Assessment of Blood Tumor Mutational Burden as a Potential Biomarker for Immunotherapy in Patients With Non-Small Cell Lung Cancer With Use of a Next-Generation Sequencing Cancer Gene Panel

IMPORTANCE

Tumor mutational burden (TMB), as measured by whole-exome sequencing (WES) or a cancer gene panel (CGP), is associated with immunotherapy responses. However, whether TMB estimated by circulating tumor DNA in blood (bTMB) is associated with clinical outcomes of immunotherapy remains to be explored.

OBJECTIVES

To explore the optimal gene panel size and algorithm to design a CGP for TMB estimation, evaluate the panel reliability, and further validate the feasibility of bTMB as a clinical actionable biomarker for immunotherapy.

DESIGN, SETTING, AND PARTICIPANTS

In this cohort study, a CGP named NCC-GP150 was designed and virtually validated using The Cancer Genome Atlas database. The correlation between bTMB estimated by NCC-GP150 and tissue TMB (tTMB) measured by WES was evaluated in matched blood and tissue samples from 48 patients with advanced NSCLC. An independent cohort of 50 patients with advanced NSCLC was used to identify the utility of bTMB estimated by NCC-GP150 in distinguishing patients who would benefit from anti-programmed cell death 1 (anti-PD-1) and anti-programmed cell death ligand 1 (anti-PD-L1) therapy. The study was performed from July 19, 2016, to April 20, 2018.

MAIN OUTCOMES AND MEASURES

Assessment of the Spearman correlation coefficient between bTMB estimated by NCC-GP150 and tTMB calculated by WES. Evaluation of the association of bTMB level with progression-free survival and response to anti-PD-1 and anti-PD-L1 therapy.

RESULTS

This study used 2 independent cohorts of patients with NSCLC (cohort 1: 48 patients; mean [SD] age, 60 [13] years; 15 [31.2%] female; cohort 2: 50 patients; mean [SD] age, 58 [8] years; 15 [30.0%] female). A CGP, including 150 genes, demonstrated stable correlations with WES for TMB estimation (median r2 = 0.91; interquartile range, 0.89-0.92), especially when synonymous mutations were included (median r2 = 0.92; interquartile range, 0.91-0.93), whereas TMB estimated by the NCC-GP150 panel found higher correlations with TMB estimated by WES than most of the randomly sampled 150-gene panels. Blood TMB estimated by NCC-GP150 correlated well with the matched tTMB calculated by WES (Spearman correlation = 0.62). In the anti-PD-1 and anti-PD-L1 treatment cohort, a bTMB of 6 or higher was associated with superior progression-free survival (hazard ratio, 0.39; 95% CI, 0.18-0.84; log-rank P = .01) and objective response rates (bTMB ≥6: 39.3%; 95% CI, 23.9%-56.5%; bTMB <6: 9.1%; 95% CI, 1.6%-25.9%; P = .02).

CONCLUSIONS AND RELEVANCE

The findings suggest that established NCC-GP150 with an optimized gene panel size and algorithm is feasible for bTMB estimation, which may serve as a potential biomarker of clinical benefit in patients with NSCLC treated with anti-PD-1 and anti-PD-L1 agents.

Reproducible copy number variation patterns among single circulating tumor cells of lung cancer patients

Circulating tumor cells (CTCs) enter peripheral blood from primary tumors and seed metastases. The genome sequencing of CTCs could offer noninvasive prognosis or even diagnosis, but has been hampered by low single-cell genome coverage of scarce CTCs. Here, we report the use of the recently developed multiple annealing and looping-based amplification cycles for whole-genome amplification of single CTCs from lung cancer patients. We observed characteristic cancer-associated single-nucleotide variations and insertions/deletions in exomes of CTCs. These mutations provided information needed for individualized therapy, such as drug resistance and phenotypic transition, but were heterogeneous from cell to cell. In contrast, every CTC from an individual patient, regardless of the cancer subtypes, exhibited reproducible copy number variation (CNV) patterns, similar to those of the metastatic tumor of the same patient. Interestingly, different patients with the same lung cancer adenocarcinoma (ADC) shared similar CNV patterns in their CTCs. Even more interestingly, patients of small-cell lung cancer have CNV patterns distinctly different from those of ADC patients. Our finding suggests that CNVs at certain genomic loci are selected for the metastasis of cancer. The reproducibility of cancer-specific CNVs offers potential for CTC-based cancer diagnostics.

Neoadjuvant PD-1 inhibitor (Sintilimab) in NSCLC

INTRODUCTION

Programmed death receptor-1 (PD-1) inhibitors have shown efficacy in first-line treatment of NSCLC; however, evidence of PD-1 inhibitor as neoadjuvant treatment is limited. This is a phase 1b study to evaluate the safety and outcome of PD-1 inhibitor in neoadjuvant setting.

METHODS

Treatment-naive patients with resectable NSCLC (stage IA-IIIB) received two cycles of sintilimab (200 mg, intravenously, day 1 out of 22). Operation was performed between day 29 and 43. Positron emission tomography-computed tomography scans were obtained at baseline and before the operation. The primary end point was safety. Efficacy end points included rate of major pathologic response (MPR) and objective response rate. Expression of programmed cell death ligand 1 was also evaluated (registration number: ChiCTR-OIC-17013726).

RESULTS

A total of 40 patients enrolled, all of whom received two doses of sintilimab and 37 underwent radical resection. A total of 21 patients (52.5%) experienced neoadjuvant treatment-related adverse events (TRAEs). Four patients (10.0%) experienced grade 3 or higher neoadjuvant TRAEs, and one patient had grade 5 TRAE. Eight patients achieved radiological partial response, resulting in an objective response rate of 20.0%. Among 37 patients, 15 (40.5%) achieved MPR, including six (16.2%) with a pathologic complete response in primary tumor and three (8.1%) in lymph nodes as well. Squamous cell NSCLC exhibited superior response compared with adenocarcinoma (MPR: 48.4% versus 0%). Decrease of maximum standardized uptake values after sintilimab treatment correlated with pathologic remission (p < 0.00001). Baseline programmed cell death ligand 1 expression of stromal cells instead of tumor cells was correlated with pathologic regression (p = 0.0471).

CONCLUSIONS

Neoadjuvant sintilimab was tolerable for patients with NSCLC, and 40.5% MPR rate is encouraging. The decrease of maximum standardized uptake values after sintilimab might predict pathologic response.

Third-generation inhibitors targeting EGFR T790M mutation in advanced non-small cell lung cancer

The tyrosine kinase inhibitors (TKI) against epidermal growth factor receptor (EGFR) are widely used in patients with non-small cell lung cancer (NSCLC). However, EGFR T790M mutation leads to resistance to most clinically available EGFR TKIs. Third-generation EGFR TKIs against the T790M mutation have been in active clinical development. These agents include osimertinib, rociletinib, HM61713, ASP8273, EGF816, and PF-06747775. Osimertinib and rociletinib have shown clinical efficacy in phase I/II trials in patients who had acquired resistance to first- or second-generation TKIs. Osimertinib (AZD9291, TAGRISSO) was recently approved by FDA for metastatic EGFR T790M mutation-positive NSCLC. HM61713, ASP8237, EGF816, and PF-06747775 are still in early clinical development. This article reviews the emerging data regarding third-generation agents against EGFR T790M mutation in the treatment of patients with advanced NSCLC.

EAI045: The fourth-generation EGFR inhibitor overcoming T790M and C797S resistance

The third-generation tyrosine kinase inhibitors (TKI), AZD9291 (osimertinib) and CO-1686 (rociletinib) of epidermal growth factor receptor (EGFR) are highly active against T790M positive non-small cell lung cancer (NSCLC). However, resistance develops rapidly. EGFR C797S mutation was reported to be a leading mechanism of resistance to the third-generation inhibitors. The C797S mutation appears to be an ideal target for overcoming the acquired resistance to the third-generation inhibitors. This review summarizes the latest development on the discovery of a fourth-generation EGFR TKI, EAI045.3.

Current Diagnosis and Management of Small-Cell Lung Cancer

Small-cell lung cancer (SCLC) is an aggressive disease with distinct pathological, clinical, and molecular characteristics from non-small-cell lung cancer. SCLC has high metastatic potential, resulting in a clinically poor prognosis. Early concurrent chemo-radiation is the standard of care for limited-stage SCLC (LS-SCLC). Prophylactic cranial irradiation (PCI) is recommended for patients with LS-SCLC without progression of disease after initial therapy. A combination of etoposide and cisplatin or carboplatin remains the mainstay of first-line treatment for ES-SCLC, with the addition of atezolizumab, now becoming standard. Most SCLCs initially respond to therapy but almost invariably recur. Topotecan and amrubicin (in Japan) remain the primary chemotherapy options for relapsed SCLC. Immunotherapy, including nivolumab with or without ipilimumab, is now available for refractory disease. In general, the poor prognosis of SCLC has not improved significantly for more than 3 decades. Recently, next-generation molecular profiling studies have identified new therapeutic targets for SCLC. A variety of proapoptotic agents, compounds capitalizing on DNA-repair defects, immunotherapy agents, and antibody-drug conjugates are being evaluated in SCLC, with a number of them showing early promise.

TCR Repertoire Diversity of Peripheral PD-1+CD8+ T Cells Predicts Clinical Outcomes after Immunotherapy in Patients with Non-Small Cell Lung Cancer

T-cell receptor (TCR)-based biomarkers might predict patient response to immune checkpoint blockade (ICB) but need further exploration and validation for that use. We sequenced complementarity-determining region 3 of TCRβ chains isolated from PD-1+ CD8+ T cells to investigate its value for predicting the response to anti-programmed cell death 1 (PD-1)/PD-ligand 1 (PD-L1) therapy in patients with non-small cell lung cancer (NSCLC). Two independent patient cohorts (cohort A, n = 25; cohort B, n = 15) were used as discovery and validation sets, respectively. Pre- and post-ICB peripheral blood samples were collected. In cohort A, patients with high PD-1+ CD8+ TCR diversity before ICB treatment showed better response to ICB and progression-free survival (PFS) compared with patients with low diversity [6.4 months vs. 2.5 months, HR, 0.39; 95% confidence interval (CI), 0.17-0.94; P = 0.021]. The results were validated in cohort B. Pre-ICB PD-1+ CD8+ TCR diversity achieved an optimal Youden's index of 0.81 (sensitivity = 0.87 and specificity = 0.94) for differentiating the ICB response in the merged dataset (cohort A plus cohort B). Patients with increased PD-1+ CD8+ TCR clonality after ICB treatment had longer PFS (7.3 months vs. 2.6 months, HR, 0.26; 95% CI, 0.08-0.86; P = 0.002) than those with decreased clonality. Thus, TCR diversity and clonality in peripheral blood PD-1+ CD8+ T cells may serve as noninvasive predictors of patient response to ICB and survival outcomes in NSCLC.

Comutations in DNA Damage Response Pathways Serve as Potential Biomarkers for Immune Checkpoint Blockade

Biomarkers such as programmed death receptor 1 ligand (PD-L1) expression, tumor mutational burden (TMB), and high microsatellite instability are potentially applicable to predict the efficacy of immune checkpoint blockade (ICB). However, several challenges such as defining the cut-off value, test platform uniformity, and low frequencies limit their broad clinical application. Here we identify comutations in the DNA damage response (DDR) pathways of homologous recombination repair and mismatch repair (HRR-MMR) or HRR and base excision repair (HRR-BER; defined as co-mut+) that are associated with increased TMB and neoantigen load and increased levels of immune gene expression signatures. In four public clinical cohorts, co-mut+ patients presented a higher objective response rate and a longer progression-free survival or overall survival than co-mut- patients. Overall, identification of DDR comutations in HRR-MMR or HRR-BER as predictors of response to ICB provides a potentially convenient approach for future clinical practice.Significance: Identification of comutations in specific DDR pathways as predictors of superior survival outcomes in response to immune checkpoint blockade provide a clinically convenient approach for estimation of tumor mutational burden and delivery of ICB therapy. Cancer Res; 78(22); 6486-96. ©2018 AACR.

Influence of chemotherapy on EGFR mutation status among patients with non-small-cell lung cancer

PURPOSE

EGFR mutation is a predictor of epidermal growth factor receptor-tyrosine kinase inhibitor treatment response in patients with non-small-cell lung cancer (NSCLC). However, it remains unclear whether chemotherapy affects EGFR mutation status in NSCLC. We investigated the influence of chemotherapy on EGFR mutations in plasma and tumor tissues from patients with NSCLC.

PATIENTS AND METHODS

Samples were derived from three cohorts: one, 264 patients with advanced NSCLC who received first-line chemotherapy with matched pre- and postchemotherapy blood samples; two, 63 patients with stages IIb to IIIb disease with pre- and post-neoadjuvant chemotherapy tumor tissues; and three, 79 patients with advanced NSCLC who underwent palliative surgery. EGFR mutation status was determined and analyzed to reveal potential impact of chemotherapy.

RESULTS

In the first cohort, EGFR mutations were detected in 34.5% of the prechemotherapy plasma samples (91 of 264) but in only 23.1% of the postchemotherapy plasma samples (61 of 264). The decrease in EGFR mutation rate was statistically significant (P < .001). Patients whose EGFR mutations switched from positive to negative after chemotherapy had a better partial response (PR) than patients with a reverse change (P = .037). A similar decrease in EGFR mutation rate was observed in tissues after neoadjuvant chemotherapy in the second cohort (34.9% [22 of 63] v 19.0% [12 of 63]; P = .013). In the third cohort, 38.0% of the tumors (30 of 79) showed an intratumor heterogeneity of EGFR mutation, whereas 62.0% (49 of 79) were homogeneous, either with EGFR mutation or no mutation.

CONCLUSION

Our results suggest that chemotherapy may reduce EGFR mutation frequency in patients with NSCLC, likely the result of a preferential response of subclones with EGFR mutations in tumors with heterogeneous tumor cell populations.

EGFR C797S mutation mediates resistance to third-generation inhibitors in T790M-positive non-small cell lung cancer

T790M mutation is the most common mechanism for resistance to first- and second-generation tyrosine kinase inhibitors (TKI) for epidermal growth factor receptor (EGFR). Several third-generation EGFR mutant selective TKIs are being explored to conquer this resistance. AZD9291 (osimertinib, tagrisso) has been approved for treatment of the metastatic EGFR T790M mutation-positive non-small cell lung cancer. Resistance to AZD9291 has been described. C797S mutation was reported to be a major mechanism for resistance to T790M-targeting EGFR inhibitors. This review summarizes the latest development in identifying the C797S mutation and EAI045, the novel selective inhibitor overcoming the C797S mutant.

Perspectives of tumor-infiltrating lymphocyte treatment in solid tumors

Tumor-infiltrating lymphocyte (TIL) therapy is a type of adoptive cellular therapy by harvesting infiltrated lymphocytes from tumors, culturing and amplifying them in vitro and then infusing back to treat patients. Its diverse TCR clonality, superior tumor-homing ability, and low off-target toxicity endow TIL therapy unique advantages in treating solid tumors compared with other adoptive cellular therapies. Nevertheless, the successful application of TIL therapy currently is still limited to several types of tumors. Herein in this review, we summarize the fundamental work in the field of TIL therapy and the current landscape and advances of TIL clinical trials worldwide. Moreover, the limitations of the current TIL regimen have been discussed and the opportunities and challenges in the development of next-generation TIL are highlighted. Finally, the future directions of TIL therapy towards a broader clinical application have been proposed.

Quantification and dynamic monitoring of EGFR T790M in plasma cell-free DNA by digital PCR for prognosis of EGFR-TKI treatment in advanced NSCLC

BACKGROUND

Among advanced non-small cell lung cancer (NSCLC) patients with an acquired resistance to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI), about 50% carry the T790M mutation, but this frequency in EGFR-TKI-naïve patients and dynamic change during therapy remains unclear. This study investigated the quantification and dynamic change of T790M mutation in plasma cell-free DNA (cf-DNA) of advanced NSCLC patients to assess the clinical outcomes of EGFR-TKI therapy.

MATERIALS AND METHODS

We retrospectively investigated 135 patients with advanced NSCLC who obtained progression-free survival (PFS) after EGFR-TKI for >6 months for their EGFR sensitive mutations and T790M mutation in matched pre- and post-TKI plasma samples, using denaturing high-performance liquid chromatography (DHPLC), amplification refractory mutation system (ARMS), and digital-PCR (D-PCR). Real-time PCR was performed to measure c-MET amplification.

RESULTS

Detection limit of D-PCR in assessing the T790M mutation was approximately 0.03%. D-PCR identified higher frequency of T790M than ARMS in pre-TKI (31.3% vs. 5.5%) and post-TKI (43.0% vs. 25.2%) plasma samples. Patients with pre-TKI T790M showed inferior PFS (8.9 vs. 12.1 months, p = 0.007) and overall survival (OS, 19.3 vs. 31.9 months, p = 0.001) compared with those without T790M. In patients harboring EGFR sensitive mutation, high quantities of pre-TKI T790M predicted poorer PFS (p = 0.001) on EGFR-TKI than low ones. Moreover, patients who experienced increased quantity of T790M during EGFR-TKI treatment showed superior PFS and OS compared with those with decreased changes (p = 0.044 and p = 0.015, respectively).

CONCLUSION

Qualitative and quantitative T790M in plasma cf-DNA by D-PCR provided a non-invasive and sensitive assay to predict EGFR-TKI prognosis.

Potential clinical significance of a plasma-based KRAS mutation analysis in patients with advanced non-small cell lung cancer

PURPOSE

Non-small cell lung cancer (NSCLC) with KRAS mutation may be resistant to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKI). This study aims to evaluate a plasma-based KRAS mutation analysis and the clinical significance of plasma KRAS mutation as a predictive marker for tumor resistance to EGFR-TKIs in patients with NSCLC.

EXPERIMENTAL DESIGN

DNA extracted from plasma and matched tumor tissues were obtained from 273 patients with advanced stage NSCLC. Patients were followed up prospectively for treatment outcomes. KRAS mutations in codon 12 and 13 were detected using PCR-restriction fragment length polymorphism. Mutations in plasma and matched tumors were compared. Associations between KRAS mutation status and patients' clinical outcomes were analyzed.

RESULTS

KRAS mutation was found in 35 (12.8%) plasma samples and 30 (11.0%) matched tumor tissues. The consistency of KRAS mutations between plasma and tumors is 76.7% (23 of 30; kappa = 0.668; P < 0.001). Among 120 patients who received EGFR-TKI treatment, the response rate was only 5.3% (1 of 19) for patients with plasma KRAS mutation compared with 29.7% for patients with no KRAS mutation in plasma DNA (P = 0.024). The median progression-free survival time of patients with plasma KRAS mutation was 2.5 months compared with 8.8 months for patients with wild-type KRAS (P < 0.001).

CONCLUSIONS

KRAS mutation in plasma DNA correlates with the mutation status in the matched tumor tissues of patients with NSCLC. Plasma KRAS mutation status is associated with a poor tumor response to EGFR-TKIs in NSCLC patients and may be used as a predictive marker in selecting patients for such treatment.

Mechanisms of resistance to third-generation EGFR tyrosine kinase inhibitors

The tyrosine kinase inhibitors (TKI) of the epidermal growth factor receptor (EGFR) are becoming the first line of therapy for advanced non-small cell lung cancer (NSCLC). Acquired mutations in EGFR account for one of the major mechanisms of resistance to the TKIs. Three generations of EGFR TKIs have been used in clinical applications. AZD9291 (osimertinib; Tagrisso) is the first and only FDA approved third-generation EGFR TKI for T790M-positive advanced NSCLC patients. However, resistance to AZD9291 arises after 9-13 months of therapy. The mechanisms of resistance to third-generation inhibitors reported to date include the EGFR C797S mutation, EGFR L718Q mutation, and amplifications of HER-2, MET, or ERBB2. To overcome the acquired resistance to AZD9291, EAI045 was discovered and recently reported to be an allosteric EGFR inhibitor that overcomes T790M- and C797S-mediated resistance. This review summarizes recent investigations on the mechanisms of resistance to the EGFR TKIs, as well as the latest development of EAI045 as a fourth-generation EGFR inhibitor.

Clinical applications of PD-L1 bioassays for cancer immunotherapy

Programmed death ligand 1 (PD-L1) has emerged as a biomarker that can help to predict responses to immunotherapies targeted against PD-L1 and its receptor (PD-1). Companion tests for evaluating PD-L1 expression as a biomarker of response have been developed for many cancer immunotherapy agents. These assays use a variety of detection platforms at different levels (protein, mRNA), employ diverse biopsy and surgical samples, and have disparate positivity cutoff points and scoring systems, all of which complicate the standardization of clinical decision-making. This review summarizes the current understanding and ongoing investigations regarding PD-L1 expression as a potential biomarker for clinical outcomes of anti-PD-1/PD-L1 immunotherapy.

Inferring the Evolution and Progression of Small-Cell Lung Cancer by Single-Cell Sequencing of Circulating Tumor Cells

PURPOSE

Genomic analyses of small-cell lung cancer (SCLC) are limited by the availability of tumor specimens. This study aimed to investigate the suitability of single-cell sequencing of circulating tumor cells (CTC) as a method of inferring the evolution and progression of SCLCs.

EXPERIMENTAL DESIGN

Between July 1, 2011, and July 28, 2014, 48 consecutively diagnosed patients with SCLC were recruited for this study. CTCs were captured from each patient with CellSearch system. Somatic mutations and copy number alterations (CNA) were monitored by single-cell sequencing of CTCs during chemotherapy.

RESULTS

Single-cell sequencing of CTCs can provide a mutational atlas for SCLC. A 10-CNA score based on single CTCs was established as a classifier for outcomes of initial chemotherapy in patients with SCLC. The survival analyses demonstrated that patients with low CNA scores (<0) had significantly prolonged progression-free survival (PFS) and overall survival (OS) after first-line chemotherapy in comparison with those with high scores (≥0; PFS: 212 days vs. 110.5 days, P = 0.0042; and OS: 223.5 days vs. 424 days, P = 0.0006). The positive predictive value and negative predictive value of the CNA score for clinical subtype (refractory vs. sensitive) were 80.0% and 93.7%, respectively. By tracing allele-specific CNAs in CTCs isolated at different time points during chemotherapy, we showed that CNA heterogeneity might result from allelic losses of initially consistent CNAs.

CONCLUSIONS

Single CTC-based sequencing can be utilized to depict the genomic profiles and evolutionary history of SCLC, thus offering the potential for clinical stratification of patients with SCLC.

Allele Frequency-Adjusted Blood-Based Tumor Mutational Burden as a Predictor of Overall Survival for Patients With NSCLC Treated With PD-(L)1 Inhibitors

INTRODUCTION

Blood-based tumor mutational burden (bTMB) has been studied to identify patients with NSCLC who would benefit from anti-programmed cell death protein 1 (anti-PD-1) or anti-programmed death ligand 1 (anti-PD-L1) therapies. However, it failed to predict overall survival (OS) benefits, which warrants further exploration.

METHODS

Three independent cohorts of patients with NSCLC treated with immunotherapy were used in this study. A new bTMB algorithm was first developed in the two independent cohorts (POPLAR, N = 211, and OAK, N = 462) and further validated in the third National Cancer Center (NCC) cohort (N = 64).

RESULTS

bTMB-H (bTMB ≥ cutoff point) was not associated with favorable OS after immunotherapy regardless of the cutoff points in either the POPLAR and OAK or the NCC cohorts (p > 0.05) owing to its correlation with the amount of circulating tumor DNA, which was associated with poor OS. In the POPLAR and OAK cohorts, with allele frequency (AF) adjustment, a high AF bTMB (HAF-bTMB, mutation counts with an AF > 5%) was strongly correlated with the amount of circulating tumor DNA (Pearson r = 0.65), whereas a low AF bTMB (LAF-bTMB, mutation counts with an AF ≤ 5%) was not (Pearson r = 0.09). LAF-bTMB-H was associated with favorable OS (hazard ratio [HR] = 0.70, 95% confidence interval [CI]: 0.52-0.95, p = 0.02), progression-free survival (PFS; HR = 0.62, 95% CI: 0.47-0.80, p < 0.001), and objective response rate (ORR) (p < 0.001) after immunotherapy but not chemotherapy, with a cutoff point of 12 trained in the POPLAR cohort and validated in the OAK cohort. The LAF-bTMB algorithm was further validated in the NCC cohort in which LAF-bTMB-H was associated with OS (HR = 0.20, 95% CI: 0.05-0.84, p = 0.02), PFS (HR = 0.30, 95% CI: 0.13-0.70, p = 0.003), and ORR (p = 0.001).

CONCLUSIONS

We developed and validated a new LAF-bTMB algorithm as a feasible predictor of OS, PFS, and ORR after anti-PD-(L)1 therapies in patients with NSCLC, which needs to be prospectively validated.

Changes in clinical trials of cancer drugs in mainland China over the decade 2009-18: a systematic review

As a result of recent, substantial capacity building, a new landscape for cancer drug trials is emerging in China. However, data on the characteristics of cancer drug trials, and how they have changed over time, are scarce. Based on clinical trials published on the China Food and Drug Administration Registration and Information Disclosure Platform for Drug Clinical Studies, we aimed to systematically review changes over time in clinical trials of cancer drugs in mainland China from 2009 to 2018, to provide insight on the effectiveness of the pharmaceutical industry and identify unmet clinical needs of stakeholders. A total of 1493 trials of 751 newly tested cancer drugs were initiated. Increases over time were observed for the annual number of initiated trials, newly tested drugs, and newly added leading clinical trial units, with a sharp increase after 2016. Of the 1385 trials in which cancer types were identified, solid tumours (325 [23%] trials), non-small-cell lung cancer (232 [17%]), and lymphoma (126 [9%]) were the most common. A markedly uneven distribution was also observed in the geography of leading units with the largest number of leading units located in east China (50 [41%]) and the smallest number located in southwest China (4 [3%]). The growth trends we observed illustrate the progress in and increasing capability of cancer drug research and development achieved in mainland China over the decade from 2009. The low number of clinical trials on tumours with epidemiological characteristics unique to the Chinese population and the unbalanced geographical distribution of leading clinical trial units will provide potential targets for policy makers and other stakeholders. Further research efforts should address cancers uniquely relevant to Chinese populations, globally rare cancers, and the balance between equitable drug access, efficiency, and sustainability of cancer drug research and development in mainland China.

Hypoxia-inducible factor-1α and nuclear factor-κB play important roles in regulating programmed cell death ligand 1 expression by epidermal growth factor receptor mutants in non-small-cell lung cancer cells

Some driver gene mutations, including epidermal growth factor receptor (EGFR), have been reported to be involved in expression regulation of the immunosuppressive checkpoint protein programmed cell death ligand 1 (PD-L1), but the underlying mechanism remains obscure. We investigated the potential role and precise mechanism of EGFR mutants in PD-L1 expression regulation in non-small-cell lung cancer (NSCLC) cells. Examination of pivotal EGFR signaling effectors in 8 NSCLC cell lines indicated apparent associations between PD-L1 overexpression and phosphorylation of AKT and ERK, especially with increased protein levels of phospho-IκBα (p-IκBα) and hypoxia-inducible factor-1α (HIF-1α). Flow cytometry results showed stronger membrane co-expression of EGFR and PD-L1 in NSCLC cells with EGFR mutants compared with cells carrying WT EGFR. Additionally, ectopic expression or depletion of EGFR mutants and treatment with EGFR pathway inhibitors targeting MEK/ERK, PI3K/AKT, mTOR/S6, IκBα, and HIF-1α indicated strong accordance among protein levels of PD-L1, p-IκBα, and HIF-1α in NSCLC cells. Further treatment with pathway inhibitors significantly inhibited xenograft tumor growth and p-IκBα, HIF-1α, and PD-L1 expression of NSCLC cells carrying EGFR mutant in nude mice. Moreover, immunohistochemical analysis revealed obviously increased protein levels of p-IκBα, HIF-1α, and PD-L1 in NSCLC tissues with EGFR mutants compared with tissues carrying WT EGFR. Non-small-cell lung cancer tissues with either p-IκBα or HIF-1α positive staining were more likely to possess elevated PD-L1 expression compared with tissues scored negative for both p-IκBα and HIF-1α. Our findings showed important roles of phosphorylation activation of AKT and ERK and potential interplay and cooperation between NF-κB and HIF-1α in PD-L1 expression regulation by EGFR mutants in NSCLC.

The state of the art of bispecific antibodies for treating human malignancies

Bispecific antibodies (bsAb) that target two independent epitopes or antigens have been extensively explored in translational and clinical studies since they were first developed in the 1960s. Many bsAbs are being tested in clinical trials for treating a variety of diseases, mostly cancer. Here, we provide an overview of various types of bsAbs in clinical studies and discuss their targets, safety profiles, and efficacy. We also highlight the current challenges, potential solutions, and future directions of bsAb development for cancer treatment.

Drug conjugate-based anticancer therapy - Current status and perspectives

Drug conjugates are conjugates comprising a tumor-homing carrier tethered to a cytotoxic agent via a linker that are designed to deliver an ultra-toxic payload directly to the target cancer cells. This strategy has been successfully used to increase the therapeutic efficacy of cytotoxic agents and reduce their toxic side effects. Drug conjugates are being developed worldwide, with the potential to revolutionize current cancer treatment strategies. Antibody-drug conjugates (ADCs) have developed rapidly, and 14 of them have received market approval since the first approval event by the Food and Drug Administration in 2000. However, there are some limitations in the use of antibodies as carriers. Other classes of drug conjugates are emerging, such as targeted drugs conjugated with peptides (peptide-drug conjugates, PDCs) and polymers (polymer-drug conjugates, PolyDCs) with the remaining constructs similar to those of ADCs. These novel drug conjugates are gaining attention because they overcome the limitations of ADCs. This review summarizes the current state and advancements in knowledge regarding the design, constructs, and clinical efficacy of different drug conjugates.

The efficiency of 18F-FDG PET-CT for predicting the major pathologic response to the neoadjuvant PD-1 blockade in resectable non-small cell lung cancer

PURPOSE

Investigate whether 18F-FDG PET-CT has the potential to predict the major pathologic response (MPR) to neoadjuvant sintilimab in resectable NSCLC patients, and the potential of sifting patients who probably benefit from immunotherapy.

METHODS

Treatment-naive patients with resectable NSCLC (stage IA-IIIB) received two cycles of sintilimab (200 mg, intravenously, day 1 and 22). Surgery was performed between day 29 and 43. PET-CT was obtained at baseline and prior to surgery. The following lean body mass-corrected metabolic parameters were calculated by PET VCAR: SULmax, SULpeak, MTV, TLG, ΔSULmax%, ΔSULpeak%, ΔMTV%, ΔTLG%. PET responses were classified using PERCIST. The above metabolic information on FDG-PET was correlated with the surgical pathology. (Registration Number: ChiCTR-OIC-17013726).

RESULTS

Thirty-six patients received 2 doses of sintilimab, all of whom underwent PET-CT twice and had radical resection (35) or biopsy (1). MPR occurred in 13 of 36 resected tumors (36.1%, 13/36). The degree of pathological regression was positively correlated with SULmax (p = 0.036) of scan-1, and was negatively correlated with all metabolic parameters of scan-2, and the percentage changes of the metabolic parameters after neoadjuvant therapy (p < 0.05). According to PERCIST, 13 patients (36.1%, 13/36) showed partial metabolic response (PMR), 21 (58.3%, 21/36) had stable metabolic disease, and 2 (5.6%, 2/36) had progressive metabolic disease (PMD). There was a significant correlation between the pathological response and the PET responses which were classified using PERCIST. All (100.0%) the PMR (ΔSULpeak% < - 30.0%) tumors showed MPR.

CONCLUSIONS

18F-FDG PET-CT can predict MPR to neoadjuvant sintilimab in resectable non-small cell lung cancer.