Phase III KEYNOTE-789 Study of Pemetrexed and Platinum With or Without Pembrolizumab for Tyrosine Kinase Inhibitor‒Resistant, EGFR-Mutant, Metastatic Nonsquamous Non-Small Cell Lung Cancer.

PURPOSE: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are standard first-line therapy for EGFR-mutant, metastatic non-small cell lung cancer (NSCLC); however, most patients experience disease progression. We report results from the randomized, double-blind, phase III KEYNOTE-789 study of pemetrexed and platinum-based chemotherapy with or without pembrolizumab for TKI-resistant, EGFR-mutant, metastatic nonsquamous NSCLC (ClinicalTrials.gov identifier: NCT03515837). METHODS: Adults with pathologically confirmed stage IV nonsquamous NSCLC, documented DEL19 or L858R EGFR mutation, and progression after EGFR-TKI treatment were randomly assigned 1:1 to 35 cycles of pembrolizumab 200 mg or placebo once every 3 weeks plus four cycles of pemetrexed and carboplatin or cisplatin once every 3 weeks and then maintenance pemetrexed. Dual primary end points were progression-free survival (PFS) and overall survival (OS). Final PFS testing was completed at the second interim analysis (IA2; data cutoff, December 3, 2021); OS was tested at final analysis (FA; data cutoff, January 17, 2023). Efficacy boundaries were one-sided P = .0117 for PFS and OS. RESULTS: Four hundred ninety-two patients were randomly assigned to pembrolizumab plus chemotherapy (n = 245) or placebo plus chemotherapy (n = 247). At IA2, the median PFS was 5.6 months for pembrolizumab plus chemotherapy versus 5.5 months for placebo plus chemotherapy (hazard ratio [HR], 0.80 [95% CI, 0.65 to 0.97]; P = .0122). At FA, the median OS was 15.9 versus 14.7 months, respectively (HR, 0.84 [95% CI, 0.69 to 1.02]; P = .0362). Grade ≥3 treatment-related adverse events occurred in 43.7% of pembrolizumab plus chemotherapy recipients versus 38.6% of placebo plus chemotherapy recipients. CONCLUSION: Addition of pembrolizumab to chemotherapy in patients with TKI-resistant, EGFR-mutant, metastatic nonsquamous NSCLC did not significantly prolong PFS or OS versus placebo plus chemotherapy in KEYNOTE-789.

Impact of Genomic Alterations on Efficacy of Trastuzumab Deruxtecan Against Human Epidermal Growth Factor Receptor-2-Positive Advanced Gastric Cancer.

PURPOSE: The impact of genomic alterations on response and resistance to trastuzumab deruxtecan (T-DXd) has not been elucidated. Thus, we sought to identify factors predicting sensitivity to T-DXd in gastric or gastroesophageal junction (G/GEJ) cancer. METHODS: We conducted a retrospective study using real-world clinical data and next-generation sequencing-based comprehensive genomic profiling (CGP) data from patients with advanced G/GEJ cancers, collected by the nationwide database in Japan. We analyzed the associations between genomic alterations and the patients' survivals after T-DXd treatment. RESULTS: In 114 patients with human epidermal growth factor receptor-2 (HER2)-positive G/GEJ cancer treated with T-DXd, the most frequently altered genes were TP53 (82%), ERBB2 (80%), and CCNE1 (36%). Multivariate Cox regression analysis revealed CCNE1 amplification to be a significant predictor of shorter progression-free survival (PFS) after T-DXd treatment among 91 patients whose CGP samples were obtained before T-DXd (median PFS, 131 days v 189 days; hazard ratio [HR], 1.90 [95% CI, 1.02 to 3.53]; P = .044). Analyses of 1,450 G/GEJ cancers revealed significant CCNE1/ERBB2 coamplification (41% relative to 11% CCNE1 amplification in ERBB2-nonamplified tumors; P < .0001). ERBB2-activating mutations were also detected in 3.7% of G/GEJ cancers and in 8.8% of HER2-positive G/GEJ cancers treated with T-DXd. Patients with ERBB2-mutated tumors showed shorter PFS than those without ERBB2 mutations after T-DXd treatment (mPFS, 105 v 180 days; P = .046). CONCLUSION: CCNE1 amplification may confer primary resistance to T-DXd in HER2-positive G/GEJ cancer, suggesting that the cell cycle could be a potential therapeutic target in CCNE1/ERBB2 coamplified tumors. ERBB2-activating mutation may also attenuate T-DXd efficacy in HER2-positive G/GEJ cancer.

Clinical outcomes in patients with non-small cell lung cancer harboring EGFR Exon20 in-frame insertions in the near-loop and far-loop: Results from LC-SCRUM-Asia.

OBJECTIVES: In this study, we explored the clinical outcomes of non-small cell lung cancer (NSCLC) patients with EGFR Exon20 in-frame insertions (Exon20ins), and the impact of the location of Exon20ins on these clinical outcomes. MATERIALS AND METHODS: The efficacies of current systemic therapies in NSCLC patients harboring Exon20ins were investigated using a large-scale clinico-genomic database of LC-SCRUM-Asia, and compared with that of amivantamab in the CHRYSALIS trial. RESULTS: Of the 11,397 patients enrolled in LC-SCRUM-Asia, Exon20ins were detected in 189 patients (1.7 %). Treatment with classical EGFR tyrosine-kinase inhibitors (classical TKIs) was associated with a significantly shorter progression-free survival (PFS) in NSCLC patients with Exon20ins as compared with Exon19 deletions and L858R. Post platinum-based chemotherapy, classical TKIs and immune checkpoint inhibitors (ICIs) were associated with a shorter PFS than with docetaxel in patients with Exon20ins (HR [95 % CI]; TKIs vs docetaxel, 2.16 [1.35-3.46]; ICIs vs docetaxel, 1.49 [1.21-1.84]). Patients treated with amivantamab in the CHRYSALIS trial showed a risk reduction in PFS and overall survival as compared with LC-SCRUM-Asia patients treated with docetaxel, classical TKIs, or ICIs. Among the 189 patients, Exon20ins were classified as near-loop or far-loop insertions in 115 (61 %) and 56 (30 %) patients, respectively. Treatment with osimertinib was associated with a longer PFS in patients with Exon20ins in near-loop as compared with far-loop (median, 5.6 vs. 2.0 months; HR [95 % CI], 0.22 [0.07-0.64]). CONCLUSIONS: After platinum-based chemotherapy, classical TKIs and ICIs are less effective in NSCLC patients with Exon20ins, and amivantamab may be a promising targeted therapy. There is a possibility that the location of Exon20ins has an impact on the efficacy of TKIs.

Tracheomediastinal fistula induced by concurrent chemoradiotherapy in small cell lung cancer: A case report and literature review.

Tracheomediastinal fistula is a rare but life-threatening complication of cancer. We report a case of tracheomediastinal fistula induced by concurrent chemoradiotherapy in limited stage small cell lung cancer. Despite the treatment response, the metastatic paratracheal lymph node increased gradually during concurrent chemoradiotherapy, resulting in the occurrence of tracheomediastinal fistula and mediastinitis. Without any surgical intervention, the patient achieved successful recovery from mediastinitis through antibiotic treatment, although the tracheomediastinal fistula remained open. In this report, we also review previous studies of tracheomediastinal and bronchomediastinal fistulas and summarize the clinical features.

TP53 gain-of-function mutations promote osimertinib resistance via TNF-α-NF-κB signaling in EGFR-mutated lung cancer.

EGFR tyrosine kinase inhibitors (TKIs) are effective against EGFR-mutated lung cancer, but tumors eventually develop resistance to these drugs. Although TP53 gain-of-function (GOF) mutations promote carcinogenesis, their effect on EGFR-TKI efficacy has remained unclear. We here established EGFR-mutated lung cancer cell lines that express wild-type (WT) or various mutant p53 proteins with CRISPR-Cas9 technology and found that TP53-GOF mutations promote early development of resistance to the EGFR-TKI osimertinib associated with sustained activation of ERK and expression of c-Myc. Gene expression analysis revealed that osimertinib activates TNF-α-NF-κB signaling specifically in TP53-GOF mutant cells. In such cells, osimertinib promoted interaction of p53 with the NF-κB subunit p65, translocation of the resulting complex to the nucleus and its binding to the TNF promoter, and TNF-α production. Concurrent treatment of TP53-GOF mutant cells with the TNF-α inhibitor infliximab suppressed acquisition of osimertinib resistance as well as restored osimertinib sensitivity in resistant cells in association with attenuation of ERK activation and c-Myc expression. Our findings indicate that induction of TNF-α expression by osimertinib in TP53-GOF mutant cells contributes to the early development of osimertinib resistance, and that TNF-α inhibition may therefore be an effective strategy to overcome such resistance in EGFR-mutant lung cancer with TP53-GOF mutations.

Artemis: A Multicenter, Open-Label, Single-Arm, Phase II Study to Evaluate the Efficacy and Safety of First-Line Carboplatin/Paclitaxel/Lenvatinib/Pembrolizumab Combination for Previously Untreated Advanced or Recurrent Thymic Carcinomas.

BACKGROUND: Thymic carcinoma is a rare cancer with an aggressive clinical presentation and no organotypic symptoms. Despite using platinum-based chemotherapy as first-line treatment, the prognosis remains poor, necessitating a novel therapeutic strategy. METHODS: The artemis trial is a Phase II, single-arm, multicenter study designed to evaluate the efficacy and safety of carboplatin, paclitaxel, lenvatinib, and pembrolizumab as first-line chemotherapy for patients with advanced or recurrent thymic carcinoma. A total of 35 patients will be enrolled in this study and will receive induction therapy every 3 weeks for up to 4 cycles, followed by pembrolizumab every 3 weeks, and daily lenvatinib as maintenance therapy for up to 31 cycles (for 2 years). Lenvatinib will be continued until disease progression or unacceptable toxicity based on the discretion of the attending physician. CONCLUSION: The primary endpoint of the study is the objective response rate, with secondary endpoints including progression-free survival, overall survival, duration of response, disease control rate, and safety profile. TRIAL REGISTRATION: ClinicalTrials.gov NCT05832827 Registered on April 27, 2023, https://classic. CLINICALTRIALS: gov/ct2/show/NCT05832827. Japan Registry of Clinical Trials (jRCT), jRCT2031230114. Registered on May 22, 2023, https://jrct.niph.go.jp/latest-detail/jRCT2031230114.

Osimertinib readministration for central nervous system metastases in non-small cell lung cancer positive for EGFR activating mutations.

BACKGROUND: Osimertinib shows pronounced efficacy for EGFR mutation-positive non-small cell lung cancer (NSCLC) including associated central nervous system (CNS) metastases. Tumors inevitably develop resistance to the drug, however. Osimertinib is sometimes readministered after completion of standard chemotherapy. To clarify which patients might receive benefit from osimertinib readministration, we have retrospectively assessed its efficacy with a focus on CNS metastases. METHODS: A retrospective analysis of medical records was performed for 21 patients who underwent osimertinib readministration at Kyushu University Hospital between March 2016 and April 2023. CNS metastases were evaluated according to modified Response Evaluation Criteria in Solid Tumors (RECIST). RESULTS: Among the 21 enrolled patients, 16 individuals had target lesions on the basis of RECIST. One (6.3%) of these 16 patients achieved a partial response to osimertinib readministration, with the remaining 15 patients showing stable or progressive disease. The median overall progression-free survival (PFS) and median overall survival for all 21 patients were 3.8 and 13.9 months, respectively. The efficacy of osimertinib readministration for CNS metastases was evaluable in eight patients including five individuals with leptomeningeal metastases. The objective response rate for CNS metastases and the improvement rate for leptomeningeal metastases were both 100%. The median PFS with regard to CNS or non-CNS lesions for these eight patients was 24.7 and 10.5 months, respectively. CONCLUSIONS: Osimertinib readministration showed limited efficacy for non-CNS lesions but excellent efficacy for CNS metastases, suggesting that such treatment is an option for EGFR-mutated NSCLC patients with CNS metastases.

YAP mediates resistance to EGF-induced apoptosis in EGFR-mutated non-small cell lung cancer cells.

Mechanisms underlying the growth and survival of non-small cell lung cancer (NSCLC) cells positive for activating mutations of the epidermal growth factor receptor gene (EGFR) have remained unclear. We here examined the functional relation between such mutant forms of EGFR and Yes-associated protein (YAP), a transcriptional coactivator of the Hippo signaling pathway that regulates cell proliferation and survival. Under the condition of serum deprivation, epidermal growth factor (EGF) induced activation of YAP in NSCLC cell lines positive for mutated EGFR but not in those wild type (WT) for EGFR. Similar EGF-induced activation of YAP was apparent in A549 lung cancer cells forcibly expressing mutant EGFR but not in those overexpressing the WT receptor. Furthermore, EGF induced apoptotic cell death in serum-deprived A549 cells overexpressing the WT form of EGFR but not in those expressing mutant EGFR, and knockdown of YAP rendered the latter cells sensitive to this effect of EGF. Our results thus suggest that activation of YAP mediates resistance of EGFR-mutated NSCLC cells to EGF-induced apoptosis and thereby contributes specifically to the survival of such cells.

MicroRNA-326 negatively regulates CD155 expression in lung adenocarcinoma.

Treatment with immune checkpoint inhibitors induces a durable response in some patients with non-small-cell lung cancer, but eventually gives rise to drug resistance. Upregulation of CD155 expression is implicated as one mechanism of resistance to programmed death receptor-1 (PD-1)/PD-1 ligand (PD-L1) inhibitors, and it is therefore important to characterize the mechanisms underlying regulation of CD155 expression in tumor cells. The aim of this study was to identify microRNAs (miRNAs) that might regulate CD155 expression at the posttranscriptional level in lung cancer. Comprehensive miRNA screening with target prediction programs and a dual-luciferase reporter assay identified miR-346, miR-328-3p, miR-326, and miR-330-5p as miRNAs that bind to the 3'-UTR of CD155 mRNA. Forced expression of these miRNAs suppressed CD155 expression in lung cancer cell lines. Immunohistochemical staining of CD155 in tissue specimens from 57 patients with lung adenocarcinoma revealed the median tumor proportion score for CD155 to be 68%. The abundance of miR-326 in these specimens with a low level of CD155 expression was significantly greater than in specimens with a high level (p < 0.005). Our results thus suggest that miR-326 negatively regulates CD155 expression in lung adenocarcinoma and might therefore play a role in the development of resistance to PD-1/PD-L1 inhibitors.

Regulation of PD-L1 expression in non-small cell lung cancer by interleukin-1ß.

Introduction: Programmed cell death-ligand 1 (PD-L1) is a biomarker for prediction of the clinical efficacy of immune checkpoint inhibitors in various cancer types. The role of cytokines in regulation of PD-L1 expression in tumor cells has not been fully characterized, however. Here we show that interleukin-1ß (IL-1ß) plays a key role in regulation of PD-L1 expression in non-small cell lung cancer (NSCLC). Methods: We performed comprehensive screening of cytokine gene expression in NSCLC tissue using available single-cell RNA-Sequence data. Then we examined the role of IL-1ß in vitro to elucidate its induction of PD-L1 on NSCLC cells. Results: The IL-1ß gene is highly expressed in the tumor microenvironment, particularly in macrophages. The combination of IL-1ß and interferon-γ (IFN-γ) induced a synergistic increase in PD-L1 expression in NSCLC cell lines. IL-1ß and IFN-γ also cooperatively activated mitogen-activated protein kinase (MAPK) signaling and promoted the binding of downstream transcription factors to the PD-L1 gene promoter. Furthermore, inhibitors of MAPK signaling blocked upregulation of PD-L1 by IL-1ß and IFN-γ. Discussion: Our study reports high levels of IL-1ß in the tumor microenvironment may cooperate with IFN-γ to induce maximal PD-L1 expression in tumor cells via activation of MAPK signaling, with the IL-1ß-MAPK axis being a promising therapeutic target for attenuation of PD-L1-mediated suppression of antitumor immunity.

Impact of increased plasma levels of calreticulin on prognosis of patients with advanced lung cancer undergoing combination treatment of chemotherapy and immune checkpoint inhibitors.

BACKGROUND: Damage-associated molecular pattern (DAMP)-related immunogenic cell death triggers secondary adaptive immune responses. The relationship between DAMP levels and prognosis in patients with non-small cell lung cancer (NSCLC) who undergo a combination therapy of immune checkpoint inhibitors (ICI) and chemotherapy remains unclear. METHODS: Serial plasma samples were prospectively collected from 45 patients treated with ICI combination therapy for advanced NSCLC. Plasma concentrations of high-mobility group box 1 (HMGB1), calreticulin (CRT), annexin A1, and heat shock protein 70 were measured. Associations between increases in plasma DAMP levels and the efficacy of the ICI combination therapy were evaluated. RESULTS: The maximum fold changes in plasma levels differed across individuals but demonstrated a marked increase, especially for CRT (mean ± SEM, 11.61 ± 46.15). Increased plasma DAMP levels were not clearly associated with clinical responses. There was a significant correlation between the maximum fold change in CRT levels and progression-free survival (PFS; r = 0.49, P < 0.001). Median PFS and overall survival (OS) rates were higher in patients with a ≥ 2-fold increase in plasma CRT levels than in those with a < 2-fold increase (PFS, 14.9 versus 6.0 months, hazard ratio (HR), 0.58; P = 0.17; OS, not reached versus 21.6 months, HR, 0.31, P = 0.02). CONCLUSIONS: Plasma CRT level monitoring has the potential to predict the efficacy of ICI combination therapy and shed light on the mechanisms underlying DAMP-related immunogenic cell death.

Evaluation of appropriate conditions for Oncomine DxTT testing of FFPE specimens for driver gene alterations in non-small cell lung cancer.

BACKGROUND: The Oncomine Dx Target Test Multi-CDx System (ODxTT) is a next-generation sequencing panel approved as a companion diagnostic for drugs targeted to corresponding gene alterations in non-small cell lung cancer. However, appropriate slide conditions for ODxTT have remained unclear. METHODS: We focused on the production of the number of tumor cells on a formalin-fixed paraffin-embedded (FFPE) section and the number of prepared slides, designated the TS value, and determined a TS value of ≥4000 as a target slide condition for ODxTT. We evaluated the impact of this condition on ODxTT testing with tumor specimens found to have a TS of <4000 (n = 23) or a TS of ≥4000 (n = 142). RESULTS: A positive correlation was apparent between the TS value and the concentrations of both DNA and RNA. Among the 142 samples with a TS of ≥4000, a sufficient concentration of DNA or RNA for ODxTT analysis was achieved in 100% and 98% samples, respectively. Among samples explored for driver gene alterations after determination of the target slide condition (TS ≥4000), most (84.9%) had a TS of ≥4000 and were submitted for ODxTT analysis. CONCLUSION: Our findings indicate that a TS of ≥4000 is a feasible and relevant criterion for ODxTT testing, and its adoption should help to improve the success rate of such testing in clinical practice.

A phase II study (WJOG12819L) to assess the efficacy of osimertinib in patients with EGFR mutation-positive NSCLC in whom systemic disease (T790M-negative) progressed after treatment with first- or second-generation EGFR TKIs and platinum-based chemotherapy.

BACKGROUND: Osimertinib is a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) that is an established standard treatment option for chemotherapy-naive patients with EGFR mutation-positive non-small cell lung cancer (NSCLC). However, of such patients who have received prior treatment with a first- or second-generation EGFR TKI, only approximately half are eligible for osimertinib therapy because its indication as second-line treatment and beyond is limited to metastatic NSCLC that is positive for the T790M resistance mutation of the EGFR gene. This study was initiated at the request of a dedicated network for patients with lung cancer in Japan. METHODS: We conducted a phase II study to assess the efficacy of osimertinib in patients with EGFR mutation-positive NSCLC in whom systemic disease (T790M-negative) progressed after treatment with first- or second-generation EGFR TKIs and platinum-based chemotherapy. The primary end point was response rate (assessed by a central imaging reviewer). RESULTS: From August 2020 to February 2021, 55 patients from 15 institutions were enrolled in the study. The overall response for primary analysis was achieved in 16 patients (29.1 %; 95 % CI, 17.6-42.9), which exceeded the threshold response rate necessary for analysis. Stable disease was found in 16 patients (29.1 %), and progressive disease, in 18 (32.7 %). The median length of progression-free survival (PFS) was 4.07 months (95 % CI 2.10-4.30), and the rate of 12-month PFS was 17.3 %. CONCLUSIONS: Osimertinib demonstrated modest antitumor activity against progressive EGFR T790M-negative disease.

Mutant forms of EGFR promote HER2 trafficking through efficient formation of HER2-EGFR heterodimers.

INTRODUCTION: Human epidermal growth factor receptor 2 (HER2) forms homodimers and is retained at the surface of cancer cells positive for HER2 amplification. The dimerization, internalization, and intracellular trafficking of HER2 in cancer cells without HER2 amplification have remained uncharacterized, however. MATERIALS AND METHODS: HER2 homodimers and heterodimers were detected in various cell lines with the use of an in situ proximity ligation assay. The effects of wild-type or mutant forms of epidermal growth factor receptor (EGFR) on intracellular trafficking of HER2 were examined by live-cell imaging. The sensitivity of cell lines without HER2 amplification to ado-trastuzumab emtansine (T-DM1), an anti-HER2 (trastuzumab)-cytotoxic drug conjugate (ADC) was also investigated. RESULTS: HER2 preferentially formed heterodimers with EGFR rather than homodimers and was rapidly internalized together with EGFR in cells without HER2 amplification. HER2-EGFR heterodimers were more abundant and HER2 was more efficiently transferred to lysosomes in such cells with than in those without EGFR activating mutations. T-DM1 showed a high cytotoxic efficacy in the cells with EGFR mutations, suggesting that mutant forms of EGFR promote the transfer of HER2-bound T-DM1 to lysosomes through efficient formation of HER2-EGFR heterodimers. CONCLUSION: Our findings reveal that HER2 trafficking is affected by EGFR, especially by mutant forms of the receptor, and they provide a rationale for the use of HER2-targeting ADCs in the treatment of EGFR-mutated lung cancer.

Immunostimulatory oncolytic activity of coxsackievirus A11 in human malignant pleural mesothelioma.

Malignant pleural mesothelioma (MPM) is an aggressive solid cancer with a poor prognosis, whereas coxsackievirus A11 (CVA11) is a potential oncolytic virus for cancer treatment. We here investigated the oncolytic activity of CVA11 with human MPM cell lines. CVA11 infection was cytotoxic in all six MPM cell lines examined and showed no or minimal cytotoxicity toward normal human normal cell lines. MPM cells with a higher surface level of intercellular adhesion molecule-1 (ICAM-1) expression tended to be more susceptible to CVA11-induced cytotoxicity, and a neutralizing antibody to ICAM-1 attenuated such cytotoxicity. CVA11 infection activated signaling by Akt and extracellular signal-regulated kinase (ERK) pathways, and inhibitors of such signaling also abrogated CVA11-mediated cytotoxicity. Furthermore, CVA11 infection-triggered multiple modes of tumor cell death including apoptosis, pyroptosis, and necroptosis, and such death was accompanied by the release or exposure of the proinflammatory cytokine interleukin-1ß and damage-associated molecular patterns such as calreticulin, high-mobility group box-1, annexin A1, and heat shock protein 70, which are hallmarks of immunogenic cell death. Notably, in vivo treatment of human MPM xenografts with intratumoral CVA11 injection resulted in significant suppression of tumor growth in SCID mice, and all mice infected with CVA11 showed no significant change in body weight. Our findings collectively suggest that the oncolytic activity of CVA11 for MPM is dependent on ICAM-1 as a virus receptor, as well as on Akt and ERK signaling, and that oncolytic virotherapy with CVA11 is a promising treatment modality with immunostimulatory activity for human MPM.

Association of thyroid transcription factor-1 (TTF-1) expression with efficacy of PD-1/PD-L1 inhibitors plus pemetrexed and platinum chemotherapy in advanced non-squamous non-small cell lung cancer.

Background: Thyroid transcription factor-1 (TTF-1) expression in advanced non-squamous non-small cell lung cancer (NSCLC) has been associated with the efficacy of pemetrexed plus platinum chemotherapy. However, the relation between TTF-1 expression and efficacy of the combination of programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) inhibitors plus pemetrexed and platinum chemotherapy, a standard first-line treatment regimen for advanced non-squamous NSCLC, has remained unclear. Methods: We retrospectively evaluated TTF-1 expression in tumor tissue of patients with advanced or recurrent non-squamous NSCLC treated with PD-1/PD-L1 inhibitors plus pemetrexed and platinum chemotherapy in the first-line setting. Clinical characteristics and pathological data for each patient were assessed, and progression-free survival (PFS) was evaluated. Bias due to patient background was minimized by application of inverse probability of treatment weighting (IPTW) analysis. Results: A total of 122 patients, 75 (61.5%) of whom were positive for TTF-1 immunostaining in tumor specimens, was included in this multicenter study. At the time of analysis, 89 (73.0%) patients had experienced progression events and 44 (36.1%) had died [median follow-up 14.6 months (range, 0.53-29.5 months)]. PFS was longer for TTF-1-positive patients than for TTF-1-negative patients [median, 12.2 vs. 6.0 months; hazard ratio (HR) =0.63 (95% CI: 0.37-1.06); log-rank P=0.028]. IPTW-adjusted PFS was significantly longer for TTF-1-positive than for TTF-1-negative patients [HR =0.62 (95% CI: 0.46-0.83); log-rank P=0.024]. Conclusions: TTF-1 expression in advanced non-squamous NSCLC can serve as a basis for prediction of PFS in patients treated with PD-1/PD-L1 inhibitors plus pemetrexed and platinum chemotherapy in the first-line setting.

Trastuzumab emtansine for patients with non-small cell lung cancer positive for human epidermal growth factor receptor 2 exon-20 insertion mutations.

BACKGROUND: Human epidermal growth factor receptor 2 (HER2) mutations are present in ∼3% of patients with non-small cell lung cancer (NSCLC), with exon-20 insertions accounting for ∼90% of such HER2 mutations and having been identified as driver oncogenic alterations. Antibody-cytotoxic drug conjugates including trastuzumab deruxtecan have shown an excellent efficacy for NSCLC with HER2 mutations. We have now performed a phase II study to evaluate the efficacy of ado-trastuzumab emtansine (T-DM1) for NSCLC positive for HER2 exon-20 insertion mutations. PATIENTS AND METHODS: Eligible patients with HER2 exon-20 insertion mutations confirmed by next-generation sequencing or multiplex polymerase chain reaction platforms and a history of one or two lines of chemotherapy received T-DM1 (3.6 mg/kg) intravenously every 21 days. The primary end-point of the study was the objective response rate (ORR). RESULTS: Between February 2019 and July 2020, 22 patients were enrolled in the study. A775_G776insYVMA was the most frequent HER2 exon-20 insertion mutation, accounting for 19 (86.4%) of the 22 patients. The ORR was 38.1% (90% confidence interval, 23.0-55.9%), and the disease control rate was 52.4%. The median duration of response was 3.5 months, and the median progression-free survival and median overall survival were 2.8 and 8.1 months, respectively. Toxicity was mild, with the frequency of adverse events of grade ≥3 being low. CONCLUSION: T-DM1 is a potential treatment option for patients with NSCLC with HER2 exon-20 insertion mutations. Further investigation of biomarkers for T-DM1 is warranted to improve its efficacy for NSCLC with such mutations. CLINICAL TRIAL NUMBER: JapicCTI-194620.