Zongbi Yi

ctDNA dynamics: a novel indicator to track resistance in metastatic breast cancer treated with anti-HER2 therapy

Background Most studies utilizing circulating tumor DNA (ctDNA) to monitor disease interrogated only one or a few genes and failed to develop workable criteria to inform clinical practice. We evaluated the feasibility of detecting resistance to anti-HER2 therapy by serial gene-panel ctDNA sequencing. Results Primary therapeutic resistance was identified in 6 out of 14 patients with events of progressive disease. For this subset comparison of pre- and post-treatment ctDNA assay results revealed that HER2 amplification concurred with disease progression (4/6, 66.7%). Mutations in TP53 (3/6, 50.0%) and genes implicated in the PI3K/mTOR pathway (3/6, 50.0%) were also dominant markers of resistance. Together, resistance to HER2 blockade should be indicated during treatment if any of the following situations applies: 1) recurrence or persistence of HER2 amplification in the blood; 2) emergence or ≥20% increase in the fraction of mutations in any of these resistance-related genes including TP53/PIK3CA/MTOR/PTEN. Compared with CT scans, dynamic ctDNA profiling utilizing pre-defined criteria was sensitive in identifying drug resistance (sensitivity 85.7%, specificity 55.0%), with a concordance rate up to 82.1%. Besides, the ctDNA criteria had a discriminating role in the prognosis of HER2-positive metastatic breast cancer. Methods 52 plasma samples were prospectively collected from 18 patients with HER2-positive metastatic breast cancer who were treated with an oral anti-HER1/HER2 tyrosine kinase inhibitor (ClinicalTrials.gov NCT01937689). ctDNA was assayed by gene-panel target-capture next-generation sequencing. Conclusions Longitudinal gene-panel ctDNA sequencing could be exploited to determine resistance and guide the precise administration of anti-HER2 targeted therapy in the metastatic setting.

Phase I Study and Biomarker Analysis of Pyrotinib, a Novel Irreversible Pan-ErbB Receptor Tyrosine Kinase Inhibitor, in Patients With Human Epidermal Growth Factor Receptor 2–Positive Metastatic Breast Cancer

Purpose This phase I study assessed the safety, tolerability, pharmacokinetics, antitumor activity, and predictive biomarkers of pyrotinib, an irreversible pan-ErbB inhibitor, in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer. Patients and Methods Pyrotinib was administered continuously, orally, once per day to patients who did not have prior exposure to tyrosine kinase inhibitors of HER2. Planned dose escalation was 80, 160, 240, 320, 400, and 480 mg. For pharmacokinetic analysis, timed blood samples were collected on day 1 and day 28. Next-generation sequencing was performed on circulating tumor DNA and genomic DNA from tumor samples. Results Thirty-eight patients were enrolled. The dose-limiting toxicity was grade 3 diarrhea, which occurred in two patients administered 480 mg of pyrotinib; thus, the maximum tolerated dose was 400 mg. Common pyrotinib-related adverse events included diarrhea (44.7% [17 of 38]), nausea (13.2% [five of 38]), oral ulceration (13.2% [five of 38]), asthenia (10.5% [four of 38]), and leukopenia (10.5% [four of 38]). The only grade 3 adverse event was diarrhea. Pharmacokinetic analyses indicated that pyrotinib exposure was dose dependent. The overall response rate was 50.0% (18 of 36), and the clinical benefit rate (complete response + partial response + stable disease ≥ 24 weeks) was 61.1% (22 of 36). The median progression-free survival was 35.4 weeks (95% CI, 23.3 to 40.0 weeks). The overall response rate was 83.3% (10 of 12) in trastuzumab-naive patients and 33.3% (eight of 24) in trastuzumab-pretreated patients. Preliminary results suggest that PIK3CA and TP53 mutations in circulating tumor DNA ( P = .013) rather than in archival tumor tissues ( P = .474) may predict the efficacy of pyrotinib. Conclusion Continuous once-per-day pyrotinib was well tolerated and demonstrated promising antitumor activity in HER2-positive patients with metastatic breast cancer. The maximum tolerated dose was established as 400 mg. Diarrhea was the dose-limiting toxicity. The promising antitumor activity and acceptable tolerability of pyrotinib warrant its further evaluation in a phase II study.

The Efficacy and Safety of Programmed Cell Death 1 and Programmed Cell Death 1 Ligand Inhibitors for Advanced Melanoma: A Meta-Analysis of Clinical Trials Following the PRISMA Guidelines

AbstractThe purpose of this study was to investigate the efficacy and safety of programmed cell death 1 (PD-1) and programmed cell death 1 ligand (PD-L1) inhibitors using a meta-analysis of present trials for advanced melanoma.A fully recursive literature search of the primary electronic databases for available trials was performed. The objective response rate (ORR) and the median progression-free survival (PFS) of clinical responses were considered the main endpoints to evaluate the efficacy, whereas Grade 3–4 adverse effects (AEs) were analyzed to evaluate safety.The ORR of PD-1 and PD-L1 inhibitors was 30% (95% CI: 25–35%). No significant difference in the ORR was observed after the comparisons of low-dose, median-dose, and high-dose cohorts. In addition, the rate of Grade 3–4 AEs was 9% (95% CI: 6–12%). According to the 3 randomized controlled trials that compared PD-1 inhibitors with chemotherapy, the difference between these 2 groups was found to be statistically significant with respect to the ORR, PFS and the incidence of Grade 3–4 AEs; that is, the relative risk (RR) of the ORR was 3.42 (95% CI: 2.49–4.69, P < 0.001), the hazard ratio (HR) of the PFS was 0.50 (95% CI: 0.44–0.58, P < 0.001), and the RR of Grade 3–4 AEs was 0.45 (95% CI: 0.31–0.65, P < 0.001).According to a meta-analysis of limited concurrent studies, PD-1 and PD-L1 inhibitors appear to be associated with improved response rates, superior response durability and tolerable toxicity in patients with advanced melanoma.

Analysis of the hormone receptor status of circulating tumor cell subpopulations based on epithelial-mesenchymal transition: a proof-of-principle study on the heterogeneity of circulating tumor cells

Although the enumeration of circulating tumor cells (CTCs) has been demonstrated to be a prognostic indicator in metastatic breast cancer, the heterogeneous characteristics of CTCs, such as variations in the epithelial-mesenchymal transition (EMT), may limit its broad clinical application. To investigate an uncomplicated and practicable detection approach based on the potential utility of the heterogeneity of CTCs from the standpoint of the EMT phenotype and ER/PR status of CTCs, an analysis was conducted using peripheral blood samples obtained from 28 metastatic breast cancer patients. The CanPatrol CTC enrichment technique was used to identify different CTC subpopulations, including epithelial-dominated CTCs, biophenotypic epithelial/mesenchymal CTCs, and mesenchymal-dominated CTCs, according to epithelial and mesenchymal markers. Furthermore, the hormone receptor (HR) status of each CTC was determined based on the expression levels of three reference genes and was characterized by four levels, which ranged from high-level expression to non-expression. We subsequently concluded that based on EMT phenotypes, the order of different CTC subgroups differed according to the HR expression status of the primary tumor. With respect to the HR status between tissues and CTCs, the variation tendency from high-level expression to non-expression of HR in CTCs was significantly correlated with the HR status of the primary tumor. The findings could provide evidence for the potential application of this uncomplicated and practicable detection approach for prognostic analysis and individualized endocrine therapeutic direction in a real-time manner via confirmation in further large-scale trials.

Landscape of somatic mutations in different subtypes of advanced breast cancer with circulating tumor DNA analysis

It is particularly important to provide precise therapies and understand tumor heterogeneity based on the molecular typing of mutational landscape. However, the landscape of somatic mutations in different subtypes of advanced breast cancer (ABC) is largely unknown. We applied target-region capture deep sequencing to determine the frequency and spectrum of common cancer-related gene mutations in circulating tumor DNA (ctDNA) among different ABC subtypes and analyze their association with clinical features. In this retrospective study of 100 female advanced breast cancer patients, 96 (96.0%) had somatic genomic alterations in ctDNA, including copy number variants and point mutations. The results revealed that different subtypes of ABC have distinct features in terms of genetic alterations. Multivariate regression analyses revealed that the number of somatic mutations increased with the line of endocrine therapy and the fractions of trunk mutations was positive associated with the line of target therapy.

The application of estrogen receptor-1 mutations' detection through circulating tumor dna in breast cancer

Breast cancer is the most common cancer in women worldwide. Endocrine therapy is the cornerstone of treatment for patients with hormone receptor-positive advanced breast cancer. Unfortunately, although most patients initially respond to endocrine treatment, they will eventually acquire resistance to endocrine therapy. The mechanisms of endocrine resistance are complicated. In particular, the estrogen receptor-1 (ESR1) mutation has been recognized as an important topic in recent years. Mutation of ESR1 leads to complete aromatase inhibitor resistance and partial resistance to estrogen receptor agonists and antagonists. Therefore, during clinical treatment, it is of great importance to continuously monitor ESR1 mutations before and after endocrine therapy. Conventional tissue biopsies have unavoidable disadvantages, and therefore, the use of circulating tumor DNA (ctDNA) has become more prevalent because it is noninvasive and convenient, has excellent sensitivity, and can quickly assess the overall situation of the tumor. The current methods for detecting ctDNA ESR1 mutations mainly include droplet digital polymerase chain reaction and next-generation sequencing techniques. Based on their advantages and disadvantages, we can establish an initial ESR1 mutation monitoring system. However, developing robust methods to monitor ESR1 mutation, detecting endocrine drug resistance, and evaluating prognoses for guiding clinical treatment strategies require long-term exploration. In this review, we will summarize recent concepts and advancements regarding ESR1 mutation monitoring, ctDNA detection technology, and their application in endocrine therapy of breast cancer.