Nationwide data from comprehensive genomic profiling assays for detecting driver oncogenes in non-small cell lung cancer.

Driver oncogenes are investigated upfront at diagnosis using multi-CDx systems with next-generation sequencing techniques or multiplex reverse-transcriptase polymerase chain reaction assays. Additionally, from 2019, comprehensive genomic profiling (CGP) assays have been available in Japan for patients with advanced solid tumors who had completed or were expected to complete standard chemotherapy. These assays are expected to comprehensively detect the driver oncogenes, especially for patients with non-small cell lung cancer (NSCLC). However, there are no reports of nationwide research on the detection of driver oncogenes in patients with advanced NSCLC who undergo CGP assays, especially in those with undetected driver oncogenes at diagnosis. In this study, we investigated the proportion of driver oncogenes detected in patients with advanced NSCLC with undetectable driver oncogenes at initial diagnosis and in all patients with advanced NSCLC who underwent CGP assays. We retrospectively analyzed data from 986 patients with advanced NSCLC who underwent CGP assays between August 2019 and March 2022, using the Center for Cancer Genomics and Advanced Therapeutics database. The proportion of driver oncogenes newly detected in patients with NSCLC who tested negative for driver oncogenes at diagnosis and in all patients with NSCLC were investigated. Driver oncogenes were detected in 451 patients (45.7%). EGFR was the most common (16.5%), followed by KRAS (14.5%). Among the 330 patients with undetected EGFR, ALK, ROS1, and BRAF V600E mutations at diagnosis, 81 patients (24.5%) had newly identified driver oncogenes. CGP assays could be useful to identify driver oncogenes in patients with advanced NSCLC, including those initially undetected, facilitating personalized treatment.

Epithelial-mesenchymal transition status is a remarkable biomarker for the combination treatment with avutometinib and defactinib in KRAS-mutated non-small cell lung cancer.

BACKGROUND: Recent therapeutic strategies for KRAS-mutated cancers that inhibit the MAPK pathway have attracted considerable attention. The RAF/MEK clamp avutometinib (VS-6766/CH5126766/RO5126766/CKI27) is promising for patients with KRAS-mutated cancers. Although avutometinib monotherapy has shown clinical activity in patients with KRAS-mutated cancers, effective combination strategies will be important to develop. METHODS: Using a phosphorylation kinase array kit, we explored the feedback mechanism of avutometinib in KRAS-mutated NSCLC cells, and investigated the efficacy of combining avutometinib with inhibitors of the feedback signal using in vitro and in vivo experiments. Moreover, we searched for a biomarker for the efficacy of combination therapy through an in vitro study and analysis using the The Cancer Genome Atlas Programme dataset. RESULTS: Focal adhesion kinase (FAK) phosphorylation/activation was increased after avutometinib treatment and synergy between avutometinib and FAK inhibitor, defactinib, was observed in KRAS-mutated NSCLC cells with an epithelial rather than mesenchymal phenotype. Combination therapy with avutometinib and defactinib induced apoptosis with upregulation of Bim in cancer cells with an epithelial phenotype in an in vitro and in vivo study. CONCLUSIONS: These results demonstrate that the epithelial-mesenchymal transition status may be a promising biomarker for the efficacy of combination therapy with avutometinib and defactinib in KRAS-mutated NSCLC.

Prospective Observational Study of Ramucirumab Plus Docetaxel After Combined Chemoimmunotherapy in Patients With Non-Small-Cell Lung Cancer.

BACKGROUND: A history of pre-administration of immune checkpoint inhibitors has been reported to be associated with good outcomes of ramucirumab (RAM) plus docetaxel (DOC) combination therapy for advanced non-small-cell lung cancer (NSCLC). However, existing knowledge on the clinical significance of RAM and DOC following combined chemoimmunotherapy is limited. Therefore, we evaluated the efficacy and safety of RAM plus DOC therapy after combined chemoimmunotherapy and attempted to identify the predictors of its outcomes. PATIENTS AND METHODS: This multicenter, prospective study investigated the efficacy and safety of RAM plus DOC after combined chemoimmunotherapy. The primary endpoint was progression-free survival (PFS). Secondary endpoints were the objective response rate (ORR), disease control rate (DCR), overall survival (OS), and incidence of adverse events. An exploratory analysis measured serum cytokine levels at the start of treatment. RESULTS: Overall, 44 patients were enrolled from 10 Japanese institutions between April 2020 and June 2022. The median PFS and OS were 6.3 and 22.6 months, respectively. Furthermore, the ORR and DCR were 36.4% and 72.7%, respectively. The high vascular endothelial growth factor D (VEGF-D) group had a significantly shorter PFS and OS. A combination of high VEGF-A and low VEGF-D levels was associated with a longer PFS. CONCLUSION: Our results showed that RAM plus DOC after combined chemoimmunotherapy might be an effective and relatively feasible second-line treatment for patients with advanced NSCLC in a real-world setting.

Pan-HER inhibitors overcome lorlatinib resistance caused by NRG1/HER3 activation in ALK-rearranged lung cancer.

Lorlatinib, a third-generation anaplastic lymphoma kinase (ALK)-tyrosine kinase inhibitor (TKI) with a broad coverage against ALK mutations, has demonstrated dramatic effects in patients with ALK-rearranged lung cancer. The mechanisms of acquired resistance to lorlatinib by secondary ALK compound mutations have recently been reported; however, resistance mechanisms other than secondary mutations remain unclear. Here, we investigated the molecular mechanisms of the acquired resistance in ALK-rearranged lung cancer cells in vitro. We established two different lorlatinib-resistant ALK-rearranged lung cancer cell lines (H3122LR and A925LLR) via long-term administration of lorlatinib. These resistant cells did not harbor the secondary ALK mutations and showed cross-resistance to the other kinds of ALK-TKIs (crizotinib or alectinib) compared with the parental cells; however, these resistant cells overexpressed the phosphorylated human epidermal growth factor receptor 3 (HER3) protein and the ligand of HER3 (neuregulin 1; NRG1). Pharmacological inhibition of HER3 with pan-HER inhibitors or genetic knockdown of HER3 with siRNA resensitized H3122LR and A925LLR cells to lorlatinib in vitro, indicating that H3122LR and A925LLR acquired resistance by NRG1/HER3 activation. These findings demonstrated that targeting NRG1/HER3 is a potential novel therapeutic option for lorlatinib-resistant ALK-rearranged lung cancer.

High levels of AXL expression in untreated EGFR-mutated non-small cell lung cancer negatively impacts the use of osimertinib.

For non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations, the initial therapeutic interventions will have crucial impacts on their clinical outcomes. Drug tolerant factors reportedly have an impact on EGFR-tyrosine kinase inhibitor sensitivity. This prospective study investigated the impacts of drug tolerant-related protein expression in tumors based on the efficacy of osimertinib in the first-setting of EGFR-mutated advanced NSCLC patients. A total of 92 patients with EGFR-mutated advanced or postoperative recurrent NSCLC were analyzed and treated with osimertinib at 14 institutions in Japan. AXL, p53, and programmed death-ligand 1 (PD-L1) expression in patient tumors was determined using immunohistochemistry. The AXL signaling pathway was investigated using a cell line-based assay and AXL-related gene expression in The Cancer Genome Atlas (TCGA) database. High levels of AXL and positive-p53 expression were detected in 26.1% and 53.3% of the pretreatment EGFR-mutated NSCLC tumors, respectively. High AXL expression levels were significantly associated with a shorter progression-free survival compared with low AXL expression levels, irrespective of the EGFR activating mutation status (p = 0.026). Cell line-based assays indicated that the overexpression of AXL protein accelerated PD-L1 expression, which induced insensitivity to osimertinib. In the TCGA database, AXL RNA levels were positively correlated with PD-L1 expression in the lung adenocarcinoma cohort. The results show that high AXL expression levels in tumors impact clinical predictions when using osimertinib to treat EGFR-mutated NSCLC patients. Trial Registration: UMIN000043942.

Predictive value of p53 and AXL immunostaining for the efficacy of immune checkpoint inhibitor-based therapy after osimertinib treatment in patients with epidermal growth factor-mutant non-small cell lung cancer.

BACKGROUND: Current evidence indicates that immune checkpoint inhibitors (ICIs) have a limited efficacy in patients with lung cancer harboring epidermal growth factor receptor (EGFR) mutations. However, there is a lack of data on the efficacy of ICIs after osimertinib treatment, and the predictors of ICI efficacy are unclear. METHODS: We retrospectively assessed consecutive patients with EGFR-mutant NSCLC who received ICI-based therapy after osimertinib treatment at 10 institutions in Japan, between March 2016 and March 2021. Immunohistochemical staining was used to evaluate the expression of p53 and AXL. The deletions of exon 19 and the exon 21 L858R point mutation in EGFR were defined as common mutations; other mutations were defined as uncommon mutations. RESULTS: A total of 36 patients with advanced or recurrent EGFR-mutant NSCLC were analyzed. In multivariate analysis, p53 expression in tumors was an independent predictor of PFS after ICI-based therapy (p = 0.002). In patients with common EGFR mutations, high AXL expression was a predictor of shorter PFS and overall survival after ICI-based therapy (log-rank test; p = 0.04 and p = 0.02, respectively). CONCLUSION: The levels of p53 in pretreatment tumors may be a predictor of ICI-based therapy outcomes in patients with EGFR-mutant NSCLC after osimertinib treatment. High levels of AXL in tumors may also be a predictor of ICI-based therapy outcomes, specifically for patients with common EGFR mutations. Further prospective large-scale investigations on the predictors of ICI efficacy following osimertinib treatment are warranted.

Significance of localized expression of full-length growth differentiation factor-15 in cachexia of advanced non-small cell lung cancer.

PURPOSE: Growth differentiation factor-15 (GDF-15) is one of the key cachexia-inducing factors. Clinical trials on therapies targeting GDF-15 for cancer and cancer cachexia are underway. While the role of circulating GDF-15 in cachexia has been clarified, the effects of GDF-15 expression within cancer cells remain to be fully elucidated. Hence, the objective of this study was to investigate the expression of GDF-15 in advanced lung cancer tissues and to understand its role in cachexia. METHODS: We retrospectively examined the expression level of full-length GDF-15 in advanced non-small cell lung cancer tissues and analyzed the relationship between the staining intensity and clinical data in 53 samples. RESULTS: We found that 52.8% of the total samples were GDF-15 positive, and GDF-15 expression significantly correlated with improved C-reactive protein/albumin ratio (p = 0.008). It did not correlate with the existence of cancer cachexia and overall survival (p = 0.43). CONCLUSION: Our findings show that GDF-15 expression significantly correlated with improved C-reactive protein/albumin ratio, but not the existence of cancer cachexia in advanced NSCLC patients.

Phase II Study on Biweekly Combination Therapy of Gemcitabine plus Carboplatin for the Treatment of Elderly Patients with Advanced Non-Small Cell Lung Cancer.

LESSONS LEARNED: The biweekly GEM plus CBDCA dose and schedule showed satisfactory efficacy with mild toxicities in elderly patients with advanced NSCLC. The biweekly GEM plus CBDCA regimen could be considered an alternative to the 3-week regimen in NSCLC. BACKGROUND: The gemcitabine (GEM)-carboplatin (CBDCA) combination is widely used for non-small cell lung cancer (NSCLC) and has some efficacy in elderly patients; however, a high incidence of thrombocytopenia is observed, and the optimal dosage and administration schedules are unknown. This multicenter phase II trial evaluated the efficacy and tolerability of GEM-CBDCA for elderly patients with chemotherapy-naive NSCLC. METHODS: Patients with chemotherapy-naive performance status 0-1 and with stage IIIB/IV NSCLC were administered chemotherapy biweekly (GEM 1,000 mg/m2 with CBDCA area under the blood concentration-time curve (AUC) 3 on days 1 and 15 every 4 weeks). The primary endpoint was the objective response rate (ORR), and the secondary endpoints were progression-free survival (PFS), overall survival (OS), and safety. RESULTS: Forty-eight patients were enrolled. Median age was 76 years (range, 70-83); 35 patients were men (73%), and 27 patients had adenocarcinoma (56%). The ORR was 29.2% (95% confidence interval [CI], 17.0-44.1). The median PFS, median OS, and 1-year survival was 5.9 months (95% CI, 4.1-6.6), 13.3 months (95% CI, 8.3-23.5), and 58%, respectively. Grade ≥3 hematological toxicities included neutropenia (29.2%), thrombocytopenia (4.2%), and anemia (20.8%). The incidence of grade ≥3 nonhematological toxicities was <5%. CONCLUSION: This GEM-CBDCA combination administered biweekly showed satisfactory efficacy with mild toxicities in elderly patients with advanced NSCLC.

Randomized Phase II Study of First-Line Biweekly Gemcitabine and Carboplatin Versus Biweekly Gemcitabine and Carboplatin plus Maintenance Gemcitabine in Elderly Patients with Untreated Non-Small Cell Lung Cancer: LOGIK0801.

LESSONS LEARNED: The usefulness of maintenance gemcitabine (GEM) after biweekly carboplatin + GEM in elderly patients with non-small cell lung cancer could not be proved. Superior overall survival was obtained in the group that did not receive maintenance therapy. BACKGROUND: The primary objective of this randomized phase II study was to assess progression-free survival (PFS) in elderly patients with advanced non-small cell lung cancer (NSCLC) treated with gemcitabine (GEM) maintenance therapy versus best supportive care following first-line GEM plus carboplatin (CBDCA). METHODS: Elderly chemotherapy-naive patients with stage IIIB or IV NSCLC were randomly assigned 1:1 to the control arm or the study arm. All patients received biweekly combination therapy with GEM and CBDCA (1,000 mg/m2 GEM and CBDCA at an area under the curve [AUC] of 3 on days 1 and 15, every 4 weeks). In the study arm, patients with objective response or stable disease following three or four cycles of initial chemotherapy received maintenance GEM. RESULTS: Eighty-four patients were enrolled. The objective response rates (ORRs) were 17.5% in the control arm and 14.0% in the study arm. The most common toxicity was neutropenia (control arm: 47.5% and study arm: 69.8%). The median progression-free survivals were 4.99 months (control arm) and 4.44 months (study arm), and the median overall survivals (OSs) were 21.7 months (control arm) and 8.2 months (study arm). CONCLUSION: Our data do not support maintenance GEM after biweekly CBDCA+GEM in elderly patients with NSCLC.

Phase II Study of S-1 and Paclitaxel Combination Therapy in Patients with Previously Treated Non-Small Cell Lung Cancer.

LESSONS LEARNED: In terms of efficacy and safety, good results were obtained with S-1 and paclitaxel (PTX) combination therapy.The findings suggest that S-1 and PTX combination therapy is a feasible treatment option in patients with previously treated non-small cell lung cancer. BACKGROUND: Although monotherapy with cytotoxic agents, including docetaxel and pemetrexed, is recommended for patients with previously treated advanced non-small cell lung cancer (NSCLC), its outcomes are unsatisfactory. S-1 is an oral fluoropyrimidine agent that consists of tegafur, 5- chloro-2, 4-dihydroxypyridine, and potassium oxonate. S-1 is approved for patients with gastric cancer in 7 Asian countries and 15 European countries. It is also approved for patients with eight type of cancers, including NSCLC, in Japan. We evaluated the efficacy and toxicity of S-1 and paclitaxel (PTX) combination therapy in patients with previously treated NSCLC. METHODS: Oral S-1 was administered thrice weekly on days 1-14 at 80, 100, and 120 mg/day in patients with body surface areas of <1.25, 1.25-1.5, and >1.5 m2, respectively. PTX was administered at 80 mg/m2 on days 1 and 8. Primary endpoint was response rate, and secondary endpoints were progression-free survival (PFS), overall survival (OS), and safety. RESULTS: Forty patients were enrolled, with response and disease control rates of 27.5% and 75.0%, respectively (Fig. 1). Median PFS and OS were 6.5 and 20.7 months, respectively. Grade 3/4 anemia and thrombocytopenia were seen in five (12%) and one (2%) patients, respectively. Febrile neutropenia occurred in three patients (7%). Common grade 3/4 nonhematological toxicities were stomatitis (5% of patients), diarrhea (7% of patients), and interstitial lung disease (one patient). No treatment-related deaths were observed. CONCLUSION: This S-1 and PTX cotherapy dose and schedule showed satisfactory efficacy, with mild toxicities, in patients with previously treated advanced NSCLC.

A Phase II Study of S-1 and Paclitaxel Combination Therapy as a First-Line Treatment in Elderly Patients with Advanced Non-Small Cell Lung Cancer.

LESSONS LEARNED: Coadministration of S-1 and paclitaxel in elderly patients with advanced non-small cell lung cancer showed favorable efficacy.Coadministration of S-1 and paclitaxel in elderly patients with advanced non-small lung cancer showed tolerable toxicity. BACKGROUND: Although monotherapy with cytotoxic agents including docetaxel or vinorelbine are recommended for elderly patients with advanced non-small cell lung cancer (NSCLC), the outcome is not satisfactory. We evaluated the efficacy and safety of S-1 and paclitaxel (PTX) as a first-line cotreatment in elderly patients with advanced NSCLC. METHODS: Oral S-1 was administered on days 1-14 every 3 weeks at 80, 100, and 120 mg per day for patients with body surface area < 1.25 m2, 1.25-1.5 m2, and > 1.5 m2, respectively. PTX was administered at 80 mg/m2 on days 1 and 8. The primary endpoint was response rate, and secondary endpoints were progression-free survival (PFS), overall survival (OS), and safety. RESULTS: Seventeen patients were enrolled with response and disease control rates of 47.1% and 88.2%, respectively. Median PFS and OS were 5.6 and 35.0 months, respectively. Hematological grade 3 or 4 toxicities included leukopenia (55.8%), neutropenia (52.9%), febrile neutropenia (11.8%), and anemia (11.8%). Nonhematological grade 3 toxicities included stomatitis (23.5%), diarrhea (5.9%), and interstitial lung disease (5.9%), and grade 5 toxicities included interstitial lung disease (5.9%). CONCLUSION: This S-1 and PTX cotherapy dose and schedule showed satisfactory efficacy with mild toxicities in elderly patients with advanced NSCLC.

Osimertinib in Elderly Patients with Epidermal Growth Factor Receptor T790M-Positive Non-Small-Cell Lung Cancer Who Progressed During Prior Treatment: A Phase II Trial.

LESSONS LEARNED: Non-small-cell lung cancer (NSCLC) represents 85% of lung cancer in elderly patients.In the present study performed in the 36 elderly subjects with epidermal growth factor receptor (EGFR) T790M mutation-positive NSCLC, osimertinib 80 mg demonstrated statistically significant improvement in the objective response rate, which was comparable to those in the nonelderly population.Osimertinib appears to be an effective and safe treatment option in elderly patients with advanced NSCLC with EGFR mutation; further research in larger scale is warranted. BACKGROUND: Previous findings suggest the possibility of relatively safe use of osimertinib for patients with T790M-positive non-small-cell lung cancer (NSCLC), with few serious adverse events for the elderly in comparison with conventional endothelial growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), and with an antitumor effect. METHODS: This phase II study was performed to prospectively investigate the efficacy and safety of osimertinib for elderly patients aged ≥75 years with ineffective prior EGFR TKI treatment or with recurrence in T790M EGFR TKI resistance mutation-positive NSCLC. RESULTS: A total of 36 patients were included in the analyses. Among the 36 subjects, 63.9% were female, with mean age of 79.9 years. The objective response rate (ORR) was 58.3% (95% confidence interval [CI], 42.2%-72.9%), demonstrating statistically significant efficacy of osimertinib (p = .0017). The median duration of response (DOR) was 27.9 weeks (95% CI, 21.1-82.0). Complete response (CR) and partial response (PR) were 2.8% and 55.6%, respectively. Disease control rate (DCR) was 97.2%. A waterfall plot revealed that 33 (91.6%) subjects exhibited tumor shrinkage during treatment, including 12 of 14 subjects who had stable disease (SD). All adverse events were not reason for discontinuation of the study drug. CONCLUSION: Osimertinib may be an effective and safe treatment option in elderly patients with advanced NSCLC with EGFR mutation.

Phase I study of S-1 plus paclitaxel combination therapy as a first-line treatment in elderly patients with advanced non-small cell lung cancer.

This phase I study was aimed at determining the maximum tolerated dose (MTD) and recommended dose (RD) for oral S-1 plus paclitaxel combination therapy in elderly patients with non-small cell lung cancer (NSCLC). Chemotherapy-naïve patients (age, >70 years) with stage III/IV NSCLC were treated with paclitaxel intravenously at four dose levels (DLs), 60, 70, 80, and 90 mg/m2, on day 1 and 8, and with S-1 (80 mg/m2) orally on days 1-14 every 3 weeks. MTD was defined as the dose at which two of the initial three patients experienced dose-limiting toxicities (DLTs). Three patients were added when the initial three patients experienced DLTs. The dose administered in three of the six patients with DLTs met the definition of MTD. The RD was defined as a dose 1 DL below the MTD. Fifteen patients including six on DL 1 and three each on DLs 2, 3, and 4 were enrolled. One patient experienced a DLT (febrile neutropenia) at DL 1. The remaining DLTs were noted at DL 4 (in one patient each): febrile neutropenia, grade (G) 3 skin rash, G3 diarrhea, G3 stomatitis, and G3 international normalized ratio (INR) elevation. The MTD of paclitaxel was 90 mg/m2. The RD for both S-1 and paclitaxel was 80 mg/m2 (DL 3). The response rate was 45.5% (8 of 15 patients achieved a partial response). In conclusion, the RD of both S-1 and paclitaxel was 80 mg/m2 in the combination therapy for chemotherapy-naïve patients with advanced NSCLC.

Nab-paclitaxel maintenance therapy following carboplatin + nab-paclitaxel combination therapy in chemotherapy naïve patients with advanced non-small cell lung cancer: multicenter, open-label, single-arm phase II trial.

Background A global multicenter study demonstrated superiority of carboplatin + nab-paclitaxel (PTX) therapy compared to carboplatin + PTX in terms of response rate (RR) and non-inferiority in terms of progression free survival (PFS) and overall survival (OS) in untreated patients with stage IIIB/IV non-small cell lung cancer; no clinical findings have so far been reported on maintenance therapies with nab-PTX. The aim of this study was to determine the efficacy and safety of maintenance therapy with nab-PTX following carboplatin + nab-PTX combination therapy. Methods Carboplatin (AUC 6) was administered on Day 1; and nab-PTX 100 mg/m2 on Days 1, 8, and 15, and dosing was repeated in 4 courses of 4 weeks each. In patients with clinical response was observed at the end of the 4th course, nab-PTX maintenance therapy was repeated. Results Out of 39 patients included in the efficacy analysis, 19 (48.7%) patients completed the induction therapy and 15 (38.5%) were transitioned to maintenance therapy. The median PFS in the maintenance phase was 6.5 (90%CI 1.4-11.4) months. The median OS in 15 patients was 12.6 (95%CI: 7.4-not reached). Grade ≥ 3 toxicities observed in more than 5% of patients were neutropenia (55.0%), anemia (15.0%), and febrile neutropenia (5.0%), with no increase during the maintenance phase. Conclusions Although statistically significance was not demonstrated presumably due to a limited transition rate from induction to maintenance phase, nab-PTX was suggested to be a useful treatment option following the induction therapy with nab-PTX in patients with advanced NSCLC.

The impact of the tumor shrinkage by initial EGFR inhibitors according to the detection of EGFR-T790M mutation in patients with non-small cell lung cancer harboring EGFR mutations.

BACKGROUND: The EGFR-T790M mutation is clinically detected using re-biopsy in approximately 50% of patients with acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in advanced non-small cell lung cancer (NSCLC) who harbor EGFR mutations. However, little is known about the population of NSCLC patients who develop acquired resistance due to the T790M mutation. In this study, we focused on the emergence of the T790M mutation and analyzed patients refractory to initial EGFR-TKIs with successful re-biopsy samples. METHODS: Seventy-eight advanced NSCLC patients with EGFR mutations who had successful re-biopsy samples after resistance to initial EGFR-TKI treatment were enrolled at 5 institutions in Japan. We validated the association between the emergence of the T790M mutation and their clinical profiles. RESULTS: Thirty-nine patients tested positive for T790M and 39 tested negative in the re-biopsy samples. The objective response rate to initial EGFR-TKIs was higher in patients with the T790M mutation than in those without the mutation (89.7% versus 51.2%, p < 0.001). Moreover, there was a significant difference in the maximal tumor shrinkage rate relative to baseline in T790M-positive tumors compared with T790M-negative tumors (42.7% versus 24.0%, p = 0.001). Multivariate analysis demonstrated that the maximum tumor shrinkage rate was a significant predictive factor for the detection of the T790M mutation (p = 0.023, odds ratio 1.03, 95% confidence interval 1.00-1.05). CONCLUSIONS: Our retrospective observations suggested that the maximum tumor shrinkage rate with initial EGFR-TKI treatment might be one of the promising predictive biomarkers for emerging refractory tumors with the EGFR-T790M mutation.

Pulmonary carcinosarcoma showing an obvious response to pazopanib: a case report.

BACKGROUND: Pulmonary carcinosarcoma (PCS) is a rare primary lung malignancy and has a poor prognosis among lung tumor histological subtypes. However, an appropriate treatment strategy has not been developed for unresectable PCS. CASE PRESENTATION: A 65-year-old man who was diagnosed with PCS was treated by surgical removal of the primary lung lesion, followed by six cycles of adjuvant chemotherapy with cisplatin plus irinotecan. Following the chemotherapy, he experienced a relapse with brain metastasis, which induced the rapid onset of left leg paralysis. Radical surgical resection and stereotactic radiosurgery to the resection cavity were performed. However, meningeal dissemination and new lung metastases occurred after a year and half. To control these multiple metastatic lesions, the patient was treated with the multiple kinase inhibitor pazopanib. No change was observed in the meningeal dissemination, while the metastatic lung lesions were prominently reduced in size following treatment with pazopanib. Consequently, the patient showed a partial response to pazopanib treatment, although the dose of pazopanib was reduced by half as a result of thrombocytopenia. CONCLUSION: This is the first report of metastatic PCS showing an evident therapeutic response to tumor-targeted therapy. We suggest that pazopanib may be a therapeutic option for patients with metastatic PCS.

Impact of MET inhibition on small-cell lung cancer cells showing aberrant activation of the hepatocyte growth factor/MET pathway.

Small-cell lung cancer (SCLC) accounts for approximately 15% of all lung cancers, and is characterized as extremely aggressive, often displaying rapid tumor growth and multiple organ metastases. In addition, the clinical outcome of SCLC patients is poor due to early relapse and acquired resistance to standard chemotherapy treatments. Hence, novel therapeutic strategies for the treatment of SCLC are urgently required. Accordingly, several molecular targeted therapies were evaluated in SCLC; however, they failed to improve the clinical outcome. The receptor tyrosine kinase MET is a receptor for hepatocyte growth factor (HGF), and aberrant activation of HGF/MET signaling is known as one of the crucial mechanisms enabling cancer progression and invasion. Here, we found that the HGF/MET signaling was aberrantly activated in chemoresistant or chemorelapsed SCLC cell lines (SBC-5, DMS273, and DMS273-G3H) by the secretion of HGF and/or MET copy number gain. A cell-based in vitro assay revealed that HGF/MET inhibition, induced either by MET inhibitors (crizotinib and golvatinib), or by siRNA-mediated knockdown of HGF or MET, constrained growth of chemoresistant SCLC cells through the inhibition of ERK and AKT signals. Furthermore, treatment with either crizotinib or golvatinib suppressed the systemic metastasis of SBC-5 cell tumors in natural killer cell-depleted SCID mice, predominantly through cell cycle arrest. These findings reveal the therapeutic potential of targeting the HGF/MET pathway for inhibition, to constrain tumor progression of SCLC cells showing aberrant activation of HGF/MET signaling. We suggest that it would be clinically valuable to further investigate HGF/MET-mediated signaling in SCLC cells.

Amphiregulin triggered epidermal growth factor receptor activation confers in vivo crizotinib-resistance of EML4-ALK lung cancer and circumvention by epidermal growth factor receptor inhibitors.

Crizotinib, a first-generation anaplastic lymphoma kinase (ALK) tyrosine-kinase inhibitor, is known to be effective against echinoderm microtubule-associated protein-like 4 (EML4)-ALK-positive non-small cell lung cancers. Nonetheless, the tumors subsequently become resistant to crizotinib and recur in almost every case. The mechanism of the acquired resistance needs to be deciphered. In this study, we established crizotinib-resistant cells (A925LPE3-CR) via long-term administration of crizotinib to a mouse model of pleural carcinomatous effusions; this model involved implantation of the A925LPE3 cell line, which harbors the EML4-ALK gene rearrangement. The resistant cells did not have the secondary ALK mutations frequently occurring in crizotinib-resistant cells, and these cells were cross-resistant to alectinib and ceritinib as well. In cell clone #2, which is one of the clones of A925LPE3-CR, crizotinib sensitivity was restored via the inhibition of epidermal growth factor receptor (EGFR) by means of an EGFR tyrosine-kinase inhibitor (erlotinib) or an anti-EGFR antibody (cetuximab) in vitro and in the murine xenograft model. Cell clone #2 did not have an EGFR mutation, but the expression of amphiregulin (AREG), one of EGFR ligands, was significantly increased. A knockdown of AREG with small interfering RNAs restored the sensitivity to crizotinib. These data suggest that overexpression of EGFR ligands such as AREG can cause resistance to crizotinib, and that inhibition of EGFR signaling may be a promising strategy to overcome crizotinib resistance in EML4-ALK lung cancer.

Podoplanin promotes progression of malignant pleural mesothelioma by regulating motility and focus formation.

Malignant pleural mesothelioma (MPM) is characterized by dissemination and aggressive growth in the thoracic cavity. Podoplanin (PDPN) is an established diagnostic marker for MPM, but the function of PDPN in MPM is not fully understood. The purpose of this study was to determine the pathogenetic function of PDPN in MPM. Forty-seven of 52 tumors (90%) from Japanese patients with MPM and 3/6 (50%) MPM cell lines tested positive for PDPN. Knocking down PDPN in PDPN-high expressing MPM cells resulted in decreased cell motility. In contrast, overexpression of PDPN in PDPN-low expressing MPM cells enhanced cell motility. PDPN stimulated motility was mediated by activation of the RhoA/ROCK pathway. Moreover, knocking down PDPN with short hairpin (sh) RNA in PDPN-high expressing MPM cells resulted in decreased development of a thoracic tumor in mice with severe combined immune deficiency (SCID). In sharp contrast, transfection of PDPN in PDPN-low expressing MPM cells resulted in an increase in the number of Ki-67-positive proliferating tumor cells and it promoted progression of a thoracic tumor in SCID mice. Interestingly, PDPN promoted focus formation in vitro, and a low level of E-cadherin expression and YAP1 activation was observed in PDPN-high MPM tumors. These findings indicate that PDPN is a diagnostic marker as well as a pathogenetic regulator that promotes MPM progression by increasing cell motility and inducing focus formation. Therefore, PDPN might be a pathogenetic determinant of MPM dissemination and aggressive growth and may thus be an ideal therapeutic target.