CAPP3 (Clinical Trial)

Full Study Name

CAPP3: A randomised double blind dose non-inferiority trial of a daily dose of 600mg versus 300mg versus 100mg of enteric coated aspirin as a cancer preventive in carriers of a germline pathological mismatch repair gene defect, Lynch Syndrome

Local Principal Investigator

Professor Gareth Evans

Study Status


Main Aims

To determine whether the cancer preventive properties of enteric coated aspirin in Lynch syndrome are dose sensitive by comparing overall cumulative Lynch syndrome cancer incidence rates after 5 years in people who took 100mg, 300mg or 600mg enteric coated aspirin for at least 2 years

Compare overall cumulative incidence of primary colorectal, endometrial and other cancers using Poisson regression to allow for multiple primaries in individual patients in the three treatment groups.

Inclusion Criteria
  • Over 18
  • Confirmed germline pathological variant in one of the mismatch repair genes; MSH2, MLH1, PMS2 or MSH6 or a 3’ EPCAM deletion associated with MSH2 silencing or be a carriers of a constitutional epimutation manifesting a classic Lynch syndrome phenotype.
  • Able to swallow tablets.
  • Willing to complete the CaPP3 consent process.
Exclusion Criteria
  • Regular use of a non-steroidal anti-inflammatory agent on a prescription and/or long-term basis. Regular is defined as > 3 doses per week, for more than 3 months in the last 3 years.
  • Previous regular use of aspirin at a daily dose of 150mg or less does not exclude enrolment but duration and quantity need to be documented in detail. More than 3 months use of > 150mg or more per day in the last 3 years is an exclusion
  • Known aspirin intolerance or hypersensitivity, including aspirin-sensitive asthma.
  • Existing clinically significant liver impairment.
  • Existing renal failure.
  • Confirmed active peptic ulcer disease within the previous three months.
  • Known bleeding diathesis or concomitant anticoagulant therapy.
  • Inability to comply with study procedures and agents.
  • Women reporting that they are pregnant or actively planning to achieve a pregnancy within the next two years.
  • Women who are breastfeeding.
  • Any significant medical illness that would interfere with study participation. (If hypertension is discovered, the participant should be advised to have this treated before commencing trial medication).
  • Participation in the previous CAPP2 study will not exclude patients from this study, apart from the small number recruited less than 10 years previously.
Open Sites

Aberdeen: North of Scotland Genetic Service

Belfast: Northern Ireland Regional Genetics Service

Birmingham: West Midlands Regional Genetics Service

Bristol: Bristol Clinical Genetics Service

Cambridge: East Anglian Medical Genetics Service

Cardiff: All Wales Medical Genetics Service

Dundee: East of Scotland Genetic Service

Edinburgh: South East Scotland Genetic Service

Exeter: Peninsula Genetics Service

Glasgow: West of Scotland Genetic Service

Leeds: Yorkshire Regional Genetics Service

Leicester: Leicestershire Genetics Centre

Liverpool: Cheshire & Merseyside Regional Genetic Service

London: North East Thames Regional Genetics Service. Great Ormond Street Hospital

London:  North West Thames Regional Genetics Service, St Mark’s Hospital

London: South West Thames Regional Genetics Service, St George’s Hospital

London: Guy’s Hospital Genetic Centre

London: Royal Marsden Hospital

Manchester: Manchester Centre for Genomic Medicine

Newcastle: Northern Genetics Service

Nottingham: Nottingham Regional Genetics Service

Oxford: Oxford Genetics Service

Rhyl: All Wales Medical Genetics Service

Sheffield: Sheffield Genetic Services

Southampton: Wessex Clinical Genetics Service

Swansea: All Wales Medical Genetics Service

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