Mechanisms of resistance and correlation between pre-treatment co-alterations and p-prognosis to osimertinib in chemo-naïve advanced non-small cell lung cancer.

BACKGROUND: Several patients treated with osimertinib experience progressive disease. The aim was to clarify the mechanisms underlying resistance to osimertinib. METHODS: ELUCIDATOR: A multi-centre, prospective, observational study involved chemotherapy-naive patients with advanced non-small cell lung cancer receiving osimertinib. Mutations in cancer-associated genes, detected via ultrasensitive next-generation sequencing of circulating tumour deoxyribonucleic acid samples, were collected at baseline and after progressive disease detection. These paired plasma samples were compared. RESULTS: Of 188 patients enrolled (May 2019-January 2021), 178 (119 females [67 %]) median age 74 years, were included. Patients, n = 95 (53 %) had epidermal growth factor receptor exon 19 deletion mutations. Among 115 patients with progressive disease, circulating tumour deoxyribonucleic acid levels of 85 patients were analysed. MET amplification (n = 4), TP53 mutations (n = 4), PIK3CA mutations (n = 3), BRINP3 mutation (n = 2), BRAF mutation (n = 2), APC mutation (n = 1), RET mutation (n = 1) and epidermal growth factor receptor (EGFR) resistance mutation, and C797S (n = 1) were detected. Patients with baseline TP53 mutations, with MET or EGFR amplification had shorter progression-free (PFS) and overall survival. Patients with PIK3CA mutations tended to shorter PFS. CONCLUSION: MET amplification and PIK3CA mutation mechanisms underly resistance to osimertinib in patients. Patients with coexisting mutations or amplifications at baseline had shorter PFS and overall survival.

Baseline genetic abnormalities and effectiveness of osimertinib treatment in patients with chemotherapy-naïve EGFR-mutated NSCLC based on performance status.

BACKGROUND/AIM: For patients treated with osimertinib as first-line therapy, there have been no studies comparing both progression-free survival (PFS) and overall survival (OS) according to performance status (PS). Furthermore, no studies have examined differences in baseline genetic abnormalities between patients with poor and good PS. Therefore, we aimed to investigate differences in baseline genetic abnormalities and treatment effects between patients with poor and good PS who received osimertinib as the primary treatment. PATIENTS AND METHODS: This is a secondary analysis of the ELUCIDATOR study, which is a multi-center prospective observational study in Japan that assessed mechanisms underlying resistance to osimertinib as first-line treatment for advanced non-small cell lung cancer with epidermal growth factor receptor mutations. RESULTS: There were 153 and 25 patients in the good and poor PS groups, respectively. Multivariate analysis revealed no significant between-group differences in PFS (hazards ratio [HR]: 0.98, 95% confidence interval [CI]: 0.52-1.72, p = 0.946). Multivariate analysis of OS revealed that poor PS was a poor prognostic factor (HR: 2.67, 95% CI: 1.43-4.73, p = 0.003). Regarding baseline genetic abnormalities, there was a significant increase in APC-positive cases (20.0% vs. 2.2%, p = 0.009) and a trend toward more CTNNB1-positive cases in the poor PS group than in the good PS group (14.3% vs. 2.9%, p = 0.062). CONCLUSION: There was no between-group difference in PFS, although OS was significantly inferior in the poor PS group. Additionally, there was a significant increase in APC-positive cases and a trend toward more CTNNB1-positive cases in the poor PS group.

Differential properties of KRAS transversion and transition mutations in non-small cell lung cancer: associations with environmental factors and clinical outcomes.

BACKGROUND: KRAS-mutated non-small cell lung cancer (NSCLC) accounts for 23-35% and 13-20% of all NSCLCs in white patients and East Asians, respectively, and is therefore regarded as a major therapeutic target. However, its epidemiology and clinical characteristics have not been fully elucidated because of its wide variety of mutational subtypes. Here, we focused on two distinct base substitution types: transversion mutations and transition mutations, as well as their association with environmental factors and clinical outcome. METHODS: Dataset from the Japan Molecular Epidemiology Study, which is a prospective, multicenter, and molecular study epidemiology cohort study involving 957 NSCLC patients who underwent surgery, was used for this study. Questionnaire-based detailed information on clinical background and lifestyles was also used to assess their association with mutational subtypes. Somatic mutations in 72 cancer-related genes were analyzed by next-generation sequencing, and KRAS mutations were classified into three categories: transversions (G > C or G > T; G12A, G12C, G12R, G12V), transitions (G > A; G12D, G12S, G13D), and wild-type (WT). Clinical correlations between these subtypes have been investigated, and recurrence-free survival (RFS) and overall survival (OS) were evaluated. RESULTS: Of the 957 patients, KRAS mutations were detected in 80 (8.4%). Of these, 61 were transversions and 19 were transitions mutations. Both pack-years of smoking and smoking duration had significant positive correlation with the occurrence of transversion mutations (p = 0.03 and < 0.01, respectively). Notably, transitions showed an inverse correlation with vegetable intake (p = 0.01). Patients with KRAS transitions had the shortest RFS and OS compared to KRAS transversions and WT. Multivariate analysis revealed that KRAS transitions, along with age and stage, were significant predictors of shorter RFS and OS (HR 2.15, p = 0.01; and HR 2.84, p < 0.01, respectively). CONCLUSIONS: Smoking exposure positively correlated with transversions occurrence in a dose-dependent manner. However, vegetable intake negatively correlated with transitions. Overall, KRAS transition mutations are significantly poor prognostic factors among resected NSCLC patients.

Prognostic impact of pretreatment T790M mutation on outcomes for patients with resected, EGFR-mutated, non-small cell lung cancer.

BACKGROUND: Many previous studies have demonstrated that minor-frequency pretreatment T790M mutation (preT790M) could be detected by ultrasensitive methods in a considerable number of treatment-naïve, epidermal growth factor receptor (EGFR)-mutated, non-small cell lung cancer (NSCLC) cases. However, the impact of preT790M in resected cases on prognosis remains unclear. METHODS: We previously reported that preT790M could be detected in 298 (79.9%) of 373 surgically resected, EGFR-mutated NSCLC patients. Therefore, we investigated the impact of preT790M on recurrence-free survival (RFS) and overall survival (OS) in this cohort by multivariate analysis. All patients were enrolled from July 2012 to December 2013, with follow-up until November 30, 2017. RESULTS: The median follow-up time was 48.6 months. Using a cutoff value of the median preT790M allele frequency, the high-preT790M group (n = 151) had significantly shorter RFS (hazard ratio [HR] = 1.51, 95% confidence interval [CI]: 1.01-2.25, P = 0.045) and a tendency for a shorter OS (HR = 1.87, 95% CI: 0.99-3.55, P = 0.055) than the low-preT790M group (n = 222). On multivariate analysis, higher preT790M was independently associated with shorter RFS (high vs low, HR = 1.56, 95% CI: 1.03-2.36, P = 0.035), irrespective of advanced stage, older age, and male sex, and was also associated with shorter OS (high vs low, HR = 2.16, 95% CI: 1.11-4.20, P = 0.024) irrespective of advanced stage, older age, EGFR mutation subtype, and history of adjuvant chemotherapy. CONCLUSIONS: Minor-frequency, especially high-abundance of, preT790M was an independent factor associated with a poor prognosis in patients with surgically resected, EGFR-mutated NSCLC.

Prospective Observational Study of Treatment Resistance-related Gene Screening Using Plasma Circulating Tumor DNA in Third-generation EGFR-TKI Osimertinib Therapy (Elucidator).

BACKGROUND: Osimertinib is a third-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) that potently and selectively inhibits EGFR activating and EGFR T790M resistance mutations. Osimertinib was found to be more effective than first-generation EGFR-TKIs in patients with previously untreated advanced non-small-cell lung cancer (NSCLC) harboring EGFR-positive mutations in a prior phase III trial. Osimertinib is, therefore, one of the most important standard therapies for EGFR mutation-positive patients. However, there are few reports about osimertinib resistance mechanisms in first-line EGFR-TKI therapy. Understanding first-line osimertinib resistance mechanisms is essential for future therapeutic strategies in patients with NSCLC with EGFR-positive mutations. To clarify the resistance mechanisms of first-line osimertinib, we proposed to analyze circulating tumor (ct) deoxyribonucleic acid (DNA) by the ultra-sensitive next-generation sequencing method. PATIENTS AND METHODS: We aim to collect ctDNA samples from patients with the following key inclusion criteria: histologically or cytologically proven NSCLC, activating EGFR mutation-positive, planned treatment with first-line osimertinib, and written informed consent. Patients with comorbidities, who are deemed unsuitable for participation by an attending physician, would be excluded. We plan to enroll 180 cases and estimate a final analysis of 120 cases following registration and 2-year observation. ctDNA samples are collected at osimertinib treatment initiation, 3 and 12 months later, and disease progression. The key primary endpoint is to clarify the incidence and ratio of osimertinib resistance. The key secondary endpoint is to examine how the quantity of osimertinib resistance-associated mutations detected in ctDNA at treatment initiation influences disease progression.

Can smoking duration alone replace pack-years to predict the risk of smoking-related oncogenic mutations in non-small cell lung cancer? A cross-sectional study in Japan.

OBJECTIVE: To investigate whether smoking duration alone can replace pack-years to predict the risk of oncogenic mutations in non-small cell lung cancer (NSCLC). DESIGN: A cross-sectional study using the baseline dataset from the Japan Molecular Epidemiology for Lung Cancer Study. SETTING: Forty-three medical institutions nationwide in Japan. PARTICIPANTS: From July 2012 to December 2013, 957 patients with newly diagnosed stage I-IIIB NSCLC who underwent surgery were enrolled, and molecular analyses were performed on 876 samples (from 441 ever-smokers and 435 never-smokers). MAIN OUTCOMES MEASURED: We calculated the area under the receiver operating characteristic curve (AUC) values using logistic regression to compare between the predictive values of smoking duration and pack-years for mutational frequencies in the v-Ki-ras2 Kirsten rat sarcoma (KRAS), tumour suppressor p53 (TP53), and epidermal growth factor receptor (EGFR) genes and for cytosine-to-adenine base substitution (C>A). RESULTS: For predicting KRAS mutations, the AUC values for smoking duration and pack-years were 0.746 (95% CI 0.682 to 0.800) and 0.759 (95% CI 0.700 to 0.810), respectively (p=0.058). For predicting KRAS mutations in smokers, the AUC values for smoking duration and pack-years were 0.772 (95% CI 0.697 to 0.833) and 0.787 (95% CI 0.714 to 0.845), respectively (p=0.036). There were no significant differences between the AUC values for smoking duration and pack-years in terms of predicting TP53 and EGFR mutations and C>A. Pack-years was a significantly better predictor of KRAS mutations than smoking duration. CONCLUSION: Smoking duration was not significantly different from pack-years in predicting the likelihood of smoking-related gene mutations. Given the recall bias in obtaining smoking information, smoking duration alone should be considered for further investigation as a simpler alternative to pack-years.

A Multivariable Regression Model-based Nomogram for Estimating the Overall Survival of Patients Previously Treated With Nivolumab for Advanced Non-small-cell Lung Cancer.

AIM: Although nivolumab improves progression-free (PFS) and overall (OS) survival of patients previously treated for metastatic non-small-cell lung cancer (NSCLC), approximately 50% of treated patients experience disease progression within 3 months. As predictive biomarkers of response are not yet established, development of biomarkers to predict longer PFS and OS of patients treated with nivolumab is crucial. Therefore, we analyzed the impact of predictive markers of response to nivolumab and quantified the impact of each factor using nomograms. PATIENTS AND METHODS: Clinical data at nivolumab commencement were retrospectively collected from 201 patients treated with nivolumab between December 2015 and July 2016. Immunohistochemistry for programmed cell death ligand 1 (PD-L1) was performed using two assay systems (22C3 and 28-8). OS was calculated from nivolumab treatment initiation. Multivariate Cox regression analysis was conducted to identify independent predictors of OS. A nomogram was constructed to estimate OS. RESULTS: The median patient age was 68 years (135 males). Thirty-nine patients had driver mutations (epidermal growth factor receptor mutations and anaplastic lymphoma kinase rearrangement). In 22C3 and 28-8 immunostaining assays, 36.3% and 36.8% patients had PD-L1-negative cells, 17.4% and 14.4% had 1-49% PD-L1-positive cells, 11.9% and 14.9% had ≥50% PD-L1-positive cells, and 34.3% and 33.8% had unknown PD-L1 status, respectively. Kendall's rank correlation coefficient between the staining assays was 0.8414. The median OS of the whole patient cohort was 12.27 months [95% confidence interval (CI)=10.87-15.6]. Performance status ≥2 [hazard ratio (HR)=2.15, 95% CI=1.35-3.42, p=0.001) and high baseline lactate dehydrogenase (HR=1.15, 95% CI=1.05-1.26, p=0.004] were independent predictors of shorter OS. There was no significant correlation between PD-L1 status and OS. We constructed a nomogram to estimate the OS of patients previously treated with nivolumab. CONCLUSION: The multivariate analysis-based nomogram might be useful to estimate the OS of patients previously treated with nivolumab for advanced NSCLC.

Impact of somatic mutations on prognosis in resected non-small-cell lung cancer: The Japan Molecular Epidemiology for lung cancer study.

BACKGROUND: To report the follow up data and clinical outcomes of the JME study (UMIN 000008177), a prospective, multicenter, molecular epidemiology examination of 876 surgically resected non-small-cell lung cancer (NSCLC) cases, and the impact of somatic mutations (72 cancer-associated genes) on recurrence-free survival (RFS) and overall survival (OS). METHODS: Patients were enrolled between July 2012 and December 2013, with follow up to 30th November 2017. A Cox proportional hazards model was used to assess the impact of gene mutations on RFS and OS, considering sex, smoking history, age, stage, histology, EGFR, KRAS, TP53, and number of coexisting mutations. RESULTS: Of 876 patients, 172 had ≥2 somatic mutations. Median follow-up was 48.4 months. On multivariate analysis, number of coexisting mutations (≥2 vs 0 or 1, HR = 2.012, 95% CI: 1.488-2.695), age (≥70 vs <70 years, HR = 1.583, 95% CI: 1.229-2.049), gender (male vs female, HR = 1.503, 95% CI: 1.045-2.170) and pathological stage (II vs I, HR = 3.386, 95% CI: 2.447-4.646; ≥III vs I, HR = 6.307, 95% CI: 4.680-8.476) were significantly associated with RFS, while EGFR mutation (yes vs no, HR = 0.482, 95% CI: 0.309-0.736), number of coexisting mutations (≥2 vs 0 or 1, HR = 1.695, 95% CI: 1.143-2.467), age (≥70 vs <70 years, HR = 1.932, 95% CI: 1.385-2.726), and pathological stage (II vs I, HR = 2.209, 95% CI: 1.431-3.347; ≥III vs I, HR = 5.286, 95% CI: 3.682-7.566) were also significant for OS. CONCLUSION: A smaller number of coexisting mutations, earlier stage, and younger age were associated with longer RFS and OS, while EGFR mutations were significantly associated with improved OS.

Chemotherapy versus erlotinib as second-line treatment in patients with advanced non-small cell lung cancer and wild-type epidermal growth factor receptor: an individual patient data (IPD) analysis.

The efficacy of second-line treatment in patients with epidermal growth factor receptor (EGFR) wild-type tumours is still debatable. We assessed the efficacy of a standard second-line chemotherapy compared with erlotinib in an individual patient data approach for meta-analysis. The primary endpoint was overall survival (OS), and secondary endpoint was progression-free survival (PFS). Both were compared by log-rank test. The 'restricted mean survival time' (RMST) was estimated in each study and the difference in mean survival time up to the last available time point was calculated. The Cox proportional hazards model was used on survival analyses to provide HRs, to adjust for confounding variables and to test possible interaction with selected factors. Three randomised trials comparing chemotherapy versus erlotinib were analysed, including 587 randomised patients. Overall, 74% of patients included in the original trials were considered. 464 deaths and 570 progressions or deaths were observed. Compared with erlotinib, chemotherapy was associated to a decreased risk of progression (29%; HR: 0.71, 95% CI: 0.60 to 0.84, p< 0.0001;) but with no statistical significant reduction in OS (HR: 0.89, 95% CI: 0.74 to 1.06; p<0.20). No heterogeneity was found in both analyses. Patients treated with chemotherapy gained an absolute 1.5 and 1.6 months, respectively, in PFS and lifetime (RMST 95% CI: PFS 0.49 to 2.44; OS 95% CI: -1.04 to 4.25). These results showed that patients without a constitutively activated EGFR had better PFS with chemotherapy rather than with erlotinib while no statistical difference was observed in OS.

Clinical Characteristics of Liver Metastasis in Nivolumab-treated Patients with Non-small Cell Lung Cancer.

BACKGROUND: Recent studies have revealed that liver metastasis is associated with poor outcomes after treatment using immune checkpoint inhibitors, although the cause remains unclear. PATIENTS AND METHODS: We retrospectively identified 201 patients at three Japanese Centers who received nivolumab for advanced non-small cell lung cancer between December 2015 and July 2016. The patients' baseline clinical characteristics and subsequent outcomes were compared according to liver metastasis status. RESULTS: Liver metastasis was associated with inferior progression-free survival (PFS) and a lower response rate. Additionally, liver metastasis was significantly associated with younger age, poorer Eastern Cooperative Oncology Group performance status (ECOG PS), and more metastatic sites. Multivariate analyses revealed that poor PFS was independently associated with poor baseline ECOG PS (p=0.039) and high number of metastatic sites (p=0.007), although liver metastasis (p=0.2) was not. CONCLUSION: Baseline clinical characteristics were a strong predictor of outcome in nivolumab-treated patients with liver metastasis.