Case Report: Case series: association between blood concentration and side effects of sotorasib.

Introduction: Sotorasib is a crucial therapeutic agent for patients with non-small cell lung cancer (NSCLC) harboring the KRAS p.G12C mutation. Despite its efficacy, the relationship between blood sotorasib concentrations and side effects remains largely unexplored. Methods: This study enrolled five patients with KRAS p.G12C-positive NSCLC treated with sotorasib (LUMAKRAS® Tablets, Amgen, Japan) between July 2022 and February 2023 at Asahikawa Medical University Hospital. Blood sotorasib levels were monitored, and their association with adverse events was examined, with no adjustments made to drug dosages based on these levels. Results: Variable blood sotorasib levels were observed among the participants. Notably, one patient developed interstitial pneumonitis, although a definitive attribution to sotorasib was uncertain due to prior pembrolizumab treatment. The study revealed no consistent association between blood sotorasib levels and adverse events or therapeutic outcomes, with some patients experiencing severe side effects at higher concentrations, while others did not. Conclusion: Preliminary findings suggested that monitoring blood sotorasib levels may aid in anticipating adverse events in this small cohort. However, future studies with larger sample sizes and extended follow-up periods are required to validate these initial observations. Such studies could potentially offer insights into personalized dosing strategies, thereby mitigating adverse effects and enhance patient care for individuals with KRAS p.G12C-positive NSCLC.

Detection of resistance mutations in patients with anaplastic lymphoma kinase-rearranged lung cancer through liquid biopsy.

Background: Tyrosine kinase inhibitors (TKIs) significantly improve clinical outcomes in patients with non-small cell lung cancer due to anaplastic lymphoma kinase (ALK) gene rearrangement. However, the rate of relapse with TKIs is high owing to the development of resistance mutations during treatment. Repeated biopsies during disease progression are crucial for elucidating the molecular mechanisms underlying the development of resistance to ALK inhibitors. Analysis of cell-free DNA (cfDNA) obtained from plasma is a novel approach for tumor genotyping. Methods: In this mixed prospective and retrospective observational cohort study, we investigated the clinical feasibility of continuous quantitative monitoring of ALK-acquired mutations in plasma obtained from patients with ALK+ non-small cell lung cancer by using a highly sensitive and specific droplet digital polymerase chain reaction (ddPCR) assay. We enrolled nine patients, including three treatment-naïve patients recently diagnosed with ALK+ non-small cell lung cancer via tissue biopsy and expected to receive ALK TKIs and six patients already receiving ALK TKIs. Plasma samples were collected from these patients every 3 months. cfDNA was extracted from 66 samples during the study period, and 10 ALK mutations were simultaneously evaluated. Results: The numbers of samples showing the G1202R, C1156Y, G1269A, F1174L, T1151ins, and I1171T mutations were 32, 16, 5, 4, 1, and 1, respectively. The L1196M, L1152R, V1180L, and S1206Y mutations were not detected. Correlation analyses between progression-free survival and the time from treatment initiation (or treatment modification) to the detection of resistance mutations revealed that although resistance mutations may occur before a drug change becomes necessary, there is a duration during which the disease does not progress. Conclusions: Our findings suggest that real-time quantitative monitoring of ALK resistance mutations during the response period could provide a time course of changes while acquiring resistance mutations. This information would be beneficial for designing an appropriate treatment strategy.

Two Cases of SMARCA4-Deficient Non-small Cell Lung Cancer (NSCLC) with Improved Performance Status (PS) after Treatment with Immune Checkpoint Inhibitors (ICIs).

SWItch/Sucrose Non-Fermentable (SWI/SNF)-related, matrix-associated, actin-dependent regulator of chromatin, subfamily A, member 4 (SMARCA4) mutations are commonly reported in non-small cell lung cancer (NSCLC) and are associated with a poor prognosis. There is insufficient evidence regarding the efficacy of immune checkpoint inhibitors (ICIs) in SMARCA4-deficient NSCLC patients with poor performance status (PS). We report two cases of advanced SMARCA4-deficient NSCLC treated with ICIs, in which marked regression of the tumor and improved general condition of the patients were achieved.

MET-Induced CD73 Restrains STING-Mediated Immunogenicity of EGFR-Mutant Lung Cancer.

Immunotherapy has shown limited efficacy in patients with EGFR-mutated lung cancer. Efforts to enhance the immunogenicity of EGFR-mutated lung cancer have been unsuccessful to date. Here, we discover that MET amplification, the most common mechanism of resistance to third-generation EGFR tyrosine kinase inhibitors (TKI), activates tumor cell STING, an emerging determinant of cancer immunogenicity (1). However, STING activation was restrained by ectonucleosidase CD73, which is induced in MET-amplified, EGFR-TKI-resistant cells. Systematic genomic analyses and cell line studies confirmed upregulation of CD73 in MET-amplified and MET-activated lung cancer contexts, which depends on coinduction of FOSL1. Pemetrexed (PEM), which is commonly used following EGFR-TKI treatment failure, was identified as an effective potentiator of STING-dependent TBK1-IRF3-STAT1 signaling in MET-amplified, EGFR-TKI-resistant cells. However, PEM treatment also induced adenosine production, which inhibited T-cell responsiveness. In an allogenic humanized mouse model, CD73 deletion enhanced immunogenicity of MET-amplified, EGFR-TKI-resistant cells, and PEM treatment promoted robust responses regardless of CD73 status. Using a physiologic antigen recognition model, inactivation of CD73 significantly increased antigen-specific CD8+ T-cell immunogenicity following PEM treatment. These data reveal that combined PEM and CD73 inhibition can co-opt tumor cell STING induction in TKI-resistant EGFR-mutated lung cancers and promote immunogenicity. SIGNIFICANCE: MET amplification upregulates CD73 to suppress tumor cell STING induction and T-cell responsiveness in TKI-resistant, EGFR-mutated lung cancer, identifying a strategy to enhance immunogenicity and improve treatment.

MPS1 inhibition primes immunogenicity of KRAS-LKB1 mutant lung cancer.

KRAS-LKB1 (KL) mutant lung cancers silence STING owing to intrinsic mitochondrial dysfunction, resulting in T cell exclusion and resistance to programmed cell death (ligand) 1 (PD-[L]1) blockade. Here we discover that KL cells also minimize intracellular accumulation of 2'3'-cyclic GMP-AMP (2'3'-cGAMP) to further avoid downstream STING and STAT1 activation. An unbiased screen to co-opt this vulnerability reveals that transient MPS1 inhibition (MPS1i) potently re-engages this pathway in KL cells via micronuclei generation. This effect is markedly amplified by epigenetic de-repression of STING and only requires pulse MPS1i treatment, creating a therapeutic window compared with non-dividing cells. A single course of decitabine treatment followed by pulse MPS1i therapy restores T cell infiltration in vivo, enhances anti-PD-1 efficacy, and results in a durable response without evidence of significant toxicity.

The feasibility of circulating tumor DNA analysis as a marker of recurrence in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) has a poorer prognosis than other breast cancer subtypes; therefore, identifying markers of early recurrence is important. The present study aimed to establish a liquid biopsy protocol for droplet digital PCR-based detection of frequently mutated genes in patients with TNBC. Tumor DNA from 36 patients with TNBC who relapsed within 2 years after surgical resection was retrospectively analyzed. Somatic mutational profiles were evaluated using targeted sequencing to identify frequently mutated genes and genes associated with molecularly targeted therapies. The association between genetic alterations and associated protein phosphorylation was investigated using immunohistochemical analysis. Recurrent hot spot mutations in the plasma were monitored over time. Mutation-specific probes were used to successfully detect mutations in the blood samples of patients who were positive for PIK3CA H1047R and AKT1 E17K mutations. Somatic mutations in AKT1 (14.9%) and PIK3CA (25.5%) were frequently identified in the data. Robust phosphorylation of AKT and S6RP was more common in tumors with PIK3CA H1047R and AKT1 E17K mutational background than in tumors with wild-type PIK3CA and AKT1. In conclusion, the present study evaluated a high-sensitivity detection system for frequently mutated genes that was also applicable for cell-free DNA. The PI3K/AKT pathway was revealed to be activated in patients harboring PIK3CA H1047R and AKT1 E17K mutations; therefore, the PI3K/AKT pathway may be a promising candidate for targeted therapy in these patients.

Monitoring epidermal growth factor receptor C797S mutation in Japanese non-small cell lung cancer patients with serial cell-free DNA evaluation using digital droplet PCR.

Osimertinib is a third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) that is effective in treating both naïve and T790M-mutated EGFR-TKI-resistant non-small cell lung cancer patients. The EGFR C797S mutation is the major osimertinib resistance mechanism. The present study monitored the EGFR C797S mutation during osimertinib treatment in Japanese patients using droplet digital PCR (ddPCR). In our first cohort, C797S detection was validated with tumor specimens and/or plasma samples from 26 patients using ddPCR with custom-designed probes detecting and discriminating T790M and C797S in cis and trans positions. In our second cohort, 18 patients with EGFR-T790M who were going to start osimertinib were analyzed using ddPCR by collecting the plasma samples every month from the beginning of the course of osimertinib. In the first cohort, C797S was detected in 15.4% of patients. C797S and T790M in cis and trans positions were distinguished using ddPCR. In the second cohort, serial cfDNA evaluation revealed that the rate of EGFR mutation changes with disease state. Increases of EGFR mutation were detected, including C797S several months before the diagnosis of disease progression. As with the first cohort, C797S and T790M in cis and trans position were distinguished by ddPCR at disease progression. Coincidentally, in the first cohort, next generation sequencing detected NRAS Q61K mutation and the resistance with NRAS Q61K mutation was overcome by trametinib. In the second cohort, serial cfDNA analysis was useful for evaluating bone oligo-progression and local radiation therapy.

Tumor-Derived cGAMP Regulates Activation of the Vasculature.

Intratumoral recruitment of immune cells following innate immune activation is critical for anti-tumor immunity and involves cytosolic dsDNA sensing by the cGAS/STING pathway. We have previously shown that KRAS-LKB1 (KL) mutant lung cancer, which is resistant to PD-1 blockade, exhibits silencing of STING, impaired tumor cell production of immune chemoattractants, and T cell exclusion. Since the vasculature is also a critical gatekeeper of immune cell infiltration into tumors, we developed a novel microfluidic model to study KL tumor-vascular interactions. Notably, dsDNA priming of LKB1-reconstituted tumor cells activates the microvasculature, even when tumor cell STING is deleted. cGAS-driven extracellular export of 2'3' cGAMP by cancer cells activates STING signaling in endothelial cells and cooperates with type 1 interferon to increase vascular permeability and expression of E selectin, VCAM-1, and ICAM-1 and T cell adhesion to the endothelium. Thus, tumor cell cGAS-STING signaling not only produces T cell chemoattractants, but also primes tumor vasculature for immune cell escape.

Suppression of STING Associated with LKB1 Loss in KRAS-Driven Lung Cancer.

KRAS-driven lung cancers frequently inactivate TP53 and/or STK11/LKB1, defining tumor subclasses with emerging clinical relevance. Specifically, KRAS-LKB1 (KL)-mutant lung cancers are particularly aggressive, lack PD-L1, and respond poorly to immune checkpoint blockade (ICB). The mechanistic basis for this impaired immunogenicity, despite the overall high mutational load of KRAS-mutant lung cancers, remains obscure. Here, we report that LKB1 loss results in marked silencing of stimulator of interferon genes (STING) expression and insensitivity to cytoplasmic double-strand DNA (dsDNA) sensing. This effect is mediated at least in part by hyperactivation of DNMT1 and EZH2 activity related to elevated S-adenylmethionine levels and reinforced by DNMT1 upregulation. Ectopic expression of STING in KL cells engages IRF3 and STAT1 signaling downstream of TBK1 and impairs cellular fitness, due to the pathologic accumulation of cytoplasmic mitochondrial dsDNA associated with mitochondrial dysfunction. Thus, silencing of STING avoids these negative consequences of LKB1 inactivation, while facilitating immune escape. SIGNIFICANCE: Oncogenic KRAS-mutant lung cancers remain treatment-refractory and are resistant to ICB in the setting of LKB1 loss. These results begin to uncover the key underlying mechanism and identify strategies to restore STING expression, with important therapeutic implications because mitochondrial dysfunction is an obligate component of this tumor subtype.See related commentary by Corte and Byers, p. 16.This article is highlighted in the In This Issue feature, p. 1.

Highly sensitive detection of ALK resistance mutations in plasma using droplet digital PCR.

BACKGROUND: On-target resistance mechanisms found in one-third of patients receiving anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs) are secondary ALK mutations in ALK-rearranged non-small cell lung cancer (NSCLC). There are large variations in the resistant mutations, unlike the epithelial growth factor receptor (EGFR) T790 M seen with the use of EGFR-TKIs. Liquid biopsy approaches using cell-free DNA (cfDNA) are used for screening and monitoring of mutations in NSCLC. However, feasible protocol for the simultaneous detection of multiple secondary ALK mutations using droplet digital PCR (ddPCR) has not been developed. An efficient strategy using cfDNA in cancer diagnostics, the development of more accurate and cost-effective tools to identify informative multiple secondary ALK mutations is clinically required. METHODS: To establish a feasible assay to monitor ALK-TKI resistance mutations, we first evaluated the feasibility of ddPCR-based screening for cfDNA mutation detection of 10 distinct secondary ALK mutations. Positive samples were then re-analyzed using mutation-specific probes to track the growth of mutation clones with a high sensitivity. RESULTS: Blood samples from seven ALK-positive patients were analyzed using the ddPCR protocol. Secondary G1202R ALK mutations were identified in 2 of 7 patients by the screening assay. Using the mutation-specific probes, monitoring the resistant clone during the clinical course of the disease was well demonstrated in each of the patients. CONCLUSION: The protocol for ddPCR-based liquid biopsy has a feasibility for the screening of secondary ALK-TKI resistance mutations and offers a tool for a cost-effective monitoring of progression in NSCLC.

Effect of alloy element on weld pool dynamics in laser welding of aluminum alloys.

In this manuscript, weld pool dynamics in laser welding of various series of aluminum alloys were investigated by the in situ X-ray phase contrast imaging system. The experimental results showed that metal irradiated by laser was evaporated immediately, which generated the keyhole. Then metal surrounding the keyhole was melted gradually with the heat from keyhole. The growth rate of keyhole depth had a positive linear correlation with the total content of low boiling temperature elements (TCE), so did the keyhole depth and diameter at the stable stage. Longitudinal view area of the molten pool had a negative linear correlation with the thermal conductivity of aluminum alloy. The measured laser absorption rate had the same variation trend with the ratio of keyhole depth to diameter, and the highest absorption rate of 58% appeared in laser welding of aluminum alloy with TCE equal to 2.1%. Violent fluctuation in keyhole shape was avoided in aluminum alloy with TCE lower than 2.1%, where the surface tension and recoil pressure of metal vapor were balanced. To sum up, the effect of alloy element on weld pool dynamics in laser welding of aluminum alloys was firstly quantified in this manuscript.

Neuromyelitis optica spectrum disorder secondary to treatment with anti-PD-1 antibody nivolumab: the first report.

BACKGROUND: Immune checkpoint blockade is developed as standard treatment for non-small cell lung cancer. However immune-related adverse events (irAE) have still unknown complications. Here, we report a patient with lung squamous cell carcinoma who developed neuromyelitis optica spectrum disorder with nivolumab. CASE PRESENTATION: A 75-year-old Japanese man with lung squamous cell carcinoma was administered nivolumab as second-line treatment. Two months after treatment with nivolumab, he presented acute paralysis in the bilateral lower limbs, sensory loss. Spinal magnetic resonance imaging showed T2 hyperintense lesions between C5-6 and Th12-L1. He was diagnosed with neuromyelitis optica spectrum disorder (NMOSD) by anti-aquaporin-4 antibody-positive in the serum and other examinations. After treatment, steroid reactivity was poor. CONCLUSION: This is the first patient who developed anti-AQP4 antibody-positive NMOSD as a nivolumab-induced irAE. Clinicians should be aware of this kind of potential neurological complication by using immune check point inhibitor and start the treatment of this irAE as soon as possible.

Activation of Src signaling mediates acquired resistance to ALK inhibition in lung cancer.

Anaplastic lymphoma kinase (ALK) fusion oncogenes occur in approximately 3-5% of non-small cell lung cancer (NSCLC) cases. Various ALK inhibitors are in clinical use for the treatment of ALK-NSCLC, including the first generation ALK inhibitor, crizotinib, and recently the more highly potent alectinib and ceritinib. However, most tumors eventually become resistant to ALK specific inhibitors. To address the mechanisms underlying the development of ALK inhibitor resistance, we used iTRAQ quantitative mass spectrometry and phosphor-receptor tyrosine kinase arrays to investigate intracellular signaling alterations in ALK inhibitor resistant NSCLC cell lines. Src signaling was identified as an alectinib resistance mechanism, and combination treatment with ALK and Src inhibitors was highly effective for inhibiting the growth of ALK inhibitor resistant cells in vitro and in mouse xenograft models. Furthermore, phospho-receptor tyrosine kinase activation and downstream PI3K/AKT signaling was effectively blocked by inhibiting Src in alectinib resistant cells. Finally, we showed that the combined use of ALK and Src inhibitors inhibited the growth of other ALK-NSCLC cell lines, including those that were ceritinib or lorlatinib resistant. Our data suggest that targeting Src signaling may be an effective approach to the treatment of ALK-NSCLC with acquired resistance to ALK inhibitors.