Afatinib plus PEM and CBDCA overcome osimertinib resistance in EGFR-mutated NSCLC with high thrombospondin-1 expression.

Osimertinib induces a marked response in non-small-cell lung cancer (NSCLC) patients harboring epidermal growth factor receptor (EGFR) gene mutations. However, acquired resistance to osimertinib remains an inevitable problem. In this study, we aimed to investigate osimertinib-resistant mechanisms and evaluate the combination therapy of afatinib and chemotherapy. We established osimertinib-resistant cell lines (PC-9-OR and H1975-OR) from EGFR-mutant lung adenocarcinoma cell lines PC-9 and H1975 by high exposure and stepwise method. Combination therapy of afatinib plus carboplatin (CBDCA) and pemetrexed (PEM) was effective in both parental and osimertinib-resistant cells. We found that expression of thrombospondin-1 (TSP-1) was upregulated in resistant cells using cDNA microarray analysis. We demonstrated that TSP-1 increases the expression of matrix metalloproteinases through integrin signaling and promotes tumor invasion in both PC-9-OR and H1975-OR, and that epithelial-to-mesenchymal transition (EMT) was involved in H1975-OR. Afatinib plus CBDCA and PEM reversed TSP-1-induced invasion ability and EMT changes in resistant cells. In PC-9-OR xenograft mouse models (five female Balb/c-Nude mice in each group), combination therapy strongly inhibited tumor growth compared with afatinib monotherapy (5 mg/kg, orally, five times per week) or CBDCA (75 mg/kg, intraperitoneally, one time per week) + PEM (100 mg/kg, intraperitoneally, one time per week) over a 28-day period. These results suggest that the combination of afatinib plus CBDCA and PEM, which effectively suppresses TSP-1 expression, may be a promising option in EGFR-mutated NSCLC patients after the acquisition of osimertinib resistance.

Induction of resistance to neurotrophic tropomyosin-receptor kinase inhibitors by HMGCS2 via a mevalonate pathway.

INTRODUCTION: A neurotrophic tropomyosin receptor kinase (NTRK)-tyrosine kinase inhibitor (TKI) has shown dramatic efficacy against malignant tumors harboring an NTRK fusion gene. However, almost all tumors eventually acquire resistance to NTRK-TKIs. METHOD: To investigate the mechanism of resistance to NTRK-TKIs, we established cells resistant to three types of NTRK-TKIs (larotrectinib, entrectinib, and selitrectinib) using KM12 colon cancer cells with a TPM3-NTRK1 rearrangement. RESULT: Overexpression of 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2) was observed in three resistant cells (KM12-LR, KM12-ER, and KM12-SR) by microarray analysis. Lower expression of sterol regulatory element-binding protein 2 (SREBP2) and peroxisome proliferator activated receptor α (PPARα) was found in two cells (KM12-ER and KM12-SR) in which HMGCS2 was overexpressed compared to the parental KM12 and KM12-LR cells. In resistant cells, knockdown of HMGCS2 using small interfering RNA improved the sensitivity to NTRK-TKI. Further treatment with mevalonolactone after HMGCS2 knockdown reintroduced the NTRK-TKI resistance. In addition, simvastatin and silibinin had a synergistic effect with NTRK-TKIs in resistant cells, and delayed tolerance was observed after sustained exposure to clinical concentrations of NTRK-TKI and simvastatin in KM12 cells. In xenograft mouse models, combination treatment with entrectinib and simvastatin reduced resistant tumor growth compared with entrectinib alone. CONCLUSION: These results suggest that HMGCS2 overexpression induces resistance to NTRK-TKIs via the mevalonate pathway in colon cancer cells. Statin inhibition of the mevalonate pathway may be useful for overcoming this mechanistic resistance.

Phosphoproteomic Analysis Identified Mutual Phosphorylation of FAK and Src as a Mechanism of Osimertinib Resistance in EGFR-Mutant Lung Cancer.

Introduction: Osimertinib is a standard treatment for patients with EGFR-mutant NSCLC. Although some osimertinib resistance mechanisms have been identified, nearly 50% of the mechanisms remain to be elucidated. This study was aimed at identifying non-genetic mechanisms underlying osimertinib resistance. Methods: We established two osimertinib-resistant cell lines from EGFR mutation-positive PC-9 and HCC827 NSCLC cell lines (PC-9OR and HCC827OR, respectively) using a stepwise method. We compared the phosphoproteomic profiles of the osimertinib-resistant and parental cells using mass spectrometry. Upstream kinases were identified using the application Kinase Enrichment Analysis version 3. Results: Phosphoproteomic analysis revealed 80 phosphorylation sites that were mutually up-regulated in PC-9OR and HCC827OR cells. The Kinase Enrichment Analysis version 3 analysis identified focal adhesion kinase (FAK) and proto-oncogene tyrosine-protein kinase Src (Src) as upstream kinases of these up-regulated phosphoproteins. The small-interfering RNA-mediated knockdown of FAK reduced Src phosphorylation and that of Src reduced FAK phosphorylation in both cell lines. Furthermore, FAK- or Src-specific small-interfering RNA treatments restored EGFR phosphorylation in PC-9OR and HCC827OR cells. The combination of FAK and Src inhibitors inhibited PC-9OR and HCC827OR cell proliferation in vitro and suppressed tumor growth in a xenograft mouse model. Immunohistochemistry of tumors from patients with EGFR-mutant NSCLC suggested that phosphorylated FAK and Src are involved in initial and acquired resistance to osimertinib. Conclusions: Phosphoproteomic analysis may help elucidate the mechanisms of resistance to molecular-targeted therapies in lung cancer. Mutual phosphorylation of FAK and Src is involved in osimertinib resistance. Thus, FAK and Src inhibition may be novel treatment strategies for osimertinib-resistant NSCLC.

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.

Phase II Study of Durvalumab Immediately after Completion of Chemoradiotherapy in Unresectable Stage III Non-small Cell Lung Cancer: TORG1937 (DATE Study).

PURPOSE: Concurrent chemoradiotherapy (CCRT) followed by durvalumab consolidation for up to 12 months is the standard of care for patients with unresectable stage III non-small cell lung cancer (NSCLC). However, exactly when to initiate durvalumab therapy after chemoradiation completion remains unknown. We evaluated the efficacy and safety of durvalumab, administered immediately after CCRT completion, for patients with unresectable stage III NSCLC. PATIENTS AND METHODS: This study was a prospective, single-arm, open-label phase II clinical trial. Patients without disease progression after definitive CCRT (two cycles of platinum-based doublet chemotherapy with 60 Gy/30 Fr radiotherapy) received durvalumab (every 2 weeks for up to 12 months) from the next day (up to 5 days) after the final radiation dose. The primary endpoint was the 1-year progression-free survival (PFS) from registration before the start of CCRT. RESULTS: From January 2020 to August 2020, 47 of 50 enrolled patients were evaluable for treatment efficacy and safety. The 1-year PFS from registration was 75.0% [60% confidence interval (CI), 69.0-80.0 and 95% CI, 59.4-85.3]. The objective response rate throughout the study treatment and median PFS from registration were 78.7% and 14.2 months (95% CI, 13.4 to not reached), respectively. Grade 3/4 pneumonitis and febrile neutropenia were each 4.3%. CONCLUSIONS: Our study met the primary endpoint. The incidence of pneumonitis was similar to that of a Japanese subset in the PACIFIC study. Our data support the efficacy and safety of durvalumab administered immediately after the completion of CCRT for patients with unresectable stage III NSCLC.

A Phase â ¡ Study of Ubenimex Combined With Pembrolizumab, Nab-Paclitaxel, and Carboplatin for Previously Untreated Advanced Squamous Non-Small-Cell Lung Cancer: TORG2241 (UBE-Q).

BACKGROUND: According to the results of the KEYNOTE-407 trial, pembrolizumab plus platinum-based chemotherapy is the standard of care for patients with previously untreated advanced squamous non-small-cell lung cancer (NSCLC). Ubenimex, a potent aminopeptidase inhibitor, is an oral drug with immunostimulatory and antitumor activities. We aim to assess the safety and efficacy of ubenimex in combination with pembrolizumab, nab-paclitaxel, and carboplatin in patients with previously untreated advanced squamous NSCLC. PATIENTS AND METHODS: This prospective, single-arm, multicenter, phase II clinical trial is conducted to confirm the tolerability and efficacy of the tested drugs. Patients with previously untreated advanced squamous NSCLC will receive a predetermined daily dose of ubenimex orally plus 4 cycles of pembrolizumab, nab-paclitaxel, and carboplatin, followed by continuous administration of ubenimex and pembrolizumab for a maximum of 2 years. To confirm tolerability, the daily dose of ubenimex will begin at level 1 (30 mg), which will be increased to levels 2 (60 mg) and 3 (120 mg) according to the escalation criteria, with a standard 3 + 3 design for achieving the target dose-limiting toxicity rate of 33%. The efficacy, safety, and tolerability of ubenimex at the determined dose level will be analyzed. The primary endpoint of the efficacy evaluation will be the objective response rate assessed by an independent review committee. CONCLUSIONS: This is the first study to evaluate the efficacy and safety of ubenimex combined with pembrolizumab, nab-paclitaxel, and carboplatin in patients with previously untreated advanced squamous NSCLC. The results will help devise future treatment strategies.

Osimertinib early dose reduction as a risk to brain metastasis control in EGFR-mutant non-small cell lung cancer.

BACKGROUND: The epidermal growth factor receptor (EGFR) mutation is a risk factor associated with brain metastases (BMs) in patients with non-small cell lung cancer (NSCLC). This study aimed to evaluate the impact of osimertinib early dose reduction on BM worsening. METHODS: We retrospectively analyzed EGFR-mutant NSCLC patients treated with osimertinib as first-line treatment between August 2018 and October 2021. To evaluate the impact of osimertinib early dose reduction, we performed a landmark analysis of patients who achieved disease control at 4 months. Patients were divided into two groups according to whether the osimertinib dose was reduced or not, within 4 months after the start of treatment. We evaluated the time to BMs onset or progression, progression-free survival, and overall survival. RESULTS: In total, 62 NSCLC patients with EGFR mutations were analyzed. Thirteen patients experienced early dose reduction of osimertinib treatment. Seven patients received osimertinib 40 mg daily, and six received 80 mg every other day. The most common reason for dose reduction was gastrointestinal toxicity (n = 4), followed by skin rashes (n = 3). The time to BMs onset or progression was significantly shorter in patients who experienced early dose reduction than in those who continued regular treatment (Hazard ratio 4.47, 95% confidence interval, 1.52-13.11). The 1-year cumulative incidence of BM onset or progression was 23.1% in the reduced-dose group and 5.0% in the standard dose group. The risk of worsening BMs with early dose reduction of osimertinib treatment was higher in patients who had BMs before treatment and in younger patients. CONCLUSION: Early dose reduction of osimertinib was a risk factor for the worsening of BMs. A higher risk was associated with younger patients and those presenting BMs before treatment.

Remarkable Clinical Response of ALK-Rearranged/TP53-Mutant Lung Adenocarcinoma with Liver Metastasis to Atezolizumab-Bevacizumab-Carboplatin-Paclitaxel After ALK Inhibitors: A Case Report.

Anaplastic lymphoma kinase-positive (ALK-positive) lung adenocarcinoma with multiple liver metastases accounts for a relatively small number of cases of non-small cell lung cancer. Several ALK-tyrosine kinase inhibitors (ALK-TKIs) are available for the treatment of lung cancer. However, there is limited evidence on the treatment of multiple liver metastases in patients with lung cancer that are refractory to ALK-TKIs. We report the case of a 42-year-old male patient with ALK-positive lung adenocarcinoma who experienced rapid progression to multiple liver metastases while receiving treatment with alectinib. Biopsy of the liver metastases revealed echinoderm microtubule-associated protein-like 4-ALK (EML4-ALK) fusion and tumor protein p53 (TP53) mutation; notably, ALK secondary mutations were not detected. Despite the sequential administration of third-generation ALK-TKIs, the liver metastases did not respond, the serum levels of total bilirubin and biliary enzymes continued to increase, and the patient's general appearance worsened. Finally, the patient exhibited a remarkable clinical response to treatment with a combination of atezolizumab, bevacizumab, carboplatin, and paclitaxel (ABCP). ABCP is one of the optimal options for ALK-positive lung cancer with liver metastasis that is refractory to ALK-TKIs therapy.

Lower optimal dose of amrubicin for relapsed small-cell lung cancer: a retrospective study.

BACKGROUND: Amrubicin (AMR) is one of the most active agents for small-cell lung cancer (SCLC). However, hematologic toxicity and infection at a commonly used dose (40 mg/m2) is problematic; the optimal dose remains undetermined. PATIENTS AND METHODS: To evaluate the optimal dose of AMR in terms of efficacy and safety, we reviewed consecutive data on patients with relapsed SCLC who received AMR at doses of 40, 35, and 30 mg/m2 (on days 1-3) at Nippon Medical School Hospital between October 2010 and November 2021. RESULTS: We reviewed the data of 86 patients (20, 45, 27 who received AMR doses of 40, 35, 30 mg/m2, respectively) according to our study criteria. For patients ≥ 75 years, the proportion who received second-line treatment tended to be higher in the 30-35 mg/m2 group. Objective response rates were 37/46/35%, median progression-free survival (PFS) were 3.0/4.7/3.2 months, and median overall survival (OS) were 7.8/16.3/8.0 months, respectively. Grade 4 neutropenia occurred in 58/39/31% of patients, which was higher for the 40 mg/m2 group. The incidence of febrile neutropenia did not differ between groups. Multivariate analysis identified the AMR dose was not associated with longer PFS and OS. CONCLUSION: Treatment with AMR between 30 and 35 mg/m2 showed relatively mild hematologic toxicity compared with AMR at 40 mg/m2, without any significant difference in efficacy. Lower dose of AMR for relapsed SCLC could be a promising treatment option.

Successful Treatment with Definitive Concurrent Chemoradiotherapy Followed by Durvalumab Maintenance Therapy in a Patient with Tracheal Adenoid Cystic Carcinoma.

Adenoid cystic carcinoma (ACC) is a rare type of malignant tracheal tumor originating from the secretory glands. Complete surgical resection is the current standard of care for tracheal ACC. However, there have been few case reports of chemoradiotherapy for unresectable tracheal ACC. We herein report a 28-year-old man with unresectable tracheal ACC who received concurrent chemoradiotherapy (CCRT) followed by maintenance therapy with durvalumab. CCRT was completed with a good response and safety, and the patient is currently receiving durvalumab as maintenance therapy. Durvalumab after CCRT can be a treatment option for patients with unresectable tracheal ACC.

Serum-derived exosomal miR-125a-3p predicts the response to anti-programmed cell death-1/programmed cell death-ligand 1 monotherapy in patients with non-small cell lung cancer.

BACKGROUND: Versatile biomarkers for immune checkpoint inhibitors (ICI) efficacy in patients with cancer remain to be identified. Liquid biopsy using serum-derived exosomal microRNAs (miRNAs) are widely investigated as diagnostic and therapeutic outcome predictors in patients with cancer. However, exosomal miRNAs linked to the response to ICI in patients with non-small cell lung cancer (NSCLC) remain elusive thus far. METHODS: The value of serum-derived exosomal miRNAs in predicting the effect of anti-programmed cell death-1 (PD-1)/anti-programmed cell death-ligand 1 (PD-L1) monotherapy in 41 patients with advanced NSCLC was assessed. We performed functional analysis of candidate miRNAs using NSCLC cell lines. RESULTS: Exosomal miR-125a-3p was associated with response to treatment with ICI. Exosomal miR-125a-3p was more useful in predicting response to ICI versus tumoral PD-L1 in patients with low PD-L1 expression <50 %). Moreover, high expression of miR-125a-3p was associated with worse progression-free and overall survival. In H1975 and H441 cells, induction of miR-125a-3p regulated PD-L1 expression via suppression of neuregulin 1 (NRG1). CONCLUSIONS: Exosomal miR-125a-3p is a potential predictor of response to anti-PD-1/PD-L1 therapy in advanced NSCLC patients with low PD-L1 expression.

Alectinib-Induced Severe Hemolytic Anemia in a Patient with ALK-Positive Non-Small Cell Lung Cancer: A Case Report.

Alectinib is a selective anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitor as standard therapy for ALK-rearranged non-small cell lung cancer (NSCLC). Hemolytic anemia is considered as a rare but significant adverse event with alectinib. Here, we report a case of a 73-year-old female with lung adenocarcinoma, harbouring an ALK fusion gene, who received alectinib as second-line therapy and developed gradually progressive grade 4 (6.4 g/dL) drug-induced hemolytic anemia (DIHA) after complete response. We discontinued alectinib and performed a blood transfusion for the severe anemia. The anemia improved with no recurrence of lung adenocarcinoma over 10 months. Regular hematologic monitoring and the possibility of DIHA should be considered in case of progressive hemolytic anemia during alectinib treatment.

Successful Treatment with Short-Term Steroid Against Severe Hepatitis Confirmed by Liver Biopsy in a Patient with Advanced Squamous-Cell Lung Cancer Receiving a Combination of Pembrolizumab, Carboplatin, and Nab-Paclitaxel: A Case Report.

Pembrolizumab is an immune checkpoint inhibitor (ICI) that targets programmed death-1. Although ICIs have shown efficacy in the treatment of lung cancer, they have also been reported to cause a variety of immune-related adverse events (irAEs). Hepatotoxicity is a known irAEs, but currently, there is not enough information on its pathological characteristics and treatment. We report the case of a 70-year-old man with advanced squamous-cell lung cancer who developed severe grade 4 hepatitis on day 8 after receiving carboplatin, nab-paclitaxel, and pembrolizumab as fourth-line therapy. We treated him with steroid therapy the day after a liver biopsy was performed to investigate his pathological features, which led to a rapid and remarkable improvement. Confirmation of immune-related hepatotoxicity by pathological findings allowed the early tapering and discontinuation of steroid therapy. Performing a liver biopsy and verifying histological characteristics are needed for successful treatment with short-term steroids when drug-induced hepatitis caused by anti-cancer therapy including pembrolizumab is considered.

Effectiveness of Corticosteroid Therapy for Non-Severe COVID-19 in Patients Not Requiring Supplemental Oxygen Who Have Risk Factors for Severe Disease.

BACKGROUND: Because they suppress cytokine production, corticosteroids are a candidate therapy for coronavirus disease 2019 (COVID-19). However, the effectiveness of corticosteroids is unclear for non-severe COVID-19 that does not require supplemental oxygen. This study investigated the effectiveness of corticosteroid therapy for patients with non-severe COVID-19. METHODS: This retrospective observational study analyzed data from 10 patients with non-severe COVID-19 who received corticosteroid therapy at our center between July 1, 2020 and January 31, 2021. RESULTS: The median age of the 10 patients was 60 years, and nine were male. Nine of the 10 patients had multiple comorbid conditions (e.g., hypertension, diabetes, and obesity). Although blood oxygen saturation was maintained above 95%, all patients had persistent fever and deterioration in chest imaging findings, which led to initiation of corticosteroid treatment. The median duration symptom onset to initiation of corticosteroid therapy was 8 days. All patients received dexamethasone 6 mg/day as corticosteroid therapy, and the median period was 7.5 days. After the start of corticosteroid therapy, clinical improvement was rapid in all patients, and no patient developed severe disease. CONCLUSION: The latest World Health Organization guidance recommends against corticosteroid treatment for patients with non-severe COVID-19. In this report, early administration of corticosteroids during the non-critical phase, when oxygen supplementation was not required, was associated with early improvement and prevention of severe disease in patients with risk factors for severe COVID-19 and worsening clinical symptoms.

Two cases of superior mesenteric artery syndrome during chemotherapy in patients with lung cancer.

Superior mesenteric artery (SMA) syndrome is a rare disease, characterized by the narrowing of the third portion of the duodenum between the aorta and SMA. The cause of the stenosis is a decrease in retroperitoneal fat between the aorta and SMA. In this report, we present two cases of SMA syndrome that occurred during chemotherapy for lung cancer. The first case was a 61-year-old male treated with nanoparticle albumin-bound-paclitaxel (nab-PTX) for lung adenocarcinoma. On day 23 of the first course of nab-PTX, he was admitted to our hospital due to vomiting and weight loss of 15.6 kg in 10 months. He was diagnosed with SMA syndrome through computed tomography, and drainage was performed using a nasogastric tube. Conservative treatment was successful, and the patient was able to continue therapy with nab-PTX. The second case was a 70-year-old male with epidermal growth factor receptor (EGFR) mutation-positive non-small cell lung cancer. He was admitted to our hospital due to vomiting and dizziness while receiving treatment with pembrolizumab, as well as weight loss of 14.6 kg in 6 months. He was diagnosed with SMA syndrome using computed tomography. Conservative treatment using a nasogastric tube led to improvement, and the patient was able to continue treatment with pembrolizumab after discharge. This is the first report of SMA syndrome in patients with lung cancer undergoing chemotherapy with nab-PTX or pembrolizumab. Late diagnosis and treatment render SMA syndrome a potentially fatal disease. Vomiting and weight loss during chemotherapy are known treatment-related side effects; in patients developing these adverse effects, the presence of SMA syndrome should be suspected and managed appropriately.

Carboplatin plus nanoparticle albumin-bound paclitaxel for the treatment of thymic carcinoma.

Thymic carcinoma is a relatively rare type of malignant tumor. The present retrospective study evaluated the efficacy and safety of carboplatin plus nanoparticle albumin-bound paclitaxel for the treatment of advanced thymic carcinoma. The study included data from 12 patients with advanced thymic carcinoma treated in the Nippon Medical School Hospital (Tokyo, Japan). Response to treatment, patient survival and treatment safety were assessed. The objective response rate was 66.7% (8/12 patients). Disease control was achieved in 11 patients (91.7%). At the median follow-up time of 27.6 months (range, 6.2-75.1 months), the median progression-free survival and median first-line overall survival times were 16.7 months [95% confidence interval (CI), 13.2-37.7] and 14.3 months (95% CI, 4.7-54.6), respectively. There was no occurrence of febrile neutropenia or treatment-related death. The results of the present study showed that carboplatin plus nanoparticle albumin-bound paclitaxel was effective and safe. Therefore, it is a promising chemotherapy regimen for the treatment of advanced thymic carcinoma.

A Novel Molecular Target in EGFR-mutant Lung Cancer Treated With the Combination of Osimertinib and Pemetrexed.

BACKGROUND/AIM: Synergistic effects of epidermal growth factor receptor tyrosine kinase inhibitors and chemotherapy have been reported. Here, we evaluated the therapeutic potential of combining osimertinib with pemetrexed and investigated the molecular mechanisms. MATERIALS AND METHODS: We analyzed the antitumor effects of osimertinib± pemetrexed in PC-9 and H1975 cells. Gene expression on exposure to osimertinib±pemetrexed was assessed in these cultured cells. Cell lines resistant to osimertinib±pemetrexed were established to explore mechanisms of resistance. RESULTS: Osimertinib+pemetrexed treatment delayed the emergence of resistance relative to monotherapy in vitro and in vivo. Expression of the anti-apoptotic gene PLK1 was down-regulated in PC-9 and H1975 exposed to osimertinib+ pemetrexed, whereas it was up-regulated in resistant cells. Furthermore, inhibition of PLK1 induced apoptosis and inhibited proliferation of resistant cells. CONCLUSION: Blocking PLK1 contributes to mediating the synergistic anti-proliferative effect of osimertinib+pemetrexed. PLK1 over-expression may be a critical mechanism for acquired resistance to osimertinib+pemetrexed.

Efficacy with Trastuzumab Deruxtecan for Non-Small-Cell Lung Cancer Harboring HER2 Exon 20 Insertion Mutation in a Patient with a Poor Performance Status: A Case Report.

Antibody-drug conjugate (ADC) was novel type of anticancer drugs. Trastuzumab deruxtecan (T-DXd), a human epidermal growth factor receptor 2 (HER2) targeting ADC, can be a novel treatment option for HER2 alternation (mutation, expression, amplification) advanced-stage non-small-cell lung cancer (NSCLC) from DESTINY-Lung01 result. Herein, we report a successful treatment with T-DXd for NSCLC harboring HER2 exon 20 insertion mutation in a patient with poor performance status (PS). We presented a case of a 52-year-old heavily pretreated female patient diagnosed with lung adenocarcinoma (cT1bN3M0, stage IIIB). After fifth-line pretreatment of systemic chemotherapy, primary tumor recurrence, pleural effusion, and miliary lung metastases were observed. The patient presented with hypoxia requiring oxygen therapy via nasal cannula at a flow rate of 4 L per minute, cancer pain, and cachexia requiring opioid treatment. Her Eastern Cooperative Oncology Group PS score was assessed 3. Comprehensive genomic profiling revealed HER2 exon 20 insertion mutation. After treatment with T-DXd was approved by the ethical review committee of Nippon Medical School Hospital, treatment was started. The tumor size decreased significantly, and her PS score decreased from 3 to 1, with improvement of hypoxia, cancer pain, and cachexia. The patient is still receiving treatment, without disease progression 6 months after starting treatment with T-DXd. Despite cases of poor PS, NGS should be performed and target therapy including ADCs should be considered.

PD-L1 Expression Status Predicting Survival in Pulmonary Pleomorphic Carcinoma.

BACKGROUND/AIM: Pulmonary pleomorphic carcinoma (PPC) is a rare and aggressive tumor that is resistant to treatment. The expression and prognostic value of programmed cell death-ligand 1 (PD-L1) and its association with epithelial-mesenchymal transition (EMT) in PPC remains unclear. PATIENTS AND METHODS: The expression of PD-L1 and EMT markers, such as E-cadherin, vimentin, zinc finger E-box-binding homeobox 1 (ZEB-1), and cellular mesenchymal-epithelial transition (c-Met) was evaluated by immuno - histochemistry in 16 patients with PPC who underwent surgical resection. RESULTS: The expression of PD-L1 varied between carcinomatous and sarcomatous areas. Positive correlations between PD-L1 and vimentin expression in carcinomatous areas (r=0.668, p=0.005) and PD-L1 and ZEB-1 expression in sarcomatous areas (r=0.562, p=0.023) were found. High PD-L1 and ZEB-1 expression in sarcomatous areas predicted poor survival (p=0.045 and p=0.012, respectively). CONCLUSION: PD-L1 expression associated with ZEB1 expression in the sarcomatoid component of patients with PPC may be useful for predicting patient prognosis.

Long Non-Coding RNA CRNDE Is Involved in Resistance to EGFR Tyrosine Kinase Inhibitor in EGFR-Mutant Lung Cancer via eIF4A3/MUC1/EGFR Signaling.

(1) Background: Acquired resistance to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) is an intractable problem for many clinical oncologists. The mechanisms of resistance to EGFR-TKIs are complex. Long non-coding RNAs (lncRNAs) may play an important role in cancer development and metastasis. However, the biological process between lncRNAs and drug resistance to EGFR-mutated lung cancer remains largely unknown. (2) Methods: Osimertinib- and afatinib-resistant EGFR-mutated lung cancer cells were established using a stepwise method. A microarray analysis of non-coding and coding RNAs was performed using parental and resistant EGFR-mutant non-small cell lung cancer (NSCLC) cells and evaluated by bioinformatics analysis through medical-industrial collaboration. (3) Results: Colorectal neoplasia differentially expressed (CRNDE) and DiGeorge syndrome critical region gene 5 (DGCR5) lncRNAs were highly expressed in EGFR-TKI-resistant cells by microarray analysis. RNA-protein binding analysis revealed eukaryotic translation initiation factor 4A3 (eIF4A3) bound in an overlapping manner to CRNDE and DGCR5. The CRNDE downregulates the expression of eIF4A3, mucin 1 (MUC1), and phospho-EGFR. Inhibition of CRNDE activated the eIF4A3/MUC1/EGFR signaling pathway and apoptotic activity, and restored sensitivity to EGFR-TKIs. (4) Conclusions: The results showed that CRNDE is associated with the development of resistance to EGFR-TKIs. CRNDE may be a novel therapeutic target to conquer EGFR-mutant NSCLC.