Why BRAF V600E-mutated metastatic colorectal cancer stops responding to targeted treatment
Studies tumor, blood and stool samples from adults with BRAF V600E-mutated metastatic colorectal cancer.
Plain-language title generated from the registry record
Registry title: Primary and Acquired Resistance to Targeted Treatment in BRAF V600E-mutated Metastatic Colorectal Cancer
Key facts
- Where
- Aarau, Baden, Basel, Bern, Biel, Chur, Lucerne, Sankt Gallen, Solothurn, Villars-sur-Glâne, Winterthur, and Zurich, SwitzerlandSee the 13 sites
Where in Switzerland
- Kantonsspital AarauAarau, SwitzerlandTaking people
- Kantonsspital BadenBaden, SwitzerlandTaking people
- St. ClaraspitalBasel, SwitzerlandTaking people
- Universitaetsspital BaselBasel, SwitzerlandTaking people
- Inselspital BernBern, SwitzerlandTaking people
- Spitalzentrum Biel - MEDIN La TourBiel, SwitzerlandTaking people
- Kantonsspital GraubundenChur, SwitzerlandTaking people
- Luzerner KantonsspitalLucerne, SwitzerlandTaking people
- HOCH Health Ostschweiz - Kantonsspital St. GallenSankt Gallen, SwitzerlandTaking people
- Bürgerspital SolothurnSolothurn, SwitzerlandTaking people
- HFR Freiburg - KantonsspitalVillars-sur-Glâne, SwitzerlandTaking people
- Kantonsspital WinterthurWinterthur, SwitzerlandTaking people
- Universitätsspital Zürich USZZurich, SwitzerlandTaking people
Questions to ask the study team
- How often do I need to come in, and for how long each time?
- Are travel costs paid?
- Can I keep my own doctor?
- What happens if I want to stop?
Trial details
- Who runs it
- Swiss Cancer Institute
- Trial code
- NCT07617610
- Record updated
- 16 July 2026
- Original description
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.Read full original descriptionShow less
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.
Inclusion: 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: Medical or surgical contraindication for tumor biopsy; Previous treatment with a BRAF inhibitor; 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.