Efficacy of Aumolertinib (HS-10296) in Patients With Advanced EGFR T790M+ NSCLC: Updated Post-National Medical Products Administration Approval Results From the APOLLO Registrational Trial

IntroductionAumolertinib (formerly almonertinib; HS-10296) is a novel third-generation EGFR tyrosine kinase inhibitor (TKI) with revealed activity against EGFR-sensitizing mutations and EGFR T790M mutation.MethodsPatients with locally advanced or metastatic NSCLC who developed an EGFR T790M mutation after progression on first- or second-generation EGFR TKI therapy were enrolled in this registrational phase 2 trial of aumolertinib at 110 mg orally once daily (NCT02981108). The primary end point was objective response rate (ORR) by independent central review.ResultsA total of 244 patients with EGFR T790M-positive NSCLC were enrolled. The ORR by independent central review was 68.9% (95% confidence interval [CI]: 62.6–74.6). The disease control rate was 93.4% (95% CI: 89.6–96.2). The median duration of response was 15.1 months (95% CI: 12.5–16.6). The median progression-free survival was 12.4 months (95% CI: 9.7–15.0). Among 23 patients with assessable central nervous system (CNS) metastases, the CNS-ORR and CNS-disease control rate were 60.9% (95% CI: 38.5–80.3) and 91.3% (95% CI: 72.0–98.9), respectively. The median CNS-duration of response was 12.5 months (95% CI: 5.6–not reached). Treatment-related adverse events of more than or equal to grade 3 occurred in 16.4% of the patients, with the most common being increased blood creatine phosphokinase level (7%) and increased alanine aminotransferase level (1.2%). The relative dose density of aumolertinib was 99.2% in this study.ConclusionsAumolertinib is an effective and well-tolerated third-generation EGFR TKI for patients with EGFR T790M-positive advanced NSCLC after disease progression on first- and second-generation EGFR TKI therapy. On the basis of these findings, aumolertinib was approved in the People’s Republic of China for patients positive for EGFR T790M NSCLC.     

Safety,Efficacy, and Pharmacokinetics of Rezivertinib (BPI-7711) in Patients With Advanced NSCLC With EGFR T790M Mutation: A Phase 1 Dose-Escalation and Dose-Expansion Study

IntroductionRezivertinib (BPI-7711) is a novel third-generation EGFR tyrosine kinase inhibitor selective for EGFR-sensitizing and T790M mutations. This study was designed to evaluate the safety, efficacy, and pharmacokinetics of rezivertinib for patients having advanced NSCLC with EGFR T790M mutation.MethodsThis phase 1 study (NCT03386955) was conducted across 20 sites in the People's Republic of China. Patients received rezivertinib at six oral dose levels (30 mg, 60 mg, 120 mg, 180 mg, 240 mg, 300 mg) once daily until disease progression, unacceptable toxicity, or patient withdrawal. The primary end points were safety for the dose-escalation phase and objective response rate by the blinded independent central review for the total study population.ResultsA total of 19 patients in dose-escalation phase using the standard 3 + 3 design principle and 153 patients in dose-expansion phase were enrolled from September 11, 2017, to August 23, 2019. The data cutoff date was on June 15, 2020. No dose-limiting toxicity occurred in the dose-escalation phase. The treatment-related adverse events were observed in 82.0% (141 of 172) of patients, and 17.4% (30 of 172) had grade greater than or equal to 3, among which decreased neutrophil count (2.9%), leukopenia (2.9%), and pneumonia (2.9%) were the most common. The overall blinded independent central review–evaluated objective response rate was 59.3% (102 of 172, 95% confidence interval: 51.6–66.7), and the median progression-free survival was 9.7 (95% confidence interval: 8.3–11.1) months.ConclusionsRezivertinib was found to have promising efficacy with a manageable safety profile in patients with EGFR T790M-mutated advanced NSCLC. Further study is warranted.     

Safety,Clinical Activity,and Pharmacokinetics of Alflutinib (AST2818) in Patients With Advanced NSCLC With EGFR T790M Mutation

IntroductionAlflutinib (AST2818) is a newly developed third-generation EGFR tyrosine kinase inhibitor selective for EGFR-sensitizing and T790M-resistant mutations. We assessed the safety, efficacy, and pharmacokinetics of alflutinib in patients with advanced NSCLC with confirmed EGFR T790M mutation, whose status progressed after the first- or second-generation EGFR tyrosine kinase inhibitor therapy.MethodsIn the dose-escalation (NCT02973763) and dose-expansion (NCT03127449) studies, patients received alflutinib orally until disease progression, unacceptable toxicity, or subject withdrawal. The primary end points were safety, tolerability, and pharmacokinetics for the dose-escalation study and the objective response rate (assessed by an independent radiological review committee) for the dose-expansion study.ResultsBetween November 30, 2016, and July 24, 2018, a total of 130 patients (14 in dose escalation, 116 in dose expansion) received alflutinib treatment (20 mg, 40 mg, 80 mg, 160 mg, or 240 mg once daily). On October 30, 2018, 79 patients (61%) remained on the treatment. No dose-limiting toxicities were observed in the dose-escalation study. In the dose-expansion study (40–240 mg), the overall objective response rate was 76.7% (89 of 116), and it was 70.6% in patients with central nervous system metastases (12 of 17). A total of 79% of all patients had possibly treatment-related adverse events (AEs) (103 of 130); 8% had treatment-related grade 3 or higher AEs (11 of 130). Serious AEs were reported in 15% of patients (20 of 130), and two serious AEs were related to treatment. No clear dose-response (antitumor activity and AEs) relationships were observed. Exposures to alflutinib and its active metabolite (AST5902) were comparable at steady state.ConclusionsAlflutinib was clinically effective with an acceptable toxicity profile in patients with advanced NSCLC (including those with central nervous system metastases) with EGFR T790M mutation. Further investigation is ongoing.     

Poor response to erlotinib in patients with tumors containing baseline EGFR T790M mutations found by routine clinical molecular testing

BackgroundEGFR T790M is the most common mutation associated with acquired resistance to EGFR tyrosine kinase inhibitors (TKIs). Baseline EGFR T790M mutations in EGFR TKI-naïve patients have been reported, but the frequency and their association with response to EGFR TKIs remain unclear.Patients and methodsThe frequency of baseline EGFR T790M as detected by routine molecular genotyping was determined by reviewing clinical results obtained at our institution from 2009 to 2013. We also collected outcome data for treatment with EGFR TKIs.ResultsTo define the incidence of EGFR T790M, we reviewed 2774 sequentially tested patients with lung cancer who underwent molecular testing using a mass spectrometry-based assay, and 11 (0.5%) had baseline EGFR T790M. Compiling results from several molecular techniques, we observed EGFR T790M in tumors from 20 patients who had not previously been treated with an EGFR TKI. In all cases, EGFR T790M occurred concurrently with another EGFR mutation, L858R (80%, 16/20), or exon 19 deletion (20%, 4/20). Two percent of all pre-treatment EGFR-mutant lung cancers harbored an EGFR T790M mutation. Thirteen patients received erlotinib monotherapy as treatment for metastatic disease. The response rate was 8% (1/13, 95% confidence interval 0%–35%). For the patients who received erlotinib, the median progression-free survival was 2 months and the median overall survival was 16 months.ConclusionsDe novo EGFR T790M mutations are rare (<1%) when identified by standard sensitivity methods. TKI therapy for patients with baseline EGFR T790M detected by standard molecular analysis has limited benefit.     

A Phase 1/2 Study of Lazertinib 240 mg in Patients With Advanced EGFR T790M-Positive NSCLC After Previous EGFR Tyrosine Kinase Inhibitors

IntroductionThis integrated analysis of a phase 1/2 study (NCT03046992) evaluated the efficacy and safety of lazertinib, a third-generation EGFR tyrosine kinase inhibitor (TKI), in patients with advanced EGFR T790M-positive NSCLC after previous EGFR TKI therapy.MethodsAdults with EGFR mutation-positive NSCLC that progressed after prior EGFR-directed TKIs received once daily oral lazertinib 240 mg continuously until disease progression. Prior TKIs to treat T790M-positive NSCLC were prohibited. Primary endpoints were safety and objective response rate (ORR). Secondary endpoints included progression-free survival, overall survival, and intracranial ORR.ResultsA total of 78 patients received lazertinib 240 mg at 17 centers in South Korea. Among patients with T790M-positive tumors at baseline (N = 76), one (1.3%) had a complete response and 41 (53.9%) had partial responses, giving an ORR of 55.3% (95% confidence interval [CI]: 44.1–66.4). Median progression-free survival was 11.1 months (95% CI: 5.5–16.4). Median overall survival was not reached (median follow-up = 22.0 mo). In patients with measurable intracranial lesions (n = 7), one (14.3%) had a complete intracranial response and five (71.4%) had partial responses, giving an intracranial ORR of 85.7% (95% CI: 59.8%–100.0%). The most common treatment-emergent adverse events were rash (37.2%), pruritus (34.6%), and paresthesia (33.3%); most were mild to moderate in severity. Serious drug-related adverse events occurred in three patients (gastritis, pneumonia, pneumonitis). The major mechanism of resistance was EGFR T790M loss.ConclusionsLazertinib 240 mg/d has a manageable safety profile with durable antitumor efficacy, including brain metastases, in patients with advanced T790M-positive NSCLC after previous EGFR TKI therapy.     

Efficacy and Safety of Befotertinib (D-0316) in Patients With EGFR T790M-Mutated NSCLC That Had Progressed After Prior EGFR Tyrosine Kinase Inhibitor Therapy: A Phase 2, Multicenter,Single-Arm,Open-Label Study

IntroductionBefotertinib (D-0316) is a novel, third-generation EGFR tyrosine kinase inhibitor (TKI). This study evaluated befotertinib in patients with locally advanced or metastatic NSCLC who developed an EGFR T790M mutation after progression on first- or second-generation EGFR TKI therapy.MethodsThis was a single-arm, open-label, phase 2 study at 49 hospitals across mainland China. Patients with locally advanced or metastatic NSCLC harboring EGFR T790M mutations with disease progression after prior first- or second-generation EGFR TKI therapy received oral befotertinib of 50 mg (cohort A) or 75 to 100 mg (cohort B) once daily. The primary end point was objective response rate (ORR) assessed by an independent review committee in intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT03861156.ResultsA total of 176 patients and 290 patients were included in cohorts A (50 mg) and B (75–100 mg), respectively. At data cutoff (August 15, 2021), independent review committee–assessed ORR was 67.6% (95% confidence interval [CI]: 61.9%–72.9%) in cohort B. The investigator-assessed ORR was 54.0% (95% CI: 46.3%–61.5%) in cohort A and 65.9% (95% CI: 60.1%–71.3%) in cohort B. The median investigator-assessed progression-free survival was 11.0 (95% CI: 9.6–12.5) months in cohort A and 12.5 (95% CI: 11.1–13.8) months in cohort B. The median independent review committee–assessed progression-free survival in cohort B was 16.6 (95% CI: 15.0–not evaluable [NE]) months. The intracranial ORR was 26.7% (95% CI: 7.8%–55.1%) in cohort A by investigator assessment, while 57.1% (95% CI: 34.0%–78.2%) and 55.9% (95% CI: 37.9%–72.8%) in cohort B by investigator and independent review committee assessment, respectively. The median investigator-assessed intracranial progression-free survival was 16.5 (95% CI: 8.6–NE) months in cohort A, while the median intracranial progression-free survival was not evaluable in cohort B due to immature data regardless of investigator or independent review committee assessment. and NE (95% CI: 13.8–NE) in cohort B. The overall survival was immature. Grade 3 or higher treatment-related adverse events and treatment-related serious adverse events occurred in 20.5% and 11.4% of patients in cohort A and in 29.3% and 10.0% of patients in cohort B, respectively.ConclusionsBefotertinib of 75 to 100 mg has satisfying efficacy and manageable toxicity in patients with locally advanced or metastatic NSCLC harboring T790M mutation with resistance to first- or second-generation EGFR TKIs. A phase 3 randomized trial is underway (NCT04206072).     

Afatinib for the Treatment of NSCLC Harboring Uncommon EGFR Mutations: A Database of 693 Cases

IntroductionLimited clinical data are available regarding the efficacy of EGFR tyrosine kinase inhibitors (EGFR TKIs) in patients with NSCLC harboring uncommon EGFR mutations. This pooled analysis assessed the activity of afatinib in 693 patients with tumors harboring uncommon EGFR mutations treated in randomized clinical trials, compassionate-use and expanded-access programs, phase IIIb trials, noninterventional trials, and case series or studies.MethodsPatients had uncommon EGFR mutations, which were categorized as follows: (1) T790M; (2) exon 20 insertions; (3) “major” uncommon mutations (G719X, L861Q, and S768I, with or without any other mutation except T790M or an exon 20 insertion); (4) compound mutations; and (5) other uncommon mutations. Key end points were overall response rate (ORR), duration of response, and time to treatment failure (TTF).ResultsIn EGFR TKI–naive patients (n = 315), afatinib demonstrated activity against major uncommon mutations (median TTF = 10.8 mo; 95% confidence interval [CI]: 8.1–16.6; ORR = 60.0%), compound mutations (median TTF = 14.7 mo; 95% CI: 6.8–18.5; ORR = 77.1%), other uncommon mutations (median TTF = 4.5 mo; 95% CI: 2.9–9.7; ORR = 65.2%), and some exon 20 insertions (median TTF = 4.2 mo; 95% CI: 2.8–5.3; ORR = 24.3%). The median duration of response for major uncommon mutations, compound mutations, other uncommon mutations, and some exon 20 insertions was 17.1, 16.6, 9.0, and 11.9 months, respectively. Activity of afatinib was also observed in EGFR TKI–pretreated patients (n = 378). A searchable database of these outcomes by individual genotype was generated.ConclusionsAfatinib has clinical activity in NSCLC against major uncommon and compound EGFR mutations. It also has broad activity against other uncommon EGFR mutations and some exon 20 insertions. The data support the use of afatinib in these settings.     

EGFR Mutation Analysis for Prospective Patient Selection in Two Phase II Registration Studies of Osimertinib

IntroductionOsimertinib is an oral, central nervous system–active, EGFR tyrosine kinase inhibitor (TKI) for the treatment of EGFR T790M–positive advanced NSCLC. Here we have evaluated EGFR mutation frequencies in two phase II studies of osimertinib (AURA extension and AURA2).MethodsAfter progression while receiving their latest line of therapy, patients with EGFR mutation–positive advanced NSCLC provided tumor samples for mandatory central T790M testing for the study selection criteria. Tumor tissue mutation analysis for patient selection was performed with the Roche cobas EGFR Mutation Test (European Conformity–in vitro diagnostic, labeled investigational use only) (Roche Molecular Systems, Pleasanton, CA). Patients should not have been prescreened for T790M mutation status. The cobas test results were compared with those of the MiSeq next-generation sequencing system (Illumina, San Diego, CA), which was used as a reference method.ResultsSamples from 324 and 373 patients screened for AURA extension and AURA2, respectively, produced valid cobas test results. The T790M detection rates were similar between AURA extension and AURA2 (64% and 63%, respectively). The pooled T790M rate was 63%, with no difference by ethnicity (63% for Asian and non-Asian patients alike) or immediately prior treatment with an EGFR TKI (afatinib, 69%; erlotinib, 69%; and gefitinib, 63%). A higher proportion of patients had T790M detected against a background of exon 19 deletions versus L858R mutation (73% versus 58% [p = 0.0002]). In both trials the cobas test demonstrated high sensitivity (positive percent agreement) and specificity (negative percent agreement) for T790M detection when compared with the next-generation sequencing reference method: positive percent agreement of 91% versus 89% and negative percent agreement of 97% versus 98%.ConclusionsIn both trials, the rate of detection of T790M mutation in patients with advanced NSCLC was approximately 63% and was unaffected by immediately prior treatment with an EGFR TKI or ethnicity.     

Osimertinib in patients with epidermal growth factor receptor T790M advanced non‐small cell lung cancer selected using cytology samples

Osimertinib is a potent, irreversible epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) selective for EGFR‑TKI sensitizing (EGFRm) and T790M resistance mutations. The primary objective of the cytology cohort in the AURA study was to investigate safety and efficacy of osimertinib in pretreated Japanese patients with EGFR T790M mutation‐positive non‐small cell lung cancer (NSCLC), with screening EGFR T790M mutation status determined from cytology samples. The cytology cohort was included in the Phase I dose expansion component of the AURA study. Patients were enrolled based on a positive result of T790M by using cytology samples, and received osimertinib 80 mg in tablet form once daily until disease progression or until clinical benefit was no longer observed at the discretion of the investigator. Primary endpoint for efficacy was objective response rate (ORR) by investigator assessment. Twenty‐eight Japanese patients were enrolled into the cytology cohort. At data cut‐off (February 1, 2016), 12 (43%) were on treatment. Investigator‐assessed ORR was 75% (95% confidence interval [CI] 55, 89) and median duration of response was 9.7 months (95% CI 3.8, not calculable [NC]). Median progression‐free survival was 8.3 months (95% CI 4.2, NC) and disease control rate was 96% (95% CI 82, 100). The most common all‐causality adverse events were paronychia (46%), dry skin (46%), diarrhea (36%) and rash (36%). Osimertinib provided clinical benefit with a manageable safety profile in patients with pretreated EGFR T790M mutation‐positive NSCLC whose screening EGFR T790M mutation‐positive status was determined from cytology samples. (ClinicalTrials.gov number NCT01802632).     

Acquired Resistance to Third-Generation EGFR Tyrosine Kinase Inhibitors in Patients With De Novo EGFRT790M-Mutant NSCLC

IntroductionEGFR^T790M mostly exists subclonally and is acquired as the most common mechanism of resistance to EGFR tyrosine kinase inhibitors (TKIs). Nevertheless, because de novo EGFR^T790M-mutant NSCLC is rare, little is known on acquired resistance mechanisms to third-generation EGFR TKIs.MethodsAcquired resistance mechanisms were analyzed using tumor and plasma samples before and after third-generation EGFR TKI treatment in four patients with de novo EGFR^T790M-mutant NSCLC. Genetic alterations were analyzed by whole-exome sequencing, targeted sequencing, fluorescence in situ hybridization, and droplet digital PCR. MTOR^L1433S, confirmed for oncogenicity using the Ba/F3 system, was reproduced in H1975 cell lines using CRISPR/Cas9-RNP.ResultsOf seven patients with NSCLC with de novo EGFR^T790M/L858R mutation, four (LC1–4) who received third-generation EGFR TKIs acquired resistance after achieving a partial response (median = 27 mo, range: 17–48 mo). Novel MTOR^L1433S and EGFR^C797S/L798I mutations in cis, MET amplification, and EGFR^C797S mutation were identified as acquired resistance mechanisms to third-generation EGFR TKIs. The MTOR^L1433S mutation was oncogenic in Ba/F3 models and revealed resistance to osimertinib through AKT signaling activation in NCI-H1975 cells harboring the MTOR^L1433S mutation edited by CRISPR/Cas9 (half-maximal inhibitory concentration, 800 ± 67 nM). Osimertinib in combination with mTOR inhibitors abrogated acquired resistance to osimertinib.ConclusionsActivation of bypass pathways and the EGFR^C797S or EGFR^C797S/L798I mutation were identified as acquired resistance mechanisms to third-generation EGFR TKIs in patients with NSCLC with de novo EGFR^T790M mutation. In addition, MTOR^L1433S- and EGFR^L858R/T790M-mutant NSCLC cells were sensitive to osimertinib plus mTOR inhibitors.     

Efficacy and Safety of SH-1028 in Patients With EGFR T790M-Positive NSCLC: A Multicenter,Single-Arm,Open-Label,Phase 2 Trial

IntroductionAs a novel third-generation EGFR tyrosine kinase inhibitor (TKI), SH-1028 (formerly oritinib) is developed to inhibit both sensitizing EGFR mutations and EGFR T790M mutation.MethodsThis was a multicenter, single-arm, open-label, phase 2 trial (NCT03823807). Eligible patients were those with advanced NSCLC with centrally confirmed EGFR T790M mutation who progressed after first- or second-generation EGFR TKIs or with primary EGFR T790M mutations. Each patient received SH-1028 tablets orally at 200 mg/d until disease progression or intolerable toxicity. Tumor response was evaluated every 6 weeks per the Response Evaluation Criteria in Solid Tumors, version 1.1. The primary end point was objective response rate by an independent review committee. The secondary end points were progression-free survival, overall survival (OS), disease control rate, safety, and so on.ResultsA total of 286 patients with EGFR T790M-positive advanced NSCLC were enrolled in this study, including 59 patients in part A (dose-verification study) and 227 patients in part B (second-line registration study). By data cutoff on September 17, 2021, the independent review committee–assessed objective response rate was 55.9% (95% confidence interval [CI]: 42.4–68.8) in part A and 60.4% (95% CI: 53.7–66.8) in part B. The median progression-free survival was 12.4 months (95% CI: 8.3–20.8) in part A and 12.6 months (95% CI: 9.7–15.3) in part B. The median OS was 26.0 months (95% CI: 23.3–not reached) in part A, and OS was immature in part B. Among the 286 patients, 44 of them experienced at least one grade 3 or higher treatment-related adverse event, with the most common ones as increased serum creatinine phosphokinase level (13 [4.5%]), diarrhea (six [2.1%]), and prolonged QT interval (three [1.0%]). Treatment-related skin rash was reported in 26 patients (9.1%), all grade 1 or 2. There was no interstitial lung disease reported in this study.ConclusionsSH-1028 is efficacious and tolerable in second-line treatment of patients with advanced NSCLC with positive EGFR T790M.     

Emergence of RET rearrangement co-existing with activated EGFR mutation in EGFR-mutated NSCLC patients who had progressed on first- or second-generation EGFR TKI

ObjectivesThe gatekeeper mutation T790M mutation is the responsible for the majority of the resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in patients with EGFR-mutated non-small cell lung cancer (NSCLC). Other previously described resistance mechanisms include HER2 amplification, MET amplification, PIK3CA mutation, epithelial–mesenchymal transition (EMT), small cell transformation have also been identified. However other resistance mechanisms remains to be discovered.Materials and methodsHybrid-capture based comprehensive genomic profiling (CGP) was performed on pre- and post-EGFR TKI progression EGFR-mutated NSCLC tumor samples during routine clinical care. We identify two paired pre- and post-EGFR TKI progression EGFR-mutated NSCLC patient tumor samples where both post EGFR TKI samples harbored in-frame CCDC6-RET rearrangements but not in the pre-EGFR TKI tumor samples. Furthermore analysis of the clinical database revealed one additional NCOA4-RET rearrangement co-existing with activated EGFR mutation in an EGFR-mutated NSCLC patient who had progressed on afatinib. None of the known resistance mechanisms to EGFR TKI including EGFR T790M, EGFR amplification, HER2 amplification, MET amplification, PIK3CA mutation, BRAF mutation, EMT or small cell transformation was identified in the three post progression samples that now harbored RET rearrangements.Results and conclusionsThis is the first report of RET rearrangement co-existing with activated EGFR mutations in EGFR-mutated patients who had progressed on either first- or second generation EGFR TKI. As such, RET rearrangement may serve as a potential resistance mechanism to EGFR TKI in EGFR-mutated NSCLC.     

Efficacy and Safety of Rezivertinib (BPI-7711) in Patients With Locally Advanced or Metastatic/Recurrent EGFR T790M-Mutated NSCLC: A Phase 2b Study

IntroductionRezivertinib (BPI-7711) is a novel third-generation EGFR tyrosine kinase inhibitor (TKI) targeting both EGFR-sensitizing mutations and EGFR T790M mutation. This study aimed to evaluate the efficacy and safety of rezivertinib in patients with locally advanced or metastatic/recurrent EGFR T790M-mutated NSCLC.MethodsPatients with locally advanced or metastatic/recurrent NSCLC with confirmed EGFR T790M mutation who progressed after first-/second-generation EGFR TKI therapy or primary EGFR T790M mutation were enrolled. Patients received rezivertinib at 180 mg orally once daily until disease progression, unacceptable toxicity, or withdrawal of consent. The primary end point was objective response rate (ORR) assessed by blinded independent central review per Response Evaluation Criteria in Solid Tumors version 1.1. Secondary end points included disease control rate (DCR), duration of response, progression-free survival (PFS), overall survival, and safety. This study is registered with Clinical Trials.gov (NCT03812809).ResultsA total of 226 patients were enrolled from July 5, 2019, to January 22, 2020. By the data cutoff date on January 24, 2022, the median duration of follow-up was 23.3 months (95% confidence interval [CI]: 22.8–24.0). The ORR by blinded independent central review was 64.6% (95% CI: 58.0%–70.8%), and DCR was 89.8% (95% CI: 85.1%–93.4%). The median duration of response was 12.5 months (95% CI: 10.0–13.9), and median PFS was 12.2 months (95% CI: 9.6–13.9). The median overall survival was 23.9 months (95% CI: 20.0–not calculated [NC]). Among 91 (40.3%) patients with central nervous system (CNS) metastases, the median CNS PFS was 16.6 months (95% CI: 11.1–NC). In 29 patients with more than or equal to one brain target lesion at baseline, the CNS ORR and CNS DCR were 69.0% (95% CI: 49.2%–84.7%) and 100% (95% CI: 88.1%–100%), respectively. Time to progression of CNS was 16.5 months (95% CI: 9.7–NC). Of 226 patients, 188 (83.2%) had at least one treatment-related adverse event, whereas grade more than or equal to 3 occurred in 45 (19.9%) patients. No interstitial lung disease was reported.ConclusionsRezivertinib was found to have promising efficacy and favorable safety profile for patients with locally advanced or metastatic/recurrent NSCLC with EGFR T790M mutation.     

Detection of EGFR-Activating and T790M Mutations Using Liquid Biopsy in Patients With EGFR-Mutated Non–Small-Cell Lung Cancer Whose Disease Has Progressed During Treatment With First- and Second-Generation Tyrosine Kinase Inhibitors: A Multicenter Real-Life Retrospective Study

BackgroundIn advanced epidermal growth factor receptor (EGFR)-mutated non–small-cell lung cancer (NSCLC) patients whose disease has progressed during treatment with first- and second-generation tyrosine kinase inhibitors (TKIs), liquid biopsy (LB) is routinely used to evaluate the presence of EGFR T790M as an acquired resistance mechanism. The objective of this study was to assess a real-life picture of EGFR T790M detection in LB.Materials and MethodsLiquid biopsies performed between June 2016 and October 2018 for advanced EGFR-mutated NSCLC at disease progression during treatment with first- and second-generation TKIs were retrospectively evaluated in 5 Italian centers. Circulating tumor DNA was extracted from plasma and tested with different commercial kits. The detection rate in LBs and the patients’ characteristics were correlated.ResultsWe enrolled 120 consecutive patients. The overall T790M detection rate observed using LB was 25.8%. Fifty-four of 89 (60.7%) patients with negative LB results underwent tissue rebiopsy, and 56% were positive for T790M. The overall rate of T790M positivity in the study cohort was 49.2%. LB performed before formal tumor progression according to Response Evaluation Criteria In Solid Tumors criteria was negative for T790M in all patients (n = 21; P = .012). T790M positivity was statistically significantly higher in cases of disease progression at extrathoracic metastatic sites (P = .008) and, specifically, in the case of worsening bone disease (P = .003).ConclusionOur study shows that the detection of T790M-positive patients whose disease progressed during treatment with first- and second-generation TKIs in real life was according to the literature. However, this result was obtained with a specific clinical course (repeat LBs and tissue rebiopsy), thus implying the necessity for multidisciplinary management.     

Rebiopsy for patients with non‐small‐cell lung cancer after epidermal growth factor receptor‐tyrosine kinase inhibitor failure

Although third‐generation epidermal growth factor receptor‐tyrosine kinase inhibitors (EGFR‐TKI) can overcome T790M‐mediated resistance in non‐small‐cell lung cancer (NSCLC), rebiopsy to confirm T790M status is occasionally difficult. We aimed to investigate the current tendency and the limitations of rebiopsy in clinical practice. This study included 139 consecutive NSCLC patients with EGFR mutations, who had experienced progressive disease (PD) after EGFR‐TKI treatment. We retrospectively reviewed patient characteristics, tumor progression sites and rebiopsy procedures. Of 120 patients (out of the original 139) who were eligible for clinical trials, 75 (63%) underwent rebiopsy for 30 pleural effusions, 32 thoracic lesions, four bone, two liver, and seven at other sites. Rebiopsy procedures included 30 thoracocentesis, 24 transbronchial biopsies, 13 computed tomography (CT)‐guided needle biopsies and 8 other procedures. Of the 75 rebiopsied patients, 71 (95%) were pathologically diagnosed with malignancy; and 34 (45%) had available tissue samples for EGFR analyses. Of the 75 biopsied patients, 61 (81%) were analyzed for EGFR mutation, using tissue or cytology samples; T790M mutations were identified in 20 (33%) of the 61 patients. Of the 120 patients, 45 (38%) did not undergo rebiopsy, because of inaccessible tumor sites (n = 19), patient refusal (n = 6) or decision of physician (n = 10). In conclusion, among patients with EGFR mutations who had PD after EGFR‐TKI treatment, 63% underwent rebiopsy. Most rebiopsy samples were diagnosed with malignancy. However, tissue samples were less available and T790M mutations were identified less frequently than in previous studies. Skill and experience with rebiopsy and noninvasive alternative methods will be increasingly important.     

Tumor immune microenvironment and nivolumab efficacy in EGFR mutation-positive non-small-cell lung cancer based on T790M status after disease progression during EGFR-TKI treatment

BackgroundThe efficacy of programmed death-1 blockade in epidermal growth factor receptor gene (EGFR) mutation-positive non-small-cell lung cancer (NSCLC) patients with different mechanisms of acquired resistance to EGFR tyrosine kinase inhibitors (TKIs) is unknown. We retrospectively evaluated nivolumab efficacy and immune-related factors in such patients according to their status for the T790M resistance mutation of EGFR.Patients and methodsWe identified 25 patients with EGFR mutation-positive NSCLC who were treated with nivolumab after disease progression during EGFR-TKI treatment (cohort A). Programmed death-ligand 1 (PD-L1) expression and tumor-infiltrating lymphocyte (TIL) density in tumor specimens obtained after acquisition of EGFR-TKI resistance were determined by immunohistochemistry. Whole-exome sequencing of tumor DNA was carried out to identify gene alterations. The relation of T790M status to PD-L1 expression or TIL density was also examined in an independent cohort of 60 patients (cohort B).ResultsIn cohort A, median progression-free survival (PFS) was 2.1 and 1.3 months for T790M-negative and T790M-positive patients, respectively (P = 0.099; hazard ratio of 0.48 with a 95% confidence interval of 0.20–1.24). Median PFS was 2.1 and 1.3 months for patients with a PD-L1 expression level of ≥1% or <1%, respectively (P = 0.084; hazard ratio of 0.37, 95% confidence interval of 0.10–1.21). PFS tended to increase as the PD-L1 expression level increased with cutoff values of ≥10% and ≥50%. The proportion of tumors with a PD-L1 level of ≥10% or ≥50% was higher among T790M-negative patients than among T790M-positive patients of both cohorts A and B. Nivolumab responders had a significantly higher CD8⁺ TIL density and nonsynonymous mutation burden.ConclusionT790M-negative patients with EGFR mutation-positive NSCLC are more likely to benefit from nivolumab after EGFR-TKI treatment, possibly as a result of a higher PD-L1 expression level, than are T790M-positive patients.     

Monitoring EGFR T790M with plasma DNA from lung cancer patients in a prospective observational study

Use of plasma DNA to detect mutations has spread widely as a form of liquid biopsy. EGFR T790M has been observed in half of lung cancer patients who have acquired resistance to EGFR tyrosine kinase inhibitors (EGFR‐TKI). Effectiveness of monitoring T790M via plasma DNA during treatment with EGFR‐TKI has not been established as an alternative to re‐biopsy. This was a prospective multicenter observational study involving non‐small cell lung cancer patients carrying EGFR L858R or exon 19 deletions, treated with EGFR‐TKI. The primary objective was to determine whether T790M could be detected using plasma DNA in patients with progressive disease (PD). T790M was examined using the mutation‐biased PCR and quenching probe (MBP‐QP) method, a sensitive, fully‐automated system developed in our laboratory. Eighty‐nine non‐small cell lung cancer patients were enrolled from seven hospitals in Japan. Sequential examinations revealed T790M in plasma DNA among 40% of patients who developed PD. Activating mutations, such as L858R and exon 19 deletions, were detected in 40% of patients using plasma DNA, and either T790M or activating mutations were observed in 62%. Dividing into four periods (before PD, at PD, at discontinuation of EGFR‐TKI and subsequently), T790M was detected in 10, 19, 24 and 27% of patients, respectively. Smokers, males, patients having exon 19 deletions and patients who developed new lesions evidenced significantly frequent presence of T790M in plasma DNA. Monitoring T790M with plasma DNA using MBP‐QP reflects the clinical course of lung cancer patients treated with EGFR‐TKI. Detection of T790M with plasma DNA was correlated with EGFR mutation type, exon 19 deletions and tumor progression. Re‐biopsy could be performed only in 14% of PD cases, suggesting difficulty in obtaining re‐biopsy specimens in practice. Monitoring T790M with plasma DNA reflects the clinical course, and is potentially useful in designing strategies for subsequent treatment.     

First-in-Human Phase 1 Study of ES-072, an Oral Mutant-Selective EGFR T790M Inhibitor,in Non–Small-Cell Lung Cancer

BackgroundThird-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are rapidly being developed for treatment of non–small-cell lung cancer (NSCLC) in patients harboring EGFR T790M mutations. This first-in-human phase 1 study evaluated the maximum tolerated dose, recommended phase 2 dose (RP2D), safety, tolerability, and pharmacokinetics (PK), and preliminarily determined the antitumor activity of ES-072 in NSCLC patients with EGFR T790M mutations.Patients and MethodsDose escalation and expansion studies were performed using an accelerated titration method. Oral ES-072 doses (25-450 mg) were administrated once daily for single- and multiple-dose escalation trials. Characteristic PK parameters were assessed in the single-dose escalation phase and in the first cycle of the multiple-dose escalation phase. Tumor responses were assessed using the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 to evaluate ES-072 antitumor activity.ResultsNineteen patients were enrolled onto this study, 16 to the dose-escalation phase and 3 to the dose-expansion phase. The most common adverse events were QT interval prolongation (11/19, 57.9%), anemia (5/19, 26.3%), mouth ulceration (4/19, 21.1%), keratosis (4/19, 21.1%), and cough (4/19, 21.1%). Safety and tolerability evaluation of ES-072 showed an maximum tolerated dose of 300 mg, and the RP2D dose was therefore 300 mg once daily. PK analysis showed an ES-072 half-life of 24.5 hours and a T_max of approximately 4 hours. The total objective response rate and disease control rate were 46.2% and 76.9%, respectively.ConclusionES-072 was safe and well tolerated in NSCLC patients harboring EGFR T790M mutations, and adverse events were controllable and reversible. A RP2D of 300 mg once daily was determined, and preliminary investigations showed promising antitumor activity.     

Phase 1 study of twice weekly pulse dose and daily low-dose erlotinib as initial treatment for patients with EGFR-mutant lung cancers

BackgroundPatients with EGFR-mutant lung cancers treated with EGFR tyrosine kinase inhibitors (TKIs) develop clinical resistance, most commonly with acquisition of EGFR T790M. Evolutionary modeling suggests that a schedule of twice weekly pulse and daily low-dose erlotinib may delay emergence of EGFR T790M. Pulse dose erlotinib has superior central nervous system (CNS) penetration and may result in superior CNS disease control.MethodsWe evaluated toxicity, pharmacokinetics, and efficacy of twice weekly pulse and daily low-dose erlotinib. We assessed six escalating pulse doses of erlotinib.ResultsWe enrolled 34 patients; 11 patients (32%) had brain metastases at study entry. We observed 3 dose-limiting toxicities in dose escalation: transaminitis, mucositis, and rash. The MTD was erlotinib 1200 mg days 1–2 and 50 mg days 3–7 weekly. The most frequent toxicities (any grade) were rash, diarrhea, nausea, fatigue, and mucositis. 1 complete and 24 partial responses were observed (74%, 95% CI 60–84%). Median progression-free survival was 9.9 months (95% CI 5.8–15.4 months). No patient had progression of an untreated CNS metastasis or developed a new CNS lesion while on study (0%, 95% CI 0–13%). Of the 18 patients with biopsies at progression, EGFR T790M was identified in 78% (95% CI 54–91%).ConclusionThis is the first clinical implementation of an anti-cancer TKI regimen combining pulse and daily low-dose administration. This evolutionary modeling-based dosing schedule was well-tolerated but did not improve progression-free survival or prevent emergence of EGFR T790M, likely due to insufficient peak serum concentrations of erlotinib. This dosing schedule prevented progression of untreated or any new central nervous system metastases in all patients.     

Potential Resistance Mechanisms Revealed by Targeted Sequencing from Lung Adenocarcinoma Patients with Primary Resistance to Epidermal Growth Factor Receptor (EGFR) Tyrosine Kinase Inhibitors (TKIs)

IntroductionEGFR tyrosine kinase inhibitors (TKIs) have greatly improved the prognosis of lung adenocarcinoma. However, approximately 5% to 10% of patients with lung adenocarcinoma with EGFR sensitive mutations have primary resistance to EGFR TKI treatment. The underlying mechanism is unknown.MethodsThis study used next-generation sequencing to explore the mechanisms of primary resistance by analyzing 11 patients with primary resistance and 11 patients sensitive to EGFR TKIs. Next-generation targeted sequencing was performed on the Illumina X platform for 483 cancer-related genes. EGFR mutation was initially detected using the amplification refractory mutation system.ResultsPotential primary resistance mechanisms were revealed by mutations unique to the EGFR TKI resistance group. Among the 11 resistant patients, 45% (five of 11) harbored a known resistance mechanism, such as MNNG HOS Transforming gene (MET) amplification de novo T790M mutation or overlapping T790M and phosphatase and tensin homolog gene (PTEN) loss and erb-b2 receptor tyrosine kinase 2 gene (ERBB2) amplification. In six of 11 resistant cases (54%), potential novel mutations that might lead to drug resistance were identified (including transforming growth factor beta receptor 1 gene [TGFBR1] mutation and/or EGFR structural rearrangement mechanistic target of rapamycin kinase gene [MTOR] mutation, transmembrane protease, serine 2 gene [TMPRSS2] fusion gene, and v-myc avian myelocytomatosis viral oncogene homolog gene [MYC] amplification). By analyzing somatic mutation patterns, the frequency of C:G→T:A transitions in the patients with primary resistance was significantly higher than that in sensitive group and occurred more frequently in the non-CpG region (Cp(A/C/T)→T).ConclusionThe mechanisms of primary resistance to EGFR TKIs may be highly heterogeneous. Mutations in EGFR and its downstream pathway, as well as mutations that affect tumor cell function, are related to primary resistance. Somatic single-nucleotide mutation patterns might be associated with primary resistance to EGFR TKIs.