Longitudinal liquid biopsy anticipates hyperprogression and early death in advanced non-small cell lung cancer patients treated with immune checkpoint inhibitors.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have revolutionised treatment of advanced non-small cell lung cancer (aNSCLC), but a proportion of patients had no clinical benefit and even experienced detrimental effects. This study aims to characterise patients experiencing hyperprogression (HPD) and early death (ED) by longitudinal liquid biopsy. METHODS: aNSCLC receiving ICIs were prospectively enrolled. Plasma was collected at baseline (T1) and after 3/4 weeks of treatment, according to the treatment schedule (T2). Cell-free DNA (cfDNA) was quantified and analysed by NGS. cfDNA quantification and variant allele fraction (VAF) of tumour-associated genetic alterations were evaluated for their potential impact on outcome. The genetic alteration with the highest VAF (maxVAF) at baseline was considered as a reference. RESULTS: From March 2017 to August 2019, 171 patients were enrolled. Five cases matched criteria for HPD and 31 ED were recorded; one overlapped. Quantification of cfDNA at T2 and its absolute and relative variation (T2-T1) were significantly associated with the risk of ED (P = 0.012, P = 0.005, P = 0.009). MaxVAF relative change (T2-T1/T1) was significantly associated with the risk of HPD (P = 0.02). After identifying optimal cut-off values, a two-step risk assessment model was proposed. DISCUSSION: Liquid biopsy performed early during treatment has the potential to identify patients at high risk of ED and HPD.

Early assessment of KRAS mutation in cfDNA correlates with risk of progression and death in advanced non-small-cell lung cancer.

BACKGROUND: Liquid biopsy has the potential to monitor biological effects of treatment. KRAS represents the most commonly mutated oncogene in Caucasian non-small-cell lung cancer (NSCLC). The aim of this study was to explore association of dynamic plasma KRAS genotyping with outcome in advanced NSCLC patients. METHODS: Advanced NSCLC patients were prospectively enrolled. Plasma samples were collected at baseline (T1), after 3 or 4 weeks, according to treatment schedule (T2) and at first radiological restaging (T3). Patients carrying KRAS mutation in tissue were analysed in plasma with droplet digital PCR. Semi-quantitative index of fractional abundance of mutated allele (MAFA) was used. RESULTS: KRAS-mutated cohort included 58 patients, and overall 73 treatments (N = 39 chemotherapy and N = 34 immune checkpoint inhibitors) were followed with longitudinal liquid biopsy. Sensitivity of KRAS detection in plasma at baseline was 48.3% (95% confidence interval (CI): 35.0-61.8). KRAS mutation at T2 was associated with increased probability of experiencing progressive disease as best radiological response (adjusted odds ratio: 7.3; 95% CI: 2.1-25.0, p = 0.0016). Increased MAFA (T1-T2) predicted shorter progression-free survival (adjusted hazard ratio (HR): 2.1; 95% CI: 1.2-3.8, p = 0.0142) and overall survival (adjusted HR: 3.2; 95% CI: 1.2-8.4, p = 0.0168). CONCLUSIONS: Longitudinal analysis of plasma KRAS mutations correlated with outcome: its early assessment during treatment has great potentialities for monitoring treatment outcome in NSCLC patients.

Peripheral Blood Markers Identify Risk of Immune-Related Toxicity in Advanced Non-Small Cell Lung Cancer Treated with Immune-Checkpoint Inhibitors.

BACKGROUND: Immune-checkpoint inhibitors (ICIs) are now standard of care for advanced non-small cell lung cancer (NSCLC). Unfortunately, many patients experience immune-related adverse events (irAEs), which are usually mild and reversible, but they require timely management and may be life threatening. No predictive markers of irAEs are available. MATERIALS AND METHODS: The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) were evaluated in patients with NSCLC consecutively treated with ICIs. Prespecified cutoff values of NLR and PLR were used and related to outcome and onset of irAEs. A control group of patients with advanced NSCLC not receiving ICIs was included. RESULTS: The study included 184 patients: 26 (14.1%) received pembrolizumab upfront, and 142 (77%) received ICIs (pembrolizumab, nivolumab or atezolizumab) after one or more lines of chemotherapy. The median number of ICIs cycles was six (range, 1-61). The median progression-free survival and overall survival were 4.8 (95% CI, 3.4-6.3) and 20.6 (95% CI, 14.7-26.5) months, respectively. Sixty patients (32.6%) developed irAEs, mainly grade 1-2 (65.0%), causing ICI interruption in 46 cases (25.0%). Low NLR and low PLR at baseline were significantly associated with the development of irAEs (odds ratio [OR], 2.2; p = .018 and OR, 2.8; p = .003, respectively). Multivariate analyses confirmed PLR as independent predictive marker of irAEs (OR, 2.3; p = .020). CONCLUSION: NLR and PLR may predict the appearance of irAEs in non-oncogene-addicted aNSCLC, although this conclusion warrants prospective validation. IMPLICATIONS FOR PRACTICE: This study was designed to investigate the role of blood biomarkers in predicting the occurrence of immune-related adverse events (irAEs) in patients with advanced non-small cell lung cancer receiving immunotherapy. The results of the study suggest a potential predictive role of neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio as markers for irAE development in this category of patients. These data provide rationale for an easy and feasible application to be validated in clinical practice.

LKB1 and Tumor Metabolism: The Interplay of Immune and Angiogenic Microenvironment in Lung Cancer.

Liver kinase B1 (LKB1) is a tumor suppressor gene whose inactivation is frequent in different tumor types, especially in lung adenocarcinoma (about 30% of cases). LKB1 has an essential role in the control of cellular redox homeostasis by regulating ROS production and detoxification. Loss of LKB1 makes the tumor cell more sensitive to oxidative stress and consequently to stress-inducing treatments, such as chemotherapy and radiotherapy. LKB1 loss triggers complex changes in tumor microenvironment, supporting a role in the regulation of angiogenesis and suggesting a potential role in the response to anti-angiogenic treatment. On the other hand, LKB1 deficiency can promote an immunosuppressive microenvironment and may be involved in primary resistance to anti-PD-1/anti-PD-L1, as it has been reported in lung cancer. The aim of this review is to discuss interactions of LKB1 with the tumor microenvironment and the potential applications of this knowledge in predicting response to treatment in lung cancer.

Uncommon and Rare EGFR Mutations in Non-Small Cell Lung Cancer Patients with a Focus on Exon 20 Insertions and the Phase 3 PAPILLON Trial: The State of the Art.

Uncommon (ucEGFRmuts) and rare epidermal growth factor receptor (EGFR) mutations account for 10-15% of diagnosed cases and consist of a heterogeneous group represented by several clusters within exons 18-21 (e.g., exon 18 point mutations, exon 21 L861X, exon 20 S768I), as well as exon 20 insertions (Ex20ins). Their incidence is under molecular and clinical investigation following recent findings that reported an increase of sensitivity and specificity of next-generation sequencing (NGS) methods. Consequently, their detection allows for the selection of emerging treatment options to significantly improve patients' outcomes in these particular subgroups of EGFR-mutated advanced non-small cell lung cancer (NSCLC). Specifically, this commentary is focused on the notable progress of the Phase 3 PAPILLON study that showed primary efficacy results from amivantamab, a bispecific antibody with specific binding and affinity to extracellular domains of EGFR and MET, plus chemotherapy in the first-line setting for EGFR exon 20 insertion-mutated advanced or metastatic NSCLC patients, as compared with chemotherapy alone, thus becoming the new standard of care in this group of patients.

Face to face among different chemo-immunotherapy combinations in the first line treatment of patients with advanced non-small cell lung cancer: Results of an international expert panel meeting by the italian association of thoracic oncology (AIOT).

BACKGROUND: The combination of platinum-based chemotherapy with immune-checkpoint inhibitors (ICIs) is a standard of care option in the front-line treatment of advanced non-small cell lung cancer (NSCLC). Positive efficacy and safety results have been demonstrated with different chemo-ICI combinations in the corresponding clinical trials, however no randomized prospective comparison is available and there is no evidence on how to choose among the available regimens. METHODS: A virtual International Expert Panel took place in July 2023 to review data on chemo-ICI regimens available in the first-line setting in patients with NSCLC, and reach common considerations both in clinical practice and in research setting. RESULTS: Overall, all panelists agreed that safety of the chemo-immunotherapy combination regimens is supported by reviewed data, showing no additional toxicity concerns over those of the individual components of each regimen and highlighting differences in toxicity profile based on ICI component (single anti-PD-1 versus double anti-PD-1 and anti-CTLA-4). Among disease characteristics, PD-L1 value (<1%) but not histology was considered a potential selection factor in favor of the combination with dual ICI. With regards to clinical features, the panelists agreed that chemotherapy, whichever the ICI combination regimen, remains the backbone to counteract disease-related symptoms included those conditioning worse performance status. The panelists defined high, medium, and low priorities in clinical research. High priority was attributed to prospectively evaluating the impact of the addition of anti-CTLA-4 on brain metastasis, biomarker subgroups, and the optimal duration and schedule of combination regimens. CONCLUSIONS: Based on the available evidence, the panelists reached common considerations on strengths and differences between chemotherapy plus single agent ICI and chemotherapy plus double agent ICIs in patients with advanced NSCLC. In the absence of direct comparison, different toxicity profile and subgroup analysis by PD-L1 are considered as the main potential features to select among the two regimens, however to be confirmed by recommended prospective randomized clinical research.

Alectinib vs. Lorlatinib in the Front-Line Setting for ALK-Rearranged Non-Small-Cell Lung Cancer (NSCLC): A Deep Dive into the Main Differences across ALEX and CROWN Phase 3 Trials.

Various next-generation ALK TKIs are available as first-line options for ALK-positive NSCLC, with alectinib and lorlatinib being commonly preferred. However, no direct comparison between them has been conducted, making it impossible to pick a winner. We performed an analytic, 'non-comparative' assessment of the two phase 3 pivotal clinical trials showing superiority of alectinib (ALEX) and lorlatinib (CROWN) in comparison to crizotinib. Overall, the two studies were very similar in the study design and patient characteristics, with the exception of the selection and evaluation of brain metastases. PFS hazard ratios numerically favored lorlatinib, both according to the investigator and to BICR. Notably, the 3-year PFS rate was numerically higher with lorlatinib (64%) than with alectinib (46.4%). Despite similar response rates and overall intracranial response, the rate of complete intracranial response was higher with lorlatinib, with a cumulative incidence risk of CNS disease progression at 12 months of 9.4% with alectinib and 2.8% with lorlatinib. The peculiar toxicities of lorlatinib were related to lipidic profile alterations, peripheral oedema and cognitive effects, with no impact on cardiovascular risk nor impairment in quality of life versus crizotinib. Furthermore, the rate of permanent treatment discontinuation due to adverse events was numerically higher with alectinib (26%) than with lorlatinib (7%). In conclusion, despite the immature OS data for both drugs, the efficacy of lorlatinib appears higher than alectinib while maintaining a manageable toxicity profile.

The Evolving Scenario of ES-SCLC Management: From Biology to New Cancer Therapeutics.

Small cell lung cancer (SCLC) is an aggressive neuroendocrine carcinoma accounting for 15% of lung cancers with dismal survival outcomes. Minimal changes in therapy and prognosis have occurred in SCLC for the past four decades. Recent progress in the treatment of extensive-stage disease (ES-SCLC) has been marked by incorporating immune checkpoint inhibitors (ICIs) into platinum-based chemotherapy, leading to modest improvements. Moreover, few second-line-and-beyond treatment options are currently available. The main limitation for the molecular study of SCLC has been the scarcity of samples, because only very early diseases are treated with surgery and biopsies are not performed when the disease progresses. Despite all these difficulties, in recent years we have come to understand that SCLC is not a homogeneous disease. At the molecular level, in addition to the universal loss of retinoblastoma (RB) and TP53 genes, a recent large molecular study has identified other mutations that could serve as targets for therapy development or patient selection. In recent years, there has also been the identification of new genetic subtypes which have shown us how intertumor heterogeneity exists. Moreover, SCLC can also develop intratumoral heterogeneity linked mainly to the concept of cellular plasticity, mostly due to the development of resistance to therapies. The aim of this review is to quickly present the current standard of care of ES-SCLC, to focus on the molecular landscapes and subtypes of SCLC, subsequently present the most promising therapeutic strategies under investigation, and finally recap the future directions of ongoing clinical trials for this aggressive disease which still remains a challenge.

Immune checkpoint inhibitors in EGFR-mutant non-small cell lung cancer: A systematic review.

BACKGROUND: Since their first introduction in clinical practice, immune checkpoint inhibitors showed limited benefit in patients with NSCLC harboring EGFR mutations. With the rationale of increasing immune activation, combinatorial ICI strategies have been evaluated also in this subgroup of patients. METHODS: We performed a systematic review on efficacy of ICI-based strategies in EGFR-mutant NSCLC according to most updated evidence. RESULTS: Overall, ICI monotherapy and ICI plus chemotherapy confirm to be ineffective in EGFR-mutant NSCLC, whereas the combination of ICI with antiangiogenic and chemotherapy showed promising results. Limited data are available with alternative ICI combination strategies, driven by strong biological rationale of modulating the tumor immune microenvironment. CONCLUSIONS: To date, the available evidence do not support the use of ICI in patients with NSCLC harboring EGFR mutations. Clinical trials are ongoing to define which is the best timing and exploring novel combinations with ICI in this specific disease.

Sustained Improvement in the Management of Patients with Non-Small-Cell Lung Cancer (NSCLC) Harboring ALK Translocation: Where Are We Running?

ALK translocation amounts to around 3-7% of all NSCLCs. The clinical features of ALK+ NSCLC are an adenocarcinoma histology, younger age, limited smoking history, and brain metastases. The activity of chemotherapy and immunotherapy is modest in ALK+ disease. Several randomized trials have proven that ALK inhibitors (ALK-Is) have greater efficacy with respect to platinum-based chemotherapy and that second/third generation ALK-Is are better than crizotinib in terms of improvements in median progression-free survival and brain metastases management. Unfortunately, most patients develop acquired resistance to ALK-Is that is mediated by on- and off-target mechanisms. Translational and clinical research are continuing to develop new drugs and/or combinations in order to raise the bar and further improve the results attained up to now. This review summarizes first-line randomized clinical trials of several ALK-Is and the management of brain metastases with a focus on ALK-I resistance mechanisms. The last section addresses future developments and challenges.

Stage III Non-Small-Cell Lung Cancer: An Overview of Treatment Options.

Lung cancer is the second-most commonly diagnosed cancer and the leading cause of cancer death worldwide. The most common histological type is non-small-cell lung cancer, accounting for 85% of all lung cancer cases. About one out of three new cases of non-small-cell lung cancer are diagnosed at a locally advanced stage-mainly stage III-consisting of a widely heterogeneous group of patients presenting significant differences in terms of tumor volume, local diffusion, and lymph nodal involvement. Stage III NSCLC therapy is based on the pivotal role of multimodal treatment, including surgery, radiotherapy, and a wide-ranging option of systemic treatments. Radical surgery is indicated in the case of hilar lymphnodal involvement or single station mediastinal ipsilateral involvement, possibly after neoadjuvant chemotherapy; the best appropriate treatment for multistation mediastinal lymph node involvement still represents a matter of debate. Although the main scope of treatments in this setting is potentially curative, the overall survival rates are still poor, ranging from 36% to 26% and 13% in stages IIIA, IIIB, and IIIC, respectively. The aim of this article is to provide an up-to-date, comprehensive overview of the state-of-the-art treatments for stage III non-small-cell lung cancer.

Sharing Experience with Anaplastic Lymphoma Kinase Tyrosine Kinase Inhibitors in Lung Cancer: An Italian Expert Panel Discussion.

BACKGROUND: ALK tyrosine kinase inhibitors (TKIs) have revolutionized the treatment and largely improved the survival outcomes of patients with NSCLC harboring ALK rearrangements. Different ALK TKI compounds have demonstrated antitumor activity in these patients and are available in clinical practice. However, clinical expertise across countries varies according to local regulatory approval of different drugs, identifying multiple treatment scenarios to comply with international guidelines and clinical practice. METHODS: A virtual webinar was held on July 2023 to discuss the state of the art and future perspectives in the treatment of ALK rearrangement in advanced NSCLC in Italy. The faculty hosting the webinar was composed of eight medical oncologists from different regions of Italy with clinical expertise in treating patients with lung cancer. Live-shared notes were used to produce a report to serve as the basis of a review manuscript on the topic. RESULTS: Alectinib and brigatinib are the preferred front-line treatment options in Italy, pending approval of the front-line medicine lorlatinib, which would be considered among the choices. Due to a local regulatory limitation of second-line lorlatinib, which is not allowed after front-line brigatinib, alectinib is commonly the preferred front-line choice to follow a sequence of alectinib, followed by lorlatinib, followed by platinum plus pemetrexed chemotherapy. Age and performance status were not considered per se as clinical features influencing treatment choice. However, treatment compliance is deemed a relevant factor in decision making with regard to the number of pills to be administered. In general, given the availability of alternative choices, the spectrum of patients' comorbidities and polypharmacotherapy interactions should be taken into account in treatment selection according to the toxicity profile of each compound. In addition, several issues were debated with regard to improving treatment outcomes, including testing, brain metastases, and management of an oligoprogressive disease. CONCLUSIONS: The treatment scenario of ALK-positive disease is dynamically evolving. Furthermore, not all FDA- and EMA-approved compounds are approved in Italy with the same indications. This influences therapeutic opportunities and increases the need for greater clinical expertise to help and guide treatment selection.

MET in Non-Small-Cell Lung Cancer (NSCLC): Cross 'a Long and Winding Road' Looking for a Target.

Non-Small-Cell Lung Cancer (NSCLC) can harbour different MET alterations, such as MET overexpression (MET OE), MET gene amplification (MET AMP), or MET gene mutations. Retrospective studies of surgical series of patients with MET-dysregulated NSCLC have shown worse clinical outcomes irrespective of the type of specific MET gene alteration. On the other hand, earlier attempts failed to identify the 'druggable' molecular gene driver until the discovery of MET exon 14 skipping mutations (METex14). METex14 are rare and amount to around 3% of all NSCLCs. Patients with METex14 NSCLC attain modest results when they are treated with immune checkpoint inhibitors (ICIs). New selective MET inhibitors (MET-Is) showed a long-lasting clinical benefit in patients with METex14 NSCLC and modest activity in patients with MET AMP NSCLC. Ongoing clinical trials are investigating new small molecule tyrosine kinase inhibitors, bispecific antibodies, or antibodies drug conjugate (ADCs). This review focuses on the prognostic role of MET, the summary of pivotal clinical trials of selective MET-Is with a focus on resistance mechanisms. The last section is addressed to future developments and challenges.

Adjuvant Treatments for Surgically Resected Non-Small Cell Lung Cancer Harboring EGFR Mutations: A Review.

Importance: The use of adjuvant chemotherapy for stage IB-IIIA resected non-small cell lung cancer (NSCLC) has limited benefit for improving cure rates. The proportion of epidermal growth factor receptor (EGFR) alterations among patients with resected NSCLC is comparable to that observed in patients with advanced disease, and the use of EGFR tyrosine kinase inhibitors (TKIs) has been demonstrated to prolong disease-free survival (DFS). With recent approval of osimertinib in this context, a focus on the rapidly evolving scenario and future perspective in clinical practice is needed and was the aim of the current review. Observations: Randomized phase 3 clinical trials demonstrated DFS benefit with adjuvant EGFR TKI therapy in patients with resected EGFR mutation-positive NSCLC. The most recent trial (ADAURA) assessed 3-year adjuvant osimertinib and showed consistent DFS benefit and a significant role of the intervention in preventing the occurrence of brain metastasis. However, the role of adjuvant chemotherapy, the appropriate duration of treatment, the management of disease relapse, and the effective cure rate remain undetermined. A deeper investigation on molecular biomarkers, covariant patterns, and dynamic monitoring of postsurgical circulating DNA would be helpful for the implementation of future strategies to further improve survival rates after adjuvant therapy for EGFR mutation-positive NSCLC. Conclusions and Relevance: Adjuvant osimertinib revolutionized the treatment algorithm for patients with stage IB-IIIA resected EGFR mutation-positive NSCLC. Further evidence driven by clinical issues will be key for further optimization of the goals of adjuvant treatment in these patients.

New Generations of Tyrosine Kinase Inhibitors in Treating NSCLC with Oncogene Addiction: Strengths and Limitations.

Tyrosine kinase inhibitors (TKIs) revolutionized the treatment of patients with advanced or metastatic non-small cell lung cancer (NSCLC) harboring most driver gene alterations. Starting from the first generation, research rapidly moved to the development of newer, more selective generations of TKIs, obtaining improved results in terms of disease control and survival. However, the use of novel generations of TKIs is not without limitations. We reviewed the main results obtained, as well as the ongoing clinical trials with TKIs in oncogene-addicted NSCLC, together with the biology underlying their potential strengths and limitations. Across driver gene alterations, novel generations of TKIs allowed delayed resistance, prolonged survival, and improved brain penetration compared to previous generations, although with different toxicity profiles, that generally moved their use from further lines to the front-line treatment. However, the anticipated positioning of novel generation TKIs leads to abolishing the possibility of TKI treatment sequencing and any role of previous generations. In addition, under the selective pressure of such more potent drugs, resistant clones emerge harboring more complex and hard-to-target resistance mechanisms. Deeper knowledge of tumor biology and drug properties will help identify new strategies, including combinatorial treatments, to continue improving results in patients with oncogene-addicted NSCLC.

Association between Contrast-Enhanced Computed Tomography Radiomic Features, Genomic Alterations and Prognosis in Advanced Lung Adenocarcinoma Patients.

Non-invasive methods to assess mutational status, as well as novel prognostic biomarkers, are warranted to foster therapy personalization of patients with advanced non-small cell lung cancer (NSCLC). This study investigated the association of contrast-enhanced Computed Tomography (CT) radiomic features of lung adenocarcinoma lesions, alone or integrated with clinical parameters, with tumor mutational status (EGFR, KRAS, ALK alterations) and Overall Survival (OS). In total, 261 retrospective and 48 prospective patients were enrolled. A Radiomic Score (RS) was created with LASSO-Logistic regression models to predict mutational status. Radiomic, clinical and clinical-radiomic models were trained on retrospective data and tested (Area Under the Curve, AUC) on prospective data. OS prediction models were trained and tested on retrospective data with internal cross-validation (C-index). RS significantly predicted each alteration at training (radiomic and clinical-radiomic AUC 0.95-0.98); validation performance was good for EGFR (AUC 0.86), moderate for KRAS and ALK (AUC 0.61-0.65). RS was also associated with OS at univariate and multivariable analysis, in the latter with stage and type of treatment. The validation C-index was 0.63, 0.79, and 0.80 for clinical, radiomic, and clinical-radiomic models. The study supports the potential role of CT radiomics for non-invasive identification of gene alterations and prognosis prediction in patients with advanced lung adenocarcinoma, to be confirmed with independent studies.

Neoadjuvant Chemotherapy Plus Immunotherapy in Early-Stage Resectable Non-Small-Cell Lung Cancer.

The Oncology Grand Rounds series is designed to place original reports published in the Journal into clinical context. A case presentation is followed by a description of diagnostic and management challenges, a review of the relevant literature, and a summary of the authors' suggested management approaches. The goal of this series is to help readers better understand how to apply the results of key studies, including those published in the Journal of Clinical Oncology, to patients seen in their own clinical practice.

Uncommon EGFR Compound Mutations in Non-Small Cell Lung Cancer (NSCLC): A Systematic Review of Available Evidence.

Compound epidermal growth factor receptor (EGFR) mutations represent a heterogeneous subgroup of non-small cell lung cancer (NSCLC) patients with uncommon EGFR mutations. We conducted a systematic review to investigate the available data on this patients' subgroup. Overall, we found a high heterogeneity in the incidence of compound mutations (4-26% of total EGFR mutant cases), which is dependent on the different testing methods adopted and the specific mutations considered. In addition, the relative incidence of distinct compound subclasses identified is reported with extreme variability in different studies. Preclinical and clinical data, excluding de novoEGFR exon 20 p.T790M compound mutations, show good responses with EGFR tyrosine kinase inhibitors (TKIs) (combined common mutations: response rate (RR) ≥ 75% with either first- or second-generation TKIs; combined common plus uncommon: RR 40-80% and 100% with first-generation TKIs and afatinib, respectively; combined uncommon: RR 20-70%, ~80% and ~75% with first-generation TKIs, afatinib and osimertinib, respectively). Overall, data are consistent in supporting the use of EGFR TKIs in treating compound EGFR mutations, taking into account different sensitivity profile of accompanying EGFR mutations for selecting the most adequate EGFR TKI for individual patients.