OBJECTIVES : Preferences in clinical trials can help researchers understand which aspects of treatments patients or other stakeholders value most, and their perceptions of benefit-risk trade-offs for a treatment. They can also be used to adjust outcomes for preference biases, increasing outcome precision. The aim of the study was to identify the extent to which oncology trials capture treatment preferences (TP).

METHODS : Clinicaltrials.gov was used to identify use of TP methods in oncology trials in Europe and the US. Drug databases also supplemented regulatory information. The search included completed cancer or neoplasm studies, TP as outcome measures, and adult patients. No time limit was specified. Identified studies were screened for relevance, and characteristics were extracted.

RESULTS : Of 90 records identified, 23 were included (Europe: n=15; US: n=8). The majority of studies came from either Phase 3 trials (n=7) or ‘Not applicable’ (n=6). Others included Phase 1 (n=2), Phase 2 (n=4) and Phase 4 trials (n=4). Studies most commonly included patients with breast cancer (n=6), prostate cancer (n=4) or various cancer types (n=3). Eleven studies used TP as the primary endpoint, whereas 17 studies used TP as the secondary and/or exploratory endpoint. Objectives included mode of administration (n=6), treatment location (n=1), treatment provider (n=1), or overall TP (drug therapy: n=12; radiation: n=2). One study explored health states associated with treatment choice. Studies used different methods, including non-validated and validated preference questionnaires (e.g. standard gamble; n=16), a single preference question (n=6), or in-trial patient interviews (n=1).

CONCLUSIONS : Findings revealed different methods were used in trials to capture TP primarily as secondary endpoints across cancer types. These findings may have impacts on trial designs, outcomes, and decisions, and there may be a need to standardize approaches to capture TP data for regulatory endorsement. Further work is needed to examine influences of TP in oncology trials on clinical decision-making.