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Primary and Acquired Resistance to Targeted Treatment in BRAF V600E-mutated Metastatic Colorectal Cancer (PARTACER)

15 juillet 2026 mis à jour par: Swiss Cancer Institute

Primary and Acquired Resistance to Targeted Treatment in BRAF V600E-mutated Metastatic Colorectal Cancer (PARTACER-Suisse)

This study prospectively investigates the molecular mechanisms of primary and acquired resistance to standard-of-care BRAF V600E-directed therapy in patients with metastatic colorectal cancer and aims to pre-clinically develop novel strategies to reverse therapy resistance. Clinically approved combination treatment with cetuximab, encorafenib and chemotherapy improves patient outcomes, yet patients eventually experience disease progression. In this prospective multicenter study, tumor tissue, blood, and stool samples will be collected before treatment and at progression, to identify genetic and non-genetic mechanisms of resistance. Additionally, tumor tissue-based in vitro models (patient-derived organoids, PDOs) will be generated and exploited for functional in vitro testing, including genomic and pharmacologic perturbation studies. The overarching goal is to generate knowledge that can help develop new and more effective treatment strategies for future patients.

Aperçu de l'étude

Statut

Recrutement

Les conditions

Intervention / Traitement

Description détaillée

BRAF V600E-mutated metastatic colorectal cancer accounts for about 8-10% of cases and is an aggressive disease with poor prognosis and limited treatment options. The current standard treatment for patients is the combination of the BRAF inhibitor encorafenib and the anti-EGFR antibody cetuximab, together with FOLFOX or FOLFIRI chemotherapy in 1st line systemic treatment, which improves survival and response rates compared to chemotherapy alone. However, nearly all patients eventually develop resistance to this treatment, and there are no well-established therapies after progression. Resistance develops through complex and often multiple mechanisms, including genetic changes in signaling pathways such as MAPK and receptor tyrosine kinases, as well as non-genomic factors such as changes in gene expression, the tumor microenvironment, and potentially the microbiome. These mechanisms are not yet fully understood, especially in combination and over time during treatment.

This study, PARTACER-Suisse, is a prospective multicenter investigator-initiated study in patients with BRAF V600E-mutated metastatic colorectal cancer receiving standard treatment with encorafenib and cetuximab, with or without concomitant chemotherapy. The study is conducted across a federated network of Swiss oncology centers organized under the Swiss Cancer Center/Swiss Group for Clinical Cancer Research (SCI/SAKK), with a central translational research backbone at the University Hospital Zurich. The aim is to better understand how resistance develops by analyzing tumor samples, blood samples, and stool samples collected before treatment and at disease progression. Blood samples will be used to study circulating tumor DNA over time, and stool samples will allow analysis of the microbiome. Tumor tissue will undergo detailed molecular analyses to identify genetic and non-genetic changes associated with resistance. In addition, tumor samples will be used to generate patient-derived organoids, which are laboratory models that allow functional testing of tumor behavior and response to treatment. By combining molecular analyses with functional experiments, the study aims to identify key resistance mechanisms and explore new treatment strategies that could prevent or overcome resistance.

Overall, this study is expected to provide a more complete understanding of resistance to combined BRAF and EGFR inhibition in this patient population and to support the development of improved and more personalized treatment approaches for the future.

Type d'étude

Observationnel

Inscription (Estimé)

30

Contacts et emplacements

Cette section fournit les coordonnées de ceux qui mènent l'étude et des informations sur le lieu où cette étude est menée.

Coordonnées de l'étude

Lieux d'étude

  • Suisse
      • Aarau, Suisse, CH-5000
        • Recrutement
        • Kantonsspital Aarau
        • Contact:
        • Chercheur principal:
          • Peter Moosmann, MD et phil.
      • Baden, Suisse, 5404
        • Recrutement
        • Kantonsspital Baden
        • Contact:
        • Chercheur principal:
          • Stefanie Pederiva, MD
      • Basel, Suisse, 4058
        • Recrutement
        • St. Claraspital
        • Contact:
        • Chercheur principal:
          • Melanie Löffler-Baumann, MD
      • Basel, Suisse, CH-4031
        • Recrutement
        • Universitaetsspital Basel
        • Contact:
        • Chercheur principal:
          • Viviane Prof Hess
      • Bern, Suisse, 3010
        • Recrutement
        • Inselspital Bern
        • Contact:
        • Chercheur principal:
          • Martin Berger, Prof
      • Biel, Suisse, 2502
        • Recrutement
        • Spitalzentrum Biel - MEDIN La Tour
        • Contact:
        • Chercheur principal:
          • Emanuel Bührer, MD
      • Chur, Suisse, 7000
        • Recrutement
        • Kantonsspital Graubunden
        • Chercheur principal:
          • Sara Bastian, MD
        • Contact:
      • Lucerne, Suisse, 6004
        • Recrutement
        • Luzerner Kantonsspital
        • Chercheur principal:
          • Simon Häfliger, MD
        • Contact:
      • Sankt Gallen, Suisse, 9007
        • Recrutement
        • HOCH Health Ostschweiz - Kantonsspital St. Gallen
        • Contact:
        • Chercheur principal:
          • Barbara Denecke, MD
      • Solothurn, Suisse, 4500
        • Recrutement
        • Bürgerspital Solothurn
        • Contact:
        • Chercheur principal:
          • Julian Schardt, MD et phil.
      • Villars-sur-Glâne, Suisse, 1752
        • Recrutement
        • HFR Freiburg - Kantonsspital
        • Contact:
        • Chercheur principal:
          • Rahel Odermatt, MD
      • Winterthur, Suisse, 8004
        • Recrutement
        • Kantonsspital Winterthur
        • Contact:
        • Chercheur principal:
          • Guacimara Ortega Sanchez, MD
      • Zurich, Suisse, 8091
        • Recrutement
        • Universitätsspital Zürich USZ
        • Chercheur principal:
          • Ralph Fritsch, MD
        • Contact:

Critères de participation

Les chercheurs recherchent des personnes qui correspondent à une certaine description, appelée critères d'éligibilité. Certains exemples de ces critères sont l'état de santé général d'une personne ou des traitements antérieurs.

Critère d'éligibilité

Âges éligibles pour étudier

  • Adulte
  • Adulte plus âgé

Accepte les volontaires sains

Non

Méthode d'échantillonnage

Échantillon non probabiliste

Population étudiée

Participants will be recruited from oncology centers across Switzerland participating in the Swiss Group for Clinical Cancer Research (SAKK). The study population consists of adult patients with metastatic colorectal cancer treated in routine clinical practice at tertiary care and regional cancer centers. Eligible patients are identified by their treating oncologists at participating sites and enrolled prior to initiation of standard-of-care systemic therapy. Recruitment is limited to centers with access to molecular diagnostics and the capability to perform tumor biopsies and longitudinal sample collection.

La description

Inclusion Criteria:

  • Diagnosis of unresectable or metastatic BRAF V600E-mutated colorectal cancer
  • Planned initiation of treatment with combined anti-EGFR antibody and BRAF inhibitor
  • Patients receiving treatment in any line, with or without chemotherapy
  • At least one tumor lesion accessible for biopsy
  • ECOG performance status 0-2
  • Life expectancy of at least 3 months
  • Age ≥18 years
  • Ability to provide written informed consent

Exclusion Criteria:

  • Medical or surgical contraindication for tumor biopsy
  • Active second malignancy (except non-melanoma skin cancer)
  • Inability to comply with study procedures (e.g., due to language barriers or cognitive impairment)
  • Pregnancy or breastfeeding
  • Previous treatment with a BRAF inhibitor

Plan d'étude

Cette section fournit des détails sur le plan d'étude, y compris la façon dont l'étude est conçue et ce que l'étude mesure.

Comment l'étude est-elle conçue ?

Détails de conception

Cohortes et interventions

Groupe / Cohorte
Intervention / Traitement
Patients with BRAF V600E-mutated metastatic colorectal cancer
Patients with unresectable or metastatic BRAF V600E-mutated colorectal cancer receiving standard-of-care treatment with combined BRAF and EGFR inhibition (e.g., encorafenib and cetuximab), with or without concomitant chemotherapy. Participants are enrolled prior to treatment initiation and followed longitudinally with collection of tumor tissue, blood, and stool samples to study mechanisms of treatment resistance.
Autre: Longitudinal translational sampling
Longitudinal translational sampling (tumor tissue, plasma ctDNA, stool, PBMCs).

Que mesure l'étude ?

Principaux critères de jugement

Mesure des résultats
Description de la mesure
Délai
Detection rate of molecular alterations associated with acquired resistance
Délai: from baseline (pre-treatment) to disease progression (approximately 12 months)
Proportion of patients with detectable molecular alterations associated with acquired resistance to combined BRAF and EGFR inhibition, identified in tumor tissue collected before treatment and at disease progression using molecular profiling.
from baseline (pre-treatment) to disease progression (approximately 12 months)

Mesures de résultats secondaires

Mesure des résultats
Description de la mesure
Délai
Detection rate of targetable resistance alterations
Délai: Baseline to disease progression (approximately 12 months)
Proportion of patients with acquired resistance alterations that are potentially targetable by available or investigational therapies, identified through molecular profiling of tissue and liquid biopsy samples.
Baseline to disease progression (approximately 12 months)
Detection rate of non-genomic resistance mechanisms
Délai: Baseline to disease progression (approximately 12 months)
Proportion of patients with non-genomic mechanisms of resistance, including transcriptomic changes and tumor microenvironment alterations, identified through molecular analyses.
Baseline to disease progression (approximately 12 months)
Comparison of resistance alterations in tissue versus liquid biopsies
Délai: Baseline to disease progression (approximately 12 months)
Concordance and detection rates of resistance-associated molecular alterations in matched tumor tissue and circulating tumor DNA samples.
Baseline to disease progression (approximately 12 months)
Establishment rate of patient-derived organoids (PDOs)
Délai: From baseline biopsy collection through PDO establishment (approximately 3 to 6 months per sample)
Proportion of collected tumor biopsies (baseline and progression) from which patient-derived organoid cultures are successfully established for downstream functional analyses.
From baseline biopsy collection through PDO establishment (approximately 3 to 6 months per sample)
Longitudinal dynamics of circulating tumor DNA (ctDNA)
Délai: Baseline, every 8 to 12 weeks during treatment, and at disease progression (up to approximately 24 months)
Quantitative changes in plasma ctDNA tumor fraction and variant allele frequencies of mutations from baseline through on-treatment time points to progression, and their association with radiological response and resistance evolution.
Baseline, every 8 to 12 weeks during treatment, and at disease progression (up to approximately 24 months)
Compositional characterization of the gut microbiome
Délai: Baseline and at disease progression (approximately 12 months)
Compositional and functional features of the gut microbiome at baseline and at disease progression, and their association with treatment response and resistance.
Baseline and at disease progression (approximately 12 months)

Collaborateurs et enquêteurs

C'est ici que vous trouverez les personnes et les organisations impliquées dans cette étude.

Parrainer

Swiss Cancer Institute

Les enquêteurs

  • Chaise d'étude: Ralph Fritsch, MD, University of Zurich

Dates d'enregistrement des études

Ces dates suivent la progression des dossiers d'étude et des soumissions de résultats sommaires à ClinicalTrials.gov. Les dossiers d'étude et les résultats rapportés sont examinés par la Bibliothèque nationale de médecine (NLM) pour s'assurer qu'ils répondent à des normes de contrôle de qualité spécifiques avant d'être publiés sur le site Web public.

Dates principales de l'étude

Début de l'étude (Réel)

25 mai 2025

Achèvement primaire (Estimé)

1 septembre 2030

Achèvement de l'étude (Estimé)

1 septembre 2030

Dates d'inscription aux études

Première soumission

22 mai 2026

Première soumission répondant aux critères de contrôle qualité

22 mai 2026

Première publication (Réel)

1 juin 2026

Mises à jour des dossiers d'étude

Dernière mise à jour publiée (Réel)

16 juillet 2026

Dernière mise à jour soumise répondant aux critères de contrôle qualité

15 juillet 2026

Dernière vérification

1 juillet 2026

Plus d'information

Termes liés à cette étude

Mots clés

Termes MeSH pertinents supplémentaires

Autres numéros d'identification d'étude

  • SAKK 41/23

Plan pour les données individuelles des participants (IPD)

Prévoyez-vous de partager les données individuelles des participants (DPI) ?

NON

Description du régime IPD

This is a non-interventional observational study with translational research components. Individual participant data sharing is not planned. Aggregate study results, including de-identified molecular and clinical data summaries, will be disseminated through peer-reviewed publications and scientific meetings. De-identified data may be shared with collaborators on a case-by-case basis upon reasonable request to the Study Chair and subject to applicable Swiss data protection regulations, institutional review, and a data-transfer agreement.

Informations sur les médicaments et les dispositifs, documents d'étude

Étudie un produit pharmaceutique réglementé par la FDA américaine

Non

Étudie un produit d'appareil réglementé par la FDA américaine

Non

Ces informations ont été extraites directement du site Web clinicaltrials.gov sans aucune modification. Si vous avez des demandes de modification, de suppression ou de mise à jour des détails de votre étude, veuillez contacter register@clinicaltrials.gov. Dès qu'un changement est mis en œuvre sur clinicaltrials.gov, il sera également mis à jour automatiquement sur notre site Web .

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