and EGFRT790M dual inhibitors: Design, synthesis, molecular docking and anticancer evaluations

Herein, we report the synthesis of a series of new fourteen iodoquinazoline derivatives 7a-c to 13a-e and their evaluation as potential anticancer agents via dual targeting of EGFRT790M and VEGFR-2. The new derivatives were designed according to the target receptors structural requirements. The compounds were evaluated for their cytotoxicity against HepG2, MCF-7, HCT116 and A549 cancer cell lines using MTT assay. Compound 13e showed the highest anticancer activities with IC50 = 5.70, 7.15, 5.76 and 6.50 µM against HepG2, MCF-7, HCT116 and A549 cell lines correspondingly. Compounds 7c, 9b and 13a-d exhibited very good anticancer effects against the tested cancer cell lines. The highly effective six derivatives 7c, 10, 13b, 13c, 13d and 13e were examined against VERO normal cell lines to estimate their cytotoxic capabilities. Our conclusion revealed that compounds 7c, 10, 13b, 13c, 13d and 13e possessed low toxicity against VERO normal cells with IC50 prolonging from 41.66 to 53.99 μM. Also compounds 7a-c to 13a-e were further evaluated for their inhibitory activity against EGFRT790M and VEGFR-2. Also, their ability to bind with both EGFR and VEGFR-2 receptors was examined by molecular modeling. Compounds 13e, 13d, 7c and 13c excellently inhibited VEGFR-2 activity with IC50 = 0.90, 1.00, 1.25 and 1.50 µM respectively. Moreover, Compounds 13e, 7c, 10 and 13d excellently inhibited EGFRT790M activity with IC50 = 0.30, 0.35, 0.45 and 0.47 µM respectively. Finally, our derivatives 7b, 13d and 13e showed good in silico calculated ADMET profile.

New quinazoline sulfonamide derivatives as potential anticancer agents: Identifying a promising hit with dual EGFR/VEGFR-2 inhibitory and radiosensitizing activity

Herein, we report the synthesis of a series of new quinazoline sulfonamide conjugates 2-16 and their evaluation as potential anticancer agents via dual targeting of EGFRT790M and VEGFR-2. The newly synthesized compounds were designed based on the structure requirements of the target receptors and were confirmed using spectral data. The compounds were evaluated for their cytotoxicity against four cancer cell lines (HepG2, MCF-7, HCT116 and A549) using MTT assay. The most active compounds were further evaluated for their inhibitory activity against EGFRT790M and VEGFR-2. Compound 15 showed the most significant cytotoxic activity with IC50 = 0.0977 µM against MCF-7 and the most potent inhibitory activity against both EGFR and VEGFR with IC50 = 0.0728 and 0.0523 µM, respectively. Compound 15 was able to induce apoptosis in MCF-7 cells and cell cycle arrest at the G2/M phase. The relative safety profile of 15 was assessed using HEK-293 normal cell line and an ADMET profile was carried out. Radiosensitizing evaluation of 15 proved its significant ability to sensitize the cancer cell to the effect of radiation after being subjected to a single dose of 8 Gy gamma irradiation. Molecular docking studies revealed that 15 could bind to the ATP-binding site of EGF and VEGF receptors, inhibiting their activity.

EGFR T790M Mutation Detection in Patients With Non-Small Cell Lung Cancer After First Line EGFR TKI Therapy: Summary of Results in a Three-Year Period and a Comparison of Commercially Available Detection Kits

EGFR mutation in non-small cell lung cancer (NSCLC) offers a potential therapeutic target for tyrosine kinase inhibitor (TKI) therapy. The majority of these cases, however eventually develop therapy resistance, mainly by acquiring EGFR T790M mutation. Recently, third-generation TKIs have been introduced to overcome T790M mutation-related resistance. Cell free circulating tumor DNA (liquid biopsy) has emerged as a valuable alternative method for T790M mutation detection during patient follow up, when a tissue biopsy cannot be obtained for analysis. In this study, we summarized our experience with Super-ARMS EGFR Mutation Detection Kit (AmoyDx) on 401 samples of 242 NSCLC patients in a 3-year period in Hungary, comprising 364 plasma and 37 non-plasma samples. We also compared the performance of two commercially available detection kits, the cobas EGFR Mutation test v2 (Roche) and the Super-ARMS EGFR Mutation Detection Kit (AmoyDx). The same activating EGFR mutation was detected with the AmoyDx kit as in the primary tumor in 45.6% of the samples. T790M mutation was identified in 48.1% of the samples containing activating EGFR mutation. The detection rate of T790M mutation was not dependent on the DNA concentration of the plasma sample and there was no considerable improvement in mutation detection rate after a second, subsequent plasma sample. The concordance of EGFR activating mutation detection was 89% between the two methods, while this was 93% for T790M mutation detection. The AmoyDx kit, however showed an overall higher detection rate of T790M mutation compared to the cobas kit (p = 0.014). T790M mutation was detected at 29.8% of the patients if only plasma samples were available for analysis, while the detection rate was 70.2% in non-plasma samples. If the activating EGFR was detected in the plasma samples, the detection rate of T790M mutation was 42.4%. Although non-plasma samples provided a superior T790M mutation detection rate, we found that liquid biopsy can offer a valuable tool for T790M mutation detection, when a tissue biopsy is not available. Alternatively, a liquid biopsy can be used as a screening test, when re-biopsy should be considered in case of wild-type results.

Leptomeningeal Metastatic L858R EGFR-mutant Lung Cancer: Prompt Response to Osimertinib in the Absence of T790M-mutation and Effective Subsequent Pulsed Erlotinib

Leptomeningeal carcinomatosis (LMC) is a known sequel of metastatic lung cancer and its treatment is challenging. Nevertheless, treatment options for LMC due to metastatic epidermal growth factor receptor-mutant (EGFR-mutant) lung adenocarcinoma are expanding. We present a 52-year-old male patient with metastatic non-small-cell lung cancer (NSCLC). The patient was found to have L858R mutation in exon 21 of the EGFR gene. He was initially treated with erlotinib, followed by afatinib/cetuximab, followed by chemotherapy. Thereafter, his disease progressed to LMC. Although tissue biopsy did not show T790M-mutation, osimertinib (160 mg once daily) promptly induced clinical and radiological response that continued for five months. High dose pulsed erlotinib (1500 mg weekly) improved his quality of life and extended his survival for a further four months.

Point your SmartPhone at the code above. If you have a QR code reader the video abstract will appear. Or use:

https://youtu.be/hB2KtcuyWz4

Application of liquid biopsy-based targeted capture sequencing analysis to improve the precision treatment of non-small cell lung cancer by tyrosine kinase inhibitors

BACKGROUND

Targeted therapy of patients with non-small cell lung cancer (NSCLC) who harbour sensitising mutations by tyrosine kinase inhibitors (TKIs) has been found more effective than traditional chemotherapies. However, target genes status (eg, epidermal growth factor receptor (EGFR) TKIs sensitising and resistant mutations) need to be tested for choosing appropriate TKIs. This study is to investigate the performance of a liquid biopsy-based targeted capture sequencing assay on the molecular analysis of NSCLC.

METHODS

Plasma samples from patients with NSCLC who showed resistance to the first/second-generation EGFR TKIs treatment were collected. The AVENIO ctDNA Expanded Kit is a 77 pan-cancer genes detection assay that was used for detecting EGFR TKIs resistance-associated gene mutations. Through comparison of the EGFR gene testing results from the Cobas EGFR Mutation Test v2, and UltraSEEK Lung Panel, the effectiveness of the targeted capture sequencing assay was verified.

RESULTS

A total of 24 plasma cell-free DNA (cfDNA) samples were tested by the targeted capture sequencing assay. 33.3% (8/24) cfDNA samples were positive for EGFR exon 20 p.T790M which leads to EGFR dependent TKIs resistance. 8.3% (2/24) and 4.2% (1/24) samples were positive for mesenchymal-epithelial transition gene amplification and B-Raf proto-oncogene, serine/threonine kinase exon 15 p.V600E mutations which lead to EGFR independent TKIs resistance. The median value of the p.T790M variant allele fraction and variant copy numbers was 2% and 36.10 copies/mL plasma, respectively. The next-generation sequencing test showed higher than 90% concordance with either MassArray or qPCR-based methods for detecting either EGFR TKIs sensitising or resistance mutations.

CONCLUSION

The targeted capture sequencing test can support comprehensive molecular analysis needed for TKIs treatment, which is promising to be clinically applied for the improved precision treatment of NSCLC.

Health and Budget Impact of Liquid-Biopsy-Based Comprehensive Genomic Profile (CGP) Testing in Tissue-Limited Advanced Non-Small Cell Lung Cancer (aNSCLC) Patients

BACKGROUND AND OBJECTIVES: Molecular genetic testing using tissue biopsies can be challenging for patients due to unfavorable tumor sites, the invasive nature of a tissue biopsy, and the added time of booking a repeat biopsy (re-biopsy). Centers in Canada have found insufficient tissue rates to be approximately 10%, and even among successful biopsies, insufficient DNA in tissue samples is approximately 16%, triggering the lengthy process of re-biopsies. Using aNSCLC as an example, this study sought to characterize the health and budget impact of alternative liquid-biopsy(LBx)-based comprehensive genomic profile (CGP) testing in tissue-limited patients (TL-LBx-CGP) from a Canadian publicly funded healthcare perspective. MATERIAL AND METHODS: An economic model was developed to estimate the incremental cost and life-years gained as a population associated with adopting TL-LBx-CGP. The eligible patient population was modeled using a top-down epidemiological approach based on the published literature and expert clinician input. Treatment allocation was modeled based on biomarker prevalence in the published literature, and the availability of funded therapies. Costs included molecular testing, as well as drug, administrative, and supportive costs, and relevant health data included median overall survival and median progression-free survival data. RESULTS: Incorporation of TL-LBx-CGP demonstrated an overall impact of $14.7 million with 168 life-years gained to the Canadian publicly funded healthcare system in the 3-year time horizon.

High-Throughput Nucleotide Resolution Predictions of Assay Limitations Increase the Reliability and Concordance of Clinical Tests

PURPOSE

The ability of next-generation sequencing (NGS) assays to interrogate thousands of genomic loci has revolutionized genetic testing. However, translation to the clinic is impeded by false-negative results that pose a risk to patients. In response, regulatory bodies are calling for reliability measures to be reported alongside NGS results. Existing methods to estimate reliability do not account for sample- and position-specific variability, which can be significant. Here, we report an approach that computes reliability metrics for every genomic position and sample interrogated by an NGS assay.

METHODS

Our approach predicts the limit of detection (LOD), the lowest reliably detectable variant fraction, by taking technical factors into account. We initially explored how LOD is affected by input material amount, library conversion rate, sequencing coverage, and sequencing error rate. This revealed that LOD depends heavily on genomic context and sample properties. Using these insights, we developed a computational approach to predict LOD on the basis of a biophysical model of the NGS workflow. We focused on targeted assays for cell-free DNA, but, in principle, this approach applies to any NGS assay.

RESULTS

We validated our approach by showing that it accurately predicts LOD and distinguishes reliable from unreliable results when screening 580 lung cancer samples for actionable mutations. Compared with a standard variant calling workflow, our approach avoided most false negatives and improved interassay concordance from 94% to 99%.

CONCLUSION

Our approach, which we name LAVA (LOD-aware variant analysis), reports the LOD for every position and sample interrogated by an NGS assay. This enables reliable results to be identified and improves the transparency and safety of genetic tests.

Detection of EGFR mutations in liquid biopsy samples using allele-specific quantitative PCR: A comparative real-world evaluation of two popular diagnostic systems

PURPOSE

The detection of epidermal growth factor receptor (EGFR) mutations in plasma cell-free DNA (cfDNA) is an auxiliary tool for the molecular diagnosis of non-small cell lung cancer (NSCLC), especially when an adequate tumor tissue specimen cannot be obtained. We compared the diagnostic accuracy of two commonly used in vitro diagnostic-certified allele-specific quantitative PCR assays for detecting plasma cfDNA EGFR mutations.

METHODS

We analyzed EGFR mutations in plasma cfDNA from 90 NSCLC patients (stages I-IV) before treatment (n ​= ​60) and after clinical progression on EGFR tyrosine kinase inhibitors (n ​= ​30) using the cobas EGFR mutation test v2 (Roche Molecular Systems, Inc.) and therascreen EGFR Plasma RGQ PCR kit (Qiagen GmbH).

RESULTS

There was higher concordance between plasma cfDNA and matched tumor tissue EGFR mutations with cobas (66.67%) compared with therascreen (55.93%). The concordance rate increased to 90.00% with cobas (Cohen's kappa coefficient, κ ​= ​0.80; p ​< ​0.0001) and 73.33% with therascreen (κ ​= ​0.49; p ​= ​0.0009) in advanced NSCLC patients. In treatment-naïve patients, cobas was superior to therascreen (sensitivity: 82.35% vs. 52.94%; specificity: 100% vs. 100%). In patients with clinical progression on EGFR tyrosine kinase inhibitors, EGFR exon 20 p.T790M was detected in 30% and 23% of cfDNA samples by cobas and therascreen, respectively.

CONCLUSIONS

Cobas was superior to therascreen for detection of plasma EGFR mutations in advanced NSCLC. Plasma cfDNA EGFR mutation analysis is complex; therefore, the diagnostic accuracy of commercially available assays should be validated.

A Pan-Canadian Validation Study for the Detection of EGFR T790M Mutation Using Circulating Tumor DNA From Peripheral Blood

INTRODUCTION

Genotyping circulating tumor DNA (ctDNA) is a promising noninvasive clinical tool to identify the EGFR T790M resistance mutation in patients with advanced NSCLC with resistance to EGFR inhibitors. To facilitate standardization and clinical adoption of ctDNA testing across Canada, we developed a 2-phase multicenter study to standardize T790M mutation detection using plasma ctDNA testing.

METHODS

In phase 1, commercial reference standards were distributed to participating clinical laboratories, to use their existing platforms for mutation detection. Baseline performance characteristics were established using known and blinded engineered plasma samples spiked with predetermined concentrations of T790M, L858R, and exon 19 deletion variants. In phase II, peripheral blood collected from local patients with known EGFR activating mutations and progressing on treatment were assayed for the presence of EGFR variants and concordance with a clinically validated test at the reference laboratory.

RESULTS

All laboratories in phase 1 detected the variants at 0.5 % and 5.0 % allele frequencies, with no false positives. In phase 2, the concordance with the reference laboratory for detection of both the primary and resistance mutation was high, with next-generation sequencing and droplet digital polymerase chain reaction exhibiting the best overall concordance. Data also suggested that the ability to detect mutations at clinically relevant limits of detection is generally not platform-specific, but rather impacted by laboratory-specific practices.

CONCLUSIONS

Discrepancies among sending laboratories using the same assay suggest that laboratory-specific practices may impact performance. In addition, a negative or inconclusive ctDNA test should be followed by tumor testing when possible.

Consensus recommendations for optimizing biomarker testing to identify and treat advanced EGFR-mutated non-small-cell lung cancer

The advent of personalized therapy for non-small-cell lung carcinoma (nsclc) has improved patient outcomes. Selection of appropriate targeted therapy for patients with nsclc now involves testing for multiple biomarkers, including EGFR. EGFR mutation status is required to optimally treat patients with nsclc, and thus timely and accurate biomarker testing is necessary. However, in Canada, there are currently no standardized processes or methods in place to ensure consistent testing implementation. That lack creates challenges in ensuring that all appropriate biomarkers are tested for each patient and that the medical oncologist receives the results for making informed treatment decisions in a timely way. An expert multidisciplinary working group was convened to create consensus recommendations about biomarker testing in advanced nsclc in Canada, with a primary focus on EGFR testing. Recognizing that there are biomarkers beyond EGFR that require timely identification, the expert multidisciplinary working group considered EGFR testing in the broader context of integration into complex lung biomarker testing. Primarily, the panel of experts recommends that all patients with nonsquamous nsclc, regardless of stage, should undergo comprehensive reflex biomarker testing at diagnosis with targeted next-generation sequencing. The panel also considered the EGFR testing algorithm and the challenges associated with the pre-analytic, analytic, and post-analytic elements of testing. Strategies for funding testing by reducing silos of single biomarker testing for EGFR and for optimally implementing the recommendations presented here and educating oncology professionals about them are also discussed.

Multicenter Validation Study to Implement Plasma Epidermal Growth Factor Receptor T790M Testing in Clinical Laboratories

PURPOSE

Plasma detection of EGFR T790M mutations is an emerging alternative to tumor rebiopsy in acquired epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor resistance. Validation of analytical sensitivity and clinical utility is required before routine diagnostic use in clinical laboratories.

PATIENTS AND METHODS

Sixty-three patients with advanced EGFR-mutant lung cancer at 7 Canadian centers, who were being screened for the ASTRIS trial (ClinicalTrials.gov identifier: NCT02474355), participated in this companion study. Plasma T790M mutation was detected using droplet digital polymerase chain reaction, Cobas (Roche Diagnostics, Indianapolis, IN), or next-generation sequencing in 4 laboratories. T790M concordance was assessed between plasma and tumor samples.

RESULTS

Assessment of T790M in tumor biopsy tissue was successful in 81% of patients; 49% had confirmed T790M results (tumor or plasma) for ASTRIS. Plasma testing in this companion study yielded T790M results in 97% of patients; 62% had T790M-positive results, 36% had negative results, and 2% had indeterminate results. Of 38 patients with negative or indeterminate biopsy results, 55% had positive plasma T790M results, increasing the proportion with T790M-positive results to 73%. Sensitivity of plasma T790M testing was 75%. Overall concordance between tissue and plasma was 64%, and concordance among laboratories was 90.3%. Response to osimertinib and duration of therapy were similar irrespective of testing method (overall response rate, 62.5% for tissue, 66.7% for plasma, and 70.6% for both).

CONCLUSION

This multicenter validation study demonstrates that plasma EGFR T790M testing can identify significantly more patients than biopsy alone who may benefit from targeted therapy.

Low T790M relative allele frequency indicates concurrent resistance mechanisms and poor responsiveness to osimertinib

Background

T790M relative allele frequency (RAF) in plasma, calculated by the ratio of T790M to epidermal growth factor receptor (EGFR)-sensitizing mutation allele frequencies (AF), is associated with osimertinib response in patients with progressive non-small cell lung cancer (NSCLC) post 1^st generation EGFR-tyrosine kinase inhibitor (TKI) treatment. However, which subgroup of patients carry concurrent resistance mechanisms and have poor responsiveness to osimertinib remains unknown.

Methods

Matched re-biopsy tissue and plasma samples obtained from 32 patients who had progression following 1^st generation EGFR-TKI treatment were genotyped using next-generation sequencing (NGS) to investigate which subgroup of patients, classified by plasma position 790 (T790M) RAF, were more likely to carry concurrent resistance mechanisms. In another independent cohort, consisting of 21 T790M-positive patients, we validated whether these patients had a poor response to osimertinib treatment.

Results

In the discovery cohort, patients with T790M RAF less than 20% were more likely to harbor concurrent resistance mechanisms (P=0.018), such as MET or ERBB2 amplification, and small cell lung cancer transformation. In the validation cohort, we found that patients with low T790M RAF (<20%) had significantly lower objective response rates (ORRs) (0 vs. 68.8%, P=0.03) and disease control rates (DCRs) (60% vs. 100%, P=0.048) in response to osimertinib compared to patients with high T790M RAF.

Conclusions

In patients with progressive NSCLC post 1^st generation EGFR-TKI treatment, plasma T790M RAFs of less than 20% can be used to identify patients who carry concurrent resistance mechanisms, and can predict a poorer response to osimertinib.

Trial registration

This study was registered on http://www.chictr.org.cn (registration number: ChiCTR-DDD-16007900).

EGFR circulating tumour DNA testing: identification of predictors of ctDNA detection and implications for survival outcomes

Background

EGFR T790M testing is the standard of care for activating EGFR mutation (EGFRm) non-small cell lung cancer (NSCLC) progressing on 1st/2nd generation TKIs to select patients for osimertinib. Despite sensitive assays, detection of circulating tumour deoxyribonucleic acid (ctDNA) is variable and influenced by clinical factors. The number and location of sites of progressive disease at time of testing were reviewed to explore the effect on EGFR ctDNA detection. The prognostic value of EGFR ctDNA detection on survival outcomes was assessed.

Methods

Following extraction of cell-free DNA from plasma using the QIAamp Circulating Nucleic Acid Kit, custom droplet digital polymerase chair reaction (ddPCR) assays were used to assess EGFR ctDNA using the Bio-Rad QX200 system. The ddPCR assay has a limit of detection of ≤0.15% variant allele fraction. Baseline characteristics and imaging reports at time of EGFR ctDNA testing were reviewed retrospectively for a 1 year period.

Results

The study included 177 patients who had an EGFR ctDNA test. Liver (aOR 3.13) or bone (aOR 2.76) progression or 3–5 sites of progression (aOR 2.22) were predictive of EGFR ctDNA detection. The median OS from first ctDNA test after multiple testing iterations was 12.3 m undetectable EGFR ctDNA, 7.6 m for original EGFR mutation only and 24.1 m with T790M (P=0.001).

Conclusions

Patients with liver or bone progression and 3–5 progressing sites are more likely to have informative EGFR ctDNA testing. Detection of EGFR ctDNA is a negative prognostic indicator in the absence of a T790M resistance mutation, potentially reflecting the disease burden in the absence of targeted therapy options.

Clinical implementation of plasma EGFR T790M testing using droplet digital PCR in TKI-resistant NSCLC patients

BACKGROUND

Majority of non-small cell lung cancer (NSCLC) patients progressed on epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) due to acquired T790M mutation. Blood sample is increasingly used in clinical setting for EGFR T790M detection and our laboratory employed the droplet digital PCR (ddPCR) methodology for testing. This study investigated the positive rate, specimen type for rebiopsy and clinical impact of blood-based EGFR T790M testing.

METHODS

We retrospectively evaluated clinical samples that underwent plasma EGFR T790M testing in TTSH Molecular Diagnostic Laboratory from August 2017 to September 2019. Data on diagnosis, EGFR activating and T790M mutations, and treatment strategies were recorded.

RESULTS

A total of 104 progressive NSCLC cases were included in this study. Overall, 46 patients (44.2%) were tested T790M positive, and 47.8% of these tested positive had low levels (defined as ≤3% fractional abundance and <50 copies/mL plasma), which may be missed by the conventional methods with lower sensitivity. Of these tested with low T790M abundance, 77.3% subsequently received osimertinib. Activating mutations were not detected in 42 (40.4%) cases, indicating that the tumors were not actively shedding ctDNA. Among these, 24 patients underwent repeat testing with tissue or blood specimens. Thirteen patients were subsequently tested T790M positive and 12 of them switched treatment to osimertinib. The recommendation to repeat testing with a different biopsy or after a suitable interval increased the overall positive rate to 56.7% (59/104).

CONCLUSION

The use of a highly sensitive platform such as ddPCR for the detection of low abundance T790M, and the approach of repeat testing in cases with insufficient ctDNA increased the positive rate. This in turn identified more patients who are eligible for targeted therapy.

Clinical implementation of circulating tumour DNA testing for EGFR T790M for detection of treatment resistance in non-small cell lung cancer

Aims

Epidermal growth factor receptor (EGFR) T790M mutations can be detected in the circulating tumour DNA from plasma of patients with non-small cell lung cancer (NSCLC) to triage patients for osimertinib eligibility and monitor patients longitudinally for development of T790M-mediated resistance.

Methods

Using droplet digital PCR (ddPCR), we examined the EGFR T790M status of 343 sequential patients with NSCLC and correlated mutational status with demographic and clinical features. Where available, serial T790M blood test results were assessed to identify clinical triggers and timing of repeat testing.

Results

Of the 343 patients with liquid biopsy test results, 24% were T790M positive. No clear clinical correlation with a T790M positive test result was identified in this study, although the number of metastatic sites did correlate significantly with the presence of EGFR sensitising mutations (L858R or exon 19 deletion) in patient plasma, as a measure of tumour DNA shedding. Of the 59 serial blood tests from patients that initially tested negative, 14% were positive on sequential testing, at a time interval up to 6 months after an initially negative blood test.

Conclusions

The ddPCR test for EGFR T790M mutations effectively triaged 24% of patients for treatment with osimertinib, avoiding the need for invasive tissue biopsy in these patients. Our findings suggest that initial and repeat ctDNA testing can be used to monitor for acquired EGFR T790M resistance for NSCLC.

Pre-analytical issues in liquid biopsy – where do we stand?

It is well documented that in the chain from sample to the result in a clinical laboratory, the pre-analytical phase is the weakest and most vulnerable link. This also holds for the use and analysis of extracellular nucleic acids. In this short review, we will summarize and critically evaluate the most important steps of the pre-analytical phase, i.e. the choice of the best control population for the patients to be analyzed, the actual blood draw, the choice of tubes for blood drawing, the impact of delayed processing of blood samples, the best method for getting rid of cells and debris, the choice of matrix, i.e. plasma vs. serum vs. other body fluids, and the impact of long-term storage of cell-free liquids on the outcome. Even if the analysis of cell-free nucleic acids has already become a routine application in the area of non-invasive prenatal screening (NIPS) and in the care of cancer patients (search for resistance mutations in the EGFR gene), there are still many unresolved issues of the pre-analytical phase which need to be urgently tackled.

Canadian consensus: a new systemic treatment algorithm for advanced EGFR-mutated non-small-cell lung cancer

Background

Multiple clinical trials for the treatment of advanced EGFR-mutated non-small-cell lung cancer (nsclc) have recently been reported. As a result, the treatment algorithm has changed, and many important clinical questions have been raised:■ What is the optimal first-line treatment for patients with EGFR-mutated nsclc?■ What is preferred first-line treatment for patients with brain metastasis?■ What is the preferred second-line treatment for patients who received first-line first- or second-generation tyrosine kinase inhibitors (tkis)?■ What is the preferred treatment after osimertinib?■ What evidence do we have for treating patients whose tumours harbour uncommon EGFR mutations?

Methods

A Canadian expert panel was convened to define the key clinical questions, review recent evidence, and discuss and agree on practice recommendations for the treatment of advanced EGFR-mutated nsclc.

Results

The published overall survival results for osimertinib, combined with its central nervous system activity, have led to osimertinib becoming the preferred first-line treatment for patients with common EGFR mutations, including those with brain metastasis. Other agents could still have a role, especially when osimertinib is not available or not tolerated. Treatment in subsequent lines of therapy depends on the first-line therapy or on T790M mutation status. Treatment recommendations for patients whose tumours harbour uncommon EGFR mutations are guided mainly by retrospective and limited prospective evidence. Finally, the evidence for sequencing and combining tkis with chemotherapy, angiogenesis inhibitors, checkpoint inhibitors, and other new therapeutics is reviewed.

Conclusions

This Canadian expert consensus statement and algorithm were driven by significant advances in the treatment of EGFR-mutated nsclc.

Cell-Free Circulating Tumour DNA Blood Testing to Detect EGFR T790M Mutation in People With Advanced Non-Small Cell Lung Cancer: A Health Technology Assessment

BACKGROUND

Cell-free circulating tumour DNA blood testing (also called liquid biopsy) can determine if a person with advanced non-small cell lung cancer (NSCLC) whose disease is progressing has developed the epidermal growth factor receptor (EGFR) T790M resistance mutation. Identifying this resistance mutation can help physicians choose appropriate treatment (i.e., osimertinib if positive and chemotherapy if negative). Tissue biopsy is typically used to look for the resistance mutation, but this is an invasive test that might not be feasible if the patient is too ill. We conducted a health technology assessment of liquid biopsy for people with advanced NSCLC, which included an evaluation of the diagnostic accuracy, clinical utility, safety, cost-effectiveness, and the budget impact of publicly funding liquid biopsy, as well as an evaluation of patient preferences and values.

METHODS

We performed a systematic literature search of the clinical evidence. We assessed the risk of bias of each included study using Risk of Bias in Systematic Reviews (ROBIS), Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2), Risk of Bias Among Non-randomized Studies (RoBANS), and the Cochrane risk of bias (ROB) tool and assessed quality of evidence according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group criteria. We performed a systematic economic literature search and conducted short-term and long-term cost-effectiveness and cost-utility analyses comparing liquid biopsy as a triage test, liquid biopsy alone, and tissue biopsy alone from a public payer perspective. We also analyzed the budget impact of publicly funding liquid biopsy for people in Ontario with advanced NSCLC. To assess the potential value of liquid biopsy, we spoke with people with lung cancer and people with an understanding of the process of liquid biopsy.

RESULTS

We included 19 studies (within a published systematic review) to examine diagnostic test accuracy and 12 studies to examine clinical utility. In patients with advanced NSCLC, liquid biopsy to detect the EGFR T790M resistance mutation demonstrated a positive and negative predictive value of 89% and 61%, respectively, a sensitivity of 68%, and specificity of 86%. No studies examined the clinical utility of liquid biopsy as a triage test. When NSCLC was treated appropriately, progression-free survival was similar in patients with and without the resistance mutation, as ascertained by liquid biopsy.We estimated that it costs about $700 to conduct a liquid biopsy and $2,500 to conduct a tissue biopsy. Our analyses showed that, when considering costs and effects directly related to testing, liquid biopsy (as a triage test, which means patients who test negative undergo a follow-up tissue biopsy, or alone, which means using only liquid biopsy) was less costly than tissue biopsy alone and led to fewer tissue biopsies. Using liquid biopsy as a triage test produced the most correct treatment decisions and greatest number of people who were given osimertinib.When considering long-term costs (i.e., treatment and care) and effects (i.e., life-years and quality-adjusted life-years [QALYs]), liquid biopsy as a triage test was the most effective and most costly strategy followed by liquid biopsy alone. Tissue biopsy alone was the least effective and least costly strategy. The incremental cost-effectiveness ratios (ICERs) of liquid biopsy as a triage test compared with liquid biopsy alone and of liquid biopsy alone compared with tissue biopsy alone were greater than $100,000 per QALY. However, this result was largely driven by the cost of osimertinib, which was used more often when liquid biopsy was used as a triage test.We estimated that the total annual budget impact of publicly funding liquid biopsy as a triage test in Ontario over the next 5 years would range from approximateily $60,000 in year 1 to $3 million in year 5.People with lung cancer with whom we spoke said that liquid biopsy would likely be an appropriate test for people with NSCLC given their frail condition and because it would avoid the pain and anxiety associated with tissue biopsy.

CONCLUSIONS

As a minimally invasive test, liquid biopsy identifies a high proportion of people with the EGFR T790M resistance mutation. This identification could better guide treatment for people with advanced NSCLC. However, its relatively low negative predictive value means it is best used as a triage test (i.e., followed by tissue biopsy if the liquid biopsy does not identify a resistance mutation). Liquid biopsy as a triage test is likely more effective than tissue biopsy alone. However, owing to the high cost of treatment, liquid biopsy may not be cost-effective. We estimated that publicly funding liquid biopsy as a triage test in Ontario would result in additional costs (related to more patients being treated) of between $0.06 million and $3 million over the next 5 years.

Biopsy on progression in patients with EGFR mutation-positive advanced non-small-cell lung cancer-a Canadian experience

Background

Epidermal growth factor receptor (egfr) tyrosine kinase inhibitors (tkis) are standard therapy for patients with advanced or metastatic non-small-cell lung cancer harbouring an EGFR mutation. Upon progression, 50%-60% develop a secondary T790M mutation. Recent trials demonstrated outcome improvement with osimertinib compared with standard platinum-based chemotherapy as second-line therapy for patients with secondary T790M mutation. To identify T790M, a biopsy of the tumour or, more recently, plasma is necessary. This retrospective study aimed to evaluate biopsy procedures and mutational analysis at 2 Canadian cancer centres.

Methods

In a retrospective review of patients who were approached to enrol in the aura2, aura3, or astris studies, demographics, eligibility for rebiopsy upon progression after an egfr tki, rebiopsy methods and complications, number of rebiopsies, and incidence of the T790M mutation were collected.

Results

Of 84 patients considered for trial enrolment, 80 signed a consent. In 78 patients who underwent rebiopsy, computed tomography or ultrasonography guidance were the most common methods used. The most common biopsy sites were lung and lymph nodes. The median number of rebiopsies performed to find a T790M mutation was 2. Only 9% of patients experienced complications. Of samples obtained, 74% were adequate for testing after initial rebiopsy. A T790M mutation was found in 47 patients, of whom 44 were enrolled on a trial. After multiple rebiopsies, only 5% of samples were inadequate for molecular analysis.

Conclusions

In the Canadian setting, the acceptance of rebiopsy on progression was high. Multiple rebiopsies were clinically feasible and could increase the yield for T790M mutation. The incidence of complications was low despite the most common site for rebiopsy being lung.

Clinical feasibility of NGS liquid biopsy analysis in NSCLC patients

Background

Analysis of circulating tumor nucleic acids in plasma of Non-Small Cell Lung Cancer (NSCLC) patients is the most widespread and documented form of "liquid biopsy" and provides real-time information on the molecular profile of the tumor without an invasive tissue biopsy.

Methods

Liquid biopsy analysis was requested by the referral physician in 121 NSCLC patients at diagnosis and was performed using a sensitive Next Generation Sequencing assay. Additionally, a comparative analysis of NSCLC patients at relapse following EGFR Tyrosine Kinase Inhibitor (TKIs) treatment was performed in 50 patients by both the cobas and NGS platforms.

Results

At least one mutation was identified in almost 49% of the cases by the NGS approach in NSCLC patients analyzed at diagnosis. In 36 cases with paired tissue available a high concordance of 86.11% was observed for clinically relevant mutations, with a Positive Predictive Value (PPV) of 88.89%. Furthermore, a concordance rate of 82% between cobas and the NGS approach for the EGFR sensitizing mutations (in exons 18, 19, 21) was observed in patients with acquired resistance to EGFR TKIs, while this concordance was 94% for the p.T790M mutation, with NGS being able to detect this mutation in three 3 additional patients.

Conclusions

This study indicates the feasibility of circulating tumor nucleic acids (ctNA) analysis as a tumor biopsy surrogate in clinical practice for NSCLC personalized treatment decision making. The use of new sensitive NGS techniques can reliably detect tumor-derived mutations in liquid biopsy and provide clinically relevant information both before and after targeted treatment in patients with NSCLC. Thus, it could aid physicians in treatment decision making in clinical practice.

Optimizing the sequencing of tyrosine kinase inhibitors (TKIs) in epidermal growth factor receptor (EGFR) mutation-positive non-small cell lung cancer (NSCLC)

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer, accounting for 80-85% of cases. Epidermal growth factor receptor (EGFR) mutations are observed in approximately 40% and 20% of patients with NSCLC in Asian and non-Asian populations, respectively. First-generation (gefitinib, erlotinib) and second-generation (afatinib, dacomitinib) EGFR-tyrosine kinase inhibitors (TKIs) have been standard-of-care (SoC) first-line treatment for patients with sensitizing EGFR mutation positive advanced NSCLC following Phase III trials versus platinum-based doublet chemotherapy. However, most patients treated with first-line first- or second-generation EGFR-TKIs develop resistance. Osimertinib, a third-generation, central nervous system active EGFR-TKI which potently and selectively inhibits both EGFR-TKI sensitizing (EGFRm) and the most common EGFR T790 M resistance mutations, has shown superior efficacy versus first-generation EGFR-TKIs (gefitinib / erlotinib). Osimertinib is now a treatment option for patients with advanced NSCLC harboring EGFRm in the first-line setting, and treatment of choice for patients with T790 M positive NSCLC following disease progression on first-line EGFR-TKIs. The second-generation EGFR-TKI dacomitinib has also recently been approved for the first-line treatment of EGFRm positive metastatic NSCLC. There remains a need to determine appropriate sequencing of EGFR-TKIs in this setting, including EGFR-TKIs as monotherapy or in combination with other TKIs / signaling pathway inhibitors. This review considers the evolving role of sequencing treatments to maximize benefits for patients with EGFRm positive advanced NSCLC.

ASTRIS: a global real-world study of osimertinib in >3000 patients with EGFR T790M positive non-small-cell lung cancer

Aim: Osimertinib is a third-generation, irreversible, oral EGFR tyrosine kinase inhibitor. We report real-world effectiveness and safety data. Patients & methods: EGFR T790M positive advanced non-small-cell lung cancer adults, who received ≥1 prior EGFR tyrosine kinase inhibitor, received osimertinib 80 mg daily. Primary effectiveness outcome: overall survival. Secondary effectiveness outcomes included: investigator-assessed clinical response, progression-free survival, time-to-treatment discontinuation. Results: At data cutoff, 3015 patients had enrolled: 57.1% had investigator-assessed response (95% CI: 55.2-58.9). Median progression-free survival: 11.1 months (95% CI: 11.0-12.0) and median time-to-treatment discontinuation: 13.5 months (95% CI: 12.6-13.9). Interstitial lung disease/pneumonitis-like events reported in 28 (1%) patients. Conclusion: Osimertinib demonstrated clinical effectiveness similar to efficacy observed in the clinical trial program with no new safety signals.

Biomarkers in Non-Small Cell Lung Cancers: Indian Consensus Guidelines for Molecular Testing

Novel molecular targets and promising targeted therapies have reshaped diagnostics in patients with advanced non-small cell lung cancer (NSCLC). Despite this progress, the implementation of molecular screening to identify predictive biomarkers in Indian clinical and pathology settings has been challenging due to operational and logistical constraints. This consensus guideline brings together medical oncologists, molecular pathologists and pathologists from India to provide a quick and competent reference for biomarker testing in NSCLC. The guideline summarizes the importance of targetable mutations in NSCLC such as epidermal growth factor receptor (EGFR), rearrangements in anaplastic lymphoma kinase and receptor tyrosine kinase encoded by ROS-1 gene, overexpression of programmed cell death ligand-1 and resistant EGFR mutations. It reaffirms recommendations from international working groups, discusses vulnerable pre-analytical procedures and provides a balanced review on the pros and cons of different diagnostic tests (immunohistochemistry, fluorescence in situ hybridization, polymerase chain reaction-based testing and next-generation sequencing). The document also provides an algorithm to aid diagnostic decision-making and a checklist to assess the quality of testing laboratories that will help the medical oncologists make an informed choice. Overall, these recommendations are based on evidence and clinical experience and will aid policymakers, oncologists, health care practitioners and pathologists who strive to implement molecular strategies and make informed decisions for improved care in NSCLC in India.Funding: AstraZeneca Pharma India Limited.

A Canadian guideline on the use of next-generation sequencing in oncology

Rapid advancements in next-generation sequencing (ngs) technology have created an unprecedented opportunity to decipher the molecular profile of tumours to more effectively prevent, diagnose, and treat cancer. Oncologists now have the option to order molecular tests that can guide treatment decisions. However, to date, most oncologists have received limited training in genomics, and they are now faced with the challenge of understanding how such tests and their interpretation align with patient management. Guidance on how to effectively use ngs technology is therefore needed to aid oncologists in applying the results of genomic tests. The Canadian guideline presented here describes best practices and unmet needs related to ngs-based testing for somatic variants in oncology, including clinical application, assay and sample selection, bioinformatics and interpretation of reports performed by laboratories, patient communication, and clinical trials.