Osimertinib treatment for patients with EGFR exon 20 mutation positive non-small cell lung cancer

OBJECTIVES

Epidermal growth factor receptor (EGFR) exon 20 insertions comprise 4-10 % of EGFR mutations in non-small cell lung cancer (NSCLC) and are associated with primary resistance to first and second generation EGFR tyrosine kinase inhibitors (TKIs). In vitro and preclinical animal studies have shown that osimertinib exerts antitumor activity against EGFR exon 20 mutation positive NSCLC. We report on a cohort of advanced stage NSCLC patients who harbor an EGFR exon 20 mutation and received osimertinib treatment.

MATERIAL AND METHODS

Twenty-one patients were treated with osimertinib 80 or 160 mg once daily from April 2016 to June 2018, in four institutions in the Netherlands. Data were obtained retrospectively. Progression free survival (PFS), disease control rate (DCR), overall survival (OS) and objective response rate (ORR) were assessed using RECIST v1.1.

RESULTS

Thirteen patients received prior platinum-based chemotherapy, and three patients a first - or second generation EGFR TKI. We observed 1 partial response, 17 patients with stable disease and 3 with progressive disease as best response to osimertinib (ORR 5 %). Median PFS was 3.6 (95 % CI, 2.6-4.5) months. PFS did not differ for patients with co-occurring TP53 mutations (p = 0.937). The DCR at three months was 71 %. Median OS was 8.7 (95 % CI, 1.1-16.4) months.

CONCLUSION

Osimertinib has limited antitumor activity in patients with EGFR exon 20 mutated NSCLC, with an ORR of 5 %.

Overall survival in EGFR mutated non-small-cell lung cancer patients treated with afatinib after EGFR TKI and resistant mechanisms upon disease progression

PURPOSE

To determine survival in afatinib-treated patients after treatment with first-generation EGFR tyrosine kinase inhibitors (TKIs) and to study resistance mechanisms in afatinib-resistant tumors.

METHODS

Characteristics and survival of patients treated with afatinib after resistance to erlotinib or gefitinib in two large Dutch centers were collected. Whole exome sequencing (WES) and pathway analysis was performed on available pre- and post-afatinib tumor biopsies and normal tissue.

RESULTS

A total of 38 patients were treated with afatinib. T790M mutations were identified in 22/29 (76%) pre-afatinib treatment tumor samples. No difference in median progression-free-survival (2.8 months (95% CI 2.3-3.3) and 2.7 months (95% CI 0.9-4.6), p = 0.55) and median overall-survival (8.8 months (95% CI 4.2-13.4) and 3.6 months (95% CI 2.3-5.0), p = 0.14) were observed in T790M+ patients compared to T790M- mutations. Somatic mutations in TP53, ADAMTS2, CNN2 and multiple genes in the Wnt and PI3K-AKT pathway were observed in post-afatinib tumors of six afatinib-responding and in one non-responding patient. No new EGFR mutations were found in the post-afatinib samples of the six responding patients. Further analyses of post-afatinib progressive tumors revealed 28 resistant specific mutations in six genes (HLA-DRB1, AQP7, FAM198A, SEC31A, CNTLN, and ESX1) in three afatinib responding patients. No known EGFR-TKI resistant-associated copy number gains were acquired in the post-afatinib samples.

CONCLUSION

No differences in survival were observed in patients with EGFR-T790M treated with afatinib compared to those without T790M. Tumors from patients who had progressive disease during afatinib treatment were enriched for mutations in genes involved in Wnt and PI3K-AKT pathways.

Trastuzumab and pertuzumab combination therapy for advanced pre-treated HER2 exon 20-mutated non-small cell lung cancer

INTRODUCTION

In 1-3% of non-small cell lung cancer (NSCLC) human epidermal growth factor 2 (HER2) mutations are identified as a genomic driver. Nevertheless, no HER2-targeted treatment is approved for NSCLC. In the Drug Rediscovery Protocol (DRUP), patients are treated with off-label drugs based on their molecular profile. Here, we present the results of the cohort 'trastuzumab/pertuzumab for HER2 exon20 mutation positive (HER2m+) NSCLC'.

METHODS

Patients with treatment refractory, advanced HER2m+ NSCLC with measurable disease (RECISTv1.1) were eligible. Treatment with intravenous trastuzumab combined with pertuzumab every 3 weeks was administered. The primary end-point was clinical benefit (CB: either objective response or stable disease ≥ 16 weeks). Patients were enrolled using a Simon-like 2-stage design, with 8 patients in stage 1 and up to 24 patients in stage 2 if at least 1 patient had CB in stage 1. At baseline, a biopsy for biomarker analysis, including whole genome sequencing, was obtained.

RESULTS

Twenty-four evaluable patients were enrolled and treated between May 2017 and August 2020. CB was observed in 9 patients (38%); including an objective response rate of 8.3% (2 patients had a partial response) and 7 patients with stable disease ≥ 16 weeks. The most frequently observed HER2 mutation was p.Y772_A775dup (71%, n = 20). Median follow-up was 13 months, median progression-free survival and overall survival 4 (95% CI 3-6) and 10 months (95% CI 4 - not reached), respectively. Whole genome sequencing data (available for 67% of patients) confirmed the inclusion mutation in all cases. No unexpected toxicity was observed.

CONCLUSION

Despite the fact that the study did meet its primary end-point, trastuzumab/pertuzumab was only marginally active in a subset of patients with heavily pre-treated HER2m+ NSCLC.

Opportunities for Precision Dosing of Cytotoxic Drugs in Non-Small Cell Lung Cancer: Bridging the Gap in Precision Medicine

Precision dosing of classical cytotoxic drugs in oncology remains underdeveloped, especially in treating non-small cell lung cancer (NSCLC). Despite advancements in targeted therapy and immunotherapy, classical cytotoxic agents continue to play a critical role in NSCLC treatment. However, the current body surface area (BSA)-based dosing of these agents fails to adequately address interindividual variability in pharmacokinetics. By better considering patient characteristics, treatment outcomes can be improved, reducing risks of under-exposure and over-exposure. This narrative review explores opportunities for precision dosing for key cytotoxic agents used in NSCLC treatment: cisplatin, carboplatin, pemetrexed, docetaxel, (nab-)paclitaxel, gemcitabine, and vinorelbine. A comprehensive review of regulatory reports and an extensive literature search were conducted to evaluate current dosing practices, pharmacokinetics, pharmacodynamics, and exposure-response relationships. Our findings highlight promising developments in precision dosing, although the number of directly implementable strategies remains limited. The most compelling evidence supports using the biomarker cystatin C for more precise carboplatin dosing and adopting weekly dosing schedules for docetaxel, paclitaxel, and nab-paclitaxel. Additionally, we recommend direct implementation of therapeutic drug monitoring (TDM)-guided dosing for paclitaxel. This review stresses the urgent need to reassess conventional dosing paradigms for classical cytotoxic agents to better align with the principles of the precision dosing framework. Our recommendations show the potential of precision dosing to improve NSCLC treatment, addressing gaps in the current dosing of classical cytotoxic drugs. Given the large NSCLC patient population, optimising the dosing of these agents could significantly improve treatment outcomes and reduce toxicity for many patients.

Molecular Tumor Board of the University Medical Center Groningen (UMCG-MTB): outcome of patients with rare or complex mutational profiles receiving MTB-advised targeted therapy

PURPOSE

Molecular tumor boards (MTBs) are considered beneficial for treatment decision making for patients with cancer with uncommon, rare, or complex mutational profiles. The lack of international MTB guidelines results in significant variation in practices and recommendations. Therefore, periodic follow-up is necessary to assess and govern MTB functioning. The objective of this study was to determine the effectiveness of MTB treatment recommendations for patients with rare and complex mutational profiles as implemented in the MTB of the University Medical Center Groningen (UMCG-MTB) in 2019-2020.

PATIENTS AND METHODS

A retrospective follow-up study was carried out to determine the clinical outcome of patients with uncommon or rare (combinations of) molecular aberrations for whom targeted therapy was recommended as the next line of treatment by the UMCG-MTB in 2019 and 2020.

RESULTS

The UMCG-MTB recommended targeted therapy as the next line of treatment in 132 of 327 patients: 37 in clinical trials, 67 in the on-label setting, and 28 in the off-label setting. For on- and off-label treatment recommendations, congruence of recommended and received treatment was 85% in patients with available follow-up (67/79). Treatment with on-label therapy resulted in a response rate of 50% (21/42), a median progression-free survival (PFS) of 6.3 months [interquartile range (IQR) 2.9-14.9 months], and median overall survival (OS) of 15.8 months (IQR 6.4-34.2 months). Treatment with off-label therapy resulted in a response rate of 53% (8/15), a median PFS of 5.1 months (IQR 1.9-7.3 months), and a median OS of 17.7 months (IQR 5.1-23.7 months).

CONCLUSION

Treatment with MTB-recommended next-line targeted therapy for patients with often heavily pretreated cancer with rare and complex mutational profiles resulted in positive overall responses in over half of patients. Off-label use of targeted therapies, for which there is sufficient rationale as determined by an MTB, is an effective treatment strategy. This study underlines the relevance of discussing patients with rare and complex mutational profiles in an MTB.

[New biopsy at lung cancer progression: rational treatment of resistant lung cancer]

Nowadays, patients with advanced non-small cell lung cancer harbouring a driver mutation undergo targeted treatment. This results in profound tumour responses but inevitably induces resistance after approximately 9 to 12 months. In this article we consider the importance and clinical implications of taking new biopsies to retrieve information regarding resistance mechanisms. There is a shift in the use of other modalities such as radiotherapy and surgery in patients with oligometastatic disease, producing long-lasting responses. This is illustrated by three different patient cases: one with an EGFR exon 21 mutation, obtaining a T790M mutation upon treatment; another with a BRAF V600 mutation initially treated with chemotherapy and later with targeted therapy; and, finally, a patient with an ALK translocation with progression on crizotinib treatment, responding to subsequent alectinib therapy. The latter developed oligometastatic disease that was treated with radiotherapy, resulting in a complete response for at least 2 years.

Regional differences in predictive biomarker testing rates for patients with metastatic NSCLC in the Netherlands

BACKGROUND

Predictive biomarker testing has a key role in the treatment decision-making for patients with non-small cell lung cancer (NSCLC) and is mandated by (inter)national guidelines. The aim of this study was to establish guideline-adherent biomarker testing rates in the Netherlands in 2019 and to examine associations of demographical, clinical, and environmental factors with guideline-adherent testing.

METHODS

This study involved the integration of clinical data of the Netherlands Cancer Registry with pathology reports of the Dutch Nationwide Pathology Databank. Data extracted from these reports included sample type, diagnosis, and molecular testing status of predictive biomarkers. The study population comprised all patients diagnosed with metastatic non-squamous NSCLC in the Netherlands in 2019.

RESULTS

In the cohort of 3877 patients with metastatic non-squamous NSCLC under investigation, overall molecular testing rates for non-fusion predictive biomarkers (EGFR, KRAS, BRAF, ERBB2, MET) ranged from 73.9 to 89.0 %, while molecular testing for fusion-drivers (ALK, ROS1, RET, NTRK) ranged from 12.6 % to 63.9 %. Guideline-adherent testing of EGFR, KRAS, and ALK was performed in 85.2 % of patients, with regional rates spanning from 76.0 % to 90.8 %. Demographical and clinical factors associated with guideline-adherent biomarker testing included lower age (OR = 1.05 per one year decrease; p < 0.001), female sex (OR = 1.36; p = 0.002), diagnosis of adenocarcinoma (OR = 2.48; p < 0.001), availability of histological tumor material (OR = 2.46; p < 0.001), and clinical stage of metastatic disease (p = 0.002). Other factors associated with guideline-adherent biomarker testing included diagnosis at academic center (OR = 1.87; p = 0.002) and patient's region of residence (p < 0∙001).

CONCLUSION

Optimization of the chain-of-care of predictive biomarker testing in patients with NSCLC in the Netherlands is needed to provide adequate care for these patients.

The prediction of treatment outcome in NSCLC patients harboring an EGFR exon 20 mutation using molecular modeling

INTRODUCTION

The structural effect of uncommon heterogenous in-frame deletion and/or insertion mutations within exon 20 (EGFRex20+) in relation to therapy response is poorly understood. This study aims to elucidate the structural alterations caused by EGFRex20+ mutations and correlate these changes with patient responses.

MATERIAL AND METHOD

We selected EGFRex20+ mutations from advanced NSCLC patients in the Position20 and AFACET studies for computational analysis. Homology models representing both inactive and active conformations of these mutations were generated using the Swiss-Model server. Molecular docking studies with EGFR-TKIs was conducted using smina, followed by Molecular Dynamic (MD) simulations performed with GROMACS. These computational findings were compared with clinical outcomes to evaluate their potential in predicting patient response.

RESULTS

Our docking studies of 29 EGFRex20+ mutations revealed that the binding energies of afatinib, osimertinib, zipalertinib, and sunvozertinib, compared to the wild type, do not significantly impact either TKI's efficacy. MD simulations for eight EGFRex20+ mutations (A763_Y764insFQEA, A767_V769dup, S768_D770dup, D770_N771insG, D770_P772dup, N771_H773dup, H773_V774insY and H773_V774delinsLM) revealed varying degrees of instability. For six variants, predicted activation based on the αC-helix stability and orientation, as well as TKI sensitivity, aligned well with clinical observations from the Position20 and AFACET studies. Two mutations (D770_N771insG and N771_H773dup) predicted as poor to moderate responders, showed minimal activation of the αC-helix region, warranting further investigation.

CONCLUSION

In conclusion, MD simulations can effectively predict patient outcomes by connecting computational results with clinical data and advancing our understanding of EGFR mutations and their therapeutic responses.