European Union · Phase III · Liver-metastasis focus
EU Phase III metastatic colorectal cancer: MSS/pMMR sites, PIs and trial sizes
Vall d’Hebron leads EU site experience with 18 Phase III metastatic colorectal cancer trials, including nine focused on MSS/pMMR disease. Across 37 trials in 20 EU countries, MSS/pMMR-focused studies plan larger participant groups on average, while the two dedicated liver-metastasis studies address locally treatable or resected disease.
across 34 randomized trials
Top 10 sites · All mCRC populations
Vall d’Hebron leads with 18 trials
Istituto Oncologico Veneto follows with 16 trials and Pisa University Hospital with 15. These counts describe trial experience, not recruitment performance or current capacity.
What changes for MSS/pMMR?
MSS/pMMR-focused14 trialsThe same two sites lead: Vall d’Hebron with nine and Istituto Oncologico Veneto with eight. MSS/pMMR-focused studies account for half of each site’s overall trial count.
With liver metastasesTwo dedicated studiesThe network shifts to 17 French sites in PACHA-02 and two Dutch sites in COLLISION RELAPSE. Each site appears in one of these studies, so trial counts alone do not separate their experience in this setting.
MSS means microsatellite stable and pMMR means proficient mismatch repair. MSS/pMMR-focused studies require those features or exclude MSI-H/dMMR disease.
Top 10 principal investigators · All mCRC populations
Elena Élez Fernández and Thorsten Götze each appear in 14 trials
Chiara Cremolini, Gunnar Folprecht and Pilar García Alfonso follow with 13 each. The order changes when the focus narrows to MSS/pMMR disease.
What changes for MSS/pMMR?
MSS/pMMR-focusedA different leading groupElena Élez Fernández leads with seven trials. Dirk Arnold rises from ten trials overall to a shared second place in this subgroup, alongside Thorsten Götze, with six each.
With liver metastasesTreatment setting mattersMaximiliano Gelli at Gustave Roussy participates in PACHA-02 after liver-metastasis resection. Madelon Dijkstra at Amsterdam UMC participates in COLLISION RELAPSE for recurrent, locally treatable liver metastases.
Top 10 countries · All mCRC populations
France has the broadest footprint with 23 trials
Spain follows with 21 trials and Italy with 20. Germany and the Netherlands complete the leading five.
What changes for MSS/pMMR?
MSS/pMMR-focused15 EU countriesThe footprint narrows from 20 to 15 countries. France still leads with ten trials, while Italy and Spain share second place with nine each.
With liver metastasesFrance and the NetherlandsEach country has one dedicated study. France has 17 participating sites and the Netherlands has two, despite the equal trial count.
A multinational trial can appear in more than one country. Country counts cover EU member states.
Planned sample sizes · All mCRC populations
Trials plan an average of 471 randomized participants
The median is 435 participants, with targets ranging from 78 to 1,020 across 34 trials. Eighteen of these trials plan between 200 and 599 participants.
What changes for MSS/pMMR?
MSS/pMMR-focused12 trial targetsThe average rises to 577 participants, about 106 more than the overall average. The median rises to 594, so the difference is not confined to the largest trial.
With liver metastasesTwo trial targetsPACHA-02 plans 272 participants and COLLISION RELAPSE plans 360, averaging 316. Their resected and locally treatable populations provide more specific size references for those settings.
Targets are planned randomized participants for the whole trial, including countries outside the EU. The MSS/pMMR and liver-metastasis groups overlap with the overall group.
MSS/pMMR and liver metastases
The two dedicated studies address different surgical settings
COLLISION RELAPSE concerns recurrent metastases that can receive local treatment, while PACHA-02 begins after liver-metastasis resection. Other MSS/pMMR systemic-treatment trials also allow liver metastases, so these two do not represent every trial relevant to unresectable disease.
COLLISION RELAPSE
Recurrent, locally treatable colorectal liver metastases, excluding MSI and extrahepatic disease. Compares neoadjuvant systemic therapy followed by local treatment with upfront local treatment.
PACHA-02
MSS/pMMR colorectal cancer after liver-metastasis resection, with high recurrence risk. The liver-metastasis setting is postoperative, rather than measurable unresectable liver disease.
Source: CTIS trial records and protocols, as of 16 September 2026, with registry records for COLLISION RELAPSE and PACHA-02. Rankings count distinct Phase III trials and include historical and planned participation. Ties are ordered alphabetically, including ties at the tenth position.