Ex20ins Mutations Research Articles

P50.05 Natural History and Real-World Treatment Outcomes for NSCLC Patients with EGFR Exon 20 Insertion Mutation: An IASLC- ASCO CancerLinQ Study

Epidermal Growth Factor Receptor (EGFR) exon 20 insertion (ex20ins) mutations account for 2-3% all non-small cell lung cancer (NSCLC) patients. Patients with ex20 ins do not respond to standard EGFR TKI therapy. In this work, we have analyzed the characteristics, treatment patterns and outcomes in this subgroup of NSCLC patients. The ASCO CancerLinQ Discovery dataset was queried to identify patients diagnosed with NSCLC between the years 1995-2018 and with EGFR ex20ins mutations. Data were extracted on patient demographics, tumor characteristics, treatments and outcomes, and compared with Chi-square and ANOVA tests. Kaplan-Meier (KM) curves were generated for comparing overall survival with log-rank tests. All analyses were performed using Python 3.6. A total of 357 patients were eligible. Patient characteristics: median age 68 years, female 53.5%, white race 63% and black race 9%. Approximately 62% had stage 4 disease, and 30% had brain metastasis. 54% of the patients were treated with chemotherapy and 15% with immune check point inhibitors (ICI). In patients with brain metastasis, 16% were treated with ICI, 18% targeted therapy and 59% with chemotherapy. The median survival of the entire group is 23.8 months. Among patients with stage 4 disease: 51% were females, 64% white race, 37% had brain metastasis, 18% were treated with ICI, 14% targeted therapy and 60% treated with chemotherapy. In the analysis of stage 4 patients, the median survival of the group was 16.8 months. Stage 4 patients that received ICI had better survival vs. those who did not (29.1 vs. 14.7 months; p=0.01). Stage 4 patients treated with ICI and chemotherapy had better survival compared to those treated with chemotherapy alone (29.1 vs. 16.5 months, p=0.01). Stage 4 patients treated with targeted therapy had better survival compared to those that did not receive targeted therapy (20.6 vs. 16.1 months; p=0.03). Stage 4 NSCLC patients with EGFR ex20ins mutation had favorable real-world survival when treated with ICI and targeted therapy.

MA14.01 Distribution and Detectability of EGFR Exon 20 Insertion Variants in Non–Small Cell Lung Cancer

The population of EGFR exon 20 insertion (ex20ins) mutations includes a diverse array of insertion variants and represents 5%-10% of EGFR mutations in non–small cell lung cancer (NSCLC). Specific targeted therapies are not available for patients with EGFR ex20ins+ NSCLC, regardless of insertion variant status; however, mobocertinib and amivantamab are currently in development. Identifying patients with EGFR ex20ins is challenging due to the limited coverage of polymerase chain reaction (PCR) assays and relatively recent use of next-generation sequencing (NGS).

1224P Systematic review and meta-analysis of immunotherapy effectiveness for pretreated patients with non-small cell lung cancer harboring EGFR exon 20 insertions

EGFR exon 20 insertion (ex20ins) mutations are rare, and data on clinical outcomes with immunotherapy (IO) in these patients are scarce. Per National Comprehensive Cancer Network guidelines, IO monotherapy is not recommended over targeted therapies for non–small cell lung cancer (NSCLC) patients with an oncogenic driver. To determine the efficacy of IO monotherapy in the second-line setting and beyond (≥2nd-line) for EGFRex20ins+ NSCLC, we conducted a systematic review and meta-analysis of real-world objective response rate (ORR) data. We analyzed ORRs of ≥2nd-line IO monotherapies in EGFRex20ins+ NSCLC from: (1) PubMed literature search for clinical studies reporting ORR, disease control rate (DCR), or progression-free survival (PFS); (2) longitudinal data from the United States Flatiron Health Research Database; (3) a retrospective chart review from 12 German oncology centers; and (4) prior anticancer therapy and associated response data from a single-arm, phase I/II study of mobocertinib, an oral EGFR tyrosine kinase inhibitor targeting EGFRex20ins, in EGFRex20ins+ NSCLC patients previously treated with ≥2nd-line IO. From the meta-analysis of all data, the calculated ORR [95% confidence intervals] for ≥2nd-line IO monotherapy in patients with EGFRex20ins+ NSCLC was 3.5% [0.6%, 9.9%] (Table). Across sources (N=91), reported ORRs ranged from 0% to 14.3% (1/7 patients in single study), with 2 total responses; DCRs ranged from 23.8% to 30.0%, and median PFS ranged from 2.3 months to 4.0 months. Reported data were limited by small number of patients and studies reporting mixed lines of therapy (≥2nd-line).Table: 1224PData sourceReported ORR, n/N (%)Takeda M. (Oncotarget. 2018)1/7 (14.3%)LC-SCRUM-JAPAN/Udagawa (J Thorac Oncol. 2019)0/21 (0%)Yang G. (Lung Cancer. 2020)0/2 (0%)Flatiron database1/20 (5%)German chart review0/10 (0%)Mobocertinib study0/31 (0%)Meta-analysisMean ORR [2.5%, 97.5%]3.5% [0.6%, 9.9%] Open table in a new tab Results of this meta-analysis suggest that IO monotherapies are not effective in the ≥2nd-line setting for patients with EGFRex20ins+ NSCLC, which further highlights the need for novel treatment options in this population.

Clinical and molecular characteristics of epidermal growth factor receptor exon 20 insertion mutations in non-small-cell lung cancer

To evaluate the genomic and immune characteristics of non-small-cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) exon 20 insertion (ex20ins) mutations from a retrospective dataset with molecular spectrum, tumor mutational burden (TMB), and programmed death-ligand 1 (PD-L1) expression, as well as to evaluate the efficacy of immune checkpoint inhibitors (ICIs). A total of 283 patients with EGFR ex20ins mutations who were diagnosed with NSCLC at our hospital from August 2013 to September 2020 were enrolled in this single-center retrospective study. Among the 283 patients with EGFR ex20ins mutations, 182 patients received next-generation sequencing (NGS) test, and 51 different subtypes of insertion variants were recorded. The most common mutations were A767_V769dup (21.4%), S768_D770dup (19.2%) and A763_Y764insFQEA (7.1%). The most common co-occurring mutations were EGFR amplification (37.9%), TP53 mutation (35.0%) and PIK3CA mutation (8.7%). PD-L1 status was available for 141 patients, and 75.9% (107/141) of these samples showed negative PD-L1 expression. In the 36 cases with TMB tested by NGS, the median TMB was 4.6 mutations/Mb. Then 12 patients received ICIs monotherapy or combination therapy. No severe adverse events were observed. Low PD-L1 expression and TMB were observed in NSCLC patients harboring EGFR ex20ins mutations. Further investigations are needed to confirm the therapeutic sensitivity of ICIs in this subgroup of EGFR mutations.

Pyrotinib in HER2 heterogeneously mutated or amplified advanced non-small cell lung cancer patients: a retrospective real-world study (PEARL)

Human epidermal growth factor receptor 2 (HER2) amplification or activating mutations are found in 1.6%–4% of non-small cell lung cancer (NSCLC). Pyrotinib has been reported to have better potency in NSCLC patients with HER2 exon 20 insertion (ex20ins) mutations; however, more clinical evidence is urgently needed to guide pyrotinib-based therapy in NSCLC with HER2 amplification or heterogeneous mutations. We retrospectively analyzed advanced NSCLC patients with HER2 amplification or mutations who were treated with pyrotinib-based therapy between September 25, 2018 and October 30, 2020 in our hospital. Molecular dynamics simulation was used to explore the bioactive conformation and binding mechanisms of pan-ErbB tyrosine kinase inhibitors (TKIs) including pyrotinib for different HER2 ex20ins variants. In this study, 79 eligible patients were included with 70 ex20ins variants, 6 missense mutations and 3 primary HER2 amplifications identified. A775_G776insYVMA insertion was the most common observed subtype. The median progression-free survival (mPFS) was 5.8 (95% CI: 4.1–7.4) months. Use of pyrotinib-based therapy in first-/second-line settings showed a significantly better prognosis than that observed in third-line settings or above (mPFS: 9.1 vs. 4.4 months; P = 0.0003). Compared with HER2 amplification and exon 20 non-YVMA insertion variants, patients with HER2 missense mutations had a visible mPFS benefit (12.2 vs. 6.8 vs. 5.2 months). Computational docking simulations revealed that pyrotinib failed to interact with the specific insertion variant P780_Y781insGSP. These results indicated that pyrotinib-based therapy exhibited good anti-tumor activity and acceptable safety profile in HER2-altered advanced NSCLC.

Mobocertinib (TAK-788) in EGFR exon 20 insertion (ex20ins)+ metastatic NSCLC (mNSCLC): Additional results from platinum-pretreated patients (pts) and EXCLAIM cohort of phase 1/2 study.

9014 Background: No approved targeted therapies are available for EGFR ex20ins+ mNSCLC. Mobocertinib, a first-in-class, potent, oral TKI targeting EGFR ex20ins mutations, has Breakthrough Therapy Designation in the US and China for post-platinum-based chemotherapy pts with EGFR ex20ins+ mNSCLC. Methods: This 3-part, open-label, multicenter study (NCT02716116) has dose-escalation/expansion and extension (EXCLAIM) cohorts. Pts with EGFR ex20ins+ mNSCLC, ECOG status 0–1, and ≥1 prior line of therapy for locally advanced/metastatic disease received mobocertinib 160 mg QD. Primary endpoint was confirmed objective response rate (ORR; RECIST v1.1) assessed by independent review committee (IRC). We present additional efficacy and safety data for 114 platinum-pretreated pts (PPP) and 96 pts from EXCLAIM safety cohort. Results: Results are from Nov 1, 2020, data cutoff. Among PPP pts (n=114; median age 60 y [27–84 y]), 66% were female, 60% were Asian, and 59% had ≥2 prior systemic anticancer lines. Confirmed ORR per IRC was 28%, including 1 complete response (CR); disease control rate (DCR) was 78% [95% CI: 69–85]; median duration of response (DOR) was 17.5 mo (Table). In EXCLAIM (n=96; median age 59 y [27–80 y]), 65% were female, 69% were Asian, and 49% had ≥2 prior lines. Confirmed ORR per IRC was 25%, with 1 CR; DCR was 76% [95% CI: 66–84]; median DOR was not reached (Table). In EXCLAIM, baseline brain metastases were present in 33/96 pts (34%); the first site of disease progression by IRC was the brain in 40% of all pts and 73% of pts with baseline brain metastases. Confirmed responses were seen in all prespecified subgroups in PPP and EXCLAIM. Efficacy by EGFR ex20ins mutation variant will be presented. Treatment-related adverse events (TRAEs; >20%) in PPP were diarrhea (91%), rash (45%), paronychia (38%), decreased appetite (35%), nausea (34%), dry skin (31%), vomiting (30%), increased blood creatinine (25%), stomatitis (24%), and pruritus (21%); the only grade ≥3 TRAE in ≥5% was diarrhea (22%). AEs leading to discontinuation in >2% were diarrhea (4%) and nausea (4%). A similar safety profile was observed in EXCLAIM. Conclusions: Mobocertinib demonstrated clinically meaningful benefit for pts with EGFR ex20ins+ mNSCLC in PPP and EXCLAIM cohorts, with a manageable safety profile. Clinical trial information: NCT02716116. [Table: see text]

EGFR Exon 20 Insertion Mutations: Clinicopathological Characteristics and Treatment Outcomes in Advanced Non–Small Cell Lung Cancer

BackgroundEpidermal growth factor receptor gene (EGFR) exon 20 insertion (ex20-ins) mutations are an uncommon and heterogeneous group of non–small cell lung cancers (NSCLCs), resistant to conventional EGFR tyrosine kinase inhibitors (TKIs). Characteristics and outcomes of patients with EGFR ex20-ins have not been fully established; we sought to clarify them using a multinational patient database. Patients and MethodsPatients with NSCLC from six Australian institutions with EGFR exon 20 mutations (ex20-mut), excluding T790M, were retrospectively reviewed. Clinical characteristics and outcomes with systemic treatments were collected and analyzed using comparative statistics. ResultsAmong 109 patients with ex20-mut, 61% were females and 75% were Caucasians. More males presented with de novo metastatic disease (84% vs. 51%; P = .002). Central nervous system (48%) and liver (24%) metastases were common within metastatic patients (n = 86). Thirty-nine patients received platinum-based chemotherapy (PBC) and achieved a 43% objective response rate (ORR), median progression-free survival (mPFS) of 6.9 months, and median overall survival (mOS) of 31.0 months. Twenty-three of the patients with ex20-ins received conventional TKIs, resulting in an ORR of 13%, mPFS of 3.4 months (95% confidence interval [CI], 1.91-6.25), and mOS of 31.0 months (95% CI, 15.09-not reached). Nine patients with S786I mutations received TKIs, resulting in an ORR of 50%, mPFS of 18.2 months (2.79-not reached), and mOS of 33.4 months (95% CI, 16.14-not reached). Twenty-three patients received immune checkpoint inhibitor monotherapy (ICIm), resulting in an ORR of 4%, mPFS of 2.6 months (95% CI, 1.91-4.83), and mOS of 30.8 months (95% CI, 17.62-41.62). ConclusionAlthough phenotypically similar to patients with common EGFR mutations, patients with EGFR ex20-mut had worse survival, perhaps due to the lack of targeted therapies. Chemotherapy was superior to conventional EGFR TKIs in patients with EGFR ex20-ins, although there was moderate activity of TKIs in S768I mutations. ICIm was ineffective.

Sensitivity to Immune Checkpoint Blockade in Advanced Non-Small Cell Lung Cancer Patients with EGFR Exon 20 Insertion Mutations.

Besides platinum-based chemotherapy, no established treatment option exists for advanced non-small-cell lung cancer (NSCLC) patients with EGFR exon 20 (Ex20ins) insertion mutations. We sought to determine the clinical outcome of patients with this EGFR mutation subtype in the immunotherapy era. Thirty NSCLCs with EGFR Ex20ins mutations were identified, of whom 15 had received immune checkpoint blockade (ICB) treatment as monotherapy (N = 12), in combination with chemotherapy (N = 2) or with another immunotherapeutic agent (N = 1). The response rate was observed in 1 out of 15 patients (6.7%), median progression-free survival (PFS) was 2.0 months and median overall survival (OS) was 5.3 months. A trend towards an inferior outcome in terms of PFS and OS was observed for patients receiving ICB treatment in the first versus second line setting (PFS: 1.6 months versus 2.7 months, respectively, p = 0.16—OS: 2.0 months versus 8.1 months, respectively, p = 0.09). Median OS from the time of diagnosis of advanced disease was shorter for patients treated with ICB versus those who did not receive immunotherapy (12.9 months versus 25.2 months, respectively, p = 0.08), which difference remained associated with a worse survival outcome at multivariate analysis (p = 0.04). Treatment with ICB is poorly effective in NSCLCs with EGFR Ex20ins mutations, especially when given in the first-line setting. This information is crucial in order to select the optimal treatment strategy for patients with this subtype of EGFR mutation.

P76.43 Co-occurring genomic alterations and treatment outcomes in patients with EGFR exon 20 insertion positive NSCLC

NSCLC harboring an EGFR exon 20 insertion (ex20ins) often has additional genomic aberrations, which may influence the underlying biology and predict outcomes. Clinical outcomes data overall remain limited in patients (pts) with ex20ins and comprehensive characterization of these tumors is lacking. NSCLC samples were profiled by targeted NGS (Caris Life Sciences, Phoenix, AZ). Mutations and copy number variations (CNV) were assessed. Gene amplification was defined as gene copy number ≥ 6 and copy number loss as gene copy number < -1.4. Clinical outcomes data were obtained through an IRB-approved retrospective chart review. Among 3,359 pts with NSCLC harboring an EGFR mutation, 250 (7.4%) had EGFR ex20ins. 170 (68%) were females with a mean age 65 (range 29-90). 60 different ex20ins variants were identified with the most common being A767_V769dup (25%), followed by S768_D770dup (18%), N771_H773dup (7%), H773_dup (6%) and A763_Y764insFQEA (3%). 4% had compound ex20ins mutations. The most common co-mutations included TP53 (56.6%), followed by CTNNB1 (6.6%), RB1 (5.1%), PIK3CA (4.7%) and CDKN2A (4.3%). Commonly amplified genes included EGFR (9.6%), FOXA1 (4%), MDM2 (3.6%) and CDK4 (3.5%). Copy number loss was observed in CDKN2A (4.6%), BRCA2 (1.1%), FANCL (1.1%), CTNNB1 (0.5%), and ATR (0.5%). PD-L1 expression by 22C3 was high (TPS ≥ 50%) in 16%, low (1-49%) in 27%, and negative in 57%. Clinical data were obtained from 26 pts with advanced NSCLC with ex20ins mutations from four institutions. In the first-line setting, 12 (46%) received chemotherapy, 10 (39%) received an EGFR-TKI and 4 (15%) received chemo-IO. Mean PFS was 9.3 months with chemotherapy-based regimens and 6 months with TKI therapy. One patient with P772_H773dup treated with TKI achieved a partial response. Across all treatments, mean PFS was 8 months and mean OS was 28.3 months. The diverse spectrum of EGFR ex20ins mutations demonstrates notable molecular heterogeneity within this uncommon EGFR mutation. PFS and OS in this population remain poor. Understanding the role of co-occurring genomic alterations and their impact on outcomes may have therapeutic implications on clinical trial development.

Tackling Drug Resistance in EGFR Exon 20 Insertion Mutant Lung Cancer.

Insertion mutations in exon 20 (Ex20ins) of the epidermal growth factor receptor (EGFR) gene are the largest class of EGFR mutations in non-small cell lung cancer (NSCLC) for which there are currently no approved targeted therapies. NSCLC patients with these mutations do not respond to clinically approved EGFR tyrosine kinase inhibitors (TKIs) and have poor outcomes. A number of early phase clinical trials are currently underway to evaluate the efficacy of a new generation of TKIs that are capable of binding to and blocking Ex20ins. Although these agents have shown some clinical activity, patient responses have been restricted by dose-limiting toxicity or rapid acquisition of resistance after a short response. Here we review the current understanding of the mechanisms of resistance to these compounds, which include on-target EGFR secondary mutations, compensatory bypass pathway activation and acquisition of an EMT phenotype. Taking lessons from conventional EGFR inhibitor therapy in NSCLC, we also consider other potential sources of resistance including the presence of drug-tolerant persister cells. We will discuss therapeutic strategies which have the potential to overcome different forms of drug resistance. We conclude by evaluating recent technological developments in drug discovery such as PROTACs as a means to better tackle TKI resistance in NSCLC harbouring Ex20ins mutations.

Tumor genomics and response to chemotherapy in advanced non-small cell lung cancer with exon 20 insertion epidermal growth factor receptor mutations.

BackgroundTo characterize the effects of mutation subtypes and concomitant pathogenic mutations on progression-free survival (PFS) and overall survival (OS) in advanced non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) exon 20 insertion (ex20ins) mutations treated with chemotherapy.MethodsWe retrospectively found that patients who underwent genomic analysis from January 2017 to December 2019, and 101 patients with advanced EGFR ex20ins NSCLC were found. Binary logistic regression and Cox regression were used to determine how EGFR ex20ins mutation subtypes and concomitant mutations are associated with PFS and OS.ResultsA total of 8,348 patients were screened and 101 advanced EGFR ex20ins NSCLC patients were detected. Fifty-five patients who received chemotherapy (n=49) or TKIs (n=6) as first-line treatment were recorded for PFS and OS. PFS and OS were significantly longer in the platinum-based chemotherapy group (median PFS: 7.6 versus 5.6 months; P=0.001; median OS: 19.9 versus 7.4 months; P=0.027) than in the TKI group. Common mutations include Ala767_Val769dupAlaSerVal (A767_V769dupASV), Ser768_Asp770dupSerValAsp (S768_D770dupSVD) and Ala763_Tyr764insPheGlnGluAla (A763_Y764insFQEA). On binary logistic regression, common mutations (OR =17.04, 95% CI: 1.39–209.56; P=0.027) and number of concomitant mutations ≤1 (OR =34.67, 95% CI: 2.02–595.48; P=0.015) is significantly associated with durable clinical benefit (DCB). On multivariable analysis, common mutations (HR =0.26, 95% CI: 0.0.10–0.63; P=0.003) and the number of concomitant mutations ≤1 (HR =0.33, 95% CI: 0.15–0.73; P=0.006) were significantly associated with longer PFS.ConclusionsCommon mutations and the number of concomitant mutations ≤1 correlate with a biomarker that predicts benefit from chemotherapy and confers excellent prognosis for advanced patients with advanced EGFR ex20ins NSCLC. Patients with common mutations and with only one concomitant mutation had the greatest PFS and patients with uncommon mutations, and with over one concomitant mutation had the worst prognosis.

Impact of EGFR amplification on survival of patients with EGFR exon 20 insertion-positive non-small cell lung cancer.

BackgroundEpidermal growth factor receptor (EGFR) exon 20 insertion (EGFR ex20ins) is a common mutation in non-small cell lung cancer (NSCLC). Patients with EGFR ex20ins generally respond poor to EGFR-tyrosine kinase inhibitors (EGFR-TKIs). EGFR ex20ins are often co-occurring with EGFR amplification. However, the impact of EGFR amplification on the survival of patients with EGFR ex20ins mutations has not been determined.MethodsThis is an observational longitudinal cohort study. A prospectively managed database included consecutive treatment-naïve adult patients with advanced NSCLC and EGFR ex20ins confirmed by next-generation sequencing (NGS) at Guangdong Provincial People’s Hospital between November 2017 and February 2019. The participants were enrolled from the database and extracted their clinical characteristics, treatment and clinical outcomes. NGS was used to establish whether EGFR amplification was present in tumor tissue. Overall survival (OS) and progression-free survival (PFS) were compared between EGFR amplification and non-EGFR amplification groups using the Kaplan-Meier method and log-rank test. Subgroup analyses were performed based on the treatment used (EGFR-TKI or chemotherapy).ResultsFifteen different EGFR ex20ins mutation subtypes were identified in the 39 patients included in the analysis, and the most common subtypes were p.A767_D770dup (25.6%), p.S768_D770dup (23.1%) and p.N771_H773dup (10.3%). Among 31 patients with EGFR ex20ins mutations and NGS data for tumor tissue, EGFR amplification was identified in 12 patients (38.7%) and there were no significant differences in clinical characteristics. Among 26 patients, there were no significant differences between the EGFR amplification (n=11) and non-EGFR amplification (n=15) groups in median OS (715 vs. 452 days, P=0.912). Among 20 patients administered chemotherapy, there were no significant differences between the EGFR amplification and non-EGFR amplification groups in median PFS (206 vs. 112 days, P=0.425). Among 24 patients administered an EGFR-TKI, median PFS was longer in the non-EGFR amplification group than in the EGFR amplification group (110 vs. 31 days, P=0.030).ConclusionsThere is a tendency that EGFR amplification might be a poor predictor in EGFR ex20ins-positive NSCLC patients treated with EGFR-TKIs.

11P Preclinical evaluation of DS-2087b, a novel and selective inhibitor of EGFR/HER2 exon 20 insertions

In-frame insertions in exon 20 of the epidermal growth factor receptor (EGFR) or human epidermal growth factor receptor 2 (HER2) gene are oncogenic drivers in non-small cell lung cancer (NSCLC), breast cancer, and others. However, no pharmacologic treatments are available for EGFR/HER2 exon 20 insertions (ex20ins), and effective treatment should avoid the inhibition of wild-type (WT) EGFR, which causes dose-limiting toxicities, such as rash and diarrhea. Here we describe DS-2087b, a novel oral, potent, and selective inhibitor of EGFR/HER2 ex20ins. We evaluated the inhibitory effects of DS-2087b and poziotinib, an investigational tyrosine kinase inhibitor against Ba/F3 cells harboring WT EGFR and against EGFR/HER2 ex20ins mutations, including EGFR V769_D770 insertion ASV (EGFR ins.ASV); EGFR D770_N771 insertion SVD (EGFR ins.SVD); and HER2 A775_G776 insertion YVMA (HER2 ins.YVMA). Moreover, we measured the antitumor activity of DS-2087b in an NSCLC patient-derived xenograft (PDX) model with EGFR ins.ASV. DS-2087b inhibited the proliferation of Ba/F3 cells expressing EGFR ins.ASV, EGFR ins.SVD, and HER2 ins.YVMA with 50% maximal inhibition of cell proliferation (GI50) values of 23.5, 21.3, and 29.0 nM, respectively, but the GI50 value for Ba/F3 cells expressing EGFR WT was 368.9 nM. Poziotinib showed similar GI50 values between EGFR/HER2 ex20ins and WT EGFR. In Ba/F3 allograft models with EGFR ins.ASV, EGFR ins.SVD, and HER2 ins.YVMA and the PDX model with EGFR ins.ASV, DS-2087b showed remarkable antitumor effects in a dose-dependent manner without body weight loss. In in vitro and in vivo preclinical assays, DS-2087b is effective against EGFR/HER2 ex20ins and also showed selectivity over WT EGFR. DS-2087b may show clinical utility in patients who harbor EGFR/HER2 ex20ins mutations and reduced toxicities caused by WT EGFR inhibition.

Abstract 5199: JNJ-61186372, an EGFR-cMet bispecific antibody, in EGFR Exon 20 insertion-driven advanced non-small cell lung cancer (NSCLC)

Abstract PURPOSE: Although EGFR exon20 insertion (ex20ins) mutations account for 4~12 % of EGFR mutant NSCLC patients, there is no effective and selectable anticancer drugs targeting ex20ins mutations so far due to various variant mutations in ex20ins mutations. Moreover, most EGFR ex20ins mutants show primary resistance to EGFR TKIs. JNJ-61186372 (JNJ-372), a bispecific antibody that targets the EGFR and cMet receptors, is currently being explored in a first-in-human study in patients with NSCLC. To better understand the mechanism of JNJ-372 activity in this patient population, we conducted preclinical studies exploring the activity of JNJ-372 in different EGFR ex20ins models. METHODS: To elucidate whether JNJ-372 has antitumor effect in EGFR ex20ins mutants via EGFR and c-MET inhibition, cell viability, western blot, cell cycle, colony formation assay, FACS analysis were performed in JNJ-372 treated BaF3 cells, PDCs, PDOs, and PDX expressing EGFR ex20ins mutation. For mouse tumor models, JNJ-372 was administered i.p. twice a week at 10 mg/kg or 30 mg/kg. Antibody dependent cellular cytotoxicity (ADCC) assay was assessed to figure out whether JNJ-372 had ADCC effects. Referenced patients with ex20ins disease were administered 1050 mg JNJ-372 i.v. weekly for the first 4-week cycle, then biweekly for each subsequent cycle RESULTS: JNJ-372 inhibited the growth of BaF3 cells, PDCs, and a PDO harboring a range of ex20ins, which were resistant to osimertinib and gefitinib. Mechanistic assays revealed the reduction of EGFR and cMet receptor levels and decreases in phospho-EGFR and c-Met, as well as inhibition of their downstream signaling pathways. Cleaved caspase-3 and BIMEL were upregulated at anti-proliferative doses, suggesting caspase-mediated cell death. JNJ-372 demonstrated corresponding antitumor activity in PDC and PDX models harboring different ex20ins; inhibition of signaling and engagement of the apoptotic pathway was confirmed in tumors of JNJ-372-treated mice. In PDCs with EGFR ex20ins mutation, we verified that JNJ-372 had a significant ADCC effect compared to EGFR antibody drug cetuximab. In the first-in-human trial, CT scans from two patients treated with JNJ-372 revealed reductions in tumor burden. A 58-year patient harboring H773delinsNPY showed -63% tumor reduction with progression-free survival of &amp;gt; 20 months and a 48-year patient harboring S768_D770dup showed -38.9% tumor reduction. CONCLUSION: JNJ-372 drives antitumor activity in preclinical models of EGFR ex20ins, which have no therapeutic options in clinic, by decreasing EGFR and cMet receptor levels, inhibiting downstream signaling cascades, activating apoptotic signaling as well as ADCC. These results provide a promising therapeutic option to patients with EGFR ex20ins mutations and an understanding of the activity of JNJ-372 being observed in the first-in-human study. Citation Format: Jiyeon Yun, Han Na Kang, Soo-Hwan Lee, Seo-Yoon Jeong, Chae Won Park, Jae-Hwan Kim, Kyoung-Ho Pyo, Ji Min Lee, Seok-Young Kim, Min Hee Hong, Hye Ryun Kim, Meena Thayu, Joshua Curtin, Roland Knoblauch, Matthew Lorenzi, Byoung Chul Cho. JNJ-61186372, an EGFR-cMet bispecific antibody, in EGFR Exon 20 insertion-driven advanced non-small cell lung cancer (NSCLC) [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5199.

EGFR exon 20 insertion mutations in non-small cell lung cancer.

Mutations in the epidermal growth factor receptor (EGFR) gene are the most common targetable genomic drivers of non-small cell lung cancer (NSCLC). 90% of the EGFR mutations comprise of EGFR exon 19 deletion and exon 21 L858R mutation, while EGFR exon 20 insertion (EGFR Ex20Ins) is the third most common type of EGFR mutation. Currently, studies on EGFR Ex20Ins are relatively scarce and limited. The frequency of EGFR Ex20Ins mutations in NSCLC was 1–10%. Patients harboring EGFR Ex20Ins exhibited similar clinical characteristics except for poorer prognosis as compared to patients with sensitizing mutations in EGFR. Conventional TKIs have poor efficacy in a majority of EGFR Ex20Ins subtypes. Chemotherapy remains the preferred treatment for advanced NSCLC patients harboring EGFR Ex20Ins. However, some novel inhibitors are considered as putative candidates. This review focuses on the structural and biochemical features, clinical characteristics, treatments, and prognosis of EGFR Ex20Ins in NSCLC.

EGFR exon 20 insertion mutations in Chinese advanced non-small cell lung cancer patients: Molecular heterogeneity and treatment outcome from nationwide real-world study

ObjectivesTo describe the treatment patterns and outcomes of Chinese non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) exon 20 insertion (ex20ins) mutations in real-world as EGFR ex20ins consist of a diverse group of mutations with limited information on the clinical outcome of these patients treated with chemotherapy or EGFR tyrosine kinase inhibitors (TKIs). Materials and methodsReal-world treatment outcomes of Chinese NSCLC patients harboring EGFR ex20ins were retrospectively analyzed based on medical records at different institutions and detailed web-based patient questionnaires. ResultsBetween March 17, 2018 and December 20, 2018, 165 advanced EGFR ex20ins NSCLC patients treated in 99 hospitals from 26 different regions in China were analyzed. Thirty-nine different molecular variants of EGFR ex20ins were identified with V769_D770insASV being the most common (23.0 %). Central nervous system (CNS) metastasis occurred in 23.0 % of patients at the time of baseline diagnosis. Median progression-free survival (PFS) was significantly longer in patients who received first-line platinum-based chemotherapy (6.4 m; 95 % CI: 5.7–7.1) than all-generation EGFR TKIs (2.9 m; 95 %CI: 1.5–4.3; P < 0.001) or 1st-generation EGFR TKIs (2.0 m; 95 %CI: 0.2–3.8; P < 0.001). Median PFS was numerically longer in patients who received second-line chemotherapy (4.0 m; 95 %CI: 3.2–4.8) than those received second-line EGFR TKIs (2.0 m; 95 %CI: 1.1–2.9; P = 0.342). Patients with CNS metastasis had numerically shorter median PFS than those without CNS metastasis when treated with 1st-line chemotherapy (3.6 m; 95 %CI: 0–8.0 vs. 6.5 m; 95 %CI: 4.9–8.1; P = 0.645) or 1st-line EGFR TKIs (2.0 m; 95 %CI: 0.8–3.2 vs. 2.9 m; 95 %CI: 2.1–3.7; P = 0.058). ConclusionChemotherapy is superior to current approved EGFR TKIs as 1st- or 2nd-line treatment of EGFR ex20ins mutations. CNS metastasis conferred numerically shorter PFS with chemotherapy or EGFR TKIs treatment. Targeted agent against EGFR ex20ins with CNS activity is urgently needed.

Studies and Progress of EGFR exon 20 Insertion Mutation in Non-small Cell Lung Cancer

全球肺癌发病率及死亡率居全部恶性肿瘤的首位，与非小细胞肺癌（non-small cell lung cancer, NSCLC）相关的治疗研究也是近年来的研究热点。表皮生长因子受体-酪氨酸激酶抑制剂（epidermal growth factor receptor-tyrosinekinase inhibitors, EGFR-TKIs）的出现，给携带EGFR基因突变的NSCLC患者治疗带来巨大的转变。但携带EGFR基因的20外显子插入突变（exon 20 insertion mutation, ex20ins mutation）患者却是EGFR基因突变群体中的特殊人群，往往对EGFR-TKIs耐药。本文对EGFR ex20ins突变相关的研究进行回顾分析，归纳其特点、检测手段、治疗手段，对EGFR ex20ins突变有更加全面的认识，将为临床应用提供帮助，为患者带来更大的益处。

Abstract B002: Discovery of selective and potent EGFR kinase inhibitors for exon20 insertion mutations

Abstract The third generation EGFR tyrosine kinase inhibitors (TKIs), like Osimertinib, target classical activating EGFR mutations containing T790M resistance mutation. However, the exon 20 insertion (Ex20Ins), the third most common EGFR mutations in entire NSCLC, still lacks its therapeutic option. Recently, Robichaux JP et al., showed that Poziotinib, which had been developed as a second-generation EGFR TKI, had efficacy for the EGFR and Her2 Ex20Ins compared to EGFR T790M. Here, we developed inhibitors, structurally distinct from both Poziotinib and Osimertinib, targeting for the EGFR Ex20Ins mutations as well as EGFR T790M. According to kinase profiling, the inhibitors are highly selective to EGFR, ERBB2 and ERBB4 family. The candidate inhibitors demonstrated great activity (GI50 &amp;lt; 20 nM) in cell growth inhibition of Ba/F3 cells containing EGFR Ex20Ins (D770_N771insSVD, V769_D770insASV, D770_N771insNPG, A763_Y764insFQEA, and H773_V774insNPH), Her2 Ex20Ins (A775_G776insYVMA), or cancer cells containing activating EGFR mutations and T790M resistance mutation (L858R/T790M and Del19/T790M). Finally, in several Ex20Ins patient-derived xenograft models, the candidate inhibitors induced tumor regression as strong as Poziotinib and increased survival rates along with minimal weight loss. These novel small molecule compounds inhibiting EGFR exon 20 insertion mutations will provide future therapeutic options for patients with this molecular subtype of NSCLC. Citation Format: Sunghwan Kim, Younho Lee, Hwan Kim, Juhee Kang, Jiyoon Seok, Kyung-Ah Seo, Jaeyoung Ahn, Hee-Bum Kang, Sun-Hwa Lee, Jung Beom Son, Hwan Geun Choi, Nam Doo Kim. Discovery of selective and potent EGFR kinase inhibitors for exon20 insertion mutations [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B002. doi:10.1158/1535-7163.TARG-19-B002

Characterization of 648 non-small cell lung cancer (NSCLC) cases with 28 unique HER2 exon 20 insertions.

9063 Background: EGFR and HER2 ( ERBB2) exon 20 insertion (ex20ins) mutations represent a subset of driver alterations in NSCLC, which historically have largely not responded to available targeted therapies. Recently, inhibitors specifically targeting ex20ins have shown efficacy in the clinic. Previous studies have described the landscape of EGFR ex20ins in NSCLC (PMID: 29981927), but similar descriptions of HER2 ex20ins are lacking. Methods: Hybrid capture-based comprehensive genomic profiling (CGP) was performed on 39,644 tissue and 4,062 blood-based circulating tumor DNA (ctDNA) samples from 43,706 unique patients with advanced NSCLC. Tumor mutational burden (TMB) was determined on 0.8-1.1 Mbp of sequenced DNA for tissue samples and reported as mutations/Mb. Results: HER2 ex20ins were detected in 1.5% (648/43,706) of NSCLC cases (614 tissue and 34 ctDNA). HER2 ex20ins represented 35% (648/1,845) of HER2-altered NSCLCs overall, while 46% (843/1,845) of cases had HER2 amplification (≥5 copies), 17% (320/1,845) had a non-ex20ins HER2 short variant (SV; most commonly S310F in 84 cases and V659E in 29 cases), and 1.8% (34/1,845) had HER2 amplification + SV. There were 28 unique ex20ins including most commonly A775_G776insYVMA (69%, 450/648), G776 &gt; VC (12%, 76/648) and P780_Y781insGSP (8.6%, 56/648). Cases with HER2 ex20ins were significantly enriched for adenocarcinoma histology (89% vs 66%), female gender (64% vs 51%) and low TMB (95% vs 65% TMB &lt; 10 mut/Mb) compared to HER2 wild-type cases (all p &lt; 0.0001). HER2 amplification (7 median copies, range 5-39) co-occurred in 16% (103/648) of HER2 ex20ins cases. Co-occurrence of other known NSCLC drivers in HER2 ex20ins cases was rare (0.8%, 5/648). In contrast, non- HER2ex20ins cases with HER2 amplification or other HER2 SVs each had co-occurring known driver alterations in ~30% of cases. There was no significant difference in histology, gender, age, HER2 co-amplification or TMB in cases with YVMA vs non-YVMA ex20ins. Conclusions: HER2 ex20ins are found in 1.5% of NSCLCs and are generally mutually exclusive of other known drivers. Detection of these alterations may be critical to identify matched targeted therapy options for this subset of patients.

Discovery of a Highly Potent and Broadly Effective Epidermal Growth Factor Receptor and HER2 Exon 20 Insertion Mutant Inhibitor

AbstractExon 20 insertion (Ex20Ins) mutations are the third most prevalent epidermal growth factor receptor (EGFR) activating mutation and the most prevalent HER2 mutation in non‐small cell lung cancer (NSCLC). Novel therapeutics for the patients with Ex20Ins mutations are urgently needed, due to their poor responses to the currently approved EGFR and HER2 inhibitors. Here we report the discovery of highly potent and broadly effective EGFR and HER2 Ex20Ins mutant inhibitors. The co‐crystal structure of compound 1 b in complex with wild type EGFR clearly revealed an additional hydrophobic interaction of 4‐fluorobenzene ring within a deep hydrophobic pocket, which has not been widely exploited in the development of EGFR and HER2 inhibitors. As compared with afatinib, compound 1 a exhibited superior inhibition of proliferation and signaling pathways in Ba/F3 cells harboring either EGFR or HER2 Ex20Ins mutations, and in the EGFR P772_H773insPNP patient‐derived lung cancer cell line DFCI127. Our study identifies promising strategies for development of EGFR and HER2 Ex20Ins mutant inhibitors.