Guillaume Herbreteau

Dr. Guillaume Herbreteau

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Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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4 February 2021 in Journal of Fungi
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Journal Article
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ABAnne-Laure Bidaud
Anne-Laure Bidaud
Patrick SchwarzPatrick Schwarz
Patrick Schwarz
GHGuillaume Herbreteau
Guillaume Herbreteau
Eric DannaouiEric Dannaoui
Eric Dannaoui
Systemic fungal infections are associated with high mortality rates despite adequate treatment. Moreover, acquired resistance to antifungals is increasing, which further complicates the therapeutic management. One strategy to overcome antifungal resistance is to use antifungal combinations. In vitro, several techniques are used to assess drug interactions, such as the broth microdilution checkerboard, agar-diffusion methods, and time-kill curves. Currently, the most widely used technique is the checkerboard method. The aim of all these techniques is to determine if the interaction between antifungal agents is synergistic, indifferent, or antagonistic. However, the interpretation of the results remains difficult. Several methods of analysis can be used, based on different theories. The most commonly used method is the calculation of the fractional inhibitory concentration index. Determination of the usefulness of combination treatments in patients needs well-conducted clinical trials, which are difficult. It is therefore important to study antifungal combinations in vivo, in experimental animal models of fungal infections. Although mammalian models have mostly been used, new alternative animal models in invertebrates look promising. To evaluate the antifungal efficacy, the most commonly used criteria are the mortality rate and the fungal load in the target organs.

26 January 2022 in Journal of Experimental Medicine
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Journal Article
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GMGabriel Morin
Gabriel Morin
CDCaroline Degrugillier-Chopinet
Caroline Degrugillier-Chopinet
MVMarie Vincent
Marie Vincent
AFAntoine Fraissenon
Antoine Fraissenon
HAHélène Aubert
Hélène Aubert
GCGuillaume Canaud
Guillaume Canaud
PIK3CA-related overgrowth spectrum (PROS) includes rare genetic conditions due to gain-of-function mutations in the PIK3CA gene. There is no approved medical therapy for patients with PROS, and alpelisib, an approved PIK3CA inhibitor in oncology, showed promising results in preclinical models and in patients. Here, we report for the first time the outcome of two infants with PROS having life-threatening conditions treated with alpelisib (25 mg) and monitored with pharmacokinetics. Patient 1 was an 8-mo-old girl with voluminous vascular malformation. Patient 2 was a 9-mo-old boy presenting with asymmetrical body overgrowth and right hemimegalencephaly with West syndrome. After 12 mo of follow-up, alpelisib treatment was associated with improvement in signs and symptoms, morphological lesions and vascular anomalies in the two patients. No adverse events were reported during the study. In this case series, pharmacological inhibition of PIK3CA with low-dose alpelisib was feasible and associated with clinical improvements, including a smaller size of associated complex tissue malformations and good tolerability.

27 November 2020 in Journal of Clinical Medicine
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Journal Article
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GHGuillaume Herbreteau
Guillaume Herbreteau
ALAlexandra Langlais
Alexandra Langlais
LGLaurent Greillier
Laurent Greillier
CAClarisse Audigier-Valette
Clarisse Audigier-Valette
LULionel Uwer
Lionel Uwer
JPJean-Louis Pujol
Jean-Louis Pujol
Background: The IFCT-1603 trial evaluated atezolizumab in small cell lung cancer (SCLC). The purpose of the present study was to determine whether circulating tumor DNA (ctDNA), prospectively collected at treatment initiation, was associated with the prognosis of SCLC, and whether it identified patients who benefited from atezolizumab. Methods: 68 patients were included in this study: 46 patients were treated with atezolizumab and 22 with conventional chemotherapy. Circulating DNA was extracted from plasma and NGS (Next Generation Sequencing) looked for mutations in the TP53, RB1, NOTCH1, NOTCH2, and NOTCH3 genes. ctDNA was detectable when at least one somatic mutation was identified, and its relative abundance was quantified by the variant allele fraction (VAF) of the most represented mutation. Results: We found that 49/68 patients (70.6%) had detectable baseline ctDNA. The most frequently identified mutations were TP53 (32/49; 65.3%) and RB1 (25/49; 51.0%). Patients with detectable ctDNA had a significantly lower disease control rate at week 6 compared with patients with no detectable ctDNA, regardless of the nature of the treatment. Detection of ctDNA was associated with a poor OS prognosis. The detection of ctDNA at a relative abundance greater than the median value was significantly associated with poor overall survival (OS) and progression free survival (PFS). Interestingly, the benefit in overall survival (OS) associated with low ctDNA was more pronounced in patients treated with atezolizumab than in patients receiving chemotherapy. Among patients whose relative ctDNA abundance was below the median, those treated with atezolizumab tended to have higher OS than those in the chemotherapy arm. Conclusion: ctDNA is strongly associated with the prognosis of SCLC patients treated with second-line immunotherapy. Its analysis seems justified for future SCLC clinical trials.

11 April 2021 in Cancers
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Journal Article
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GHGuillaume Herbreteau
Guillaume Herbreteau
AVAudrey Vallée
Audrey Vallée
AKAnne-Chantal Knol
Anne-Chantal Knol
STSandrine Théoleyre
Sandrine Théoleyre
GQGaëlle Quéreux
Gaëlle Quéreux
Marc DenisMarc Denis
Marc Denis
The ability of early (first weeks of treatment) ctDNA kinetics to identify primary resistance to anti-PD1 immunotherapies was evaluated with a validation cohort of 49 patients treated with anti-PD1 for metastatic BRAF or NRAS-mutated melanoma, alone and pooled with the 53 patients from a previously described derivation cohort. BRAF or NRAS mutations were quantified on plasma DNA by digital PCR at baseline and after two or four weeks of treatment. ctDNA kinetics were interpreted according to pre-established biological response criteria. A biological progression (bP, i.e., a significant increase in ctDNA levels) at week two or week four was associated with a lack of benefit from anti-PD1 (4-month PFS = 0%; 1-year OS = 13%; n = 12/102). Patients without initial bP had significantly better PFS and OS (4-month PFS = 78%; 1-year OS = 73%; n = 26/102), as did patients whose ctDNA kinetics were not evaluable, due to low/undetectable baseline ctDNA (4-month PFS = 80%; 1-year OS = 81%; n = 64/102). ctDNA detection at first-line anti-PD1 initiation was an independent prognostic factor for OS and PFS in multivariate analysis. Overall, early ctDNA quantitative monitoring may allow the detection of primary resistances of metastatic melanoma to anti-PD1 immunotherapies.

11 July 2020 in Cancers
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Journal Article
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GHGuillaume Herbreteau
Guillaume Herbreteau
AVAudrey Vallée
Audrey Vallée
AKAnne-Chantal Knol
Anne-Chantal Knol
STSandrine Théoleyre
Sandrine Théoleyre
GQGaelle Quéreux
Gaelle Quéreux
Marc DenisMarc Denis
Marc Denis
Circulating tumour DNA (ctDNA) can be used to identify gene alterations. The purpose of this study was to determine whether the detection of ctDNA, based on the identification of BRAF and NRAS mutations before systemic treatment initiation, was associated with the prognosis of metastatic melanoma. In total, 68 BRAF or NRAS-mutated stage IV or unresectable stage III metastatic cutaneous melanoma patients were included and tested for the presence of BRAF and NRAS mutations in circulating DNA before treatment initiation, using the Cobas BRAF/NRAS Mutation Test (Roche). The expected mutation was detected in the plasma of 34/68 patients (50% sensitivity). ctDNA detection was associated with AJCC stage, along with the number and nature of metastases. ctDNA was less frequently detected in NRAS-mutated than in BRAF-mutated melanoma (36% and 66%, respectively). At initiation of first-line treatment, ctDNA detection was associated with poor prognosis in Progression Free Survival (PFS) and Overall Survival (OS) in univariate analysis (log-rank: p = 0.002 and p < 0.0001, respectively). In multivariate analysis, ctDNA detection was an independent factor of poor prognosis in OS, after adjustment for AJCC stage, number and nature of metastases and gender (HR = 4.384; 95% CI: (1.308; 14.699); p = 0.017).

20 May 2022 in Current Oncology
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Journal Article
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LMLaurent Mathiot
Laurent Mathiot
GHGuillaume Herbreteau
Guillaume Herbreteau
SRSiméon Robin
Siméon Robin
CFCharlotte Fenat
Charlotte Fenat
JBJaafar Bennouna
Jaafar Bennouna
EPElvire Pons-Tostivint
Elvire Pons-Tostivint
Introduction: Assessment of actionable gene mutations and oncogene fusions have made a paradigm shift in treatment strategies of non-small cell lung cancer (NSCLC). HRAS mutations involved around 0.2–0.8% of NSCLC patients, mostly on codon 61. For these patients, few data are available regarding clinical characteristics and response to therapies. Methods: Next-Generation Sequencing (NGS) done routinely at Nantes University Hospital was used to identify HRAS molecular alterations in NSCLC patients. We identified and described four HRAS p.GlnQ61Leu mutated patients. Literature of previously HRAS-mutant NSCLC cases was reviewed, and available data in solid tumour with the most advanced H-Ras specific inhibitor, tipifarnib, were presented. Results: Of 1614 patients diagnosed with advanced NSCLC from January 2018 to December 2020, four (0.25%) had HRAS p.Gln61Leu mutation. Three of them died during the first-line systemic therapy. Furthermore, three additional cases were identified in literature. All cases were current or former smokers, most of them had pleural or pericardial effusion at diagnosis. Conclusions: The clinical course of patients with HRAS-mutant NSCLC remains unclear. Furthers cases should be identified in order to clarify prognosis and response to therapies. Tipifarnib, a farnesyl transferase inhibitor, is a promising candidate to target HRAS-mutant tumours and should be explored in NSCLC patients.