Comparing the Effectiveness of Afatinib and Osimertinib for Patients With PD-L1-positive EGFR-mutant Non-small Cell Carcinoma.

Background/Aim: Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) are effective for treating non-small cell lung cancer (NSCLC) harboring EGFR mutations. However, higher tumor programmed death ligand-1 (PD-L1) expression is associated with a poor response to EGFR-TKIs, and information on the comparison between afatinib and osimertinib in PD-L1-positive EGFR-mutant NSCLC is scarce. Patients and Methods: We retrospectively analyzed data of patients with PD-L1-positive EGFR-mutant NSCLC to compare the effectiveness of afatinib and osimertinib. Results: A total of 177 patients were included in the study. The Cox proportion hazard model was adjusted for age, sex, performance status, EGFR mutation status, PD-L1 expression level, and brain metastasis, revealing that there was no significant difference in risk for progression [hazard ratio (HR)=0.99, 95% confidence interval (CI)=0.64-1.53] or death (HR=0.96, 95% CI=0.54-1.73) between afatinib and osimertinib. Conclusion: In conclusion, the EGFR-TKI treatment duration and overall survival after the treatment with afatinib or osimertinib were similar in patients with PD-L1-positive EGFR-mutant NSCLC in the present study.

Osimertinib in a patient with end-stage kidney disease not on hemodialysis.

Osimertinib is an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) effective in non- small cell lung cancer (NSCLC) with EGFR mutations. Since the drug is primally eliminated by the fecal route no dose adjustment is needed in patient with chronic-kidney disease (CKD); despite this there is limited data about its safety in cancer patients with end-stage renal disease (ESRD). Herein, we reported a case report of a 77-year-old woman, diagnosed in 2018 with lung adenocarcinoma EGFR mutated with lymph nodal and cerebral metastasis, who started Osimertinib 80 mg/day. She under- went 41 cycles of therapy with no Osimertinib interruptions, no severe toxicities and obtaining complete radiological response. We conclude that Osimertinib has an acceptable safety profile also in cancer patients with ESRD not undergoing hemodialysis (HD).

Radical resection in a patient with stage IIIA non-small cell lung cancer with the EGFR exon 19 deletion mutation after neoadjuvant targeted therapy with osimertinib: a case report.

Background: With the advent of targeted therapies, the survival rates of patients with locally advanced lung cancer have significantly improved. However, there is limited research on the efficacy of neoadjuvant targeted therapy in resectable advanced non-small cell lung cancer (NSCLC) patients with positive driver genes. This article reports a case of stage IIIA NSCLC with an epidermal growth factor receptor (EGFR) 19del mutation that successfully underwent radical lung cancer surgery following neoadjuvant targeted therapy. By observing the perioperative treatment outcomes and side effects in this patient, we aimed to provide insights and summarize experiences for treating similar cases in the future. Case Description: We report a case of a 54-year-old female diagnosed preoperatively with stage IIIA adenocarcinoma of the left upper lung (cT1cN2M0). The patient's course was complicated by acute sick sinus syndrome and was cured by implanting a permanent pacemaker. After multidisciplinary discussion, it was decided to administer neoadjuvant targeted therapy with osimertinib. Following 6 weeks of treatment, the tumor assessment showed partial response (PR), making the patient eligible for surgery. The patient underwent single-port thoracoscopic left upper lobectomy + mediastinal lymphadenectomy. Intraoperatively, the left hilar lymph nodes were found to be tightly adherent to the apical-anterior branch of the left upper pulmonary artery. The main trunk of the left pulmonary artery was temporarily occluded with a vascular clamp to safely dissect the left upper pulmonary artery. The procedure was completed without conversion to open thoracotomy, achieving an R0 resection. Postoperative pathology confirmed stage IIIA (ypT1bN2M0), and the patient continued adjuvant therapy with osimertinib. Conclusions: Neoadjuvant targeted therapy with osimertinib is expected to become one of the options for neoadjuvant therapy in locally advanced NSCLC with sensitizing EGFR mutations. And for those with advanced lung cancer involving tumors close to the hilum or mediastinal lymph node metastasis, preblocking of the left upper pulmonary artery can help improve surgical safety and better ensure R0 resection.

First-line Osimertinib for Lung Cancer With Uncommon EGFR Exon 19 Mutations and EGFR Compound Mutations.

Introduction: Up to 20% of EGFR-mutated NSCLC cases harbor uncommon EGFR mutations, including atypical exon 19 and compound mutations. Relatively little is known about the efficacy of osimertinib in these cases. Methods: Patients treated with first-line osimertinib for NSCLC with rare EGFR exon 19 (non E746_A750del) or compound mutations were included. Response assessment and time to progression were determined using Response Evaluation Criteria in Solid Tumors version 1.1 criteria. Kaplan-Meier analyses were used to estimate progression-free survival (PFS), time to treatment discontinuation (TTD), and overall survival (OS). Results: Thirty-seven patients with NSCLC harboring an atypical EGFR exon 19 mutation or compound mutation were treated with first-line osimertinib at Johns Hopkins from 2016 to 2021. Overall response rate (ORR) was 76% and median PFS, TTD, and OS were 13 months (95% confidence interval [CI]: 10-15), 22 months (95% CI: 17-32) and 36 months (95% CI, 29-48), respectively. Among atypical exon 19 mutations (n = 25), ORR was 80%, median PFS was 12 months (95% CI: 10-15), median TTD was 19 months (95% CI: 17-38), and median OS was 48 months (95% CI: 25-not reached). Compound mutations (n = 12) had an ORR of 67%, median PFS of 14 months (95% CI: 5-22), median TTD of 26 months (95% CI: 5-36), and median OS of 36 months (95% CI: 20-46). Twelve patients (32%) continued first-line osimertinib after local therapy for oligoprogression. Conclusions: Osimertinib exhibited favorable outcomes for rare EGFR exon 19 and compound mutations. The heterogeneity in outcomes among these groups of tumors with similar mutations underscores the need for continued reporting and further study of outcomes among rare variants to optimize management for each patient.

Subdural hematoma due to skull base bone metastasis of epidermal growth factor receptor mutated non-small cell lung cancer.

Subdural hematoma due to skull base bone metastasis of lung cancer is rare but are oncological emergency, necessitating prompt identification when a headache develops with the progression of the malignancy.

A phase II study of osimertinib in patients with NSCLC harboring EGFR exon 20 insertion: A multicenter trial of the Korean Cancer Study Group (LU17-19).

BACKGROUND: Epidermal growth factor receptor (EGFR) exon 20 insertions account for up to 10% of all EGFR mutations. Clinical outcomes in patients receiving approved EGFR exon 20 insertion-specific inhibitors have been variable. Although osimertinib has demonstrated antitumor activity in clinical trials, its clinical efficacy and translational potential remain to be determined in non-small cell lung carcinoma (NSCLC) with EGFR exon 20 insertion. METHODS: In this multicenter phase II study, patients with advanced NSCLC harboring EGFR exon 20 insertions for whom the standard chemotherapy failed received 80 mg osimertinib once daily. The primary endpoint was the investigator-assessed objective response rate (ORR) as defined by Response Evaluation Criteria in Solid Tumors version 1.1. The secondary endpoints were progression-free survival (PFS), overall survival (OS), and safety profile. RESULTS: Among 15 patients enrolled at stage 1, the best response was most commonly disease stabilization (73.3 %), which did not meet the stage 1 threshold (objective response ≥ 2/15). As of data cutoff, two patients remained on the treatment. The median PFS and OS were 3.8 (95 % confidence interval [CI] = 1.7-5.5) months and 6.5 (95 % CI = 3.9-not reached) months, respectively. Adverse events (≥grade 3) were anemia, hypercalcemia, and pneumonia (13.3 % each), and asthenia, femur fracture, increased alkaline phosphate, hyperkalemia, bone pain, and azotemia (6.7 % each). Pre-existing EGFR C797S mutation detected in plasma limited the efficacy of osimertinib. CONCLUSION: Osimertinib at 80 mg once daily had limited efficacy and mostly showed disease stabilization with an acceptable safety profile in advanced NSCLC harboring EGFR exon 20 insertions. CLINICALTRIALS: govIdentifier: NCT03414814.

Durable Response of Pembrolizmab for EGFR Mutation-positive Lung Adenocarcinoma with Early Progression to Osimertinib in First-line Treatment.

Osimertinib, a third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), is the standard first-line treatment for EGFR mutation-positive non-small-cell lung cancer (NSCLC) and demonstrates favorable disease control. Conversely, immune checkpoint inhibitors (ICIs) that target programmed cell death-1/programmed cell death ligands demonstrate a restrictive tumor response. We herein report a patient who achieved a durable response to pembrolizumab following early progression within two months of osimertinib administration for EGFR mutation-positive lung adenocarcinoma. Our findings suggest that treatment with ICIs for patients with EGFR mutation-positive NSCLC experiencing early progression to osimertinib as first-line treatment might represent a viable approach.

Transcriptomic Analysis Reveals Early Alterations Associated with Intrinsic Resistance to Targeted Therapy in Lung Adenocarcinoma Cell Lines.

Lung adenocarcinoma is the most prevalent form of lung cancer, and drug resistance poses a significant obstacle in its treatment. This study aimed to investigate the overexpression of long non-coding RNAs (lncRNAs) as a mechanism that promotes intrinsic resistance in tumor cells from the onset of treatment. Drug-tolerant persister (DTP) cells are a subset of cancer cells that survive and proliferate after exposure to therapeutic drugs, making them an essential object of study in cancer treatment. The molecular mechanisms underlying DTP cell survival are not fully understood; however, long non-coding RNAs (lncRNAs) have been proposed to play a crucial role. DTP cells from lung adenocarcinoma cell lines were obtained after single exposure to tyrosine kinase inhibitors (TKIs; erlotinib or osimertinib). After establishing DTP cells, RNA sequencing was performed to investigate the differential expression of the lncRNAs. Some lncRNAs and one mRNA were overexpressed in DTP cells. The clinical relevance of lncRNAs was evaluated in a cohort of patients with lung adenocarcinoma from The Cancer Genome Atlas (TCGA). RT-qPCR validated the overexpression of lncRNAs and mRNA in the residual DTP cells and LUAD biopsies. Knockdown of these lncRNAs increases the sensitivity of DTP cells to therapeutic drugs. This study provides an opportunity to investigate the involvement of lncRNAs in the genetic and epigenetic mechanisms that underlie intrinsic resistance. The identified lncRNAs and CD74 mRNA may serve as potential prognostic markers or therapeutic targets to improve the overall survival (OS) of patients with lung cancer.

Targeting Transient Receptor Potential Melastatin-2 (TRPM2) Enhances Therapeutic Efficacy of Third Generation EGFR Inhibitors against EGFR Mutant Lung Cancer.

There is an urgent need to fully understand the biology of third generation EGFR-tyrosine kinase inhibitors (EGFR-TKIs), particularly osimertinib, and to develop mechanism-driven strategies to manage their acquired resistance. Transient receptor potential melastatin-2 (TRPM2) functions as an important regulator of Ca2+ influx, but its role in mediating therapeutic efficacies of EGFR-TKIs and acquired resistance to EGFR-TKIs has been rarely studied. This study has demonstrated a previously undiscovered role of suppression of TRPM2 and subsequent inhibition of Ca2+ influx and induction of ROS and DNA damage in mediating apoptosis induction and the therapeutic efficacy of osimertinib against EGFR mutant NSCLC. The rebound elevation represents a key mechanism accounting for the emergence of acquired resistance to osimertinib and other third generation EGFR-TKIs. Accordingly, targeting TRPM2 is a potentially promising strategy for overcoming and preventing acquired resistance to osimertinib, warranting further study in this direction including the development of cancer therapy-optimized TRPM2 inhibitors.

Inhibition of NNMT enhances drug sensitivity in lung cancer cells through mediation of autophagy.

Introduction: This study aimed to investigate the role of Nicotinamide N-methyltransferase (NNMT) in the drug sensitivity of non-small cell lung cancer (NSCLC) cells, with a focus on its impact on autophagy and resistance to the chemotherapeutic agent osimertinib. The study hypothesized that NNMT knockdown would enhance drug sensitivity by modifying autophagic processes, providing a potential new therapeutic target for overcoming chemoresistance in lung cancer. Methods: Proteomic analysis was utilized to identify changes in protein expression following NNMT knockdown in H1975 and H1975 osimertinib resistance (H1975OR) lung cancer cell lines. Gene expression patterns and their correlation with NNMT expression in lung cancer patients were analyzed using The Cancer Genome Atlas (TCGA) dataset. Additionally, a predictive model for lung cancer survival was developed via lasso regression analysis based on NNMT-associated gene expression. Drug sensitivity was assessed using the IC50 values and apoptosis ratio, and autophagy was evaluated through Western blot and flow cytometric analysis. Results: Significant variations in the expression of 1,182 proteins were observed following NNMT knockdown, with a significant association with autophagy-related genes. Analysis of gene expression patterns unveiled a significant correlation between NNMT expression and specific changes in gene expression in lung cancer. The predictive model successfully forecasted lung cancer patient survival outcomes, highlighting the potential of NNMT-associated genes in predicting patient survival. Knockdown of NNMT reversed osimertinib resistance in H1975 cells, as evidenced by altered IC50 values and apoptosis ratio, and changes were observed in autophagy markers. Discussion: Knockdown of NNMT in lung cancer cells enhances drug sensitivity by modulating autophagy, providing a promising therapeutic target to overcome chemoresistance in NSCLC. The study underscores the importance of NNMT in lung cancer pathology and underscores its potential as a predictive marker for clinical outcomes. Additionally, the developed predictive model further supports the clinical relevance of NNMT-associated gene expression in improving the prognosis of lung cancer patients.

Cancer-associated fibroblast-derived colony-stimulating factor 2 confers acquired osimertinib resistance in lung adenocarcinoma via promoting ribosome biosynthesis.

Acquired resistance is a major obstacle to the therapeutic efficacy of osimertinib in lung adenocarcinoma (LUAD), but the underlying mechanisms are still not fully understood. Cancer-associated fibroblasts (CAFs) are the most abundant stromal cell type in LUAD tumor-microenvironment (TME) and have emerged as a key player in chemoresistance. However, the function of CAFs in osimertinib resistance is still unclear. Here, we showed that CAFs derived from osimertinib-resistant LUAD tissues (CAFOR) produced much more colony-stimulating factor 2 (CSF2) than those isolated from osimertinib-sensitive tissues. CAFOR-derived CSF2 activated the Janus kinase 2 (JAK2)/Signal transducer and activator of transcription 3 (STAT3) signaling pathway and upregulated lnc-CSRNP3 in LUAD cells. Lnc-CSRNP3 then promoted the expression of nearby gene CSRNP3 by recruiting chromodomain helicase DNA binding protein 9 (CHD9) and inhibited the phosphatase activity of the serine/threonine protein phosphatase 1 catalytic subunit α (PP1α), thereby induced osimertinib resistance by enhancing ribosome biogenesis. Collectively, our study reveals a critical role for CAFs in the development of osimertinib resistance and identifies the CSF2 pathway as an attractive target for monitoring osimertinib efficacy and overcoming osimertinib resistance in LUAD.

Synergistic Anti-Tumor Efficacy Achieved by Reversing Drug Resistance through the Regulation of the Tumor Immune Microenvironment with IL-12 and Osimertinib Combination Therapy.

The objective of this study was to investigate the role of IL-12 in enhancing the anti-tumor efficacy of the small molecule targeted drug osimertinib in resistant tumor models and reversing resistance mechanisms. We utilized paired non-small cell lung cancer H1975 tumor tissues, establishing mouse tumor models with diverse tumor immune microenvironments. Analytical methods including immunohistochemistry and immunofluorescence were employed to compare immune cell infiltration, cytokines, effector molecules, and protein changes in resistant signaling pathways in tumor tissues, shedding light on IL-12's mechanism of action in enhancing osimertinib efficacy and reversing resistance. Results showed that osimertinib monotherapy had limited tumor suppression, whereas IL-12 exhibited more significant anti-tumor effects. Combination therapy groups demonstrated even greater tumor suppression with increased immune cell infiltration, elevated immune-related factor secretion, reduced immunosuppressive MDSCs, and decreased resistance-related signaling pathway markers. In conclusion, IL-12 enhances anti-tumor efficacy and reverses osimertinib resistance through various mechanisms, including increased immune cell infiltration, reduced immunosuppressive MDSCs, enhanced immune cell granzyme and IFN-γ release, decreased PDL-1 expression, improved tumor microenvironment, restored immune surveillance, and heightened cancer cell sensitivity to osimertinib.

Real-World Treatment Patterns and Clinical Outcomes Among Patients with Metastatic or Unresectable EGFR-Mutated Non-Small Cell Lung Cancer Previously Treated with Osimertinib and Platinum-Based Chemotherapy.

INTRODUCTION: For patients with epidermal growth factor receptor-mutated (EGFRm) locally advanced/metastatic non-small cell lung cancer (mNSCLC) whose disease has progressed on or after osimertinib and platinum-based chemotherapy (PBC), no uniformly accepted standard of care exists. Moreover, limited efficacy of standard treatments indicates an unmet medical need, which is being addressed by ongoing clinical investigations, including the HERTHENA-Lung01 (NCT04619004) study of patritumab deruxtecan (HER3­DXd). However, because limited information is available on real-world clinical outcomes in such patients, early-phase trials of investigational therapies lack sufficient context for comparison. This study describes the real-world clinical characteristics, treatments, and outcomes for patients with EGFRm mNSCLC who initiated a new line of therapy following previous osimertinib and PBC, including a subset matched to the HERTHENA-Lung01 population. METHODS: This retrospective analysis used a US database derived from deidentified electronic health records. The reference cohort included patients with EGFRm mNSCLC who had initiated a new line of therapy between November 13, 2015 and June 30, 2021, following prior osimertinib and PBC. A subset of patients resembling the HERTHENA-Lung01 population was then extracted from the reference cohort; this matched subset was optimized using propensity score (PS) weighting. Endpoints were real-world overall survival (rwOS) and real-world progression-free survival (rwPFS). Confirmed real-world objective response rate (rwORR; partial/complete response confirmed ≥ 28 days later) was calculated for the response-evaluable subgroups of patients (with ≥ 2 response assessments spaced ≥ 28 days apart). RESULTS: In the reference cohort (N = 273), multiple treatment regimens were used, and none was predominant. Median rwPFS and rwOS were 3.3 and 8.6 months, respectively; confirmed rwORR (response evaluable, n = 123) was 13.0%. In the matched subset (n = 126), after PS weighting, median rwPFS and rwOS were 4.2 and 9.1 months, respectively; confirmed rwORR (response evaluable, n = 57) was 14.1%. CONCLUSION: The treatment landscape for this heavily pretreated population of patients with EGFRm mNSCLC is fragmented, with no uniformly accepted standard of care. A high unmet need exists for therapeutic options that provide meaningful improvements in clinical benefit.

Reduced frequency dosing of osimertinib in EGFR-mutant non-small cell lung carcinoma: real world data.

Introduction: Osimertinib is more efficacious and as safe as first-generation epidermal growth factor receptor (EGFR)-directed tyrosine kinase inhibitors. However, osimertinib is not affordable for most patients in developing nations. Moreover, the minimum biologically effective dose of osimertinib may be less than the approved dose. Materials and methods: This was a retrospective observational multicentric study aimed to describe the efficacy (objective response rate (ORR), disease control rate (DCR), progression free survival (PFS), overall survival (OS)) and toxicity of osimertinib 80 mg orally administered less frequently than daily (ranging from every other day to once-a-week) in patients with EGFR-mutated non-small cell lung cancer. Results: Between January 2021 and August 2023, we enrolled 22 patients. Six received osimertinib 80 mg once-a-week, nine received 80 mg once-in-3-days and seven received 80 mg on alternate days. Responses included 0 complete responses, 7 (31.8%) partial responses, 9 (40.9%) stable disease and 5 (22.7%) progressive disease. ORR was 31.8%, and DCR was 72.7%. Median PFS was 9.2 months (95% confidence interval (CI) 2.9-15.7), and median OS was 17.8 months (95% CI, 3.2-32.6). In patients who received reduced frequency osimertinib in the second line and beyond, the ORR was 29.4%, DCR was 70.5%, median PFS was 5.9 months (95% CI, 1.1-10.6) and median OS was 17.6 months (95% CI, 2.9-32.2). Grade 3 and higher toxicities were noted in 8 (36.3%) patients. Conclusion: Less frequent dosing of osimertinib may be a valid treatment option, especially in the second line and beyond setting in patients who cannot afford full dose daily osimertinib. This may provide an additional treatment option with a similar toxicity profile as that of standard dose osimertinib.

Expression of the non-coding RNA nc886 facilitates the development of tyrosine kinase inhibitor resistance in EGFR-mutated non-small-cell lung cancer cells.

Treatment of non-small-cell lung cancer (NSCLC) patients possessing EGFR-activating mutations with tyrosine kinase inhibitors (TKIs) can confer an initial promising response. However, TKI resistance inevitably arises. Numerous TKI resistance mechanisms are identified including EGFR secondary mutations, bypass receptor tyrosine kinase (RTK) signaling, and cellular transition e.g. epithelial-mesenchymal transition (EMT). To increase the knowledge of TKI resistance we performed an epigenetic screen to identify small non-coding (nc) genes with DNA methylation alterations in HCC827 NSCLC EGFR-mutated cells with acquired TKI resistance. We analyzed Infinium Methylation EPIC 850K Array data for DNA methylation changes present in both TKI-resistant HCC827 cells with EMT and MET-amplification. Hereby, we identified that the polymorphic maternal imprinted gene nc886 (vtRNA2-1) has a decrease in promoter DNA methylation in TKI-resistant cells. This epigenetic change was associated with an increase in the expression of nc886. The induction of EMT did not affect nc886 expression. CRISPR/Cas9-mediated distortion of the nc886 sequence increased the sensitivity of HCC827 cells towards TKI. Finally, nc886 sequence distortion hindered MET RTK activation and instead was EMT the endpoint TKI resistance mechanism. In conclusion, the expression of nc886 contributes to TKI resistance in the HCC827 NSCLC cell line by supporting cell survival and selection of the endpoint TKI resistance mechanism. We propose DNA methylation and expression changes for nc886 to constitute a novel TKI resistance contributing mechanism in NSCLC.

Longitudinal Analyses of Circulating-Tumor DNA for Detection of EGFR Mutation-Positive Advanced Non-Small Cell Lung Cancer Progression During Treatment: Data From FLAURA and AURA3.

INTRODUCTION: Epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI)-sensitizing and -resistance mutations may be detected in plasma via circulating tumor DNA (ctDNA). ctDNA level changes reflect alterations in tumor burden and could be a dynamic indicator of treatment effect. This analysis aimed to determine whether longitudinal EGFR-mutation ctDNA testing could detect progressive disease (PD) before radiologic detection. METHODS: This was a retrospective, exploratory ctDNA analysis in two phase 3 trials (FLAURA, NCT02296125; AURA3, NCT02151981). Patients had treatment-naïve (FLAURA) or EGFR-TKI pre-treated (AURA3) advanced non-small cell lung cancer (NSCLC) with EGFR mutations and on-study PD (RECIST), with a baseline ctDNA result and EGFR-mutation ctDNA monitoring beyond Cycle 3 Day 1. Patients received osimertinib versus comparator EGFR-TKIs (FLAURA) or chemotherapy (AURA3). Outcomes included time from ctDNA PD to RECIST PD, and to first subsequent treatment (FST; FLAURA only). RESULTS: ctDNA PD preceded/co-occurred with RECIST-defined PD in 93/146 (64%) patients in FLAURA and 82/146 (56%) in AURA3. Median time from ctDNA PD to RECIST-defined PD (months) was 3.4 and 2.6 in the osimertinib and comparator EGFR-TKI arms (FLAURA) and 2.8 and 1.5 in the osimertinib and chemotherapy arms (AURA3). In FLAURA, median time from ctDNA PD to FST (months) was 6.0 and 4.7 in the osimertinib (n = 51) and comparator EGFR-TKI arms (n = 70). CONCLUSIONS: Among patients with EGFR mutation-positive advanced NSCLC receiving EGFR-TKI or chemotherapy with ctDNA data and RECIST-defined PD, ctDNA PD preceded/co-occurred with RECIST-defined PD in approximately 60% of cases. Longitudinal ctDNA monitoring may detect PD before radiologic PD.

Spotlight on Patritumab Deruxtecan (HER3-DXd) from HERTHENA Lung01. Is a Median PFS of 5.5 Months Enough in Light of FLAURA-2 and MARIPOSA?

On December 22, 2023, the US Food and Drug Administration (FDA) approved the biologics license application for patritumab deruxtecan (HER3-DXd) for priority review. This treatment is aimed at adult patients with locally advanced or metastatic NSCLC with EGFR mutations, who have received at least two prior systemic therapies. Approval of patritumab deruxtecan would mark it as the first HER3 targeted therapy in the United States. This prioritization by the FDA is grounded in compelling results from the global Phase II HERTHENA-Lung01 trial, wherein HER3-DXd exhibited clinically meaningful efficacy, achieving a median progression-free survival (mPFS) of 5.5 months in patients with heavily treated EGFR-mutated NSCLC. A pivotal question remains: Is a mPFS of 5.5 months sufficient in the context of the evolving first-line landscape observed in the FLAURA-2 and MARIPOSA trials?

A non-enhancing, T2 fluid-attenuated inversion recovery hyperintense, diffusion-restricting brainstem lesion in an EGFR tyrosine kinase inhibitor-treated non-small-cell lung cancer patient.

Leptomeningeal metastasis (LM) is a devastating complication of malignancy. Diagnosis relies on both contrast enhancement on imaging and malignant cells in cerebral spinal fluid cytology. Though early detection and prompt intervention improves survival, the detection of LM is limited by false negatives. A rare brainstem imaging finding uncovered specifically in EGFR mutation-positive lung cancer patients may represent an early sign of LM. This sign demonstrates high signal on T2 fluid-attenuated inversion recovery and diffusion-weighted imaging sequences, but paradoxically lacks correlative contrast enhancement. Here we report a case of a 72-year-old female EGFR-positive lung cancer patient who developed this lesion following treatment with two first-generation EGFR tyrosine kinase inhibitors then showed subsequent response to osimertinib, an irreversible third-generation EGFR tyrosine kinase inhibitor.

A non-enhancing, T2 FLAIR hyperintense, diffusion-restricting brainstem lesion in an EGFR-positive lung cancer patient may represent an early indicator of leptomeningeal metastases.