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.