Add-Aspirin: A Trial Assessing the Effects of Aspirin on Disease Recurrence and Survival After Primary Therapy in Common Non Metastatic Solid Tumours

A phase III, multi-centre, double-blind, placebo-controlled randomised trial which aims to assess whether regular aspirin use after standard therapy prevents recurrence and prolongs survival in participants with non-metastatic common solid tumours. The trial has four parallel tumour site-specific cohorts (breast, colorectal, gastro-oesophageal and prostate cancer). An overarching protocol ensures each cohort is as comparable as possible to allow a combined analysis of overall survival as a co-primary outcome measure in addition to individual tumour site-specific analyses of disease recurrence and survival. Participants who have undergone potentially curative treatment (surgery or other radical treatment), including any standard neo-adjuvant or adjuvant therapy for breast, colorectal, gastro-oesophageal or prostate cancer or have participated in any pre-approved trials and satisfy the eligibility criteria. Participants will be randomly assigned to 100mg aspirin, 300mg aspirin or matched placebo. All tablets will be enteric-coated to be taken daily for at least five years. Prior to randomisation, all potential participants will take open-label 100mg aspirin daily for a run-in period of approximately 8 weeks to assess tolerability and adherence. The trial incorporates a feasibility phase during which recruitment feasibility, treatment adherence, safety and use of the run-in period will be assessed.