The Impact of On-Target Resistance Mediated by EGFR-T790M or EGFR-C797S on EGFR Exon 20 Insertion Mutation Active Tyrosine Kinase Inhibitors

Introduction

Mechanisms of resistance to EGFR exon 20 insertion mutation active inhibitors have not been extensively studied in either robust preclinical models or patient-derived rebiopsy specimens. We sought to characterize on-target resistance mutations identified in EGFR exon 20 insertion-mutated lung cancers treated with mobocertinib or poziotinib and evaluate whether these mutations would or would not have cross-resistance to next-generation inhibitors zipalertinib, furmonertinib, and sunvozertinib.

Methods

We identified mechanisms of resistance to EGFR exon 20 insertion mutation active inhibitors and then used preclinical models of EGFR exon 20 insertion mutations (A767_V769dupASV, D770_N771insSVD, V773_C774insH) plus common EGFR mutants to probe inhibitors in the absence/presence of EGFR-T790M or EGFR-C797S.

Results

Mobocertinib had a favorable therapeutic window in relation to EGFR wild type for EGFR exon 20 insertion mutants, but the addition of EGFR-T790M or EGFR-C797S negated the observed window. Zipalertinib had a favorable therapeutic window for cells driven by EGFR-A767_V769dupASV or EGFR-D770_N771insSVD in the presence or absence of EGFR-T790M. Furmonertinib and sunvozertinib had the most favorable therapeutic windows in the presence or absence of EGFR-T790M in all cells tested. EGFR-C797S in cis to all EGFR mutations evaluated generated dependent cells that were resistant to the covalent EGFR tyrosine kinase inhibitors mobocertinib, zipalertinib, furmonertinib, sunvozertinib, poziotinib, and osimertinib.

Conclusions

This report highlights that poziotinib and mobocertinib are susceptible to on-target resistance mediated by EGFR-T790M or -C797S in the background of the most prevalent EGFR exon 20 insertion mutations. Furmonertinib, sunvozertinib, and to a less extent zipalertinib can overcome EGFR-T790M compound mutants, whereas EGFR-C797S leads to covalent inhibitor cross-resistance-robust data that support the limitations of mobocertinib and should further spawn the development of next-generation covalent and reversible EGFR exon 20 insertion mutation active inhibitors with favorable therapeutic windows that are less vulnerable to on-target resistance.

Disparities in outcomes between Black and White patients in North America with thoracic malignancies and COVID-19 infection (TERAVOLT)

BACKGROUND

Patients with thoracic malignancies who develop COVID-19 infection have a higher hospitalization rate compared to the general population and to those with other cancer types, but how this outcome differs by race and ethnicity is relatively understudied.

METHODS

The TERAVOLT database is an international, multi-center repository of cross-sectional and longitudinal data studying the impact of COVID-19 on individuals with thoracic malignancies. Patients from North America with thoracic malignancies and confirmed COVID-19 infection were included for this analysis of racial and ethnic disparities. Patients with missing race data or races and ethnicities with fewer than 50 patients were excluded from analysis. Multivariable analyses for endpoints of hospitalization and death were performed on these 471 patients.

RESULTS

Of the 471 patients, 73% were White and 27% were Black. The majority (90%) were non-Hispanic ethnicity, 5% were Hispanic, and 4% were missing ethnicity data. Black patients were more likely to have an Eastern Cooperative Oncology Group (ECOG) Performance Status ≥ 2 (p-value = 0.04). On multivariable analysis, Black patients were more likely than White patients to require hospitalization (Odds Ratio (OR): 1.69, 95% CI: 1.01-2.83, p-value = 0.044). These differences remained across different waves of the pandemic. However, no statistically significant difference in mortality was found between Black and White patients (OR 1.29, 95% CI: 0.69-2.40, p-value = 0.408).

CONCLUSIONS

Black patients with thoracic malignancies who acquire COVID-19 infection are at a significantly higher risk of hospitalization compared to White patients, but there is no significant difference in mortality. The underlying drivers of racial disparity among patients with thoracic malignancies and COVID-19 infection require ongoing investigation.

EGFR Tyrosine Kinase Inhibitors for the Treatment of Metastatic Non-Small Cell Lung Cancer Harboring Uncommon EGFR Mutations: A Podcast

Supplementary file1 (MP4 21169 KB).

EGFR exon 20 insertion mutations and ERBB2 mutations in lung cancer: a narrative review on approved targeted therapies from oral kinase inhibitors to antibody-drug conjugates

Background and Objective

This review will provide an overview of EGFR and ERBB2 mutations in non-small-cell lung cancer (NSCLC) with a focus on recent clinical approvals.

Methods

We obtained data from the literature in accordance with narrative review reporting guidelines.

Key Content and Findings

EGFR mutations are present in up to 15-20% of all NSCLCs; amongst these, 10% correspond to kinase domain insertions in exon 20. Structurally similar, ERBB2 (HER2) mutations occurs in 1-4% of NSCLCs, mostly consisting of insertions or point mutations. The majority of EGFR exon 20 insertions occur within the loop following the regulatory C-helix and activate the kinase domain of EGFR without generating a therapeutic window to gefitinib, erlotinib, afatinib, dacomitinib or osimertinib. Mobocertinib represents a novel class of covalent EGFR inhibitors with a modest therapeutic window to these mutants and induces anti-tumor responses in a portion of patients [at 160 mg/day: response rate of <30% with duration of response (DoR) >17 months and progression-free survival (PFS) of >7 months] albeit with mucocutaneous and gastrointestinal toxicities. The bi-specific EGFR-MET antibody amivantamab-vmjw has modest but broad preclinical activity in EGFR-driven cancers and specifically for EGFR exon 20 insertion-mutated NSCLC has response rates <40% and PFS of <8.5 months at the cost of both infusion-related plus on-target toxicities. Both drugs were approved in 2021. The clinical development of kinase inhibitors for ERBB2-mutated NSCLC has been thwarted by mucocutaneous/gastrointestinal toxicities that preclude a pathway for drug approval, as the case of poziotinib. However, the activation of ERBB2 has allowed for repurposing of antibody-drug conjugates (ADCs) that target ERBB2 with cytotoxic payloads. The FDA approved fam-trastuzumab deruxtecan-nxki in 2022 for NSCLC based on response rate of >55%, DoR >9 months, PFS >8 months and manageable adverse events (including cytopenias, nausea and less commonly pneumonitis). Other therapies in clinical development include sunvozertinib and zipalertinib, among others. In addition, traditional cytotoxic chemotherapy has some activity in these tumors.

Conclusions

The approvals of mobocertinib, amivantamab, and trastuzumab deruxtecan represent the first examples of precision oncology for EGFR exon 20 insertion-mutated and ERBB2-mutated NSCLCs.

TIP60 is required for tumorigenesis in non-small cell lung cancer

Histone modifications play crucial roles in transcriptional activation, and aberrant epigenetic changes are associated with oncogenesis. Lysine (K) acetyltransferases 5 (TIP60, also known as KAT5) is reportedly implicated in cancer development and maintenance, although its function in lung cancer remains controversial. Here we demonstrate that TIP60 knockdown in non-small cell lung cancer cell lines decreased tumor cell growth, migration, and invasion. Furthermore, analysis of a mouse lung cancer model with lung-specific conditional Tip60 knockout revealed suppressed tumor formation relative to controls, but no apparent effects on normal lung homeostasis. RNA-seq and ChIP-seq analyses of inducible TIP60 knockdown H1975 cells relative to controls revealed transglutaminase enzyme (TGM5) as downstream of TIP60. Investigation of a connectivity map database identified several candidate compounds that decrease TIP60 mRNA, one that suppressed tumor growth in cell culture and in vivo. In addition, TH1834, a TIP60 acetyltransferase inhibitor, showed comparable antitumor effects in cell culture and in vivo. Taken together, suppression of TIP60 activity shows tumor-specific efficacy against lung cancer, with no overt effect on normal tissues. Our work suggests that targeting TIP60 could be a promising approach to treating lung cancer.

EGFR exon 19 insertion EGFR-K745_E746insIPVAIK and others with rare XPVAIK amino-acid insertions: Preclinical and clinical characterization of the favorable therapeutic window to all classes of approved EGFR kinase inhibitors

BACKGROUND

The epidermal growth factor receptor (EGFR)-K745_E746insIPVAIK and others with XPVAIK amino-acid insertions are exon 19 insertion mutations, which, at the structural modeling level, resemble EGFR tyrosine kinase inhibitor (TKI)-sensitizing mutants. An important unmet need is the characterization of therapeutic windows plus clinical outcomes of exon 19 XPVAIK amino-acid insertion mutations to available EGFR TKIs.

METHODS

We used preclinical models of EGFR-K745_E746insIPVAIK and more typical EGFR mutations (exon 19 deletion, L858R, L861Q, G719S, A763_Y764insFQEA, other exon 20 insertion mutations) to probe representative 1st (erlotinib), 2nd (afatinib), 3rd generation (osimertinib), and EGFR exon 20 insertion active (mobocertinib) TKIs. We also compiled outcomes of EGFR exon 19 insertion mutated lung cancers-from our institution plus the literature-treated with EGFR TKIs.

RESULTS

Exon 19 insertions represented 0.3-0.8% of all EGFR kinase domain mutation in two cohorts (n = 1772). Cells driven by EGFR-K745_E746insIPVAIK had sensitivity to all classes of approved EGFR TKIs when compared to cells driven by EGFR-WT in proliferation assays and at the protein level. However, the therapeutic window of EGFR-K745_E746insIPVAIK driven cells was most akin to those of cells driven by EGFR-L861Q and EGFR-A763_Y764insFQEA than the more sensitive patterns seen with cells driven by an EGFR exon 19 deletion or EGFR-L858R. The majority (69.2%, n = 26) of patients with lung cancers harboring EGFR-K745_E746insIPVAIK and other mutations with rare XPVAIK amino-acid insertions responded to clinically available EGFR TKIs (including icotinib, gefitinib, erlotinib, afatinib and osimertinib), with heterogeneous periods of progression-free survival. Mechanisms of acquired EGFR TKI resistance of this mutant remained underreported.

CONCLUSIONS

This is the largest preclinical/clinical report to highlight that EGFR-K745_E746insIPVAIK and other mutations with exon 19 XPVAIK amino-acid insertions are rare but sensitive to clinically available 1st, 2nd, and 3rd generation as well as EGFR exon 20 active TKIs; in a pattern that mostly resembles the outcomes of models with EGFR-L861Q and EGFR-A763_Y764insFQEA mutations. These data may help with the off-label selection of EGFR TKIs and clinical expectations of outcomes when targeted therapy is deployed for these EGFR mutated lung cancers.

ALK Deletion Exons 2 to 19: Case Report of a Rare ALK Inhibitor-Responsive Lung Cancer Driver Oncogene

ALK internal deletions of nonkinase domain exons occur in 0.01% of lung cancers with ALK genomic aberrations. We report a lung adenocarcinoma with a previously undescribed somatic ALK deletion of exons 2 to 19 with dramatic and sustained (>23 mo) response to alectinib. Our and other reported cases with ALK nonkinase domain deletions (between introns and exons 1-19) can display positive results in nonsequencing-based lung cancer diagnostic tests (such as immunohistochemistry) used to screen for more common ALK rearrangements. This case report emphasizes that "ALK-driven" lung cancers should be expanded to encompass those harboring not only ALK rearrangements with other genes but also ALK nonkinase domain deletions.

Safety and clinical activity of atezolizumab plus erlotinib in patients with non-small-cell lung cancer

BACKGROUND

Acquired resistance limits long-term epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) efficacy in patients with EGFR mutation-positive non-small-cell lung cancer (NSCLC) in whom anti-programmed death-ligand 1 (PD-L1) efficacy is also limited. We hypothesized that combining atezolizumab with erlotinib could enhance antitumor immunity and extend efficacy in these patients.

PATIENTS AND METHODS

This open-label phase Ib trial was conducted in adults aged ≥18 years who had advanced, unresectable NSCLC. Stage 1 (safety evaluation) enrolled EGFR TKI-naive patients regardless of EGFR status. Stage 2 (expansion) enrolled patients with EGFR-mutant NSCLC treated with ≤1 prior non-EGFR TKI therapy. Patients received 150 mg erlotinib orally once daily. After a 7-day erlotinib run-in, atezolizumab 1200 mg was administered intravenously every 3 weeks. The primary endpoint was the safety and tolerability of the combination in all patients; secondary endpoints included antitumor activity per RECIST 1.1 in stage 2 patients.

RESULTS

At the data cut-off on 7 May 2020, 28 patients (8 in stage 1, 20 in stage 2) were assessable for safety. No dose-limiting toxicities or grade 4 or 5 treatment-related adverse events occurred. Grade 3 treatment-related adverse events occurred in 46% of patients; the most common were increased alanine aminotransferase, diarrhea, pyrexia, and rash (each in 7% of patients). Serious adverse events occurred in 50% of patients. Pneumonitis (grade 1) was reported in a single patient (4%). The objective response rate was 75% [95% confidence interval (CI) 50.9% to 91.3%]), median response duration was 18.9 months (95% CI 9.5-40.5 months), median progression-free survival was 15.4 months (95% CI 8.4-39.0 months), and median overall survival was not estimable (NE) (95% CI 34.6-NE).

CONCLUSIONS

Atezolizumab combined with erlotinib demonstrated a tolerable safety profile and encouraging, durable clinical activity in patients with advanced EGFR mutation-positive NSCLC.

Complete pathologic response to short-course neoadjuvant alectinib in mediastinal node positive (N2) ALK rearranged lung cancer

OBJECTIVES

Neoadjuvant therapy prior to surgical resection for locally advanced lung cancer has evolved to incorporate systemic cytotoxic chemotherapy +/- immunotherapy +/- radiotherapy. The role of neoadjuvant precision therapies remains understudied.

MATERIALS AND METHODS

We report cases with major and complete pathologic responses to off-label neoadjuvant alectinib.

RESULTS

A case with stage IIIA (cT1b cN2 cM0) EML4-ALK variant 3a/b lung adenocarcinoma received 6 weeks of alectinib followed by R0 left upper lobectomy with complete pathological response (ypT0 ypN0). Another case with stage IIIA (cT3 cN2 cM0) EML4-ALK variant 2 received 12 weeks of alectinib followed by R0 right middle lobectomy with a major pathologic response (ypT1a ypN0) but systemic recurrence 12 months post-operatively.

CONCLUSION

Ongoing clinical trials are evaluating the role of both neoadjuvant and adjuvant ALK-directed therapy. Our cases support the completion of ongoing trials (ALINA: NCT03456076 and ALNEO: NCT05015010), and highlight the ability of second generation ALK inhibitors to induce major and complete pathologic responses in the neoadjuvant setting plus the likely role of long-term adjuvant kinase inhibitor therapy to prevent radiographic/clinical recurrence.

EGFR-D770>GY and Other Rare EGFR Exon 20 Insertion Mutations with a G770 Equivalence Are Sensitive to Dacomitinib or Afatinib and Responsive to EGFR Exon 20 Insertion Mutant-Active Inhibitors in Preclinical Models and Clinical Scenarios

Epidermal growth factor receptor (EGFR) exon 20 insertion mutations account for a tenth of all EGFR mutations in lung cancers. An important unmet clinical need is the identification of EGFR exon 20 insertion mutants that can respond to multiple classes of approved EGFR-TKIs. We sought to characterize variants involving EGFR-D770 to EGFR-G770 position equivalence changes that structurally allow for response to irreversible 2nd generation EGFR-TKIs. Our group used preclinical models of EGFR exon 20 insertion mutations to probe representative 1st (erlotinib), 2nd (afatinib, dacomitinib), 3rd generation (osimertinib) and EGFR exon 20 insertion mutant-active (poziotinib, mobocertinib) TKIs; we also queried the available clinical literature plus our institutional database to enumerate clinical outcomes. EGFR-D770>GY and other EGFR insertions with a G770 equivalence were identified at a frequency of 3.96% in separate cohorts of EGFR exon 20 insertion mutated lung cancer (n = 429). Cells driven by EGFR-D770>GY were insensitive to erlotinib and osimertinib, displayed sensitivity to poziotinib and dacomitinib and were uniquely sensitive to afatinib and dacomitinib in comparison with other more typical EGFR exon 20 insertion mutations using proliferation and biochemical assays. Clinical cases with EGFR-G770 equivalence from the literature and our center mirrored the preclinical data, with radiographic responses and clinical benefits restricted to afatinib, dacomitinib, poziotinib and mobocertinib, but not to erlotinib or osimertinib. Although they are rare, at <4% of all exon 20 insertion mutations, EGFR-G770 equivalence exon 20 insertion mutations are sensitive to approved 2nd generation EGFR TKIs and EGFR exon 20 insertion mutant-active TKIs (mobocertinib and poziotinib). EGFR-D770>GY and other insertions with a G770 equivalence join EGFR-A763_Y764insFQEA as exon 20 insertion mutationsresponsive to approved EGFR TKIs beyond mobocertinib; this data should be considered for clinical care, genomic profiling reports and clinical trial elaboration.

Activity and Safety of Mobocertinib (TAK-788) in Previously Treated Non-Small Cell Lung Cancer with EGFR Exon 20 Insertion Mutations from a Phase I/II Trial

Mobocertinib, an oral epidermal growth factor receptor (EGFR) inhibitor targeting EGFR gene mutations, including exon 20 insertions (EGFRex20ins), in non-small cell lung cancer, was evaluated in a phase I/II dose-escalation/expansion trial (ClinicalTrials.gov NCT02716116). Dose escalation identified 160 mg/d as the recommended phase 2 dose and maximum tolerated dose. Among 136 patients treated with 160 mg/d, the most common any-grade treatment-related adverse events (TRAE; >25%) were diarrhea (83%), nausea (43%), rash (33%), and vomiting (26%), with diarrhea (21%) the only grade ≥3 TRAE >5%. Among 28 EGFRex20ins patients treated at 160 mg/d, the investigator-assessed confirmed response rate was 43% (12/28; 95% confidence interval, 24%-63%) with median duration of response of 14 months (5.0-not reached) and median progression-free survival of 7.3 months (4.4-15.6). Mobocertinib demonstrated antitumor activity in patients with diverse EGFRex20ins variants with a safety profile consistent with other EGFR inhibitors. SIGNIFICANCE: No oral EGFR-targeted therapies are currently approved for patients with EGFRex20ins NSCLC. Mobocertinib demonstrated antitumor activity with manageable toxicity in patients with advanced EGFRex20ins NSCLC in this study, supporting additional development of mobocertinib in this patient population.See related commentary by Pacheco, p. 1617.This article is highlighted in the In This Issue feature, p. 1601.

Time to SARS-CoV-2 clearance among patients with cancer and COVID-19

Background

For cancer patients, coronavirus disease 19 (COVID‐19) infection can lead to delays in cancer therapy both due to the infection itself and due to the need to minimize exposure to other patients and to staff. Clearance guidelines have been proposed, but expected time to clearance has not been established.

Methods

We identified all patients at a tertiary care hospital cancer center between 25 March 2020 and 6 June 2020 with a positive nasopharyngeal reverse transcriptase polymerase chain reaction (RT‐PCR) test for the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), a cancer‐related visit within 3 years, and at least one follow‐up assay. We determined the time to clearance using American Society of Clinical Oncology (ASCO), the UK National Institute for Health and Care Excellence (UK‐NICE), and Centers for Disease Control and Prevention (CDC) criteria. A matched non‐cancer comparison cohort was also identified.

Results

Thirty‐two cancer patients were identified. Nineteen were cleared by ASCO criteria, with estimated median time to clearance of 50 days. Fourteen patients resumed chemotherapy prior to clearance. Using UK‐NICE criteria, median time to clearance would have been 31 days, and using CDC criteria, it would have been 13 days. The matched non‐cancer cohort had similar clearance time, but with less frequent testing.

Conclusion

SARS‐CoV‐2 clearance times differ substantially depending on the criteria used and may be prolonged in cancer patients. This could lead to a delay in cancer care, increased use of clearance testing, and extension of infection control precautions.

Randomized Phase II Study of 3 Months or 2 Years of Adjuvant Afatinib in Patients With Surgically Resected Stage I-III EGFR-Mutant Non-Small-Cell Lung Cancer

For patients with surgically resected disease, multiple studies suggest a benefit of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in delaying cancer recurrence. The necessary duration of therapy for benefit is unknown.

MATERIALS AND METHODS

This randomized phase II study enrolled patients with completely resected stage IA-IIIB EGFR-mutant non-small-cell lung cancer (American Joint Committee on Cancer 7th edition) after stage-appropriate standard-of-care adjuvant therapy. Patients were randomly assigned 1:1 to 3 months or 2 years of adjuvant afatinib starting at 30 mg by mouth daily. Computed tomography imaging was performed every 6 months for 3 years and then annually. The primary study end point for this planned 92-patient trial was recurrence rate at 2 years from randomization. A 20% improvement (from 70% with 3 months to 90% with 2 years) was targeted.

RESULTS

Forty-six patients enrolled and 45 were treated. The assigned course of afatinib treatment was completed by 96% (22/23) of patients in the 3-month group and only 41% (9/22) in the 2-year group. The 2-year recurrence-free survival (RFS) rates were 70% in the 3-month group and 81% in the 2-year group (P = .55). The median RFS was 42.8 months in the 3-month group and 58.6 months in the 2-year group. Side effects were consistent with those previously described for afatinib.

CONCLUSION

Recurrences at 2 years were 11% less common with 2 years versus 3 months of adjuvant afatinib. This difference did not meet the 20% primary study target, likely because of underaccrual and early drug discontinuation on the 2-year group. With the availability of osimertinib with better efficacy and tolerability than earlier-generation agents, the optimal duration of adjuvant EGFR TKI therapy remains an important question.

Association of Performance Status With Survival in Patients With Advanced Non-Small Cell Lung Cancer Treated With Pembrolizumab Monotherapy

IMPORTANCE

Despite approximately 40% of patients having Eastern Cooperative Oncology Group (ECOG) performance status (PS) scores of at least 2 in the real world, most landmark clinical trials that led to the use of pembrolizumab as standard of care in advanced non-small cell lung cancer (NSCLC) excluded this group.

OBJECTIVE

To evaluate whether an ECOG PS score of at least 2 at the start of therapy is associated with progression-free survival (PFS) and overall survival (OS) in advanced NSCLC treated with pembrolizumab monotherapy.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study included all consecutive patients with advanced NSCLC who underwent treatment with palliative pembrolizumab monotherapy from February 2016 to October 2019 at a single academic cancer center, with data censoring on January 15, 2020.

EXPOSURES

ECOG PS score at start of therapy, with 0 and 1 indicating fully active or restricted in strenuous activity and scores of 2 and higher indicating increasing disability.

MAIN OUTCOMES AND MEASURES

PFS and OS, measured from initiation of pembrolizumab monotherapy.

RESULTS

Of 74 patients (median [range] age, 68.5 [33-87] years; 36 [48.7%] women; 53 [71.6%] White individuals) with median follow-up of 19.5 (95% CI, 13.4-27.8) months, 45 (60.8%) had an ECOG PS of 0 or 1, while 29 (39.2%) had an ECOG PS of at least 2. There were no significant differences in the baseline characteristics, except in age. Compared with patients with PS scores of 0 or 1, those with PS scores of at least 2 had significantly lower disease control rates (38 [88.4%] vs 15 [53.6%]; P = .002), shorter median PFS (7.9 [95% CI, 4.6-15.4] months vs 2.3 [95% CI, 1.8-4.8] months; P = .004), and shorter median OS (23.2 [14.0 vs 35.7] months vs 4.1 [95% CI, 2.1-6.9] months; P < .001). Among those potentially eligible for subsequent cancer-directed therapy beyond pembrolizumab monotherapy, patients in the group with PS scores of at least 2 were less likely to receive it than those with PS scores of 0 or 1 (2 [8.3%] vs 14 [45.2%]; P = .003). Multivariable adjustment for baseline characteristics confirmed ECOG PS of at least 2 as an independent risk factor for worse PFS (HR, 2.02; 95% CI, 1.09-3.74; P = .03) and worse OS (HR, 2.87; 95% CI, 1.40-5.89; P = .004).

CONCLUSIONS AND RELEVANCE

In this cohort study, having an ECOG PS score of at least 2 was associated with poorer prognosis for treatment of advanced NSCLC with palliative pembrolizumab monotherapy. Further prospective studies are needed to evaluate more objective and consistent measures of functional status to facilitate identification of patients with borderline performance status who may achieve durable clinical benefit from treatment with pembrolizumab monotherapy.

Clinical Benefit of Tyrosine Kinase Inhibitors in Advanced Lung Cancer with EGFR-G719A and Other Uncommon EGFR Mutations

The optimal management of advanced non-small cell lung cancer (NSCLC) with noncanonical epidermal growth factor receptor (EGFR) mutations (i.e., exon 19 deletion and exon 21 L858R) is constrained by the heterogeneous behavior of individual uncommon mutations and limited prospective clinical data in this setting. Despite encouraging results with osimertinib from a recently published phase II trial from South Korea, afatinib remains the only currently approved drug for patients with tumors harboring uncommon EGFR mutations (i.e., S768I, L861Q, and/or G719X). When used at the standard dose of 40 mg daily, afatinib is associated with significant rates of treatment-related adverse events, leading to frequent dose reductions and treatment discontinuations. We report a case of a woman with advanced NSCLC harboring EGFR-G719A mutation treated with afatinib (at an off-label pulse dose strategy that merits further evaluation in prospective studies) with sustained partial response for 20 months with manageable expected toxicities. Subsequent disease progression was mediated by off-target pan-EGFR inhibitor (including osimertinib)-resistant KRAS mutation and not by acquisition of EGFR-T790M. We further present the current state of evidence in the literature behind use of first-, second-, and third-generation tyrosine kinase inhibitors and summarize the evolving spectrum of activity ascribed to osimertinib (and newer EGFR inhibitors with a more favorable therapeutic window and intracranial penetration) in this population of patients with advanced NSCLC and uncommon EGFR mutations. KEY POINTS: Uncommon EGFR mutations characterize a heterogeneous group of patients with advanced non-small cell lung cancer (NSCLC). Afatinib is the only currently U.S. Food and Drug Administration-approved drug for management of advanced NSCLC with uncommon EGFR mutations (S768I, L861Q, and/or G719X). Afatinib treatment at 40 mg daily is associated with high rates of adverse events and dose reductions; alternative strategies including pulse intermittent dosing should be evaluated prospectively. Osimertinib (with favorable safety profile and intracranial penetration) has shown promising results in this population in a phase II trial from South Korea; additional trials are ongoing.

Preclinical characterization of mobocertinib highlights the putative therapeutic window of this novel EGFR inhibitor to EGFR exon 20 insertion mutations

Introduction

EGFR exon 20 insertion mutations account for 10% of all EGFR mutations and are mostly insensitive to approved EGFR tyrosine kinase inhibitors (EGFR TKIs). Novel EGFR TKIs have been developed or repurposed for these mutants. A limited number of preclinical studies have detailed these EGFR TKIs. We sought to use commercially available mobocertinib (TAK-788) to characterize the preclinical therapeutic window of this EGFR TKI against EGFR mutations and to probe possible on-target mechanisms of resistance (EGFR-C797S).

Methods

We used models of EGFR mutations to probe representative first, second, third generation, and in-development EGFR exon 20-active (poziotinib, mobocertinib) TKIs. We also introduced EGFR-C797S to these models to identify mechanisms of resistance.

Results

Cells driven by the most common EGFR exon 20 insertion mutations (A767_V769dupASV, D770_N771insSVD, H773_V774insH, and others) were inhibited by in-development EGFR TKIs at doses below those affecting EGFR-wildtype; albeit more common EGFR mutations (exon 19 deletions and L858R) were inhibited more readily by mobocertinib and poziotinib. Mobocertinib was able to inhibit the phosphorylation of EGFR in multiple preclinical models. The presence of EGFR-C797S led to greater than 200-fold resistance in proliferation assays probing mobocertinib and osimertinib. A review of clinical studies of mobocertinib disclosed responses that could be lasting.

Conclusions

This is one of the initial reports to characterize the novel EGFR TKI mobocertinib and highlights its broad activity against EGFR mutants plus the therapeutic window to EGFR exon 20 insertion mutations; and EGFR-C797S as a possible mechanism of resistance. Further clinical development of mobocertinib merits continuation.

Identification of a RAS-activating TMEM87A-RASGRF1 Fusion in an Exceptional Responder to Sunitinib with Non-Small Cell Lung Cancer

PURPOSE

We pursued genomic analysis of an exceptional responder with non-small cell lung cancer (NSCLC) through a multi-platform effort to discover novel oncogenic targets.

EXPERIMENTAL DESIGN

In this open-label, single-arm phase II study (NCT01829217), an enriched cohort of patients with advanced NSCLC was treated with the multi-kinase inhibitor sunitinib. The primary endpoint was objective response rate. Tissue was collected for multi-platform genomic analysis of responders, and a candidate oncogene was validated using in vitro models edited by CRISPR-Cas9.

RESULTS

Of 13 patients enrolled, 1 patient (8%), a never smoker, had a partial response lasting 33 months. Genomic analysis of the responder identified no oncogenic variant using multi-platform DNA analysis including hotspot allelotyping, massively parallel hybrid-capture next-generation sequencing, and whole-exome sequencing. However, bulk RNA-sequencing (RNA-seq) revealed a novel fusion, TMEM87A-RASGRF1, with high overexpression of the fusion partners. RASGRF1 encodes a guanine exchange factor which activates RAS from GDP-RAS to GTP-RAS. Oncogenicity was demonstrated in NIH/3T3 models with intrinsic TMEM87A-RASGRF1 fusion. In addition, activation of MAPK was shown in PC9 models edited to express this fusion, although sensitivity to MAPK inhibition was seen without apparent sensitivity to sunitinib.

CONCLUSIONS

Sunitinib exhibited limited activity in this enriched cohort of patients with advanced NSCLC. Nonetheless, we find that RNA-seq of exceptional responders represents a potentially underutilized opportunity to identify novel oncogenic targets including oncogenic activation of RASGRF1.

Time to SARS-CoV-2 Clearance Among Patients with Cancer and COVID-19

QUESTION

What is the median time to clearance of SARS-CoV-2 among cancer patients according to currently used criteria?

FINDINGS

In this single-institution retrospective cohort study, the median time to SARS-CoV-2 clearance was 50 days using the ASCO/CDC criteria of 2 negative RT-PCR assays >24 hours apart. Using alternative criteria of 1 negative RT-PCR assay (UK-NICE) or CDC clinical criteria (10 days after first positive RT-PCR and 3 days after last symptoms), median clearance times were 31 days and 13 days, respectively. Meaning: SARS-CoV-2 clearance times differ substantially depending on criteria used and may be prolonged in cancer patients.

Extended-Interval Dosing Strategy of Immune Checkpoint Inhibitors in Lung Cancer: Will it Outlast the COVID-19 Pandemic?

Patients with lung cancer are particularly vulnerable to complications from coronavirus disease-2019 (COVID-19). Recurrent hospital visits and hospital admission are potential risk factors for acquiring infection with its causative pathogen, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). As immune checkpoint inhibitors (ICIs) constitute the therapeutic backbone for the vast majority of patients with advanced lung cancer in the absence of actionable driver oncogenes, there have been intense discussions within the oncology community regarding risk-benefit of delaying these treatments or use of alternative extended-interval treatment strategies to minimize the risk of viral transmission secondary to unintended nosocomial exposures. In the midst of the COVID-19 pandemic, the U.S. Food and Drug Administration (FDA) granted accelerated approval for extended-interval strategy of pembrolizumab at a dose of 400 mg every 6 weeks for all already approved oncologic indications. Herein, we summarize the evidence from the in silico pharmacokinetic modeling/simulation studies supporting extended-interval dosing strategies for the ICIs used in lung cancer. We further review the evolving clinical evidence behind these approaches and predict that they will continue to be used in routine practice even long after the pandemic, particularly for patients with durable disease control.

Small cell transformation of non-small cell lung cancer on immune checkpoint inhibitors: uncommon or under-recognized?

Background

Histological transformation of oncogene-driven lung adenocarcinoma to small cell lung cancer (SCLC) following treatment with tyrosine kinase inhibitors (TKIs) is a well-described phenomenon. Whether a similar transformation may drive acquired resistance to immune checkpoint inhibitors (ICPIs) in non-SCLC (NSCLC) is uncertain. Hence, tissue biopsies are not universally recommended at progression of NSCLC on ICPIs, unlike TKIs.

Case presentation

We report a case of a woman in her mid-60s with a 35 pack-years tobacco history and stage IV squamous cell lung carcinoma with no targetable genomic alterations, whose disease progressed within 4 months of first line carboplatin/gemcitabine therapy. Her treatment was switched to second line nivolumab monotherapy which resulted in sustained partial response lasting 21 months. She subsequently developed rapid, bulky progression of mediastinal disease. Biopsy showed transformation to SCLC. Comparison of genomic profiling results from the initial NSCLC diagnosis and SCLC transformation revealed near-identical tumor profiles. Her disease responded to next line carboplatin/etoposide, though lasting for only 10 months. She died 14 months after detection of neuroendocrine transformation of her NSCLC.

Systematic review

We performed a systematic review of the literature to identify similar cases of NSCLC-to-small cell transformation on ICPIs. Nine patients, including our index case, were identified, with seven (77.8%) on nivolumab and two (22.2%) on pembrolizumab monotherapy. Median survival time since small cell transformation was 13.0 months (95% CI 2.0 to 16.0). Using our patient case as a framework, we further discuss the lack of consensus criteria to distinguish small cell transformation from de novo metachronous SCLC.

Conclusions

Histological transformation to SCLC is a potential mechanism of acquired resistance to ICPIs in NSCLC. Repeat tissue biopsies should be considered at the time of progression, similar to oncogene-directed therapies. Prospective larger studies are warranted to further characterize NSCLC-to-small cell transformation on ICPIs using molecular fingerprinting with paired tumor genomic profiles, evaluation of neuroendocrine features at baseline and consideration of initial response.

Cases of ROS1-rearranged lung cancer: when to use crizotinib, entrectinib, lorlatinib, and beyond?

ROS1-rearranged (also known as ROS1 fusion-positive) non-small-cell lung cancer is an uncommon but distinct molecular subgroup seen in approximately 1–2% of cases. Oncogene addiction due to constitutive ROS1 tyrosine kinase activation has allowed development of molecularly targeted therapies with remarkable anti-tumor activity. Both crizotinib and entrectinib, multitargeted tyrosine kinase inhibitors (TKIs) have now received approval by the FDA for treatment of patients with advanced ROS1-rearranged lung cancers; however, the clinical efficacy and safety of these drugs have been derived from expansion cohorts of single-arm phase I or basket clinical trials with relatively small populations of this clinically and molecularly distinct subgroup. Both drugs lead to high objective response rates (approximately 70–80%) and have manageable side effects, although only entrectinib has potent intracranial efficacy. Lorlatinib is an oral brain-penetrant ALK/ROS1 TKI with activity in both TKI-naïve and some crizotinib-resistant settings (albeit with limited potency against the crizotinib/entrectinib-resistant ROS1-G2032R mutation). We describe cases of advanced ROS1-rearranged lung cancer receiving crizotinib, entrectinib, and/or lorlatinib in first and later line treatment settings to dissect the current state of evidence supporting management decisions for these patients. The next generation ROS1 TKIs (repotrectinib and DS-6051b), owing to their broad activity against kinase mutations including ROS1-G2032R in preclinical studies, hold promise to transform the current treatment paradigm and permit even further gains with regards to long-term outcomes in this subset of patients.

Association of Extended Dosing Intervals or Delays in Pembrolizumab-based Regimens With Survival Outcomes in Advanced Non-small-cell Lung Cancer

Background

Besides modeling/simulation-based analysis, no post-approval studies have evaluated the optimal administration frequency of pembrolizumab in non–small-cell lung cancer (NSCLC).

Patients and Methods

We performed a multicenter retrospective cohort study to evaluate the association between survival outcomes and treatment extensions/delays of pembrolizumab-based regimens in patients with advanced NSCLC. Those who had received at least 4 cycles in routine practice were divided into 2 groups: nonstandard (Non-Std, ≥ 2 cycles at intervals > 3 weeks + 3 days) and standard (Std, all cycles every 3 weeks or 1 cycle > 3 weeks + 3 days).

Results

Among 150 patients, 92 (61%) were eligible for the study (Non-Std, 27; Std, 65). The reasons for patients with extensions/delays in the Non-Std group included: immune-related adverse events (irAEs) (33%), non–irAE-related medical issues (26%), and patient-physician preference (41%). The Non-Std group was more likely to have a higher programmed death-ligand 1 tumor proportion score, a higher number of treatment cycles, and pembrolizumab monotherapy. Univariate and 6-month landmark analyses showed longer median overall survival and progression-free survival in the Non-Std group compared with the Std group. After multivariable adjustment for confounding factors, there was no significant difference in overall survival (hazard ratio, 1.2; 95% confidence interval, 0.3-4.8; P = .824) or progression-free survival (hazard ratio, 2.6; 95% confidence interval, 0.7-9.6; P = .157) between the 2 groups.

Conclusion

Our study shows that a significant proportion of patients with advanced NSCLC receive pembrolizumab-based regimens with extended intervals or delays in routine clinical practice and with similar outcomes to those receiving treatment at label-specified 3-week intervals. Given the durability of benefit seen and the potential for cost reduction and decreased infusion frequency in these patients, this requires validation in prospective trials.

Safety and efficacy of immune checkpoint inhibitors in patients with non-small cell lung cancer and hepatitis B or hepatitis C infection

OBJECTIVES

The safety and efficacy of immunotherapy among patients with history of hepatitis B (HBV) or hepatitis C virus (HCV) infection and non-small cell lung cancer (NSCLC) remains unclear as this population has traditionally been excluded from clinical trials with immune checkpoint inhibitors (ICIs).

MATERIALS AND METHODS

We retrospectively evaluated treatment toxicities and clinical outcomes in nineteen patients with NSCLC and history of past or chronic HBV (16 cases, two of these had HCV co-infection) or chronic HCV infection (five cases), who received a programmed death-1 (PD-1) pathway inhibitor.

RESULTS

The overall response rate to immunotherapy was 35 %, and the median progression-free survival was 4.5 months. After ICI initiation, increases in liver function tests (LFTs) from baseline were infrequent and mild, and no patients experienced grade 3 or 4 hepatic immune-related adverse events or required ICI discontinuation or corticosteroid administration for management of hepatic toxicity. There were no significant changes in viral load or cases of HBV reactivation or HCV flare while on ICI therapy.

CONCLUSION

In this case series, treatment with immunotherapy in patients with NSCLC and past or chronic viral hepatitis appears to be safe, and responses to ICIs can be durable in this population. Additional studies are needed in larger cohorts of patients to determine the safety of immunotherapy in patients with chronic viral infections.

Activity of the Hsp90 inhibitor luminespib among non-small-cell lung cancers harboring EGFR exon 20 insertions

Background

There are currently no approved targeted therapies for non-small-cell lung cancer (NSCLC) patients with EGFR exon 20 insertions (ins20), a subgroup of EGFR mutations that are generally refractory to first/second generation EGFR inhibitors. We report the final results of a phase II trial evaluating the activity of the Hsp90 inhibitor luminespib (AUY922) in NSCLC patients with EGFR ins20.

Patients and methods

Twenty-nine patients with stage IV NSCLC with EGFR ins20 identified on local testing and at least one prior therapy were enrolled on the trial between August 2013 and October 2016. The primary end point was objective response rate (ORR), with a pre-determined target rate of effectiveness [defined as the rate of partial response (PR) plus stable disease (SD) lasting ≥3 months] of 20%. Secondary end points were PFS, overall survival (OS), safety and response by EGFR ins20 subtype.

Results

Among the 29 patients (18 females, median age 60 years) the ORR was 17%, median progression-free survival was 2.9 months (95% CI 1.4-5.6) and median OS (mOS) was 13 months (95% CI 4.9-19.5). The results exceeded the pre-determined target rate of effectiveness with 11/29 (38%) patients having a PR or an SD ≥3 months. The most common luminespib-related toxicities were diarrhea (83%), visual changes (76%) and fatigue (45%). All study treatment was stopped on 28 February 2017 due to dissolution of study drug availability; 3 patients were on treatment at study termination.

Conclusion

The study met its primary end point, suggesting that luminespib may be an active therapy for advanced NSCLC patients with EGFR ins20. Luminespib is generally well-tolerated, though reversible low-grade ocular toxicity is common. Further study of luminespib and other hsp90 inhibitors in this population is warranted.

Study registration (ClinicalTrials.gov)

NCT01854034.

Assessment of Resistance Mechanisms and Clinical Implications in Patients With EGFR T790M-Positive Lung Cancer and Acquired Resistance to Osimertinib

Importance

Osimertinib mesylate is used globally to treat EGFR-mutant non-small cell lung cancer (NSCLC) with tyrosine kinase inhibitor resistance mediated by the EGFR T790M mutation. Acquired resistance to osimertinib is a growing clinical challenge that is poorly understood.

Objective

To understand the molecular mechanisms of acquired resistance to osimertinib and their clinical behavior.

Design, Setting, and Participants

Patients with advanced NSCLC who received osimertinib for T790M-positive acquired resistance to prior EGFR tyrosine kinase inhibitor were identified from a multi-institutional cohort (n = 143) and a confirmatory trial cohort (NCT01802632) (n = 110). Next-generation sequencing of tumor biopsies after osimertinib resistance was performed. Genotyping of plasma cell-free DNA was studied as an orthogonal approach, including serial plasma samples when available. The study and analysis were finalized on November 9, 2017.

Main Outcomes and Measures

Mechanisms of resistance and their association with time to treatment discontinuation on osimertinib.

Results

Of the 143 patients evaluated, 41 (28 [68%] women) had tumor next-generation sequencing after acquired resistance to osimertinib. Among 13 patients (32%) with maintained T790M at the time of resistance, EGFR C797S was seen in 9 patients (22%). Among 28 individuals (68%) with loss of T790M, a range of competing resistance mechanisms was detected, including novel mechanisms such as acquired KRAS mutations and targetable gene fusions. Time to treatment discontinuation was shorter in patients with T790M loss (6.1 vs 15.2 months), suggesting emergence of pre-existing resistant clones; this finding was confirmed in a validation cohort of 110 patients with plasma cell-free DNA genotyping performed after osimertinib resistance. In studies of serial plasma levels of mutant EGFR, loss of T790M at resistance was associated with a smaller decrease in levels of the EGFR driver mutation after 1 to 3 weeks of therapy (100% vs 83% decrease; P = .01).

Conclusions and Relevance

Acquired resistance to osimertinib mediated by loss of the T790M mutation is associated with early resistance and a range of competing resistance mechanisms. These data provide clinical evidence of the heterogeneity of resistance in advanced NSCLC and a need for clinical trial strategies that can overcome multiple concomitant resistance mechanisms or strategies for preventing such resistance.

TAS6417/CLN-081 Is a Pan-Mutation-Selective EGFR Tyrosine Kinase Inhibitor with a Broad Spectrum of Preclinical Activity against Clinically Relevant EGFR Mutations

Despite the worldwide approval of three generations of EGFR tyrosine kinase inhibitors (TKI) for advanced non-small cell lung cancers with EGFR mutations, no TKI with a broad spectrum of activity against all clinically relevant mutations is currently available. In this study, we sought to evaluate a covalent mutation-specific EGFR TKI, TAS6417 (also named CLN-081), with the broadest level of activity against EGFR mutations with a prevalence of ≥1%. Lung cancer and genetically engineered cell lines, as well as murine xenograft models were used to evaluate the efficacy of TAS6417 and other approved/in-development EGFR TKIs (erlotinib, afatinib, osimertinib, and poziotinib). We demonstrate that TAS6417 is a robust inhibitor against the most common EGFR mutations (exon 19 deletions and L858R) and the most potent against cells harboring EGFR-T790M (first/second-generation TKI resistance mutation). In addition, TAS6417 has activity in cells driven by less common EGFR-G719X, L861Q, and S768I mutations. For recalcitrant EGFR exon 20 insertion mutations, selectivity indexes (wild-type EGFR/mutant EGFR ratio of inhibition) favored TAS6417 in comparison with poziotinib and osimertinib, indicating a wider therapeutic window. Taken together, we demonstrate that TAS6417 is a potent EGFR TKI with a broad spectrum of activity and a wider therapeutic window than most approved/in-development generations of EGFR inhibitors. IMPLICATIONS: TAS6417/CLN-081 is a potent EGFR TKI with a wide therapeutic window and may be effective in lung cancer patients with clinically relevant EGFR mutations.

EGFR-Mutated Lung Cancers Resistant to Osimertinib through EGFR C797S Respond to First-Generation Reversible EGFR Inhibitors but Eventually Acquire EGFR T790M/C797S in Preclinical Models and Clinical Samples

INTRODUCTION

Osimertinib is approved for advanced EGFR-mutated NSCLC, and identification of on-target mechanisms of resistance (i.e., EGFR C797S) to this third-generation EGFR inhibitor are evolving. Whether durable control of subsequently osimertinib-resistant NSCLC with the EGFR-sensitizing mutation (SM)/C797S is possible with first-generation EGFR inhibitors (such as gefitinib or erlotinib) remains underreported, as does the resultant acquired resistance profile.

METHODS

We used N-ethyl-N-nitrosourea mutagenesis to determine the profile of EGFR SM/C797S preclinical models exposed to reversible EGFR inhibitors. In addition, we retrospectively probed a case of EGFR SM lung adenocarcinoma treated with first-line osimertinib, followed by second-line erlotinib in the setting of EGFR SM/C797S.

RESULTS

Use of N-ethyl-N-nitrosourea mutagenesis against the background of EGFR L858R/C797S in conjunction with administration of gefitinib revealed preferential outgrowth of cells with EGFR L858R/T790M/C797S. A patient with EGFR delE746_T751insV NSCLC was treated with osimertinib with sustained response for 10 months before acquiring EGFR C797S. The patient was subsequently treated with erlotinib, with response for a period of 4 months, but disease progression ensued. Liquid biopsy disclosed EGFR delE746_T751insV with T790M and C797S present in cis.

CONCLUSION

EGFR SM NSCLC can acquire resistance to osimertinib through development of the EGFR C797S mutation. In this clinical scenario, the tumor may respond transiently to reversible first-generation EGFR inhibitors (gefitinib or erlotinib), but evolving mechanisms of on-target resistance-in clinical specimens and preclinical systems-indicate that EGFR C797S along with EGFR T790M can evolve. This report adds to the growing understanding of tumor evolution or adaptability to sequential EGFR inhibition and augments support for exploring combination therapies to delay or prevent on-target resistance.

Abstract 320: Met/Ror1-β-catenin-Bcl-xL axis contributes to the emergence of drug-tolerant cells that evolve into resistant tumors in EGFR-mutant lung cancer

Despite of the success of targeted therapy with tyrosine kinase inhibitors (TKI) in epidermal growth factor receptor (EGFR) -mutant lung cancer, the duration of response is limited due to the inevitable development of acquired resistance. Previous studies have revealed that TKIs may induce survival in drug-tolerant cells (DTC) following initial treatment, leading to acquired resistance from further evolution over time. Moreover, recent studies have also shown that Bcl-xL is involved in the survival of DTC; however, little is known about the mechanism of how Bcl-xL regulates DTC in the presence of EGFR TKIs. Therefore, it is crucial to elucidate pathways which promote DTC emergence in order to develop more effective therapeutic protocols. In this study, we found that the Met/Ror1-β-catenin-Bcl-xL axis may contribute to the emergence of DTC in the presence of EGFR TKIs. We previously demonstrated that β-catenin has an essential role in lung tumorigenesis driven by EGFR-mutants, particularly EGFR-T790M. We found that genetic deletion of β-catenin gene reduced Bcl-xL expression both in vitro and in vivo. Secondly, in the presence of EGFR TKI, we found that Met-induced Ror1 activation led to tyrosine phosphorylation of β-catenin via Src. Our experiments further suggested tyrosine phosphorylation of β-catenin by EGFR and the Met-Ror1-Src cascade, whose sites were identified by mass spectrometry, plays a critical role in the interaction between β-catenin and a transcriptional factor, TBX5. Contrary to known transcriptional interaction with TCF/LEF, tyrosine phosphorylated β-catenin was found to form a complex with TBX5 and the transcriptional regulator, YAP1. This complex may regulate anti-apoptotic genes such as BCL2L1, which encodes Bcl-xL. Combination treatment with osimertinib and stable knockdown of Ror1 (or TBX5) effectively reduced Bcl-xL expression. Furthermore, treatment with osimertinib in lung cancer mouse model in which Bcl2l1 can be conditionally knocked out inhibited completely the emergence of resistant tumors compared to Bcl2l1 wild-type mouse model treated with osimertinib. These observations suggest that the Met/Ror1-β-catenin-Bcl-xL axis may serve to explain the underlying mechanism for the emergence of DTC. Our findings thus identify this axis as a promising target for EGFR-mutant lung cancer.

Citation Format: Masanori Fujii, Sohei Nakayama, Naoki Akanuma, Gilbert Pan, Ikei S. Kobayashi, Hisashi Takei, Kohei Shimizu, Mariko Ando, Eunyoung Heo, Carol Gergis, Hiroyuki Inuzuka, Wenyi Wei, Daniel B. Costa, Susumu S. Kobayashi. Met/Ror1-β-catenin-Bcl-xL axis contributes to the emergence of drug-tolerant cells that evolve into resistant tumors in EGFR-mutant lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 320.

Abstract 1329: Preclinical evaluation of TAS6417 as a highly effective, pan-mutation-selective EGFR tyrosine kinase inhibitor

Objectives: Three generations of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have developed to treat advanced non-small cell lung cancer (NSCLC) with EGFR mutations. However, each generation of TKI has different spectrum of activity against the different mutations. Currently, no EGFR TKIs are approved for NSCLC with EGFR insertion 20 mutation. Previously, we have shown that TAS6417, a novel EGFR TKI, is effective for cells harboring EGFR insertion mutations in vitro and in vivo. In this study, we asked whether TAS6417 is effective for tumors harboring other EGFR mutations observed in clinic.

Methods: Genetically engineered Ba/F3 cells expressing EGFR mutants, lung cancer cell lines including newly established cell lines established from tumors harboring EGFR insertion 20 were used to evaluate efficacy of erlotinib, afatinib, osimertinib, poziotinib, and TAS6417 by cell viability analyses. The selectivity indexes (the wild type EGFR/mutant EGFR ratio) were calculated to predict a therapeutic window for each TKI. Effects of each EGFR TKI on EGFR signaling and apoptosis were evaluated by western blotting. Finally, murine xenograft models were used to evaluate efficacy of TAS6417 and all generation of EGFR TKIs for the treatment of NSCLC with EGFR mutations.

Results: Cell viability assays demonstrate that TAS6417 was as potent as poziotinib against common EGFR mutations (L868R and exon 19 deletions) and the most potent against cells harboring the T790M resistant mutations. In addition, TAS6417 was effective in cells harboring EGFR rare mutations (G719X L861Q, and S768I). Even though IC50s were higher than those of poziotinib in cells harboring EGFR insertion 20, the selectivity indexes (the wild type EGFR/mutant EGFR ratio) were higher in TAS6417, indicating a wider therapeutic window. TAS6417 was effective in mice injected with cells harboring EGFR mutations with no body weight loss.

Conclusions: Our preclinical results confirm that TAS6417 is a potent EGFR TKI with a broader spectrum of activity and a wider therapeutic window and support clinical trials in the near future.

Citation Format: Hibiki Udagawa, Shinichi Hasako, Akihiro Ohashi, Naomi Abe, Tomonori Haruma, Toshiharu Komori, Miki Terasaka, Ryoto Fujita, Kaoru Funabashi, Hiroyuki Yasuda, Kazutaka Miyadera, Koichi Goto, Daniel B. Costa, Susumu S. Kobayashi. Preclinical evaluation of TAS6417 as a highly effective, pan-mutation-selective EGFR tyrosine kinase inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1329.

Impact of MET inhibitors on survival among patients with non-small cell lung cancer harboring MET exon 14 mutations: a retrospective analysis

OBJECTIVES

Although dramatic responses to MET inhibitors have been reported in patients with MET exon 14 (METex14) mutant non-small cell lung cancer (NSCLC), the impact of these treatments on overall survival in this population is unknown.

METHODS

We conducted a multicenter retrospective analysis of patients with METex14 NSCLC to determine if treatment with MET inhibitors impacts median overall survival (mOS). Event-time distributions were estimated using the Kaplan-Meier method and compared with the log-rank test. Multivariable Cox models were fitted to estimate hazard ratios.

RESULTS

We identified 148 patients with METex14 NSCLC; the median age was 72; 57% were women and 39% were never smokers. Of the 34 metastatic patients who never received a MET inhibitor, the mOS was 8.1 months; those in this group with concurrent MET amplification had a trend toward worse survival compared to cancers without MET amplification (5.2 months vs 10.5 months, P =  0.06). Of the 27 metastatic patients who received at least one MET inhibitor the mOS was 24.6 months. A model adjusting for receipt of a MET inhibitor as first- or second-line therapy as a time-dependent covariate demonstrated that treatment with a MET inhibitor was associated with a significant prolongation in survival (HR 0.11, 95% CI 0.01-0.92, P =  0.04) compared to patients who did not receive any MET inhibitor. Among 22 patients treated with crizotinib, the median progression-free survival was 7.4 months.

DISCUSSION

For patients with METex14 NSCLC, treatment with a MET inhibitor is associated with an improvement in overall survival.

miR-147b-mediated TCA cycle dysfunction and pseudohypoxia initiate drug tolerance to EGFR inhibitors in lung adenocarcinoma

Drug-tolerance is an acute defense response prior to a fully drug-resistant state and tumor relapse, however there are few therapeutic agents targeting drug-tolerance in the clinic. Here we show that miR-147b initiates a reversible tolerant-state to the EGFR inhibitor osimertinib in non-small cell lung cancer. With miRNA-seq analysis we find that miR-147b is the most upregulated microRNA in osimertinib-tolerant and EGFR mutated lung cancer cells. Whole transcriptome analysis of single-cell derived clones reveals a link between osimertinib-tolerance and pseudohypoxia responses irrespective of oxygen levels. Further metabolomics and genetic studies demonstrate that osimertinib-tolerance is driven by miR-147b repression of VHL and succinate dehydrogenase linked to the tricarboxylic acid cycle and pseudohypoxia pathways. Finally, pretreatment with a miR-147b inhibitor delays osimertinib-associated drug tolerance in patient-derived three-dimensional (3D) structures. This link between miR-147b and tricarboxylic acid cycle may provide promising targets for preventing tumor relapse.

Amplification of Wild-type KRAS Imparts Resistance to Crizotinib in MET Exon 14 Mutant Non-Small Cell Lung Cancer

PURPOSE

MET inhibitors can be effective therapies in patients with MET exon 14 (METex14) mutant non-small cell lung cancer (NSCLC). However, long-term efficacy is limited by the development of drug resistance. In this study, we characterize acquired amplification of wild-type (WT) KRAS as a molecular mechanism behind crizotinib resistance in three cases of METex14-mutant NSCLC and propose a combination therapy to target it.

EXPERIMENTAL DESIGN

The patient-derived cell line and xenograft (PDX) DFCI358 were established from a crizotinib-resistant METex14-mutant patient tumor with massive focal amplification of WT KRAS. To characterize the mechanism of KRAS-mediated resistance, molecular signaling was analyzed in the parental cell line and its KRAS siRNA-transfected derivative. Sensitivity of the cell line to ligand stimulation was assessed and KRAS-dependent expression of EGFR ligands was quantified. Drug combinations were screened for efficacy in vivo and in vitro using viability and apoptotic assays.

RESULTS

KRAS amplification is a recurrent genetic event in crizotinib-resistant METex14-mutant NSCLC. The key characteristics of this genetic signature include uncoupling MET from downstream effectors, relative insensitivity to dual MET/MEK inhibition due to compensatory induction of PI3K signaling, KRAS-induced expression of EGFR ligands and hypersensitivity to ligand-dependent and independent activation, and reliance on PI3K signaling upon MET inhibition.

CONCLUSIONS

Using patient-derived cell line and xenografts, we characterize the mechanism of crizotinib resistance mediated by KRAS amplification in METex14-mutant NSCLC and demonstrate the superior efficacy of the dual MET/PI3K inhibition as a therapeutic strategy addressing this resistance mechanism.

SELECT: A Phase II Trial of Adjuvant Erlotinib in Patients With Resected Epidermal Growth Factor Receptor-Mutant Non-Small-Cell Lung Cancer

PURPOSE

Given the pivotal role of epidermal growth factor receptor (EGFR) inhibitors in advanced EGFR-mutant non-small-cell lung cancer (NSCLC), we tested adjuvant erlotinib in patients with EGFR-mutant early-stage NSCLC.

MATERIALS AND METHODS

In this open-label phase II trial, patients with resected stage IA to IIIA (7^th edition of the American Joint Committee on Cancer staging system) EGFR-mutant NSCLC were treated with erlotinib 150 mg per day for 2 years after standard adjuvant chemotherapy with or without radiotherapy. The study was designed for 100 patients and powered to demonstrate a primary end point of 2-year disease-free survival (DFS) greater than 85%, improving on historic data of 76%.

RESULTS

Patients (N = 100) were enrolled at seven sites from January 2008 to May 2012; 13% had stage IA disease, 32% had stage IB disease, 11% had stage IIA disease, 16% had stage IIB disease, and 28% had stage IIIA disease. Toxicities were typical of erlotinib; there were no grade 4 or 5 adverse events. Forty percent of patients required erlotinib dose reduction to 100 mg per day and 16% to 50 mg per day. The intended 2-year course was achieved in 69% of patients. The median follow-up was 5.2 years, and 2-year DFS was 88% (96% stage I, 78% stage II, 91% stage III). Median DFS and overall survival have not been reached; 5-year DFS was 56% (95% CI, 45% to 66%), 5-year overall survival was 86% (95% CI, 77% to 92%). Disease recurred in 40 patients, with only four recurrences during erlotinib treatment. The median time to recurrence was 25 months after stopping erlotinib. Of patients with recurrence who underwent rebiopsy (n = 24; 60%), only one had T790M mutation detected. The majority of patients with recurrence were retreated with erlotinib (n = 26; 65%) for a median duration of 13 months.

CONCLUSION

Patients with EGFR-mutant NSCLC treated with adjuvant erlotinib had an improved 2-year DFS compared with historic genotype-matched controls. Recurrences were rare for patients receiving adjuvant erlotinib, and patients rechallenged with erlotinib after recurrence experienced durable benefit.