Oncogenic alterations detected by droplet digital PCR in patients with metastatic colorectal cancer resistant to cetuximab.

2019 ◽  
Vol 37 (4_suppl) ◽  
pp. 575-575
Author(s):  
Rujiao Liu ◽  
Zhi-Yu Chen ◽  
Weijian Guo ◽  
Xiaodong Zhu ◽  
Mingzhu Huang ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Metastatic Colorectal Cancer ◽  
Acquired Resistance ◽  
Standard Of Care ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Egfr Mutations ◽  
Exon 2 ◽  
First Line Therapy ◽  
Line Setting

575 Background: Anti-EGFR therapy is the standard of care for metastatic colorectal cancer (mCRC) patients with RAS and BRAF genes wild type (wt). Secondary alterations of several genes have been identified as possibly resistant mechanisms to EGFR blockade, these including mutations of KRAS, NRAS, BRAF, MEK and EGFR ectodomain, as well as amplifications of HER2 and c-MET. In this study, we investigated alterations of these targeted genes for mCRC patients with acquired resistance to cetuximab treatment by using non-invasive droplet digital PCR (ddPCR) method within circulating DNA. Methods: We enrolled 38 RAS and BRAF wt patients, who progressed after failure of cetuximab contained regimens between Jul 2015 and Jan 2018. Plasma samples from all 38 patients were collected and detected for seven candidates (mutation of KRAS, NRAS, EGFR, BRAF, MEK, amplification of HER2, c-MET) by using ddPCR at the time of baseline, each evaluation by interval of 2 months and documented progression. All clinical parameters were collected simultaneously. Results: A total of 23 secondary alterations were found in 17 (17/38,44.7%) cetuximab resistant patients. The targeted gene alterations were detected as follows: 9 (9/23,39%) RAS mutations, 5 (22%) HER2 amplifications, 5 (22%) EGFR mutations, 2 (9%) c-MET amplifications, 1 (4%) BRAF and 1 MEK mutation. Among 17 patients, 6 patients had multiple alterations, including 2 patients with KRAS+EGFR mutations, 2 patients with HER2+c-MET co-amplifications and 2 patients with KRAS gene exon 2 and 3 multiple mutations. Primary sites were 15 left sides and 2 right sides, descending colon (12 cases) was the most common origins. Eleven patients were synchronous disease. Twelve patients received cetuximab as first line therapy, whereas 5 patients in the ≥ 2nd line setting. All of these 17 patients, plasma levels of oncogenic alterations detected by ddPCR were showed dynamic changing and good agreement with tumor responding status. Conclusions: Oncogenic alterations detected by ddPCR were found in almost half mCRC patients resistant to cetuximab. Dynamic changes of specific alteration may facilitate making decisions for selection of anti-EGFR mAb during the treatment course.

scholarly journals Multiple Hotspot Mutations Scanning by Single Droplet Digital PCR

2018 ◽  
Vol 64 (2) ◽  
pp. 317-328 ◽  
Author(s):  
Charles Decraene ◽  
Amanda B Silveira ◽  
François-Clément Bidard ◽  
Audrey Vallée ◽  
Marc Michel ◽  
...  
Keyword(s):  
Liquid Biopsy ◽  
Limit Of Detection ◽  
Clinical Importance ◽  
Digital Pcr ◽  
Circulating Tumor Dna ◽  
Droplet Digital Pcr ◽  
Egfr Mutations ◽  
Detection Accuracy ◽  
Exon 2 ◽  
Exon 19

Abstract BACKGROUND Progress in the liquid biopsy field, combined with the development of droplet digital PCR (ddPCR), has enabled noninvasive monitoring of mutations with high detection accuracy. However, current assays detect a restricted number of mutations per reaction. ddPCR is a recognized method for detecting alterations previously characterized in tumor tissues, but its use as a discovery tool when the mutation is unknown a priori remains limited. METHODS We established 2 ddPCR assays detecting all genomic alterations within KRAS exon 2 and EGFR exon 19 mutation hotspots, which are of clinical importance in colorectal and lung cancer, with use of a unique pair of TaqMan® oligoprobes. The KRAS assay scanned for the 7 most common mutations in codons 12/13 but also all other mutations found in that region. The EGFR assay screened for all in-frame deletions of exon 19, which are frequent EGFR-activating events. RESULTS The KRAS and EGFR assays were highly specific and both reached a limit of detection of <0.1% in mutant allele frequency. We further validated their performance on multiple plasma and formalin-fixed and paraffin-embedded tumor samples harboring a panel of different KRAS or EGFR mutations. CONCLUSIONS This method presents the advantage of detecting a higher number of mutations with single-reaction ddPCRs while consuming a minimum of patient sample. This is particularly useful in the context of liquid biopsy because the amount of circulating tumor DNA is often low. This method should be useful as a discovery tool when the tumor tissue is unavailable or to monitor disease during therapy.

scholarly journals Droplet digital PCR of circulating tumour DNA for the detection of RAS/BRAF mutation in metastatic colorectal cancer

2018 ◽  
Vol 29 ◽  
pp. viii181 ◽  
Author(s):  
E. Van Cutsem ◽  
K. Lesniewski-Kmak ◽  
M.P. Saunders ◽  
H. Wasan ◽  
G. Argiles ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Metastatic Colorectal Cancer ◽  
Braf Mutation ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Circulating Tumour Dna

Pembrolizumab versus chemotherapy for microsatellite instability-high/mismatch repair deficient metastatic colorectal cancer: The phase 3 KEYNOTE-177 Study.

2020 ◽  
Vol 38 (18_suppl) ◽  
pp. LBA4-LBA4 ◽  
Author(s):  
Thierry Andre ◽  
Kai-Keen Shiu ◽  
Tae Won Kim ◽  
Benny Vittrup Jensen ◽  
Lars Henrik Jensen ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Microsatellite Instability ◽  
Metastatic Colorectal Cancer ◽  
Mismatch Repair ◽  
Standard Of Care ◽  
First Line ◽  
Phase 3 ◽  
End Points ◽  
First Line Therapy ◽  
Line Therapy

LBA4 Background: KEYNOTE-177 (NCT02563002) is a phase 3, randomized open-label study evaluating the efficacy and safety of pembrolizumab (pembro) versus standard of care chemotherapy ± bevacizumab or cetuximab (chemo) as first-line therapy for patients (pts) with microsatellite-instability high/mismatch repair deficient (MSI-H/dMMR) metastatic colorectal cancer (mCRC). We present results of the final PFS analysis. Methods: A total of 307 pts with MSI-H/dMMR mCRC as determined locally and ECOG PS 0 or 1 were randomly assigned 1:1 to first-line pembro 200 mg Q3W for up to 2 years or investigator’s choice of mFOLFOX6 or FOLFIRI Q2W ± bevacizumab or cetuximab (chemo chosen prior to randomization). Treatment continued until PD, unacceptable toxicity, pt/investigator decision to withdraw, or completion of 35 cycles (pembro only). Patients receiving chemo could crossover to pembro for up to 35 cycles after confirmed PD. Primary end points were PFS (RECIST v1.1, central review) and OS. Key secondary end points included ORR (RECIST v1.1, central review), and safety. The data cutoff date for this interim analysis was Feb 19, 2020. The study will continue without changes to evaluate OS. Results: At data cutoff, 153 pts were randomized to pembro and 154 to chemo. Median (range) study follow-up was 28.4 mo (0.2-48.3) with pembro vs 27.2 mo (0.8-46.6) with chemo. Pembro was superior to chemo for PFS (median 16.5 mo vs 8.2 mo; HR 0.60; 95% CI, 0.45-0.80; P=0.0002). The 12- and 24-mo PFS rates were 55.3% and 48.3% with pembro vs 37.3% and 18.6% with chemo. Confirmed ORR was 43.8% vs 33.1%; median (range) duration of response was not reached (2.3+ to 41.4+) with pembro vs 10.6 mo (2.8 to 37.5+) with chemo. Grade 3-5 treatment related adverse event (AE) rates were 22% vs 66% for pembro vs chemo. One pt in the chemo arm died due to a treatment-related AE. Conclusions: Pembro provided a clinically meaningful and statistically significant improvement in PFS versus chemo as first-line therapy for pts with MSI-H/dMMR mCRC, with fewer treatment-related AEs observed and should be the new standard of care for these pts. Clinical trial information: NCT02563002 .

scholarly journals Detection of KRAS mutations in liquid biopsies from metastatic colorectal cancer patients using droplet digital PCR, Idylla, and next generation sequencing

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0239819
Author(s):  
Matilda Holm ◽  
Emma Andersson ◽  
Emerik Osterlund ◽  
Ali Ovissi ◽  
Leena-Maija Soveri ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Next Generation Sequencing ◽  
Metastatic Colorectal Cancer ◽  
Disease Progression ◽  
Primary Tumor ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Plasma Samples ◽  
Liquid Biopsies ◽  
Generation Sequencing

Circulating tumor DNA (ctDNA) is released from cancer cells and oncogenic mutations in ctDNA can be measured from plasma samples. Droplet digital PCR (ddPCR) is a sensitive and specific method for the detection of mutations in ctDNA. We analyzed serial plasma samples (n = 80) from ten metastatic colorectal cancer (mCRC) patients with a known KRAS mutation in their primary tumor. The patients were undergoing oncological treatment with bevacizumab in combination with alternating capecitabine and oxaliplatin or irinotecan. Baseline ddPCR KRAS mutation allele frequency (MAF) values ranged from 0% to 63%. The first radiologic response evaluation criteria in solid tumors (RECIST) evaluation was performed 45–63 days after the initiation of treatment, and by this time three patients had an undetectable level of KRAS mutation, one had a MAF value of 0.5%, and one had a MAF value of 3% that had been reduced by 95% from the baseline value. In three of these patients the RECIST assessment was stable disease and in two partial response. In seven patients, ddPCR MAF values increased before radiological disease progression or death, while one patient remained disease-free with an undetectable KRAS mutation level. Next, we analyzed all available plasma samples with the Idylla ctKRAS system (n = 60), and found that the overall degree of agreement between ddPCR and Idylla was almost perfect (kappa value = 0.860). We used next-generation sequencing (NGS) to detect treatment-induced mutations in the last serial plasma sample of each patient, but were unable to find any new mutations when compared to the primary tumor. This study shows that ddPCR and Idylla are equally efficient for the detection of KRAS mutations in the liquid biopsies from mCRC patients and that ctDNA may indicate the disappearance of treatment responsive KRAS positive mCRC clones and serve as an early sign of disease progression.

A randomized phase II study of mFOLFOX6 plus bevacizumab versus mFOLFOX6 plus cetuximab for previously untreated, liver-limited metastatic colorectal cancer that is unsuitable for resection (ATOM trial).

2018 ◽  
Vol 36 (4_suppl) ◽  
pp. 734-734 ◽  
Author(s):  
Hiroyuki Uetake ◽  
Yasunori Emi ◽  
Takeharu Yamanaka ◽  
Kei Muro ◽  
Eiji Oki ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Liver Resection ◽  
Metastatic Colorectal Cancer ◽  
Progression Free Survival ◽  
Similar Efficacy ◽  
Resection Rate ◽  
Exon 2 ◽  
Two Agents ◽  
Line Setting ◽  
Ecog Ps

734 Background: It is still a topic of ongoing debate as to which of the two agents, anti-VEGF antibody or anti-EGFR antibody, is more effective in patients with KRAS Exon 2 or RAS wild-type metastatic colorectal cancer (mCRC) in the first-line setting. ATOM is a multicenter, randomized trial comparing mFOLFOX6 plus bevacizumab (Bmab arm) with mFOLFOX6 plus cetuximab (Cmab arm) in patients with liver-limited metastases unsuitable for upfront resection. Methods: Patients with previously untreated mCRC were eligible if they had ≥5 liver-limited metastatic lesions and/or had liver-limited metastases with the maximum lesion diameter of > 5cm. Patients with KRAS Exon2-wild were registered but after Jan 2015 limited to those with all RAS-wild. Primary endpoint was progression-free survival (PFS), which was defined as the time from randomization to disease progression, recurrence after resection by surgery, or death from any cause (Central review). Key secondary endpoints included overall response rate (ORR), liver resection rate, and overall survival (OS). Results: A total of 122 pts were enrolled between May 2013 and April 2016. Of 116 eligible (59 in the Cmab arm and 57 in the Bmab arm), median age was 65/64 in the Cmab/Bmab arm; ECOG PS 0, 86/89%; all RAS wt, 98/95%; left-sided primary tumor, 76/84%. Efficacy results were summarized in the table. With a median follow-up of 24.3 months, the median PFS was 15.0 months in Cmab arm and 11.6 months in the Bmab arm with a hazard ratio of 0.803 (95%CI, 0.513–1.256), whereas ORR was 86% in the Cmab arm and 68% in the Bmab arm. Liver resection rate was 49% and 56% in the Cmab arm and the Bmab arm, respectively. Conclusions: In patients considered unsuitable for upfront resection of liver-limited metastasis, the two agents showed a similar efficacy. OS result will be presented elsewhere. Clinical trial information: NCT01836653. [Table: see text]

Treatment strategies after failure to reversible tyrosine kinase inhibitors (rTKI) in EGFR mutant (mut) non-small cell lung cancer (NSCLC) patients (p): A retrospective analysis of 41 Spanish p.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. e19089-e19089
Author(s):  
Jordi Remon ◽  
Teresa Moran ◽  
Diego Alcaraz ◽  
Laia Capdevila ◽  
Rut Porta ◽  
...  
Keyword(s):  
Kinase Inhibitors ◽  
Acquired Resistance ◽  
Treatment Strategies ◽  
Local Therapy ◽  
Stage Iv ◽  
Standard Of Care ◽  
Therapeutic Strategies ◽  
Egfr Mutations ◽  
First Line Therapy ◽  
Egfr Mutant

e19089 Background: Different therapeutic approaches have been used in the clinical setting in NSCLC p harbouring EGFR mutations progressing to rTKI, although the standard of care in this situation is still not well established. Methods: A multi-institutional database from four different centers in Spain was review to identify EGFR mut p with acquired resistance to rTKI in order to evaluate the therapeutic strategies after rTKI failure and the effect on the post-progression survival (PPS) of these treatments. Results: 41 p with acquired resistance to rTKI were identified: 63% female; median (m) age 62 ±11 yrs; 95% Caucasian; del19 76%, never or light former smokers 100%; 90.2% adenocarcinomas; 51 % received TKI as first line therapy; 85% were initial stage IV .mPFS for the rTKI was 8.4 months (mo) and mOS was 29.7 mo for the entire population. P were treated with a median of 2 therapeutic strategies after the rTKI failure. 6 therapeutic strategies have been identified. As immediate approach, 16 p were switched to chemotherapy (CT) with a mPPS of 3 mo. 9 p were switched to an irreversible TKI obtaining a mPPS of 3.9 mo. rTKI plus other drug was maintained in 11 p: rTKI plus CT in 9 p with a mPPS of 4 mo and rTKI plus other drug different to CT in 2 with a mPPS of 2 mo. Despite the progression, rTKI was maintained in 2 p considered slow progressors and local therapy, in addition to the rTKI, was administered in 3 p with oligoM1progressive disease obtaining a mPPS of 1.4 and 36 mo, respectively. 8 p were treated sequentially with ≥5 strategies. These p attained a mOS of 27.7 mo. Conclusions: The combination of different strategies when treating EGFR mut p after rTKI failure may impact the survival especially when p are candidates to receive some of this treatments sequentially. These strategies may reflect different subsets of EGFR mut disease.

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