Real-world osimertinib pretreatment experience in patients with epidermal growth factor receptor T790M mutation-positive locally advanced or metastatic non-small cell lung cancer.

Osimertinib has demonstrated efficacy in patients with epidermal growth factor receptor (EGFR) T790M-positive non-small cell lung cancer (NSCLC) in clinical trials. However, real-world data on its effectiveness remain scarce. Taiwanese patients with T790M-positive locally advanced or metastatic NSCLC and progressive disease following treatment with at least one EGFR tyrosine kinase inhibitor (TKI) were enrolled from the osimertinib early access program. Of the 419 patients (mean age, 63 years; female, 67%), 53% were heavily pretreated (≥ third-line [3L]), making osimertinib a fourth-line (4L) intervention. The median progression-free survival (PFS) was 10.5 months (95% confidence interval [CI]: 8.95-11.41); the 18-month PFS rate was 26.5%. The median overall survival (OS) was 19.0 months (95% CI: 16.30-20.95); the 24-month OS rate was 40.9%. The objective response rate was 32.46%, and the disease control rate was 86.38%. The median time to treatment discontinuation of osimertinib monotherapy was 11.9 months (95% CI: 10.49-13.11). Subgroup analyses of median PFS and OS in the chemotherapy combination group vs. the osimertinib monotherapy group yielded no difference. Central nervous system (CNS) metastasis, number of prior lines of therapy, and types of initial EGFR-TKIs did not significantly impact outcomes. The median PFS values were 9.0 (95% CI: 5.18-11.34) and 10.9 (95% CI: 9.18-11.90) months with and without CNS metastasis, respectively, and 10.8 (95% CI: 8.59-12.69), 13.6 (95% CI: 10.89-16.3), and 9.2 (95% CI: 7.8-10.62) months for second-line (2L), 3L, and ≥4L therapy, respectively. In patients who received osimertinib as 2L therapy, the median PFS values in response to prior afatinib, erlotinib and gefitinib treatment were 11.2 (95% CI: 4.85-4.79), 10.5 (95% CI: 8.59-20.26) and 8.7 (95% CI: 7.21-16.79) months, respectively. Overall, real-world data from Taiwan support the clinical benefits of osimertinib in EGFR T790M -positive NSCLC.

Ferritinophagy mediates adaptive resistance to EGFR tyrosine kinase inhibitors in non-small cell lung cancer.

Osimertinib (Osi) is a widely used epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI). However, the emergence of resistance is inevitable, partly due to the gradual evolution of adaptive resistant cells during initial treatment. Here, we find that Osi treatment rapidly triggers adaptive resistance in tumor cells. Metabolomics analysis reveals a significant enhancement of oxidative phosphorylation (OXPHOS) in Osi adaptive-resistant cells. Mechanically, Osi treatment induces an elevation of NCOA4, a key protein of ferritinophagy, which maintains the synthesis of iron-sulfur cluster (ISC) proteins of electron transport chain and OXPHOS. Additionally, active ISC protein synthesis in adaptive-resistant cells significantly increases the sensitivity to copper ions. Combining Osi with elesclomol, a copper ion ionophore, significantly increases the efficacy of Osi, with no additional toxicity. Altogether, this study reveals the mechanisms of NCOA4-mediated ferritinophagy in Osi adaptive resistance and introduces a promising new therapy of combining copper ionophores to improve its initial efficacy.

Real-World Analysis of Post-Progression Treatment Patterns and Outcomes for EGFR Mutation-Positive Patients Treated with First-Line Osimertinib.

Introduction: The use of osimertinib in the first-line (1L) setting is an effective treatment option for sensitizing EGFR-mutations (EGFRm+) and has significantly altered the standard of care practice for EGFRm+ disease in Canada. Unfortunately, acquired resistance to osimertinib is almost universal, and outcomes are disparate. Post-progression treatment patterns and the outcome of real-world Canadian EGFRm+ patients receiving 1L osimertinib were the focus of this retrospective review. Methods: The Glans-Look Lung Cancer Research database was used to identify and collect demographic, clinical, treatment, and outcome data on EGFRm+ patients who received 1L osimertinib in the Canadian province of Alberta between 2018 and 2022. Results: A total of 150 patients receiving 1L osimertinib were identified. In total, 86 developed progressive disease, with 56 (65%) continuing systemic therapy, 73% continuing osimertinib, and 27% switching to second-line (2L) systemic therapy. Patients were similar both in clinical characteristics at 1L osimertinib initiation and patterns of treatment failure at progression; those continuing 1L osimertinib post-progression had a longer time to progression (13.5 vs. 8.8 months, p = 0.05) and subsequent post-osimertinib initiation survival (34.7 vs. 22.8 months, p = 0.11). Conclusions: The continuation of osimertinib post-progression is an effective disease management strategy for select real-world EGFRm+ patients, providing continued clinical benefit, potentially due to different underlying disease pathogenesis.

Efficacy and safety of pyrotinib combined with albumin-bound paclitaxel as first-line treatment for HER2-positive metastatic breast cancer in patients previously treated with adjuvant and/or neoadjuvant trastuzumab therapy: The stage 1 results of a single-arm, phase 2 prospective clinical trial.

OBJECTIVE: It has been observed that the prognosis of patients with HER2-positive metastatic breast cancer has improved significantly with HER2-targeted agents. However, there is still a lack of evidence regarding first-line anti-HER2 treatment options for patients who have received adjuvant and/or neoadjuvant trastuzumab for HER2-positive metastatic breast cancer. Besides, there are no reliable markers that can predict the efficacy of anti-HER2 treatment in these patients. METHODS: Patients who have received adjuvant and/or neoadjuvant trastuzumab for HER2-positive metastatic breast cancer were enrolled. Pyrotinib plus albumin-bound paclitaxel were used as first-line treatment. The primary endpoint was the objective response rate (ORR). The safety profile was also assessed. In order to explore predictive biomarkers using Olink technology, blood samples were collected dynamically. RESULTS: From December 2019 to August 2023, the first stage of the study involved 27 eligible patients. It has not yet reached the median PFS despite the median follow-up being 17.8 months. Efficacy evaluation showed that the ORR was 92.6%, and the DCR was 100%. Adverse events of grade 3 or higher included diarrhoea (29.6%), leukopenia (11.1%), neutropenia (25.9%), oral mucositis (3.7%), and hand-foot syndrome (3.7%). Toll-like receptor 3 (TLR3) and Proto-oncogene tyrosine-protein kinase receptor (RET) were proteins with significant relevance to PFS in these patients. CONCLUSIONS: This study demonstrates that pyrotinib plus albumin-bound paclitaxel as a first-line treatment regimen shows good efficacy and manageable safety for patients who have received adjuvant and/or neoadjuvant trastuzumab for HER2-positive metastatic breast cancer. Besides, a significant association was identified between the expression levels of TLR3 and RET and the PFS in patients.

Efficacy of first-line dual oral pyrotinib plus capetabine therapy in HER2-positive metastatic breast cancer: A real-world retrospective study.

BACKGROUND: The combination of dual-targeted human epidermal growth factor receptor 2 (HER2) therapy and chemotherapy is the standard first-line regimen for recurrent/metastatic breast cancer (mBC). However, the toxicity of such combination therapy can lead to some patients being unable to tolerate adverse events or bear treatment costs. As a novel irreversible pan-ErbB receptor TKI (pyrotinib), can the dual oral administration of pyrotinib plus capetabine (PyroC) provide first-line survival benefits and serve as a more affordable treatment option? METHODS: This real-world retrospective study included patients diagnosed with HER2-positive mBC who received PyroC as a first-line treatment at West China Hospital between May 2018 and July 2023. The survival data and toxicity profiles were reported in this study. RESULTS: A total of 64 patients received PyroC as first-line therapy. The median progression-free survival (PFS) was 19.6 months (95% CI 15.0-27.2), while overall survival (OS) has not yet been reached. Kaplan-Meier analysis indicated that age (≥60, p = 0.03) and metastasis sites (p = 0.004) were related to poor efficacy of PyroC, while there was no relationship between effectiveness and menstrual status, hormone receptor (HR) status or previous treatment with anti-HER2 therapy. Furthermore, the objective response rate (ORR) and disease control rate (DCR) were 79.7% and 98.4%, respectively. Of the patients, 78.1% reported treatment-related adverse events (TRAEs). The predominant adverse events were diarrhea (n = 46, 71.9%) and hand-foot syndrome (n = 10, 15.6%). CONCLUSION: The dual oral administration regimen (PyroC) has a promising ORR or PFS in HER2-positive mBC patients, with an acceptable safety profile and convenience.

Capmatinib plus nivolumab in pretreated patients with EGFR wild-type advanced non-small cell lung cancer.

INTRODUCTION: Dysregulated MET is an established oncogenic driver in non-small cell lung cancer (NSCLC). MET signaling may also suppress anticancer immune responses. Concomitant MET inhibition with capmatinib (a MET inhibitor) synergistically enhanced the efficacy of immunotherapies in murine cancer models, regardless of tumor dependency to MET signaling. Here, we report results of a multicenter, open-label, phase 2 study of capmatinib plus nivolumab (a PD-1 inhibitor) in patients with EGFR wild-type advanced NSCLC, previously treated with platinum-based chemotherapy. METHODS: Patients were allocated into high-MET or low-MET groups according to MET expression determined by immunohistochemistry, MET gene copy number as assessed by fluorescence in-situ hybridization, and presence of MET exon 14 skipping mutation, then received capmatinib 400 mg, oral, twice daily in combination with nivolumab 3 mg/kg intravenously every 2 weeks. The primary endpoint was investigator-assessed 6-month progression-free survival (PFS) rate per RECIST v1.1. RESULTS: The primary endpoint was met in both the high-MET (N = 16) and low-MET (N = 30) groups. In the high-MET and low-MET groups, respectively, the estimated mean 6-month PFS rate (95 % credible interval) by Bayesian analysis was 68.9 % (48.5-85.7) and 50.9 % (35.6-66.4). The Kaplan-Meier median PFS (95 % CI) was 6.2 months (3.5-19.2) and 4.2 months (1.8-7.4). The overall response rate (95 % CI) was 25.0 % (7.3-52.4) and 16.7 % (5.6-34.7). Most frequent treatment-related adverse events (≥30 % any grade, N = 46) were nausea (52.2 %), peripheral edema (34.8 %), and increased blood creatinine (30.4 %). CONCLUSIONS: Capmatinib plus nivolumab showed clinical activity and manageable safety in pretreated patients with advanced EGFR wild-type NSCLC, independent of MET status. TRIAL REGISTRATION: ClinicalTrials.gov NCT02323126.

Osimertinib in combination with anti-angiogenesis therapy presents a promising option for osimertinib-resistant non-small cell lung cancer.

BACKGROUND: Osimertinib has become standard care for epidermal growth factor receptor (EGFR)-positive non-small cell lung cancer (NSCLC) patients whereas drug resistance remains inevitable. Now we recognize that the interactions between the tumor and the tumor microenvironment (TME) also account for drug resistance. Therefore, we provide a new sight into post-osimertinib management, focusing on the alteration of TME. METHODS: We conducted a retrospective study on the prognosis of different treatments after osimertinib resistance. Next, we carried out in vivo experiment to validate our findings using a humanized mouse model. Furthermore, we performed single-cell transcriptome sequencing (scRNA-seq) of tumor tissue from the above treatment groups to explore the mechanisms of TME changes. RESULTS: Totally 111 advanced NSCLC patients have been enrolled in the retrospective study. The median PFS was 9.84 months (95% CI 7.0-12.6 months) in the osimertinib plus anti-angiogenesis group, significantly longer than chemotherapy (P = 0.012) and osimertinib (P = 0.003). The median OS was 16.79 months (95% CI 14.97-18.61 months) in the osimertinib plus anti-angiogenesis group, significantly better than chemotherapy (P = 0.026), the chemotherapy plus osimertinib (P = 0.021), and the chemotherapy plus immunotherapy (P = 0.006). The efficacy of osimertinib plus anlotinib in the osimertinib-resistant engraft tumors (R-O+A) group was significantly more potent than the osimertinib (R-O) group (P<0.05) in vitro. The combinational therapy could significantly increase the infiltration of CD4+ T cells (P<0.05), CD25+CD4+ T cells (P<0.001), and PD-1+CD8+ T cells (P<0.05) compared to osimertinib. ScRNA-seq demonstrated that the number of CD8+ T and proliferation T cells increased, and TAM.mo was downregulated in the R-O+A group compared to the R-O group. Subtype study of T cells explained that the changes caused by combination treatment were mainly related to cytotoxic T cells. Subtype study of macrophages showed that proportion and functional changes in IL-1ß.mo and CCL18.mo might be responsible for rescue osimertinib resistance by combination therapy. CONCLUSIONS: In conclusion, osimertinib plus anlotinib could improve the prognosis of patients with a progressed disease on second-line osimertinib treatment, which may ascribe to increased T cell infiltration and TAM remodeling via VEGF-VEGFR blockage.

Genome-wide CRISPR screens identify the YAP/TEAD axis as a driver of persister cells in EGFR mutant lung cancer.

Most lung cancer patients with metastatic cancer eventually relapse with drug-resistant disease following treatment and EGFR mutant lung cancer is no exception. Genome-wide CRISPR screens, to either knock out or overexpress all protein-coding genes in cancer cell lines, revealed the landscape of pathways that cause resistance to the EGFR inhibitors osimertinib or gefitinib in EGFR mutant lung cancer. Among the most recurrent resistance genes were those that regulate the Hippo pathway. Following osimertinib treatment a subpopulation of cancer cells are able to survive and over time develop stable resistance. These 'persister' cells can exploit non-genetic (transcriptional) programs that enable cancer cells to survive drug treatment. Using genetic and pharmacologic tools we identified Hippo signalling as an important non-genetic mechanism of cell survival following osimertinib treatment. Further, we show that combinatorial targeting of the Hippo pathway and EGFR is highly effective in EGFR mutant lung cancer cells and patient-derived organoids, suggesting a new therapeutic strategy for EGFR mutant lung cancer patients.

Osimertinib plus local treatment for brain metastases versus osimertinib alone in patients with EGFR-Mutant Non-Small Cell Lung Cancer.

OBJECTIVES: Osimertinib is a standard treatment for patients with EGFR-mutant non-small cell lung cancer (NSCLC) and is highly effective for brain metastases (BMs). However, it is unclear whether local treatment (LT) for BMs prior to osimertinib administration improves survival in EGFR-mutant NSCLC. We aimed to reveal the survival benefit of upfront local treatment (LT) for BMs in patients treated with osimertinib. MATERIALS AND METHODS: This multicenter retrospective study included consecutive patients with EGFR mutation (19del or L858R)-positive NSCLC who had BMs before osimertinib initiation between August 2018 and October 2021. We compared overall survival (OS) and central nervous system progression-free survival (CNS-PFS) between patients who received upfront LT for BMs (the upfront LT group), and patients who received osimertinib only (the osimertinib-alone group). Inverse-probability treatment weighting (IPTW) analysis was performed to adjust for potential confounding factors. RESULTS: Of the 121 patients analyzed, 57 and 64 patients had 19del and L858R, respectively. Forty-five and 76 patients were included in the upfront LT group and the osimertinib-alone groups, respectively. IPTW-adjusted Kaplan-Meier curves showed that the OS of the upfront LT group was significantly longer than that of the osimertinib-alone group (median, 95 % confidence intervals [95 %CI]: Not reached [NR], NR-NR vs. 31.2, 21.7-33.2; p = 0.021). The hazard ratio (HR) for OS and CNS-PFS was 0.37 (95 %CI, 0.16-0.87) and 0.36 (95 %CI, 0.15-0.87), respectively. CONCLUSIONS: The OS and CNS-PFS of patients who received upfront LT for BMs followed by osimertinib were significantly longer than those of patients who received osimertinib alone. Upfront LT for BMs may be beneficial in patients with EGFR-mutant NSCLC treated with osimertinib.

Real-World Data on Subsequent Therapy for First-Line Osimertinib-Induced Pneumonitis: Safety of EGFR-TKI Rechallenge (Osi-risk Study TORG-TG2101).

BACKGROUND: Although osimertinib is a promising therapeutic agent for advanced epidermal growth factor receptor (EGFR) mutation-positive lung cancer, the incidence of pneumonitis is particularly high among Japanese patients receiving the drug. Furthermore, the safety and efficacy of subsequent anticancer treatments, including EGFR-tyrosine kinase inhibitor (TKI) rechallenge, which are to be administered after pneumonitis recovery, remain unclear. OBJECTIVE: This study investigated the safety of EGFR-TKI rechallenge in patients who experienced first-line osimertinib-induced pneumonitis, with a primary focus on recurrent pneumonitis. PATIENTS AND METHODS: We retrospectively reviewed the data of patients with EGFR mutation-positive lung cancer who developed initial pneumonitis following first-line osimertinib treatment across 34 institutions in Japan between August 2018 and September 2020. RESULTS: Among the 124 patients included, 68 (54.8%) patients underwent EGFR-TKI rechallenge. The recurrence rate of pneumonitis following EGFR-TKI rechallenge was 27% (95% confidence interval [CI] 17-39) at 12 months. The cumulative incidence of recurrent pneumonitis was significantly higher in the osimertinib group than in the first- and second-generation EGFR-TKI (conventional EGFR-TKI) groups (hazard ratio [HR] 3.1; 95% CI 1.3-7.5; p = 0.013). Multivariate analysis revealed a significant association between EGFR-TKI type (osimertinib or conventional EGFR-TKI) and pneumonitis recurrence, regardless of severity or status of initial pneumonitis (HR 3.29; 95% CI 1.12-9.68; p = 0.03). CONCLUSIONS: Osimertinib rechallenge after initial pneumonitis was associated with significantly higher recurrence rates than conventional EGFR-TKI rechallenge.

CircMYBL1 suppressed acquired resistance to osimertinib in non-small-cell lung cancer.

Circular RNAs (circRNAs) play an important role in the development of acquired resistance to many anticancer drugs. We developed the Non-Small-Cell Lung Cancer (NSCLC) cell lines with acquired resistance to osimertinib, a third-generation of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs), and evaluated the different expression profiles of circRNAs in osimertinib-sensitive and -resistant NSCLC cell lines using RNA sequencing (RNA-Seq). The expression of selected differentially expressed circRNAs was verified using quantitative real-time PCR (qRT-PCR) in paired osimertinib-sensitive and -resistant NSCLC cell lines, and in plasma samples of osimertinib-sensitive and -resistant NSCLC patients. We found that circMYBL1(has_circ_0136924) was downregulated after acquired resistance to osimertinib, inhibiting circMYBL1 expression facilitated the proliferation, migration, and invasion in osimertinib-sensitive NSCLC cells. CircMYBL1 may be a novel molecular biomarker and therapeutic target for osimertinib-resistant NSCLC.

Early Metabolic Response by PET Predicts Sensitivity to Next-Line Targeted Therapy in EGFR-Mutated Lung Cancer with Unknown Mechanism of Acquired Resistance.

Targeted therapy with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) has established the precision oncology paradigm in lung cancer. Most patients with EGFR-mutated lung cancer respond but eventually acquire resistance. Methods: Patients exhibiting the EGFR p.T790M resistance biomarker benefit from sequenced targeted therapy with osimertinib. We hypothesized that metabolic response as detected by 18F-FDG PET after short-course osimertinib identifies additional patients susceptible to sequenced therapy. Results: Fourteen patients with EGFR-mutated lung cancer and resistance to first- or second-generation EGFR TKI testing negatively for EGFR p.T790M were enrolled in a phase II study. Five patients (36%) achieved a metabolic 18F-FDG PET response and continued osimertinib. In those, the median duration of treatment was not reached (95% CI, 24 mo to not estimable), median progression-free survival was 18.7 mo (95% CI, 14.6 mo to not estimable), and median overall survival was 41.5 mo. Conclusion: Connecting theranostic osimertinib treatment with early metabolic response assessment by PET enables early identification of patients with unknown mechanisms of TKI resistance who derive dramatic clinical benefit from sequenced osimertinib. This defines a novel paradigm for personalization of targeted therapies in patients with lung cancer dependent on a tractable driver oncogene.

Targeting pyruvate dehydrogenase kinase 1 overcomes EGFR C797S mutation-driven osimertinib resistance in non-small cell lung cancer.

Osimertinib, a selective third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), effectively targets the EGFR T790M mutant in non-small cell lung cancer (NSCLC). However, the newly identified EGFR C797S mutation confers resistance to osimertinib. In this study, we explored the role of pyruvate dehydrogenase kinase 1 (PDK1) in osimertinib resistance. Patients exhibiting osimertinib resistance initially displayed elevated PDK1 expression. Osimertinib-resistant cell lines with the EGFR C797S mutation were established using A549, NCI-H292, PC-9, and NCI-H1975 NSCLC cells for both in vitro and in vivo investigations. These EGFR C797S mutant cells exhibited heightened phosphorylation of EGFR, leading to the activation of downstream oncogenic pathways. The EGFR C797S mutation appeared to increase PDK1-driven glycolysis through the EGFR/AKT/HIF-1α axis. Combining osimertinib with the PDK1 inhibitor leelamine helped successfully overcome osimertinib resistance in allograft models. CRISPR-mediated PDK1 knockout effectively inhibited tumor formation in xenograft models. Our study established a clear link between the EGFR C797S mutation and elevated PDK1 expression, opening new avenues for the discovery of targeted therapies and improving our understanding of the roles of EGFR mutations in cancer progression.

Furmonertinib and intrathecal pemetrexed chemotherapy rechallenges osimertinib-refractory leptomeningeal metastasis in a non-small cell lung cancer patient harboring EGFR20 R776S, C797S, and EGFR21 L858R compound EGFR mutations: a case report.

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are considered the first-line treatment for advanced or metastatic non-small cell lung cancer (NSCLC) patients harboring EGFR mutations. However, due to the rarity of cases, the response of EGFR-TKIs in patients harboring uncommon compound EGFR mutations still needs to be determined. Here, we demonstrated the case of a 47-year-old smoker diagnosed with leptomeningeal metastasis from NSCLC and had EGFR20 R776S, C797S, and EGFR21 L858R compound mutations. He was treated with furmonertinib combined with intrathecal pemetrexed chemotherapy following progression on osimertinib, which led to clinical improvement and successfully prolonged his survival by 3 months. Regrettably, the patient eventually died from heart disease. This report provides the first reported evidence for the use of furmonertinib and intrathecal pemetrexed chemotherapy in NSCLC patients harboring EGFR R776S/C797S/L858R mutations who progressed on previous EGFR-TKIs.

Peficitinib alleviated acute lung injury by blocking glycolysis through JAK3/STAT3 pathway.

Peficitinib is a selective Janus kinase (JAK3) inhibitor recently developed and approved for the treatment of rheumatoid arthritis in Japan. Glycolysis in macrophages could induce NOD-like receptor (NLR) family and pyrin domain-containing protein 3 (NLRP3) inflammasome activation, thus resulting in pyroptosis and acute lung injury (ALI). The aim of our study was to investigate whether Peficitinib could alleviate lipopolysaccharide (LPS)-induced ALI by inhibiting NLRP3 inflammasome activation. Wild type C57BL/6J mice were intraperitoneally injected with Peficitinib (5 or 10 mg·kg-1·day-1) for 7 consecutive days before LPS injection. The results showed that Peficitinib pretreatment significantly relieved LPS-induced pulmonary edema, inflammation, and apoptosis. NLRP3 inflammasome and glycolysis in murine lung tissues challenged with LPS were also blocked by Peficitinib. Furthermore, we found that the activation of JAK3/signal transducer and activator of transcription 3 (STAT3) was also suppressed by Peficitinib in mice with ALI. However, in Jak3 knockout mice, Peficitinib did not show obvious protective effects after LPS injection. In vitro experiments further showed that Jak3 overexpression completely abolished Peficitinib-elicited inhibitory effects on pyroptosis and glycolysis in LPS-induced RAW264.7 macrophages. Finally, we unveiled that LPS-induced activation of JAK3/STAT3 was mediated by toll-like receptor 4 (TLR4) in RAW264.7 macrophages. Collectively, our study proved that Peficitinib could protect against ALI by blocking JAK3-mediated glycolysis and pyroptosis in macrophages, which may serve as a promising candidate against ALI in the future.

Delayed cardiotoxicity following osimertinib therapy in non-small cell lung cancer: a unique case report.

This case report features a 62-year-old male with stage IB lung adenocarcinoma harboring an epidermal growth factor receptor exon 19 deletion, who underwent treatment with osimertinib following a left upper lobectomy and lymph node dissection. Despite a history of smoking and well-managed type 2 diabetes, the patient developed heart failure 18 months post-initiation of osimertinib therapy, marking one of the latest occurrences of heart failure following osimertinib treatment documented in limited literature. Cardiac MRI revealed significant left ventricular enlargement, lateral wall myocardial thinning, and localized myocardial fibrosis without perfusion defects, a finding not previously reported in literature. This case underscores the severe and unusual cardiac effects of osimertinib in patients with latent risk factors, highlighting the importance of vigilant cardiac monitoring and a multidisciplinary management approach.