Transcriptome deconvolution reveals absence of cancer cell expression signature in immune checkpoint blockade response.

Immune-checkpoint therapy (ICB) has conferred significant and durable clinical benefit to some cancer patients. However, most patients do not respond to ICB, and reliable biomarkers of ICB response are needed to improve patient stratification. Here, we performed a transcriptome-wide meta-analysis across 1,486 tumors from ICB-treated patients and tumors with expected ICB outcomes based on microsatellite status. Using a robust transcriptome deconvolution approach, we inferred cancer and stroma-specific gene expression differences and identified cell-type specific features of ICB response across cancer types. Consistent with current knowledge, stromal expression of CXCL9, CXCL13, and IFNG were the top determinants of favorable ICB response. In addition, we identified a group of potential immune-suppressive genes, including FCER1A, associated with poor response to ICB. Strikingly, PD-L1 expression in stromal cells, but not cancer cells, is correlated with ICB response across cancer types. Furthermore, the unbiased transcriptome-wide analysis failed to identify cancer-cell intrinsic expression signatures of ICB response conserved across tumor types, suggesting that cancer cells lack tissue-agnostic transcriptomic features of ICB response.

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

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

Precision Endpoints for Contemporary Precision Oncology Trials.

SUMMARY: Traditional endpoints such as progression-free survival and overall survival do not fully capture the pharmacologic and pharmacodynamic effects of a therapeutic intervention. Incorporating mechanism-driven biomarkers and validated surrogate proximal endpoints can provide orthogonal readouts of anti-tumor activity and delineate the relative contribution of treatment components on an individual level, highlighting the limitation of solely relying on aggregated readouts from clinical trials to facilitate go/no-go decisions for precision therapies.

Oncogene-driven non-small cell lung cancers in patients with a history of smoking lack smoking-induced mutations.

Non-small cell lung cancers (NSCLCs) in non-smokers are mostly driven by mutations in the oncogenes EGFR, ERBB2, and MET and fusions involving ALK and RET. In addition to occurring in non-smokers, alterations in these "non-smoking-related oncogenes" (NSROs) also occur in smokers. To better understand the clonal architecture and genomic landscape of NSRO-driven tumors in smokers compared to typical-smoking NSCLCs, we investigated genomic and transcriptomic alterations in 173 tumor sectors from 48 NSCLC patients. NSRO-driven NSCLCs in smokers and non-smokers had similar genomic landscapes. Surprisingly, even in patients with prominent smoking histories, the mutational signature caused by tobacco smoking was essentially absent in NSRO-driven NSCLCs, which was confirmed in two large NSCLC datasets from other geographic regions. However, NSRO-driven NSCLCs in smokers had higher transcriptomic activities related to regulation of the cell cycle. These findings suggest that, while the genomic landscape is similar between NSRO-driven NSCLC in smokers and non-smokers, smoking still affects the tumor phenotype independently of genomic alterations.

Detection of circulating tumor DNA with ultradeep sequencing of plasma cell-free DNA for monitoring minimal residual disease and early detection of recurrence in early-stage lung cancer.

BACKGROUND: In early-stage non-small cell lung cancer (NSCLC), recurrence is frequently observed. Circulating tumor DNA (ctDNA) has emerged as a noninvasive tool to risk stratify patients for recurrence after curative intent therapy. This study aimed to risk stratify patients with early-stage NSCLC via a personalized, tumor-informed multiplex polymerase chain reaction (mPCR) next-generation sequencing assay. METHODS: This retrospective cohort study included patients with stage I-III NSCLC. Recruited patients received standard-of-care management (surgical resection with or without adjuvant chemotherapy, followed by surveillance). Whole-exome sequencing of NSCLC resected tissue and matched germline DNA was used to design patient-specific mPCR assays (Signatera, Natera, Inc) to track up to 16 single-nucleotide variants in plasma samples. RESULTS: The overall cohort with analyzed plasma samples consisted of 57 patients. Stage distribution was 68% for stage I and 16% each for stages II and III. Presurgery (i.e., at baseline), ctDNA was detected in 15 of 57 patients (26%). ctDNA detection presurgery was significantly associated with shorter recurrence-free survival (RFS; hazard ratio [HR], 3.54; 95% confidence interval [CI], 1.00-12.62; p = .009). In the postsurgery setting, ctDNA was detected in seven patients, of whom 100% experienced radiological recurrence. ctDNA positivity preceded radiological findings by a median lead time of 2.8 months (range, 0-12.9 months). Longitudinally, ctDNA detection at any time point was associated with shorter RFS (HR, 16.1; 95% CI, 1.63-158.9; p < .0001). CONCLUSIONS: ctDNA detection before surgical resection was strongly associated with a high risk of relapse in early-stage NSCLC in a large unique Asian cohort. Prospective studies are needed to assess the clinical utility of ctDNA status in this setting.

A Phase I Study of Acapatamab, a Half-life Extended, PSMA-Targeting Bispecific T-cell Engager for Metastatic Castration-Resistant Prostate Cancer.

PURPOSE: Safety and efficacy of acapatamab, a prostate-specific membrane antigen (PSMA) x CD3 bispecific T-cell engager were evaluated in a first-in-human study in metastatic castration-resistant prostate cancer (mCRPC). PATIENTS AND METHODS: Patients with mCRPC refractory to androgen receptor pathway inhibitor therapy and taxane-based chemotherapy received target acapatamab doses ranging from 0.003 to 0.9 mg in dose exploration (seven dose levels) and 0.3 mg (recommended phase II dose) in dose expansion intravenously every 2 weeks. Safety (primary objective), pharmacokinetics, and antitumor activity (secondary objectives) were assessed. RESULTS: In all, 133 patients (dose exploration, n = 77; dose expansion, n = 56) received acapatamab. Cytokine release syndrome (CRS) was the most common treatment-emergent adverse event seen in 97.4% and 98.2% of patients in dose exploration and dose expansion, respectively; grade ≥ 3 was seen in 23.4% and 16.1%, respectively. Most CRS events were seen in treatment cycle 1; incidence and severity decreased at/beyond cycle 2. In dose expansion, confirmed prostate-specific antigen (PSA) responses (PSA50) were seen in 30.4% of patients and radiographic partial responses in 7.4% (Response Evaluation Criteria in Solid Tumors 1.1). Median PSA progression-free survival (PFS) was 3.3 months [95% confidence interval (CI): 3.0-4.9], radiographic PFS per Prostate Cancer Clinical Trials Working Group 3 was 3.7 months (95% CI: 2.0-5.4). Acapatamab induced T-cell activation and increased cytokine production several-fold within 24 hours of initiation. Treatment-emergent antidrug antibodies were detected in 55% and impacted serum exposures in 36% of patients in dose expansion. CONCLUSIONS: Acapatamab was safe and tolerated and had a manageable CRS profile. Preliminary signs of efficacy with limited durable antitumor activity were observed. Acapatamab demonstrated pharmacokinetic and pharmacodynamic activity.

Canakinumab Versus Placebo in Combination With First-Line Pembrolizumab Plus Chemotherapy for Advanced Non-Small-Cell Lung Cancer: Results From the CANOPY-1 Trial.

PURPOSE: The addition of checkpoint inhibitors to first-line treatment has prolonged survival of patients with non-small-cell lung cancer (NSCLC), but prognosis remains poor, with new treatment options needed. Canakinumab, a human, monoclonal anti-interleukin (IL)-1ß antibody, has potential to enhance the activity of PD-L1 inhibitors and chemotherapy (CT) by inhibiting protumor inflammation. METHODS: CANOPY-1 was a phase III, randomized, double-blind study comparing canakinumab (200 mg subcutaneously once every 3 weeks) versus placebo, both combined with pembrolizumab (200 mg intravenously once every 3 weeks) and platinum-based doublet CT, as first-line treatment for advanced/metastatic NSCLC without EGFR or ALK mutations. The primary end points were progression-free survival (PFS) and overall survival (OS). The secondary endpoints included overall response rate, safety, and patient-reported outcomes. RESULTS: Overall, 643 patients were randomly assigned to canakinumab (n = 320) or placebo (n = 323). With a median study follow-up of 6.5 months, the median PFS was 6.8 months with canakinumab versus 6.8 months with placebo (hazard ratio [HR], 0.85; 95% CI, 0.67 to 1.09; P = .102). With a median study follow-up of 21.2 months, the median OS was 20.8 months with canakinumab versus 20.2 months with placebo (HR, 0.87; 95% CI, 0.70 to 1.10; P = .123). No unexpected safety signals were observed for canakinumab combination. Infection rates were comparable between treatment and control arms. A higher frequency of neutropenia and ALT increase (grade ≤2) were reported in the treatment arm. Higher baseline C-reactive protein and IL-6 levels were associated with shorter PFS and OS. Patients treated with canakinumab had clinically meaningful delays in deterioration of lung cancer symptoms, including chest pain and coughing per LC13 and dyspnea per LC13 and C30. CONCLUSION: The addition of canakinumab to first-line pembrolizumab and CT did not prolong PFS or OS in patients with NSCLC.

Larotrectinib efficacy and safety in adult patients with tropomyosin receptor kinase fusion sarcomas.

BACKGROUND: Larotrectinib, a first-in-class, highly selective tropomyosin receptor kinase (TRK) inhibitor, has demonstrated efficacy in adult and pediatric patients with various solid tumors harboring NTRK gene fusions. This subset analysis focuses on the efficacy and safety of larotrectinib in an expanded cohort of adult patients with TRK fusion sarcomas. METHODS: Patients (≥18 years old) with sarcomas harboring NTRK gene fusions were identified from three clinical trials. Patients received larotrectinib 100 mg orally twice daily. Response was investigator-assessed per RECIST v1.1. Data cutoff was July 20, 2021. RESULTS: At the data cutoff, 36 adult patients with TRK fusion sarcomas had initiated larotrectinib therapy: two (6%) patients had bone sarcomas, four (11%) had gastrointestinal stromal tumors, and 30 (83%) had soft tissue sarcomas. All patients were evaluable for response and demonstrated an objective response rate of 58% (95% confidence interval, 41-74). Patients responded well to larotrectinib regardless of number of prior lines of therapy. Adverse events (AEs) were mostly grade 1/2. Grade 3 treatment-emergent AEs (TEAEs) occurred in 15 (42%) patients. There were no grade 4 TEAEs. Two grade 5 TEAEs were reported, neither of which were considered related to larotrectinib. Four (11%) patients permanently discontinued treatment due to TEAEs. CONCLUSIONS: Larotrectinib demonstrated robust and durable responses, extended survival benefit, and a favorable safety profile in adult patients with TRK fusion sarcomas with longer follow-up. These results continue to demonstrate that testing for NTRK gene fusions should be incorporated into the clinical management of adult patients with various types of sarcomas. PLAIN LANGUAGE SUMMARY: Tropomyosin receptor kinase (TRK) fusion proteins result from translocations involving the NTRK gene and cause cancer in a range of tumor types. Larotrectinib is an agent that specifically targets TRK fusion proteins and is approved for the treatment of patients with TRK fusion cancer. This study looked at how well larotrectinib worked in adult patients with sarcomas caused by TRK fusion proteins. Over half of patients had a durable response to larotrectinib, with no unexpected side effects. These results show that larotrectinib is safe and effective in adult patients with TRK fusion sarcomas.

Coexisting Genomic Alterations in Risk Stratification of KRASG12C-Mutated Non-Small Cell Lung Cancer.

SUMMARY: Negrao and colleagues showed that coalterations in three genes-KEAP1, SMARCA4, and CDKN2A- correlated to poor clinical outcomes in patients with KRASG12C-mutated non-small cell lung cancer treated with sotorasib or adagrasib. Their study highlights how pooling high-resolution real-world genomic data with clinical outcomes can potentially facilitate risk-stratified precision therapies. See related article by Negrao et al., p. 1556 (2).

Landscape of germline pathogenic variants in patients with dual primary breast and lung cancer.

BACKGROUND: Cancer predisposition is most often studied in the context of single cancers. However, inherited cancer predispositions can also give rise to multiple primary cancers. Yet, there is a paucity of studies on genetic predisposition in multiple primary cancers, especially those outside of well-defined cancer predisposition syndromes. This study aimed to identify germline variants associated with dual primary cancers of the breast and lung. METHODS: Exome sequencing was performed on germline DNA from 55 Singapore patients (52 [95%] never-smokers) with dual primaries in the breast and lung, confirmed by histopathology. Using two large control cohorts: the local SG10K_Health (n = 9770) and gnomAD non-cancer East Asians (n = 9626); and two additional local case cohorts of early-onset or familial breast cancer (n = 290), and lung cancer (n = 209), variants were assessed for pathogenicity in accordance with ACMG/AMP guidelines. In particular, comparisons were made with known pathogenic or likely pathogenic variants in the ClinVar database, pathogenicity predictions were obtained from in silico prediction software, and case-control association analyses were performed. RESULTS: Altogether, we identified 19 pathogenic or likely pathogenic variants from 16 genes, detected in 17 of 55 (31%) patients. Six of the 19 variants were identified using ClinVar, while 13 variants were classified pathogenic or likely pathogenic using ACMG/AMP guidelines. The 16 genes include well-known cancer predisposition genes such as BRCA2, TP53, and RAD51D; but also lesser known cancer genes EXT2, WWOX, GATA2, and GPC3. Most of these genes are involved in DNA damage repair, reaffirming the role of impaired DNA repair mechanisms in the development of multiple malignancies. These variants warrant further investigations in additional populations. CONCLUSIONS: We have identified both known and novel variants significantly enriched in patients with primary breast and lung malignancies, expanding the body of known cancer predisposition variants for both breast and lung cancer. These variants are mostly from genes involved in DNA repair, affirming the role of impaired DNA repair in the predisposition and development of multiple cancers.

Lung Cancer Screening in Asia: An Expert Consensus Report.

INTRODUCTION: The incidence and mortality of lung cancer are highest in Asia compared with Europe and USA, with the incidence and mortality rates being 34.4 and 28.1 per 100,000 respectively in East Asia. Diagnosing lung cancer at early stages makes the disease amenable to curative treatment and reduces mortality. In some areas in Asia, limited availability of robust diagnostic tools and treatment modalities, along with variations in specific health care investment and policies, make it necessary to have a more specific approach for screening, early detection, diagnosis, and treatment of patients with lung cancer in Asia compared with the West. METHOD: A group of 19 advisors across different specialties from 11 Asian countries, met on a virtual Steering Committee meeting, to discuss and recommend the most affordable and accessible lung cancer screening modalities and their implementation, for the Asian population. RESULTS: Significant risk factors identified for lung cancer in smokers in Asia include age 50 to 75 years and smoking history of more than or equal to 20 pack-years. Family history is the most common risk factor for nonsmokers. Low-dose computed tomography screening is recommended once a year for patients with screening-detected abnormality and persistent exposure to risk factors. However, for high-risk heavy smokers and nonsmokers with risk factors, reassessment scans are recommended at an initial interval of 6 to 12 months with subsequent lengthening of reassessment intervals, and it should be stopped in patients more than 80 years of age or are unable or unwilling to undergo curative treatment. CONCLUSIONS: Asian countries face several challenges in implementing low-dose computed tomography screening, such as economic limitations, lack of efforts for early detection, and lack of specific government programs. Various strategies are suggested to overcome these challenges in Asia.

Single cell analysis in head and neck cancer reveals potential immune evasion mechanisms during early metastasis.

Profiling tumors at single-cell resolution provides an opportunity to understand complexities underpinning lymph-node metastases in head and neck squamous-cell carcinoma. Single-cell RNAseq (scRNAseq) analysis of cancer-cell trajectories identifies a subpopulation of pre-metastatic cells, driven by actionable pathways including AXL and AURK. Blocking these two proteins blunts tumor invasion in patient-derived cultures. Furthermore, scRNAseq analyses of tumor-infiltrating CD8 + T-lymphocytes show two distinct trajectories to T-cell dysfunction, corroborated by their clonal architecture based on single-cell T-cell receptor sequencing. By determining key modulators of these trajectories, followed by validation using external datasets and functional experiments, we uncover a role for SOX4 in mediating T-cell exhaustion. Finally, interactome analyses between pre-metastatic tumor cells and CD8 + T-lymphocytes uncover a putative role for the Midkine pathway in immune-modulation and this is confirmed by scRNAseq of tumors from humanized mice. Aside from specific findings, this study demonstrates the importance of tumor heterogeneity analyses in identifying key vulnerabilities during early metastasis.

Liquid Biopsies for Cancer Genotyping: Coming of Age?

Precision oncology is predicated on optimal molecular profiling that is "fit for purpose" to identify therapeutic vulnerabilities. Liquid biopsies may compensate for inadequate genotyping, but remain less sensitive and specific compared with tissue biopsies. The liquid biopsy toolbox is poised to expand through novel assays and insights from longitudinal profiling. See related article by Sugimoto et al., p. 1506.

Patient-reported outcomes in capmatinib-treated patients with METex14-mutated advanced NSCLC: Results from the GEOMETRY mono-1 study.

INTRODUCTION: Capmatinib, a MET inhibitor, showed substantial antitumour activity with manageable side effects in patients with MET exon 14 (METex14)-mutated advanced non-small cell lung cancer (aNSCLC) in the GEOMETRY mono-1 study. We report patient-reported outcomes (PROs) from this study. METHODS: Enrolled treatment-naïve (1L) or pre-treated (2L+) patients with aNSCLC with a METex14-skipping mutation received 400 mg capmatinib twice daily during 21-day treatment cycles. PROs were collected at baseline and every six weeks thereafter using EORTC QLQ-C30 global health status/quality of life (GHS/QoL), QLQ-LC13 symptoms, and EQ-5D-5L visual analogue scale (VAS) questionnaires. RESULTS: As of 6 January 2020, 27/28 1L and 65/69 2L+ patients had completed PROs at baseline; compliance rates remained >70%. Cough improved early, with meaningful improvements (≥10-point change from baseline) observed throughout cycles (mean change from baseline [SD] by week 7: 1L -13.0 [39.9], 2L+ -8.2 [28.4]; week 43: 1L -28.2 [26.7], 2L+ -10.5 [27.3]). QoL, assessed by GHS/QoL and VAS, improved by week 7 in 1L and 2L+ patients, with improvements generally sustained over time. Median time to definitive deterioration (TTDD) in GHS/QoL was 16.6 months (95% CI: 9.7, not estimable [NE]) in 1L and 12.4 months (95% CI: 4.2, 19.4) in 2L+ patients. Median TTDD for dyspnoea was 19.4 months (95% CI: 12.4, NE) and 22.1 months (95% CI: 9.9, NE) for 1L and 2L+ patients, respectively, and NE for cough and chest pain. CONCLUSIONS: Capmatinib was associated with clinically meaningful improvements in cough and preserved QoL, further supporting its use in patients with METex14-mutated aNSCLC. TRIAL REGISTRATION: ClinicalTrials.gov registry number: NCT02414139.

PD-L1 score as a prognostic biomarker in asian early-stage epidermal growth factor receptor-mutated lung cancer.

AIM: To determine the prognostic value of programmed death-ligand 1 (PD-L1) score in early-stage epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC), contrasted against EGFR-wildtype NSCLC. METHODS: Consecutive patients with Stage IA-IIIA NSCLC diagnosed 1st January 2010-31st December 2019 at National Cancer Centre Singapore with evaluable EGFR and PD-L1 status were included. Co-primary end-points were 2-year disease-free survival (DFS) and 5-year overall survival (OS) by Kaplan-Meier method. RESULTS: 455 patients were included (267 EGFR-mutated, EGFR-M+; 188 EGFR-wildtype, wt). Median age at diagnosis was 65 years, 52.3% (238/455) of patients were males, 62.9% (286/455) of patients were never-smokers and 92.5% (421/455) of patients had R0 resection. Stage IA comprised 42.4% (193/455) of patients, Stage IB comprised 23.1% (105/455) of patients, Stage IIA comprised 10.8% of patients (49/455), Stage IIB comprised 5.1% of patients (23/455) and Stage IIIA comprised 18.7% (85/455) of patients. Among EGFR-M+, 45.3% (121/267) were Ex19del and 41.9% (112/267) were L858R. PD-L1 ≥1% among EGFR-M+ and EGFR-wt was 45.3% (121/267) and 54.8% (103/188) respectively (p = 0.047). At median follow-up of 47 months, 178 patients had relapsed. Among EGFR-M+, 2-year DFS comparing PD-L1 <1% and PD-L1 ≥1% was 78.1% and 67.6% (p = 0.007) while 5-year OS was 59.5% and 42.8% (p = 0.001), respectively. Controlling for age, gender, lymphovascular invasion, adjuvant therapy and resection margin status, PD-L1 ≥1% (hazard ratio, HR 2.18, 95% CI 1.04-4.54, p = 0.038), stage IIB (HR 7.78, 95% CI 1.72-35.27, p = 0.008) and stage IIIA (HR 4.45, 95% CI 1.44-13.80, p = 0.01) emerged as independent predictors of inferior OS on multivariable analysis. In exploratory analysis, genomic analysis of 81 EGFR-M+ tumours was performed. PD-L1 ≥1% tumours had significantly higher rates of TP53 mutations (36.1% versus 15.6%, p = 0.04), with predominantly missense mutations. CONCLUSION: PD-L1 ≥1% is an independent predictor of worse OS among early-stage EGFR-mutated NSCLC and is associated with inferior DFS regardless of EGFR status. PD-L1 score as a risk stratification factor should be evaluated in prospective adjuvant studies among EGFR-mutated NSCLC.

Brief Report: Droplet Digital Polymerase Chain Reaction Versus Plasma Next-Generation Sequencing in Detecting Clearance of Plasma EGFR Mutations and Carcinoembryonic Antigen Levels as a Surrogate Measure.

Introduction: To compare the performance of droplet digital polymerase chain reaction (ddPCR) and plasma next-generation sequencing (NGS) in detecting clearance of plasma EGFR (pEGFR) mutations. Methods: Patients with treatment-naive advanced EGFR-mutated lung cancer treated with first-line tyrosine kinase inhibitors (TKIs) were included. pEGFR were measured at baseline and first response assessment using ddPCR and NGS. Clearance of pEGFR was defined as undetectable levels after a positive baseline result. Results were correlated with time-to-treatment failure (TTF). In exploratory analysis, corresponding change in carcinoembryonic antigen (CEA) levels was evaluated. Results: Between January 1, 2020, and December 31, 2021, 27 patients were recruited. Ex19del comprised 74% (20 of 27) and L858R 26% (seven of 27). Osimertinib was used in 59% (16 of 27), dacomitinib 4% (one of 27), and gefitinib/erlotinib 37% (10 of 27). Sensitivity of ddPCR and NGS in detecting pEGFR mutation at baseline was 70% (19 of 27) and 78% (21 of 27), respectively (p = 0.16). All patients with detectable pEGFR by ddPCR were detected by NGS.At a median of 8 (range 3-24) weeks post-TKI initiation, clearance of pEGFR was achieved in 68% (13 of 19) and 71% (15 of 21) using ddPCR and NGS, respectively. Concordance between ddPCR and NGS was 79% (kappa = 0.513, p = 0.013). Clearance of pEGFR was associated with longer median TTF (not reached versus 6 months, p = 0.03) and median decrease in CEA levels by 70% from baseline.In another cohort of 124 patients, decrease in CEA levels by greater than 70% within 90 days of TKI initiation was associated with doubling of both TTF and overall survival. Conclusions: Plasma NGS trended toward higher sensitivity than ddPCR in detecting pEGFR, although both had similar concordance in detecting pEGFR clearance. Our results support using NGS at diagnosis and interchangeability of NGS and ddPCR for monitoring, whereas CEA could be explored as a surrogate for pEGFR clearance.

Bystander CD4+ T cells infiltrate human tumors and are phenotypically distinct.

Tumor-specific T cells likely underpin effective immune checkpoint-blockade therapies. Yet, most studies focus on Treg cells and CD8+ tumor-infiltrating lymphocytes (TILs). Here, we study CD4+ TILs in human lung and colorectal cancers and observe that non-Treg CD4+ TILs average more than 70% of total CD4+ TILs in both cancer types. Leveraging high dimensional analyses including mass cytometry, we reveal that CD4+ TILs are phenotypically heterogeneous, within each tumor and across patients. Consistently, we find different subsets of CD4+ TILs showing characteristics of effectors, tissue resident memory (Trm) or exhausted cells (expressing PD-1, CTLA-4 and CD39). In both cancer types, the frequencies of CD39- non-Treg CD4+ TILs strongly correlate with frequencies of CD39- CD8+ TILs, which we and others have previously shown to be enriched for cells specific for cancer-unrelated antigens (bystanders). Ex-vivo, we demonstrate that CD39- CD4+ TILs can be specific for cancer-unrelated antigens, such as HCMV epitopes. Overall, our findings highlight that CD4+ TILs can also recognize cancer-unrelated antigens and suggest measuring CD39 expression as a straightforward way to quantify or isolate bystander CD4+ T cells.