Luc Cabel

Circulating tumor DNA changes for early monitoring of anti-PD1 immunotherapy: a proof-of-concept study

Background Recent clinical results support the use of new immune checkpoint blockers (ICB), such as anti-PD-1 (e.g. nivolumab and pembrolizumab) and anti-PD-L1 antibodies. Radiological evaluation of ICB efficacy during therapy is challenging due to tumor immune infiltration. Changes of circulating tumor DNA (ctDNA) levels during therapy could be a promising tool for very accurate monitoring of treatment efficacy, but data are lacking with ICB. Patients and methods This prospective pilot study was conducted in patients with nonsmall cell lung cancer, uveal melanoma, or microsatellite-instable colorectal cancer treated by nivolumab or pembrolizumab monotherapy at Institut Curie. ctDNA levels were assessed at baseline and after 8 weeks (w8) by bidirectional pyrophosphorolysis-activated polymerization, droplet digital PCR or next-generation sequencing depending on the mutation type. Radiological evaluation of efficacy of treatment was carried out by using immune-related response criteria. Results ctDNA was detected at baseline in 10 out of 15 patients. At w8, a significant correlation (r = 0.86; P = 0.002) was observed between synchronous changes in ctDNA levels and tumor size. Patients in whom ctDNA levels became undetectable at w8 presented a marked and lasting response to therapy. ctDNA detection at w8 was also a significant prognostic factor in terms of progression-free survival (hazard ratio = 10.2; 95% confidence interval 2.5-41, P < 0.001) and overall survival (hazard ratio = 15; 95% confidence interval 2.5-94.9, P = 0.004). Conclusion This proof-of-principle study is the first to demonstrate that quantitative ctDNA monitoring is a valuable tool to assess tumor response in patients treated with anti-PD-1 drugs.

Circulating tumor cells: clinical validity and utility

Circulating tumor cells (CTCs) are rare tumor cells and have been investigated as diagnostic, prognostic and predictive biomarkers in many types of cancer. Although CTCs are not currently used in clinical practice, CTC studies have accumulated a high level of clinical validity, especially in breast, lung, prostate and colorectal cancers. In this review, we present an overview of the current clinical validity of CTCs in metastatic and non-metastatic disease, and the main concepts and studies investigating the clinical utility of CTCs. In particular, this review will focus on breast, lung, colorectal and prostate cancer. Three major topics concerning the clinical utility of CTC are discussed—(1) treatment based on CTCs used as liquid biopsy, (2) treatment based on CTC count or CTC variations, and (3) treatment based on CTC biomarker expression. A summary of published or ongoing phase II and III trials is also presented.

Circulating tumor cells and circulating tumor DNA: What surgical oncologists need to know?

As a result of recent progress in detection techniques, circulating tumor DNA (ctDNA) and circulating tumor cells (CTC) can now be accurately detected in the blood of most cancer patients. While these new biomarkers can provide a better understanding of key biological mechanisms underlying cancer growth and dissemination, they also open up a wide range of possible clinical applications in medical oncology, radiation oncology and surgical oncology. In this review, we summarize the results obtained with ctDNA and CTC together with their potential future clinical applications in the field of surgical oncology, with particular focus on the perioperative setting of various types of cancer. These applications include, but are not limited to, cancer screening, early diagnosis, prognostic assessment, evaluation and management of preoperative systemic or local therapies, post-surgical detection of minimal residual disease and early detection of cancer relapse.

Circulating tumor cell count and thrombosis in metastatic breast cancer

Essentials Tumor cells circulating in blood (CTC) may favor thrombotic events in cancer patients. We assessed the impact of CTC on the risk of thrombosis in metastatic breast cancer. Baseline CTC detection was the only independent factor associated with the risk of thrombosis. CTC detection under therapy may be the hidden link between tumor progression & thrombosis.

HPV circulating tumor DNA to monitor the efficacy of anti-PD-1 therapy in metastatic squamous cell carcinoma of the anal canal: A case report

Squamous cell carcinoma of the anal canal (SCCA) is a rare HPV‐associated cancer with limited sensitivity to standard chemotherapy. In a phase 2 study, nivolumab, an anti PD‐1 immune checkpoint inhibitor, demonstrated significant efficacy as single‐agent therapy in metastatic SCCA patients. Nevertheless, imaging assessment by standard RECIST criteria of the efficacy of immune therapy can be difficult in some patients due to tumor immune cell infiltration, and biomarkers of treatment efficacy are needed. We have previously developed a quantitative droplet digital PCR (ddPCR) technique to detect HPV circulating tumor DNA (HPV ctDNA), with excellent sensitivity and specificity. Here, we report, for the first time, the kinetics of HPV ctDNA during therapy in a patient with metastatic SCCA, who obtained sustained partial response to single‐agent nivolumab. We observed an early and very significant decrease of HPV ctDNA during therapy from the baseline level of 3713 copies/ml plasma to 564 copies/ml plasma at 4 weeks, and 156 copies/ml at 6 weeks, followed by a plateau. This observation provides proof‐of‐concept that HPV ctDNA can be used as a noninvasive early dynamic biomarker to monitor the efficacy of new immunotherapy agents.

Cdk4/6 inhibitors and overall survival: power of first-line trials in metastatic breast cancer

Palbociclib, ribociclib, and abemaciclib have been investigated in combination with aromatase inhibitors as first-line therapy for metastatic hormone receptor-positive breast cancer (PALOMA-2, MONALEESA-2 and MONALEESA-7, MONARCH-3 trials, respectively); pivotal trials led to absolute median progression-free survival (PFS) gain of about 15 months. We aimed to estimate, for each trial, the statistical power to demonstrate a significant gain in overall survival (OS). Power was calculated with Freedman’s formula. Given the allocation ratio and the number of events, power was computed as a function of hazard ratio. We focused on four specific hazard ratio values (0.94, 0.89, 0.81, and 0.77), which are estimated to correspond to absolute 3, 6, 12, and 15 months gain in OS, respectively. For these calculations, the type I error rate was stated at 5% with a two-sided test, and we assumed that the risk of death was constant over time. PALOMA-2 and MONALEESA trials have an almost similar power despite different allocation ratios, while MONARCH-3 has a more limited power. Overall, the power of the four trials to demonstrate a statistically significant improvement in OS is less than 70% if the prolongation in median OS is ≤12 months, whatever the OS data maturity. This analysis shows that OS results are jeopardized by limited powers, and a meta-analysis might be required to demonstrate OS benefit. Conversely, if a significant OS improvement is observed in some but not at all trials, this discrepancy might be more attributable to chance than to a truly different drug efficacy.

Clinical potential of circulating tumour DNA in patients receiving anticancer immunotherapy

Considerable interest surrounds the use of immune-checkpoint inhibitors in patients with solid tumours following the demonstration of the impressive clinical efficacy of anti-programmed cell death protein 1 and anti-programmed cell death 1 ligand 1 antibodies in several tumour types. However, the emergence of unexpected tumour response patterns, such as pseudoprogression or hyperprogression, might complicate the management of patients receiving these agents. Analysis of circulating tumour DNA (ctDNA) has been shown to have prognostic value by enabling the detection of residual proliferating disease in the adjuvant setting and estimation of tumour burden in the metastatic setting, which are key stratification biomarkers for use of immune-checkpoint inhibition (ICI). Furthermore, examinations of ctDNA for genetic predictors of responsiveness to immunotherapy, such as mutations, tumour mutational load, and microsatellite instability provide a noninvasive surrogate for tumour biopsy sampling. Proof-of-concept reports have also demonstrated that quantitative changes in ctDNA levels early in the course of disease are a promising tool for the assessment of responsiveness to ICI that might complement standard imaging approaches. Other applications of this technology are also currently under investigation, such as early detection of resistance to immunotherapy and characterization of mechanisms of resistance. The aim of this Review is to summarize available data on the application of ctDNA in patients receiving immunotherapy and to discuss the most promising future directions.The majority of patients receiving immunotherapy do not respond to treatment but might still have adverse events. Furthermore, some patients with an initial response will develop acquired resistance to treatment. In this Review, the authors describe the role of circulating tumour DNA in the management of patients receiving immunotherapy.Key pointsAnalysis of circulating tumour DNA (ctDNA) can enable the detection of residual disease, which corresponds to a minimal tumour burden, thus enabling use of immune-checkpoint inhibition (ICI) when it is most likely to be effective.Analysis of ctDNA enables the noninvasive detection of mismatch repair deficiencies and assessment of tumour mutational burden, two predictive biomarkers of responsiveness to ICI.Monitoring ctDNA levels in patients with metastatic cancer receiving ICI enables the efficacy of therapy to be determined early in the course of treatment and might avoid the prolonged administration of ineffective treatments.Mutations that are likely to be predictive of either efficacy or resistance to ICI can be detected in ctDNA.Further clinical studies are needed to comprehensively demonstrate the clinical utility of ctDNA as a biomarker of ICI in clinical practice.

ERBB3-Activating Mutations in Small Bowel Adenocarcinomas

PurposeFunctional studies have demonstrated that some mutations of ERBB3, which encodes for human epidermal growth factor receptor (HER) 3, are oncogenic via activation of the ErbB family signaling pathway. Significant clinical activity of anti-HER2 therapies (trastuzumab plus lapatinib combination or afatinib) has been reported in patients with ERBB3-mutated cancers. This study was designed to report the rate of activating ERBB3 mutations in small bowel adenocarcinoma (SBA), a rare tumor type in which we previously reported a high rate (12%) of ERBB2-activating mutations.Materials and MethodsDNA from 74 SBAs, previously characterized for ERBB2 mutations and mismatch repair status, was submitted for sequencing of ERBB3 exons 3, 6, 7, 8, and 23. Orthogonal validation by targeted next-generation sequencing was performed.ResultsFour of 74 SBAs (5.4%) displayed ERBB3-activating mutations, including three p.V104M mutations (c.310 G>A) in exon 3 and one p.E928G mutation (c.2783 A>G) in exon 23. No mutations wer...