Overall survival and central nervous system activity of crizotinib in ROS1-rearranged lung cancer-final results of the EUCROSS trial

BACKGROUND

In 2019, we reported the first efficacy and safety analysis of EUCROSS, a phase II trial investigating crizotinib in ROS1 fusion-positive lung cancer. At that time, overall survival (OS) was immature and the effect of crizotinib on intracranial disease control remained unclear. Here, we present the final analysis of OS, systemic and intracranial activity, and the impact of co-occurring aberrations.

MATERIALS AND METHODS

EUCROSS was a prospective, single-arm, phase II trial. The primary endpoint was best overall response rate (ORR) using RECIST 1.1. Secondary and exploratory endpoints were progression-free survival (PFS), OS, and efficacy in pre-defined subgroups.

RESULTS

Median OS of the intention-to-treat population (N = 34) was 54.8 months [95% confidence interval (CI) 20.3 months-not reached (NR); median follow-up 81.4 months] and median all-cause PFS of the response-evaluable population (N = 30) was 19.4 months (95% CI 10.1-32.2 months). Time on treatment was significantly correlated with OS (R = 0.82; P < 0.0001). Patients with co-occurring TP53 aberrations (28%) had a significantly shorter OS [hazard ratio (HR) 11; 95% CI 2.0-56.0; P = 0.006] and all-cause PFS (HR 4.2; 95% CI 1.2-15; P = 0.025). Patients with central nervous system (CNS) involvement at baseline (N = 6; 20%) had a numerically shorter median OS and all-cause PFS. Median intracranial PFS was 32.2 months (95% CI 23.7 months-NR) and the rate of isolated CNS progression was 24%.

CONCLUSIONS

Our final analysis proves the efficacy of crizotinib in ROS1-positive lung cancer, but also highlights the devastating impact of TP53 mutations on survival and treatment efficacy. Additionally, our data show that CNS disease control is durable and the risk of CNS progression while on crizotinib treatment is low.

MET Fusions in NSCLC: Clinicopathologic Features and Response to MET Inhibition

INTRODUCTION

MET fusions have been described only rarely in NSCLC. Thus, data on patient characteristics and treatment response are limited. We here report histopathologic data, patient demographics, and treatment outcome including response to MET tyrosine kinase inhibitor (TKI) therapy in MET fusion-positive NSCLC.

METHODS

Patients with NSCLC and MET fusions were identified mostly by RNA sequencing within the routine molecular screening program of the national Network Genomic Medicine, Germany.

RESULTS

We describe a cohort of nine patients harboring MET fusions. Among these nine patients, two patients had been reported earlier. The overall frequency was 0.29% (95% confidence interval: 0.15-0.55). The tumors were exclusively adenocarcinoma. The cohort was heterogeneous in terms of age, sex, or smoking status. We saw five different fusion partner genes (KIF5B, TRIM4, ST7, PRKAR2B, and CAPZA2) and several different breakpoints. Four patients were treated with a MET TKI leading to two partial responses, one stable disease, and one progressive disease. One patient had a BRAF V600E mutation as acquired resistance mechanism.

CONCLUSIONS

MET fusions are very rare oncogenic driver events in NSCLC and predominantly seem in adenocarcinomas. They are heterogeneous in terms of fusion partners and breakpoints. Patients with MET fusion can benefit from MET TKI therapy.

Efficiency of B-RAF-/MEK-inhibitors in B-RAF mutated Ameloblastoma: Case report and review of literature

Background

Ameloblastoma is a benign but locally invasive and aggressive odontogenic tumor harboring activating BRAF V600E mutations in about two thirds of the cases.

Case presentation

Neoadjuvant therapy with Dabrafenib and Trametinib was given to a 42-year-old male patient with recurrent ameloblastoma of the right mandible with a BRAF V600E mutation for 18 months. The patient manifested an excellent response to the therapy with remarkable reduction in tumor size from 72.6 mm to 55.9 mm. Histopathologically, the tumor underwent significant degenerative changes with only a few sparse vital residuals revealing 0 % Ki67 proliferative index.

Conclusions

Neoadjuvant therapy with BRAF-inhibitors or BRAF-MEK-inhibitors is an effective means to reduce the size of mandibulary ameloblastomas. We propose the consideration of neoadjuvant therapy in future treatment modalities to minimize post-surgical morbidity and facial deformations.

Somatic rearrangements causing oncogenic ectodomain deletions of FGFR1 in squamous cell lung cancer

The discovery of frequent 8p11-p12 amplifications in squamous cell lung cancer (SQLC) has fueled hopes that FGFR1, located inside this amplicon, might be a therapeutic target. In a clinical trial, only 11% of patients with 8p11 amplification (detected by FISH) responded to FGFR kinase inhibitor treatment. To understand the mechanism of FGFR1 dependency, we performed deep genomic characterization of 52 SQLCs with 8p11-p12 amplification, including 10 tumors obtained from patients who had been treated with FGFR inhibitors. We discovered somatically altered variants of FGFR1 with deletion of exons 1-8 that resulted from intragenic tail-to-tail rearrangements. These ectodomain-deficient FGFR1 variants (ΔEC-FGFR1) were expressed in the affected tumors and were tumorigenic in both in vitro and in vivo models of lung cancer. Mechanistically, breakage-fusion-bridges were the source of 8p11-p12 amplification, resulting from frequent head-to-head and tail-to-tail rearrangements. Generally, tail-to-tail rearrangements within or in close proximity upstream of FGFR1 were associated with FGFR1 dependency. Thus, the genomic events shaping the architecture of the 8p11-p12 amplicon provide a mechanistic explanation for the emergence of FGFR1-driven SQLC. Specifically, we believe that FGFR1 ectodomain-deficient and FGFR1-centered amplifications caused by tail-to-tail rearrangements are a novel somatic genomic event that might be predictive of therapeutically relevant FGFR1 dependency.

Clinicopathologic and molecular characteristics of small-scale ROS1-mutant non-small cell lung cancer (NSCLC) patients

BACKGROUND

ROS1 fusions are well treatable aberrations in NSCLC. Besides solvent-front mutations (SFM) in resistance to targeted therapy, small-scale ROS1 mutations are largely unknown. We exploratively analyzed the clinical and molecular characteristics of small-scale ROS1 mutations in NSCLC patients without activating ROS1 fusions or SFMs.

METHODS

Next-generation sequencing was performed on tissue samples from NSCLC patients within the Network Genomic Medicine. Patients with ROS1 fusions and SFMs were excluded. We analyzed clinical characteristics of patients harboring small-scale ROS1-mutations, ROS1- and co-occurring mutations, and their response to systemic therapy.

RESULTS

Of 10,396 patients analyzed, 101 (1.0%) patients harbored small-scale ROS1 mutations. Most patients were male (73.3%) and smokers (96.6%). Nearly half of the patients presented with squamous-cell carcinoma (SqCC, 40.4%). Most mutations were transversions (50.5%), and 66% were in the kinase domain. Besides TP53 mutations (65.3%), KRAS (22.8%), EGFR (5.9%), PIK3CA (9.9%) and FGFR1-4 mutations (8.9%) co-occurred. In 10 (9.9%) patients, ROS1 mutation was the only aberration detected. Median overall survival (mOS) differed significantly in patients with or without KRAS co-mutations (9.7 vs 21.5 months, p = 0.02) and in patients treated with or without immune-checkpoint blockade (ICB) during treatment (21.5 vs 4.4 months, p = 0.003).

CONCLUSION

The cohort's clinical characteristics contrasted ROS1-fused cohorts. Co-occurrence of KRAS mutations led to shortened survival and patients benefited from ICB. Our data does not support the idea of ROS1 small-scale mutations as strong oncogenic drivers in NSCLC, but rather as relevant bystanders altering the efficacy of treatment approaches.

Radiomics for the non-invasive prediction of PD-L1 expression in patients with brain metastases secondary to non-small cell lung cancer

BACKGROUND

The expression level of the programmed cell death ligand 1 (PD-L1) appears to be a predictor for response to immunotherapy using checkpoint inhibitors in patients with non-small cell lung cancer (NSCLC). As differences in terms of PD-L1 expression levels in the extracranial primary tumor and the brain metastases may occur, a reliable method for the non-invasive assessment of the intracranial PD-L1 expression is, therefore of clinical value. Here, we evaluated the potential of radiomics for a non-invasive prediction of PD-L1 expression in patients with brain metastases secondary to NSCLC.

PATIENTS AND METHODS

Fifty-three NSCLC patients with brain metastases from two academic neuro-oncological centers (group 1, n = 36 patients; group 2, n = 17 patients) underwent tumor resection with a subsequent immunohistochemical evaluation of the PD-L1 expression. Brain metastases were manually segmented on preoperative T1-weighted contrast-enhanced MRI. Group 1 was used for model training and validation, group 2 for model testing. After image pre-processing and radiomics feature extraction, a test-retest analysis was performed to identify robust features prior to feature selection. The radiomics model was trained and validated using random stratified cross-validation. Finally, the best-performing radiomics model was applied to the test data. Diagnostic performance was evaluated using receiver operating characteristic (ROC) analyses.

RESULTS

An intracranial PD-L1 expression (i.e., staining of at least 1% or more of tumor cells) was present in 18 of 36 patients (50%) in group 1, and 7 of 17 patients (41%) in group 2. Univariate analysis identified the contrast-enhancing tumor volume as a significant predictor for PD-L1 expression (area under the ROC curve (AUC), 0.77). A random forest classifier using a four-parameter radiomics signature, including tumor volume, yielded an AUC of 0.83 ± 0.18 in the training data (group 1), and an AUC of 0.84 in the external test data (group 2).

CONCLUSION

The developed radiomics classifiers allows for a non-invasive assessment of the intracranial PD-L1 expression in patients with brain metastases secondary to NSCLC with high accuracy.

Resistance to MET inhibition in MET-dependent NSCLC and therapeutic activity after switching from type I to type II MET inhibitors

OBJECTIVES

Resistance to MET inhibition occurs inevitably in MET-dependent non-small cell lung cancer and the underlying mechanisms are insufficiently understood. We describe resistance mechanisms in patients with MET exon 14 skipping mutation (METΔ^ex14), MET amplification, and MET fusion and report treatment outcomes after switching therapy from type I to type II MET inhibitors.

MATERIALS AND METHODS

Pre- and post-treatment biopsies were analysed by NGS (next generation sequencing), digital droplet PCR (polymerase chain reaction), and FISH (fluorescense in situ hybridization). A patient-derived xenograft model was generated in one case.

RESULTS

Of 26 patients with MET tyrosine kinase inhibitor treatment, eight had paired pre- and post-treatment biopsies (Three with MET amplification, three with METΔ^ex14, two with MET fusions (KIF5B-MET and PRKAR2B-MET).) In six patients, mechanisms of resistance were detected, whereas in two cases, the cause of resistance remained unclear. We found off-target resistance mechanisms in four cases with KRAS mutations and HER2 amplifications appearing. Two patients exhibited second-site MET mutations (p.D1246N and p. Y1248H). Three patients received type I and type II MET tyrosine kinase inhibitors sequentially. In two cases, further progressive disease was seen hereafter. The patient with KIF5B-MET fusion received three different MET inhibitors and showed long-lasting stable disease and a repeated response after switching therapy, respectively.

CONCLUSION

Resistance to MET inhibition is heterogeneous with on- and off-target mechanisms occurring regardless of the initial MET aberration. Switching therapy between different types of kinase inhibitors can lead to repeated responses in cases with second-site mutations. Controlled clinical trials in this setting with larger patient numbers are needed, as evidence to date is limited to preclinical data and case series.

P13.03.A Radiomics for the non-invasive assessment of the PDL-1 expression in patients with non-small cell lung cancer brain metastases

BACKGROUND

The expression level of programmed cell death ligand 1 (PDL-1) might be an indicator for response to immunotherapy using checkpoint inhibitors in patients with non-small cell lung cancer (NSCLC). As intra-tumoral differences and discrepancies between the PDL-1 expression in the primary tumor and the brain metastases may occur, a method for a reliable non-invasive assessment of the intracranial PDL-1 expression would be of clinical value. We evaluated the potential of MRI radiomics for a non-invasive assessment of the PDL-1 expression in patients with NSCLC brain metastases.

PATIENTS AND METHODS

Fifty-three patients with brain metastases from NSCLC from two university brain tumor centers (group 1, 36 patients; group 2, 17 patients) underwent tumor resection with subsequent immunohistochemical assessment of the PDL-1 expression. Brain metastases were manually segmented on preoperative T1-weighted contrast-enhanced MRI. Group 1 was used for model training and validation, group 2 for model testing. After image pre-processing and radiomics feature extraction from T1-weighted contrast-enhanced MRI, a test-retest analysis was performed to identify robust features prior to feature selection. The radiomics model was trained and validated using five-fold cross validation. Finally, the best performing radiomics model was applied to the test data. Diagnostic performance was evaluated using receiver operating characteristic (ROC) analyses.

RESULTS

An intracranial PDL-1 expression was found by immunohistochemistry in 18 of 36 patients (50%) in group 1, and 7 of 17 patients (41%) in group 2. Univariate analysis identified tumor volume as a significant clinical feature for PDL-1 expression (area under the ROC curve (AUC), 0.77). A random forest classifier using a four-parameter radiomics signature including tumor volume yielded an AUC of 0.83 ± 0.18 in the training data (group 1). Finally, the classifier achieved an AUC of 0.84 in the external test data (group 2).

CONCLUSION

The developed radiomics classifiers allows a non-invasive assessment of the intracranial PD-L1 expression in patients with NSCLC brain metastases with a high diagnostic performance.

KS02.7.A Impact of FET PET on multidisciplinary neurooncological tumor board decisions in patients with brain tumors

Background

Following neurooncological treatment of brain tumors, neurooncologists are often confronted with equivocal MRI findings (e.g., treatment-related changes such as pseudoprogression, non-measurable contrast-enhancing lesions, T2/FLAIR signal alterations, pseudoresponse). Especially in Europe, amino-acid PET is increasingly integrated into multidisciplinary neurooncological tumor boards (MNTB) to overcome these diagnostic uncertainties. We evaluated the correctness of MNTB decisions, in which amino acid PET findings were taken into account.

Material and Methods

In a single-university center study, we retrospectively evaluated 182 MNTB decisions of 154 patients with histomolecularly defined WHO grade 3 or 4 gliomas (n=123), including glioblastoma (n=80), anaplastic glioma (n=42), and gliosarcoma (n=1), or brain metastases (n=31) secondary to lung cancer, melanoma, breast cancer, or colorectal cancer presenting equivocal MRI findings following anticancer treatment. All patients underwent O-(2-[18F]-fluoroethyl)-L-tyrosine (FET) PET imaging as an adjunct for decision-making. Additionally, the patients’ clinical status, pretreatment, and conventional MRI findings were considered for decision-making. The presence of neoplastic tissue was considered if the mean FET uptake as assessed by tumor-to-brain ratios was &gt; 2.0. MNTB decisions were validated using the neuropathological result in 42% (n=77) or clinicoradiologically in 58% (n=105). The diagnostic performance of MTNB decisions was evaluated using 2x2 contingency tables.

Results

The validation of all 182 MNTB recommendations, which integrated FET PET in the decision-making process, were correct in 95% (sensitivity, 97%; specificity, 75%; positive predictive value, 96%). Due to tumor progression, MNTB recommendations prompted a treatment change in 88% (n=160 of 182 decisions). When FET PET findings suggested progressive disease (n=157), MNTB decisions were correct in 96% (positive predictive value, 97%). In 22 MNTB decisions with the recommendation to continue the current treatment regimen, 82% were correctly identified as treatment-related changes.

Conclusion

FET PET seems to have a significant impact on MNTB decisions. A prospective evaluation of MNTB decisions with and without the integration of FET PET is warranted to define the added value of FET PET.

[Targeted treatment of non-small cell lung cancer]

Non-small cell lung cancer (NSCLC) has made a remarkable development in recent decades with respect to its perception. In the late 1990s it was the "problem child" as the main cause of cancer with increasing tendencies, especially in women and with a pronounced stigmatization. It is now the role model as a biologically rational targeted treatment based on molecular dependencies of the tumor with a vast improvement of the traditionally poor survival times. Molecular tumor boards have long followed the NSCLC example in the assessment of targeted treatment approaches for other tumor entities. This review article gives an overview of the current possibilities for targeted treatment of NSCLC, which nowadays are applicable for nearly one third of all patients with NSCLC.

Metastatic patterns plus clinical and molecular characteristics of ROS1 aberrations in non-small cell lung cancer patients without rearrangements

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Background: Fusions in the ROS1 proto-oncogene are among the best treatable genetic aberrations in Non-small cell lung cancer (NSCLC). Besides the occurrence of solvent-front mutations (SFM) in acquired resistance to targeted therapy, little is known about ROS1 aberrations other than fusions. We analyzed molecular and clinical characteristics and metastatic patterns of ROS1 mutations in NSCLC patients without activating ROS1 fusions or SFMs. Methods: Next-generation sequencing (NGS) was performed on tissue samples from NSCLC patients within the National Network Genomic Medicine (nNGM). Patients with activating ROS1 fusions detected by fluorescence in-situ hybridization (FISH) were excluded. Staging and restaging procedures were performed following local standards from each partner. We analyzed the mutations’ characteristics, co-occurring mutations and metastatic patterns. Results: Of 8072 patients analyzed by NGS between 2018 and 2021, 118 (1.5%) patients harbored ROS1 mutations. Most patients were male (76.3%) and had adenocarcinoma histology (57.6%). The median age at diagnosis amounted to 68 years. Nearly all of the patients (96.5%) had a smoking history, amassing 40 pack-years on average. Besides TP53 mutations (61.0%), KRAS (25.4%), EGFR (7.6%), PIK3CA and FGFR1-4 mutations (5.9% each) co-occurred most frequently. In 12 (10.2%) patients, ROS1 mutation was the only detected aberration. The majority (59.3%) of patients had UICC stage IV whereby 27.2% of patients featured Stage III; about 7% fall upon stage I and II. The metastatic pattern of all stage IV patients shows that 22.9% of metastasis is allotted to cerebral, 12.5% to lung, 16.7% to subdiaphragmatic, 14.9% to bone and 6.3% to skin metastasis. Thereby, the patients’ subgroup with mutually exclusive ROS1 mutations (10.2%) resembles this trend: about a half of these patients had UICC stage IV, too, and the metastasis distribution featured similar characteristics. Conclusions: The cohort contrasts the clinical characteristics of patients with ROS1 fusion regarding sex, age, and histology. This evidence implies a basic clinical impact exerted by this molecular subtype. We warrant further research on the detected mutations to characterize the biological impact and the potential to act as a drug target.

Screening of FGFR patients for FGFR directed clinical trials in Network Genomic Medicine (NGM): Real-world data

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Background: The fibroblast growth factor receptor (FGFR) 1-4 genes show a heterogenic landscape of alterations in non-small cell lung cancer (NSCLC) whereas only a small amount is yet considered to have oncogenic potential. The frequency of activating FGFR alterations is low, counting for approximately 2% of NSCLC. We have screened NSCLC patients (pts) for FGFR translocations/mutations within NGM and analysed them on FGFR alteration frequency, patient characteristics and outcome. Methods: From 04/2019 to 01/2020 we screened 472 squamous NSCLC for FGFR gene alterations and from 02/2020 to 12/2021 an additional 5286 patients including all NSCLC cases. Of these 5286 pts, 1097 pts were analysed for FGFR fusions. We used DNA-NGS for FGFR-mutations and RNA-NGS for FGFR–translocations. Activating mutations were defined according to the publicly available molecular data bases and published data. Results: Within the cohort of 5758 NSCLC patients, we found 316 (5.5%) patients with FGFR alterations. Sixty-six (20.9% of FGFR, 1.1% of NSCLC) patients had alterations classified as activating, of whom 39 had FGFR point mutations and 27 FGFR translocations. Concerning the patients with activating alterations, they had UICC stage III or IV at time of diagnosis; 22 were females; 58 patients had squamous cell carcinoma, 6 patients had adenocarcinoma and 2 had large cell neuroendocrine carcinoma. Fifty-three patients (80.3%) with activating FGFR alteration had a co-mutation: TP53 (inactivating) co-mutation was seen in 41 cases (62.1%) and 19 cases had either PTEN (7 pts), KRAS (4), EGFR (3), PIK3CA (2), ROS1 (1), ALK (1) or BRAF (1) mutations. Ten patients were included in a FGFR-targeted trial. Sixty patients were available for follow-up. The median overall survival (mOS) was 21.4 month (95%CI: 16.8–25.9) for all patients with activating FGFR alteration, whereas mOS was 18.5 month (95%CI: 13.2-23.9) for FGFR mutation and 25.3 months (95%CI: 17.8-32.9) for FGFR fusions. Conclusions: FGFR 1-4 gene alterations are rare. Large molecular and clinical networks are necessary to identify these pts. Prognostic factors of FGFR patients are currently not defined. Further assessments on molecular and clinical features in FGFR altered NSCLC are needed to identify sensitivity to FGFR inhibition. Clinical trials with specific FGFR inhibitors are ongoing.

Crizotinib in ROS1-rearranged lung cancer (EUCROSS): Updated overall survival

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Background: ROS1 rearrangements are found in approximately 1% of non-small cell lung cancer (NSCLC) patients. Prospective clinical trials showed high efficacy of crizotinib in this molecular subset. Lately, we reported an overall response rate (ORR) of 70% and a median progression-free survival (PFS) of 19.4 months for patients treated within the EUCROSS trial (Michels et al. Clin Oncol, 37(15_suppl):9066-9066, 2019). Here we present an updated analysis of the overall survival. Methods: EUCROSS is a European multi-centre, single arm phase 2 trial (Clinicaltrial.gov identifier: NCT02183870). Key eligibility criteria were ≥18 years of age, advanced/metastatic lung cancer, centrally confirmed ROS1-rearranged (fluorescence-in situ hybridisation) and no or stable brain metastases at baseline. Crizotinib was given at a dose of 250 mg twice daily. Primary endpoint of the trial was investigator-assessed ORR in the response-evaluable population (Response Evaluation Criteria in Solid Tumors, version 1.1), with secondary endpoints of PFS and overall survival (OS). Results: Of the 34 patients who received at least one dose of crizotinib (intention-to-treat population, ITT), 30 were included the primary efficacy analysis set (PAS). After a median follow-up of 55.9 months, 13 (43%) patients in the PAS and 15 (44%) in the ITT had died. Median OS was not reached in either group (95% CI, 17.1-NR and 20.3-NR, respectively). OS was negatively correlated with the presence of brain metastases (Log-rank p = 0.1805) and TP53 mutations (Log-rank p = 0.015). Detailed listings of the survival rates are depicted in Table. No new safety signals were observed. Owing to the approval of crizotinib by the European Medicines Agency, all patients who were still on treatment by January 24th 2018 (n=8), were prescribed crizotinib outside the trial. Conclusions: Updated OS highlights the efficacy of crizotinib in patients with ROS1-rearranged lung cancer. Patients with co-occurring TP53 mutations or brain metastases had worse outcomes and represent challenging populations. Clinical trial information: NCT02183870. [Table: see text]

Reproducibility of dynamic contrast enhanced MRI derived transfer coefficient Ktrans in lung cancer

Dynamic contrast enhanced MRI (DCE-MRI) is a useful method to monitor therapy assessment in malignancies but must be reliable and comparable for successful clinical use. The aim of this study was to evaluate the inter- and intrarater reproducibility of DCE-MRI in lung cancer. At this IRB approved single centre study 40 patients with lung cancer underwent up to 5 sequential DCE-MRI examinations. DCE-MRI were performed using a 3.0T system. The volume transfer constant Ktrans was assessed by three readers using the two-compartment Tofts model. Inter- and intrarater reliability and agreement was calculated by wCV, ICC and their 95% confident intervals. DCE-MRI allowed a quantitative measurement of Ktrans in 107 tumors where 91 were primary carcinomas or intrapulmonary metastases and 16 were extrapulmonary metastases. Ktrans showed moderate to good interrater reliability in overall measurements (ICC 0.716-0.841; wCV 30.3-38.4%). Ktrans in pulmonary lesions ≥ 3 cm showed a good to excellent reliability (ICC 0.773-0.907; wCV 23.0-29.4%) compared to pulmonary lesions < 3 cm showing a moderate to good reliability (ICC 0.710-0.889; wCV 31.6-48.7%). Ktrans in intrapulmonary lesions showed a good reliability (ICC 0.761-0.873; wCV 28.9-37.5%) compared to extrapulmonary lesions with a poor to moderate reliability (ICC 0.018-0.680; wCV 28.1-51.8%). The overall intrarater agreement was moderate to good (ICC 0.607-0.795; wCV 24.6-30.4%). With Ktrans, DCE MRI offers a reliable quantitative biomarker for early non-invasive therapy assessment in lung cancer patients, but with a coefficient of variation of up to 48.7% in smaller lung lesions.

KEAP1 mutations in squamous cell lung cancer

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Background: KEAP1 mutations have been shown to decrease the efficacy of both chemotherapy (CTX) and immune-checkpoint inhibition (ICI) in lung adenocarcinoma. However, few is known about their impact on systemic treatment of squamous cell lung cancer (SqCC). The aim of this study was to assess the impact of KEAP1 mutations on systemic treatment outcome in SqCC. Methods: Tumor biopsies of SqCC patients were analyzed within the German Network Genomic Medicine (NGM) using a next-generation DNA sequencing (NGS) panel comprising 17 genes. In subsets, PD-L1 expression was tested with immunohistochemistry (IHC). MET amplification and FGFR1 amplification was tested with fluorescence in situ hybridization (FISH). Overall survival was estimated using Kaplan Meier statistics. For comparisons, we used log rank. A cohort with KEAP1 wild-type patients from the same panel served as control group. Results: Out of 1399 SqCC patients analyzed, 151 had a KEAP1 mutation (11%). The most common co-occurring mutations besides TP53 were PTEN, KRAS and NFE2L2. The median overall survival (OS) of stage IV KEAP1 mutated patients (n = 82) compared to stage IV control group patients (n = 82) was 7.3 vs. 11.4 months (hazard ratio (HR) 0.87 [95% confidence interval (CI) 0.62-1.23], p = 0.43). The addition of a second treatment line with ICI led to marked OS improvements in both KEAP1 mutant patient group (18.7 vs. 6.6 months, HR 0.11, [95% CI 0.04-0.25], p < 0.0001) and control group (20.3 vs. 5.0 months, HR 0.12 [95% CI 0.06-0.24], p < 0.0001). PD-L1 expression did not differ significantly in both groups. Conclusions: KEAP1 mutations occur commonly in SqCC patients and do not impact the efficacy of ICI in terms of OS. To identify prognostic markers for response to ICI further research is needed.

Genetic Heterogeneity of MET-Aberrant NSCLC and Its Impact on the Outcome of Immunotherapy

INTRODUCTION

Robust data on the outcome of MET-aberrant NSCLC with nontargeted therapies are limited, especially in consideration of the heterogeneity of MET-amplified tumors (METamp).

METHODS

A total of 337 tumor specimens of patients with MET-altered Union for International Cancer Control stage IIIB/IV NSCLC were analyzed using next-generation sequencing, fluorescence in situ hybridization, and immunohistochemistry. The evaluation focused on the type of MET aberration, co-occurring mutations, programmed death-ligand 1 expression, and overall survival (OS).

RESULTS

METamp tumors (n = 278) had a high frequency of co-occurring mutations (>80% for all amplification levels), whereas 57.6% of the 59 patients with MET gene and exon 14 (METex14) tumors had no additional mutations. In the METamp tumors, with increasing gene copy number (GCN), the frequency of inactivating TP53 mutations increased (GCN < 4: 58.2%; GCN ≥ 10: 76.5%), whereas the frequency of KRAS mutations decreased (GCN < 4: 43.2%; GCN ≥ 10: 11.8%). A total of 10.1% of all the METamp tumors with a GCN ≥ 10 had a significant worse OS (4.0 mo; 95% CI: 1.9-6.0) compared with the tumors with GCN < 10 (12.0 mo; 95% confidence interval [CI]: 9.4-14.6). In the METamp NSCLC, OS with immune checkpoint inhibitor (ICI) therapy was significantly better compared with chemotherapy with 19.0 months (95% CI: 15.8-22.2) versus 8.0 months (95% CI: 5.8-10.2, p < 0.0001). No significant difference in median OS was found between ICI therapy and chemotherapy in the patients with METex14 (p = 0.147).

CONCLUSIONS

METex14, METamp GCN ≥ 10, and METamp GCN < 10 represent the subgroups of MET-dysregulated NSCLC with distinct molecular and clinical features. The patients with METex14 do not seem to benefit from immunotherapy in contrast to the patients with METamp, which is of particular relevance for the prognostically poor METamp GCN ≥ 10 subgroup.

Abstract CT255: EATON: A phase I dose-escalation trial of nazartinib (EGF816) and trametinib in EGFR-mutant NSCLC

Background: EGFR tyrosine kinase inhibitor (TKI) treatment is highly effective in EGFR-mutant NSCLC. However, resistance to treatment inevitably develops. Multiple mechanisms of resistance to EGFR TKIs have been described. Besides secondary EGFR mutations, RAS/MEK pathway activation through different mechanisms has been found in cell models and in patients, resulting in TKI failure. Inhibition of MEK, resensitized cells to EGFR-targeted treatment in pre-clinical models. We thus hypothesize that combined MEK and EGFR inhibition may break resistance and delay treatment failure in EGFR-mutant NSCLC patients. Methods: EATON (NCT03516214) is an investigator-initiated, multicenter, phase I, dose-escalation trial investigating the recommended phase 2 dose (RP2D), pharmacokinetic parameters and safety/efficacy of the combination of EGF816 (nazartinib) and trametinib. Eligibility criteria: Advanced/metastatic EGFR-mutant (del19 or p.L858R) NSCLC, EGFR p.T790M-positive/-negative, absence of other secondary EGFR-mutations, MET amplification-negative (MET/CEN7 ratio ≥2.0 and/or average MET gene copy number per cell ≥6.0), first-line or after failure of any EGFR TKI, including osimertinib. Dose level escalation will be based on a 3+3 up-and-down design (total number: 24 patients) with a dose-limiting toxicity (DLT) period of 28 days. Minimum treatment exposure for DLT assessment is 21 days. Exploratory endpoints: Identification of mechanisms of resistance by analysis of baseline tissue, PD biopsies and ctDNA. Results: At the time of data cut-off, three patients received treatment at dose-level 1 (nazartinib (EGF816) 100 mg QD and trametinib 1 mg QD). All patients met the minimum exposure criterion for DLT assessment. In one patient a grade 3 creatinine phosphokinase elevation was observed and assessed as a DLT. No other DLTs were reported. Other related adverse events (AEs) grade ≥2 were rash (n=2), anemia (n=1), soft-tissue infection (n=1), diarrhea (n=1), and elevated liver enzymes (n=1). Two patients were evaluable for efficacy assessment. One stopped treatment prior to first assessment due to a grade 4 soft tissue infection at day 37. Best objective response according to RECIST 1.1 was stable disease in one patient (afatinib-resistant, T790M-negative), lasting for more than 4 months and progressive disease in the other patient (osimertinib-resistant, T790M-negative). Conclusions: Treatment with nazartinib 100 mg QD and trametinib 1 mg QD resulted in a DLT in one of three patients. Thus, three additional patients will be enrolled at the same dose level. Efficacy data is premature. But, a significant progression-free survival period was observed in one EGFR p.T790M-negative patient.

Citation Format: Sebastian Michels, Lucia Nogova, Matthias Scheffler, Barbara Deschler-Baier, Martin Sebastian, Martin Schuler, Martin Wermke, Enriqueta Felip, Rafael Rosell, Delvys Rodriguez Abreu, Diana S.Y. Abdulla, Rieke N. Fischer, Sophia Koleczko, Anna Kron, Richard Riedel, Jan-Philipp Weber, Jana Fassunke, Sabine Merkelbach-Bruse, Heinz Haverkammp, Martin Hellmich, Reinhard Büttner, Jürgen Wolf, Lung Cancer Group Cologne (LCGC) and Network Genomic Medicine (NGM). EATON: A phase I dose-escalation trial of nazartinib (EGF816) and trametinib in EGFR-mutant 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 CT255.

Sorafenib and everolimus in patients with advanced solid tumors and KRAS-mutated NSCLC: A phase I trial with early pharmacodynamic FDG-PET assessment

BACKGROUND

Treatment of patients with solid tumors and KRAS mutations remains disappointing. One option is the combined inhibition of pathways involved in RAF-MEK-ERK and PI3K-AKT-mTOR.

METHODS

Patients with relapsed solid tumors were treated with escalating doses of everolimus (E) 2.5-10.0 mg/d in a 14-day run-in phase followed by combination therapy with sorafenib (S) 800 mg/d from day 15. KRAS mutational status was assessed retrospectively in the escalation phase. Extension phase included KRAS-mutated non-small-cell lung cancer (NSCLC) only. Pharmacokinetic analyses were accompanied by pharmacodynamics assessment of E by FDG-PET. Efficacy was assessed by CT scans every 6 weeks of combination.

RESULTS

Of 31 evaluable patients, 15 had KRAS mutation, 4 patients were negative for KRAS mutation, and the KRAS status remained unknown in 12 patients. Dose-limiting toxicity (DLT) was not reached. The maximum tolerated dose (MTD) was defined as 7.5 mg/d E + 800 mg/d S due to toxicities at previous dose level (10 mg/d E + 800 mg/d S) including leucopenia/thrombopenia III° and pneumonia III° occurring after the DLT interval. The metabolic response rate in FDG-PET was 17% on day 5 and 20% on day 14. No patient reached partial response in CT scan. Median progression free survival (PFS) and overall survival (OS) were 3.25 and 5.85 months, respectively.

CONCLUSIONS

Treatment of patients with relapsed solid tumors with 7.5 mg/d E and 800 mg/d S is safe and feasible. Early metabolic response in FDG-PET was not confirmed in CT scan several weeks later. The combination of S and E is obviously not sufficient to induce durable responses in patients with KRAS-mutant solid tumors.

Co-occurrence of targetable mutations in Non-small cell lung cancer (NSCLC) patients harboring MAP2K1 mutations

BACKGROUND

MAP2K1 mutations are rare in non-small cell lung cancer (NSCLC) and considered to be mutually exclusive from known driver mutations. Activation of the MEK1-cascade is considered pivotal in resistance to targeted therapy approaches, and MAP2K1 K57 N mutation could be linked to resistance in preclinical models. We set out this study to detect MAP2K1 mutations and potentially targetable co-mutations using a molecular multiplex approach.

METHODS

Between 2012 and 2018, we routinely analyzed 14.512 NSCLC patients with two next-generation sequencing (NGS) panels. In a subset of patients, fluorescence in-situ hybridization was performed to detect rearrangements or amplifications. We assessed clinical parameters and co-occurring mutations and compared treatment outcomes of different forms of systemic therapy.

RESULTS

We identified 66 (0.5%) patients with MAP2K1 mutations. Both adenocarcinoma (n = 62) and squamous cell carcinoma (n = 4) histology. The presence of the mutations was linked to smoking, and transversions were more common than transitions. K57 N was the most frequent MAP2K1 mutation (n = 25). Additional mutations were found in 57 patients (86.4%). Mutations of TP53 were detected in 33 patients, followed by KEAP1 mutations in 28.1%. 24 patients (36.4%) had either MAP2K1-only or a co-occurring aberration considered targetable, including EGFR mutations, a BRAF V600E mutation and ROS1 rearrangements. Outcome analyses revealed a trend toward benefit from pemetrexed treatment.

CONCLUSION

Our analysis shows that MAP2K1-mutated NSCLC patients might frequently present with potentially targetable aberrations. Their role in providing resistance in these subtypes and the possible therapeutic opportunities justify further analyses of this rare NSCLC subgroup.

Phase I experience with rogaratinib in patients (pts) with urothelial carcinoma (UC) selected based on FGFR mRNA overexpression

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Background: Aberrant activation of the fibroblast growth factor receptor (FGFR) pathway is implicated in many cancers, including UC. In a recent Phase I dose-escalation study, rogaratinib, an oral pan-FGFR1-4 inhibitor, demonstrated favorable efficacy and safety in pts with solid cancers selected based on FGFR1-3 mRNA overexpression. We report results from the Phase I expansion cohort with rogaratinib in pts with UC selected by FGFR1-3 mRNA overexpression and/or FGFR3-activating mutations (NCT01976741). Methods: Pts with advanced/metastatic UC were screened for FGFR1-3 mRNA overexpression using RNA in situ hybridization (RNAscope) and NanoString assay in fresh or archival tumor samples. Pts received rogaratinib 800 mg po BID continuously. Tumor response and safety were assessed. Results: 74 pts with UC were treated with rogaratinib; 73.0% were male, median age was 66 years (range 45-85), and 93.2% had stage IV disease. Rogaratinib was well tolerated, with adverse events being mostly mild or moderate. The most common treatment-emergent adverse events (TEAEs) are shown in the Table. The most common drug-related TEAEs (any grade) were diarrhea (52.7%), increased blood phosphorus (41.9%), and decreased appetite and dry mouth (31.1% each). No ocular toxicities were reported. Increased blood creatinine and acute kidney injury (AKI), regardless of relatedness, were reported in 16.2% and 2.7% of pts, respectively; 1 case of AKI was confirmed as acute tubular necrosis. Of 72 evaluable pts, 15 (20.8%) achieved an objective response; complete and partial responses were observed in 1 (1.4%) and 14 (19.4%) pts, respectively. Stable disease was achieved by 34 pts (47.2%), with a disease control rate of 68.1%. Conclusions: Rogaratinib demonstrated a favorable safety and efficacy profile in pts with tumor FGFR1-3 mRNA-positive UC. TEAEs observed in >25% of pts. Clinical trial information: NCT01976741. [Table: see text]

Impact of TP53 mutation status on systemic treatment outcome in ALK-rearranged non-small-cell lung cancer

Background

We analyzed whether co-occurring mutations influence the outcome of systemic therapy in ALK-rearranged non-small-cell lung cancer (NSCLC).

Patients and methods

ALK-rearranged stage IIIB/IV NSCLC patients were analyzed with next-generation sequencing and fluorescence in situ hybridization analyses on a centralized diagnostic platform. Median progression-free survival (PFS) and overall survival (OS) were determined in the total cohort and in treatment-related sub-cohorts. Cox regression analyses were carried out to exclude confounders.

Results

Among 216 patients with ALK-rearranged NSCLC, the frequency of pathogenic TP53 mutations was 23.8%, while other co-occurring mutations were rare events. In ALK/TP53 co-mutated patients, median PFS and OS were significantly lower compared with TP53 wildtype patients [PFS 3.9 months (95% CI: 2.4–5.6) versus 10.3 months (95% CI: 8.6–12.0), P < 0.001; OS 15.0 months (95% CI: 5.0–24.9) versus 50.0 months (95% CI: 22.9–77.1), P = 0.002]. This difference was confirmed in all treatment-related subgroups including chemotherapy only [PFS first-line chemotherapy 2.6 months (95% CI: 1.3–4.1) versus 6.2 months (95% CI: 1.8–10.5), P = 0.021; OS 2.0 months (95% CI: 0.0–4.6) versus 9.0 months (95% CI: 6.1–11.9), P = 0.035], crizotinib plus chemotherapy [PFS crizotinib 5.0 months (95% CI: 2.9–7.2) versus 14.0 months (95% CI: 8.0–20.1), P < 0.001; OS 17.0 months (95% CI: 6.7–27.3) versus not reached, P = 0.049] and crizotinib followed by next-generation ALK-inhibitor [PFS next-generation inhibitor 5.4 months (95% CI: 0.1–10.7) versus 9.9 months (95% CI: 6.4–13.5), P = 0.039; OS 7.0 months versus 50.0 months (95% CI: not reached), P = 0.001).

Conclusions

In ALK-rearranged NSCLC co-occurring TP53 mutations predict an unfavorable outcome of systemic therapy. Our observations encourage future research to understand the underlying molecular mechanisms and to improve treatment outcome of the ALK/TP53 co-mutated subgroup.

Overcoming acquired osimertinib-resistance in EGFR-mutant advanced non-small lung cancer mediated by activating BRAF V600E mutation

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Background: There is growing insight in the mechanisms underlying resistance to the 3rdgeneration EGFR inhibitor osimertinib. Unlike resistance to 1stgeneration inhibitors, these mechanisms not necessarily lead to sequential targeted therapy approaches. Here we report on the treatment of two patients with acquired resistance to osimertinib with a new detected BRAF V600E mutation as resistance mechanism. Methods: We identified two patients with EGFR-T790M-mutant advanced NSCLC with progression on osimertinib and detection of a new BRAFV600E mutation in a tumor rebiopsy by next-generation sequencing (NGS). No other known resistance mechanism beside T790M loss in one patient was found. Osimertinib was discontinued and BRAF-targeted combination therapy with dabrafenib and trametinib at standard dose was initiated. We monitored the clinical course with sequential 18F-2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) / computed tomography (CT) assessing maximum standard uptake value (SUVmax), sequencing based liquid biopsies and tumor marker assessment. Results: Patient (1) with EGFR del19 (E746_A750del), preserved T790M mutation and acquired BRAF V600E mutation showed reduction in FDG uptake of 18% after 2 weeks of dabrafenib/trametinib that demonstrated a slight increase of 12% in a FDG-PET/CT scan 4 weeks thereafter and combination treatment has been continued. Patient (2) with EGFR del19 (E746_A750del), T790M loss and new BRAF V600E mutation showed continuous metabolic (+8% and + 39%, respectively) and morphologic progression after 2 and 4 weeks of dabrafenib and trametinib. A tumor rebiopsy showed no additional molecular changes. We changed the treatment to osimertinib and dabrafenib combination and observed an impressive metabolic response (-33%) after 2 weeks by FDG-PET/CT. Conclusions: BRAF V600E mutation has recently been described as a novel molecular resistance mechanism in osimertinib-resistant EGFR-mutant NSCLC. We describe one patient where combined BRAF/MEK inhibition with no additional EGFR-inhibition resulted in a preliminary feasible tumor control, but confirmatory CT staging is pending. In a second patient, co-inhibition of EGFR and BRAF pathway with osimertinib and dabrafenib was needed to overcome BRAF-mediated osimertinib resistance resulting in an impressive early tumor response that was not observed to either single-target inhibition of EGFR or BRAF. FDG-PET/CT was able to monitor tumor dynamics. Updated data will be presented.

Acquired resistance to MET inhibition in MET driven NSCLC

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Background: MET mutations ( MET∆ex14), amplifications or translocations can activate oncogenic signaling in lung cancer and are sensitive to MET inhibition. Acquired resistance to therapy with MET tyrosine kinase inhibitors (TKI) occurs inevitably. Methods: Between 2015 and 2018, eighteen patients with MET-driven NSCLC were treated with capmatinib or crizotinib as single agent at our site. Rebiopsy samples from five patients were analyzed by NGS and fluoreszenz-in-situ hybridization (FISH) at time of progression. Results: Of the five patients with rebiopsy samples at time of progression, two had initially a MET amplification (one patient with low-level and one patient with high-level amplification), two patients had a MET∆ex14 and one patient had a KIF5B-MET fusion. Patient 1 (low-level MET amplification) showed a partial response to crizotinib. The rebiopsy revealed an acquired KRAS mutation as a potential mechanism of resistance. Patient 2 (high-level MET amplification) showed stable disease as best response to capmatinib and patient 3 (MET∆ex14) showed a partial response to capmatinib. Both patients developed acquired HER2 amplifications. Patient 4 ( MET∆ex14) showed initially a partial response to crizotinib. The rebiopsy sample revealed an acquired MET kinase domain mutation (p.D1246N). As preclinical findings suggested that D1246N confers resistance to type I MET inhibitors but remains sensitive to type II inhibitors, cabozantinib was started. A CT six weeks after therapy initiation showed progressive disease. Patient 5 ( KIF5B-MET) had a partial response to crizotinib. An acquired MET p.Y1248H mutation was found at time of progression. Therapy was changed to cabozantinib. A new CT scan is pending. Conclusions: Resistance to MET inhibition is heterogeneous with on- and off-target-mechanisms occurring. We found HER2 amplification as a potential new bypass mechanism. The MET mutation D1246N conferred resistance to type I and type II inhibitors. We describe the first case of an acquired mutation of the MET tyrosine kinase domain in a patient with an oncogenic MET fusion. Further investigations are needed to collect comprehensive data to understand resistance mechanisms in MET inhibition and to develop novel therapeutic strategies.

EATON: An open-label, multicenter, phase I dose-escalation trial of nazartinib (EGF816) and trametinib in patients with EGFR-mutant non-small cell lung cancer – preliminary data on safety and tolerability

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Background: Multiple mechanisms of resistance to EGFR TKIs therapy in EGFR-mutant non-small cell lung cancer (NSCLC) have been described, most often including the acquisition of the secondary resistance mutations in exon 20 of EGFR. Preclinical models and clinical findings have also shown that co-occurring activation of the RAS/MEK pathway may result in reduced EGFR dependency, which may be overcome by co-inhibition of MEK. We thus hypothesize that the combined inhibition of EGFR and MEK may restore sensitivity to EGFR inhibition in patients with acquired resistance to EGFR inhibition and may as well prolong the acquisition of resistance in treatment-naïve patients. Methods: EATON is an international, multicenter, phase I, dose escalation investigator-initiated trial investigating the recommended phase 2 dose (RP2D), safety and preliminary efficacy of the combination of the third-generation EGFR inhibitor EGF816 with the MEK inhibitor trametinib (NCT03516214). Eligibility criteria: Advanced NSCLC harboring EGFR del19 or p.L858R, first-line or after failure of any EGFR TKI including osimertinib, independently of p.T790M status. Patients with high-level MET amplification are excluded. Dose level escalation will be based on a modified traditional cumulative 3+3 design, i.e. “up and down” (dose level 1: 100 mg nazartinib (EGF816) QD + 1 mg trametinib QD). A total number of 24 patients is planned to be enrolled in 8 trial sites in Germany and Spain. At a first stage, 18 (6´3) patients will be treated and evaluated. Exploratory endpoints aim at the identification of potential mechanisms of resistance to the trial treatment by massively parallel sequencing (MPS), FISH, phospho-protein analyses and whole exome/genome sequencing of baseline and PD biopsy tumour tissue. Additionally blood samples for MPS of cell free DNA will be collected throughout the trial treatment. Results: At the time of data-cut off for this abstract, one patient received treatment at dose-level 1. Treatment was withdrawn due to a serious, bacterial soft tissue infection of the hand outside the DLT period. Conclusions: Data on safety and tolerability of the combination of nazartinib and trametinib is premature. Updated results will be presented at the conference. Clinical trial information: NCT03516214.

Genomic Profiling Identifies Outcome-Relevant Mechanisms of Innate and Acquired Resistance to Third-Generation Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor Therapy in Lung Cancer

PURPOSE

Third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are effective in acquired resistance (AR) to early-generation EGFR TKIs in EGFR-mutant lung cancer. However, efficacy is marked by interindividual heterogeneity. We present the molecular profiles of pretreatment and post-treatment samples from patients treated with third-generation EGFR TKIs and their impact on treatment outcomes.

METHODS

Using the databases of two lung cancer networks and two lung cancer centers, we molecularly characterized 124 patients with EGFR p.T790M-positive AR to early-generation EGFR TKIs. In 56 patients, correlative analyses of third-generation EGFR TKI treatment outcomes and molecular characteristics were feasible. In addition, matched post-treatment biopsy samples were collected for 29 patients with progression to third-generation EGFR TKIs.

RESULTS

Co-occurring genetic aberrations were found in 74.4% of EGFR p.T790-positive samples (n = 124). Mutations in TP53 were the most frequent aberrations detected (44.5%; n = 53) and had no significant impact on third-generation EGFR TKI treatment. Mesenchymal-epithelial transition factor (MET) amplifications were found in 5% of samples (n = 6) and reduced efficacy of third-generation EGFR TKIs significantly (eg, median progression-free survival, 1.0 months; 95% CI, 0.37 to 1.72 v 8.2 months; 95% CI, 1.69 to 14.77 months; P ≤ .001). Genetic changes in the 29 samples with AR to third-generation EGFR TKIs were found in EGFR (eg, p.T790M loss, acquisition of p.C797S or p.G724S) or in other genes (eg, MET amplification, KRAS mutations).

CONCLUSION

Additional genetic aberrations are frequent in EGFR-mutant lung cancer and may mediate innate and AR to third-generation EGFR TKIs. MET amplification was strongly associated with primary treatment failure and was a common mechanism of AR to third-generation EGFR TKIs. Thus, combining EGFR inhibitors with TKIs targeting common mechanisms of resistance may delay AR.

K-ras Mutation Subtypes in NSCLC and Associated Co-occuring Mutations in Other Oncogenic Pathways

INTRODUCTION

Although KRAS mutations in NSCLC have been considered mutually exclusive driver mutations for a long time, there is now growing evidence that KRAS-mutated NSCLC represents a genetically heterogeneous subgroup. We sought to determine genetic heterogeneity with respect to cancer-related co-mutations and their correlation with different KRAS mutation subtypes.

METHODS

Diagnostic samples from 4507 patients with NSCLC were analyzed by next-generation sequencing by using a panel of 14 genes and, in a subset of patients, fluorescence in situ hybridization. Next-generation sequencing with an extended panel of 14 additional genes was performed in 101 patients. Molecular data were correlated with clinical data. Whole-exome sequencing was performed in two patients.

RESULTS

We identified 1078 patients with KRAS mutations, of whom 53.5% had at least one additional mutation. Different KRAS mutation subtypes showed different patterns of co-occurring mutations. Besides mutations in tumor protein p53 gene (TP53) (39.4%), serine/threonine kinase 11 gene (STK11) (19.8%), kelch like ECH associated protein 1 gene (KEAP1) (12.9%), and ATM serine/threonine kinase gene (ATM) (11.9%), as well as MNNG HOS Transforming gene (MET) amplifications (15.4%) and erb-b2 receptor tyrosine kinase 2 gene (ERBB2) amplifications (13.8%, exclusively in G12C), we found rare co-occurrence of targetable mutations in EGFR (1.2%) and BRAF (1.2%). Whole-exome sequencing of two patients with co-occurring phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha gene (PIK3CA) mutation revealed clonality of mutated KRAS in one patient and subclonality in the second, suggesting different evolutionary backgrounds.

CONCLUSION

KRAS-mutated NSCLC represents a genetically heterogeneous subgroup with a high frequency of co-occurring mutations in cancer-associated pathways, partly associated with distinct KRAS mutation subtypes. This diversity might have implications for understanding the variability of treatment outcome in KRAS-mutated NSCLC and for future trial design.

Rogaratinib treatment of patients with advanced urothelial carcinomas prescreened for tumor FGFR mRNA expression

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Background: Activation of FGFR signaling is involved in a variety of malignancies including advanced urothelial cancer (UC). Rogaratinib is an oral pan-FGFR kinase inhibitor. We report here the results from a phase I expansion cohort in UC patients prescreened for FGFR1-3 mRNA expression levels and activating mutations. (NCT01976741) Methods: Patients with advanced urothelial carcinomas were selected based on high FGFR1-3 mRNA expression in biopsy specimens. Selected patients were treated with rogaratinib 800mg twice daily until tumour progression, untolerable toxicity, or withdrawal. Tumor response was assessed by RECIST, v1.1. Adverse events were reported using CTCAE v4.03 criteria. Results: A total of 219 UC patients were prescreened for FGFR1-3 mRNA expression levels and FGFR3 activating mutations, with 99 samples (45%) found to be FGFR-positive. Of those, 87% of samples were positive for FGFR3 mRNA, 5% for FGFR1 mRNA and 8% were double FGFR mRNA-positive (FGFR1/2, 1/3 or 2/3). Frequency of FGFR3 activating mutations in UC samples was 7%, all of which also had high FGFR3 mRNA. Fifty two patients (median prior line of treatment 2) started treatment and 51 were evaluable for response. Rogaratinib was generally well tolerated and AEs manageable with dose modification. The most common AEs were diarrhea (49%) and hyperphosphatemia (49%). Objective response rate (ORR) was 24% (12/51; all PRs) and disease control rate (DCR) was 73% (37/51). Eleven of 12 pts with a PR were positive for FGFR3 mRNA, 5 of whom also had FGFR3 mutations, and one patient was positive for FGFR1 mRNA. Ten FGFR-positive UC patients had prior immuno-oncology (I/O) treatment, 9 of whom had progressive disease as best response. For these 10 patients the ORR was 30% and the DCR 80%. Conclusions: Selection of pts for treatment with rogaratinib based on FGFR mRNA expression levels was feasible and identified drug-sensitive patients with and without underlying DNA alterations. Rogaratinib had a favorable safety profile and showed promising anti-tumor activity in UC patients. Responses and disease stabilization were observed with rogoratinib in UC pts refractory to prior I/O treatment. Clinical trial information: NCT01976741.

Co-occurrence of targetable aberrations in non-small cell lung cancer patients harboring MAP2K1 mutations

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Background: MAP2K1 mutations are rare in non-small cell lung cancer (NSCLC) and considered to be mutually exclusive with known driver mutations. Activation of the MEK1-cascade might play a pivotal role in resistance to targeted inhibition of BRAF V600E, EML4-ALK and EGFR T790M. So far, however, only MAP2K1 K57N could be identified and linked functionally to resistance in preclinical models. Clinical trials combining specific inhibitors for predefined NSCLC subgroups with MEK inhibitors are ongoing. We sought to characterize frequency and type of MAP2K1-mutated NSCLC regarding curated targetable aberrations. Methods: Tumor tissue collected consecutively from 4590 NSCLC patients within the German Network Genomic Medicine (NGM) between 07/2014 and 07/2015 was analyzed for MAP2K1 mutations using next-generation sequencing (NGS) with a set of 102 amplicons in 14 genes. Clinical and molecular characteristics of these patients were determined and compared with an internal control group of NSCLC patients and an independent control group of The Cancer Genome Atlas (TCGA). Results: We identified 21 (0.5%) patients with MAP2K1 mutations. They were frequently found in adenocarcinomas (n = 20) and were significantly associated with smoking. The most common MAP2K1 mutation was K57N. Most of the patients (n = 16) had additional oncogenic driver aberrations, including mutations in ALK, EGFR or BRAF, ROS1 rearrangements and MET amplification. TP53 mutations were found in 11 patients. In only five patients (23.8%) MAP2K1 occurred exclusively. TCGA analysis revealed additional 10 patients with MAP2K1 mutations, whereof 9 had additional TP53 mutations and one had BRAF mutation. Whereof most patients in our cohort had stage IV NSCLC, all patients in TCGA were systemic treatment naive. Compared with local stages in TCGA, our findings strongly suggest that targetable co-occurring mutations might occur more frequently in advanced stage NSCLC patients. Conclusions: MAP2K1 mutations co-occur frequently with targetable aberrations in smoking stage IV patients. Combination of targeted therapy against known driver aberrations with MEK inhibitors might be a promising therapeutic approach for such patients.

Molecular panel sequencing of pre-treatment samples to reveal mechanisms of innate resistance to 3rd generation EGFR TKI treatment in T790M-positive NSCLC patients

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Background: Resistance to early generation epidermal growth factor receptor ( EGFR) tyrosine kinase inhibitors (TKI) inevitably develops in EGFR-mutant lung cancer. The secondary EGFR p.T790M mutation is the driving factor in 60% of cases and 3rd generation EGFR TKIs have been developed to overcome T790M-mediated resistance. However, besides T790M other genetic aberrations such as amplifications of MET may contribute to resistance to EGFR inhibition in the same patient. We here report on the systematic analysis of co-occurring genetic aberrations that may influence response to 3rd generation EGFR TKIs. Methods: Thirty-six patients were treated with 3rd generation EGFR TKIs in the setting of acquired resistance to EGFR inhibition in cancer centers in Germany and Switzerland. Pre-treatment samples were analyzed for co-occurring genetic aberrations in a subset of resistance-related genes including MET, HER2, RAS-gene family, PIK3CA, CTNNB1 and PTEN using next-generation sequencing and fluorescence in-situ hybridization assays. We investigated the association between clinical, epidemiological and molecular data and response to treatment (RECIST 1.1). Results: Co-occurring genetic aberrations were found in 68% of the pre-treatment samples where both, analyses by sequencing and FISH were feasible (N = 25). Efficacy of 3rd generation EGFR TKIs significantly dropped in the presence of high-level MET amplification as compared to wild-type MET (ORR, 0.0%; 95% CI, 0.0-60.4 vs. 70.0%; 95% CI, 45.7-87.2; p = 0.02; median PFS, 1.0 month; 95% CI, 0.37-1.72 months vs. 8.2 months; 95% CI, 1.69-14.77 months; p ≤ 0.001). No statistically significant association was found between treatment efficacy and the molecular status of the genes analyzed or the number of prior EGFR TKIs. Conclusions: Prevalence of additional genetic aberrations is frequent in the setting of acquired resistance to early generation EGFR TKIs and may not necessarily mediate resistance to 3rd generation EGFR TKIs. However, in our analysis high-level amplification of MET was associated with primary treatment failure and might be the main factor underlying resistance in this setting.

Expanded molecular routine testing for targetable mutations in non-small cell lung cancer to reveal frequent co-occuring mutations

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Background: Using next-gen sequencing of predefined gene panels in routine clinical diagnostics of lung cancer allows, in contrast to single-gene assays, assessment of co-occuring mutations, which might underly heterogeneity of response to targeted drugs and survival. The Network Genomic Medicine (NGM) performs high sensitive next generation sequencing (NGS) based routine molecular diagnostics on a central platform for about 5000 inoperable lung cancer patients (pts) annually in Germany. Methods: NGS panel used in NGM consists of 17 genes to cover potentially targetable aberrations. Mutation analyses were run on an Illumina (MySeq) platform, while FISH analyses were performed separately. In 2016, we have started the evaluation of all NGM pts with available clinical data who had received NGS-based molecular diagnostics. In particular, we have focused on non-squamous (non-sq) and squamous (sq) NSCLC pts with co-occurring mutations: their frequency, significance and impact on overall survival. Results: From 2014 molecular genotyping was performed for 7,893 NGM pts (n = 7,246 NSCLC (5,667 non-sq and 1,487 sq pts) and n = 489 SCLC) with eligible clinical data. Genetic alterations in transformation-associated pathways were found in 79 % of all NSCLC pts. Furthermore, co-occurring mutations were detected in 39 % of these pts: 40 % in non-sq and 37 % in sq NSCLC. 11 % of pts had more than 2 co-occurring mutations. 1 % of all pts had 5 co-occurring mutations. The most frequent paired mutations were KRAS, EGFR and MET each with TP53 in non-sq and FRGF1 and TP53 in sq NSCLC. The incidences and significance of 3, 4 and 5 co-mutations as well as the impact of these co-occurring mutations on overall survival will be presented. Conclusions: Frequent occurrence of co-occuring mutations in transformation – associated pathways underlines the genetic heterogeneity also of lung cancer with classical driver mutation and the impact of co-occurring mutations on survival. This work confirms the use of molecular multiplex testing in routine molecular diagnostics of NSCLC. Assessment of co-occuring mutations will help to further specify genetically defined subgroups of lung cancer with therapeutic relevance.

Fibroblast kinase 1-3 inhibitor BGJ398 in patients with FGFR1 amplified squamous non-small cell lung cancer treated in a phase I study: Evaluation of tumor tissue and response at a single center

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Background: Fibroblast growth factor receptor 1 ( FGFR1) amplification in squamous cell non-small cell lung cancer (sqNSCLC) has been described as potential oncogenic and targetable driver in cell lines and murine models. However, a phase I study evaluating FGFR 1-3 inhibitor BGJ398 showed moderate response rate of 11% in FGFR1amplified sgNSCLC treated with dose ≥ 100mg. To identify underlying mechanisms of resistance, we analyzed tumor tissues of selected patients. Methods: Within the phase I BGJ398 study, patients (pts) with FGFR1amplified sqNSCLC were treated orally with escalating dose (5 to 150mg) of BGJ398 once daily (QD) or 50mg twice a day. In the expansion phase, pts received BGJ398 either continuously QD or on a 3-weeks on/1-week off schedule. CT scans for response were performed every 8 weeks. Available tumor tissue of pts treated with BGJ398 at our center was analyzed using hybrid capture–based massively parallel sequencing (CAGE). Results: Twenty-one pts with FGFR1 amplified sqNSCLC were treated with ≥ 100mg BGJ398 at our site. As best response, 3 pts showed partial response (PR), 7 pts stable disease (SD) and 7 pts progressive disease (PD). Two pts withdrew their consents and 2 pts died ahead of first CT scan: one due to infection and one due to sudden death. We performed CAGE covering 256 genes on 9 patients: on 3 pts with PR, 2 pts with SD, 2 pts with PD and 2 pts who died before first CT scan. All analyzed patients harbored mutations in TP53. Additionally, we detected two CDKN2A (one patient with PR and one patient who died before first CT) and three MLL2 stop codon and frame shift mutations (two patients with SD and one patient with PD). Of interest, we identified three patients with two canonical (one patient with SD and one patient who died before first CT) and one non-canonical mutations in PIK3CA(one patient with SD). Conclusions: In our analysis, MLL2 and PIK3CA mutations seem to have a negative impact on response in FGFR1 amplified pts treated with BGJ398. Further analysis with higher patient number is needed to identify the role of MLL2 and PIK3CA mutations in FGFR1 amplified sqNSCLC. Clinical trial information: NCT01004224.