Managing Cancer And Living Meaningfully (CALM) is a brief individual psychotherapy for patients with advanced cancer. In an intervention-only phase 2a trial, CALM showed promising results, leading to the present 2b pilot, which introduces procedures for randomisation and improved rigour in preparation for a phase 3 randomised controlled trial (RCT). The aim is to test trial methodology and assess feasibility of a confirmatory RCT. A parallel-arm RCT (intervention vs usual care) with 3 and 6-month follow-ups. Assessment of feasibility included rates of consent, randomisation, attrition, intervention non-compliance and usual care contamination. Primary outcome: depressive symptoms (Patient Health Questionnaire-9; PHQ-9). Secondary outcomes: major depressive disorder (MDD), generalised anxiety, death anxiety, spiritual well-being, attachment anxiety and avoidance, self-esteem, experiential avoidance, quality of life and post-traumatic growth. Bayesian conjugate analysis was used in this low-powered setting. 60 adult patients with advanced cancer from the Princess Margaret Cancer Centre. Rate of consent was 32%, randomisation 78%, attrition 25%, non-compliance 37% and contamination 17%. There was support for potential treatment effects on: PHQ-9, OR=1.48, 95% Credible Interval (CRI.95) (0.65, 3.38); MDD, OR=1.56, CRI.95 (0.50, 4.84); attachment anxiety, OR=1.72, CRI.95 (0.73, 4.03); and attachment avoidance, OR=1.58, CRI.95 (0.67, 3.71). There was no support for effects on the seven remaining secondary outcomes. Conclusions A phase 3 CALM RCT is feasible and should aim to detect effect sizes of d=0.40, with greater attention to issues of compliance and contamination.