Planned time burden for patients participating in phase 2 cancer trials

Participation in cancer trials requires a commitment of time and research burden from patients. Prior work has highlighted the time burden of clinic visits during phase 1 trial participation. We extended these findings to phase 2 cancer trials.

We reviewed a random sample of 73 phase 2 cancer trial arms with results posted on ClinicalTrials.gov 2023-2024. We extracted scheduled visit frequency and procedures from each protocol. Primary outcomes included the absolute number of planned research days (PRDs) in the first 30 days and subsequent months of participation. Secondary outcomes included procedure volume throughout the trial. We also estimated the proportion of progression-free survival (PFS) and overall survival (OS) spent in clinic.

The median number of PRDs in the first 30 days of participating in a phase 2 trial was 5 (IQR 4-7) and 2 (IQR 1-3) per month thereafter. Across the course of a trial, patients had a median of 13 PRDs and underwent a median of 13 (IQR 10-22) blood draws, 6 (IQR 2-26) infusions, and 1 (IQR 0-2) mandatory biopsy. PRDs accounted for 10.5% of median PFS and 4.0% of median OS. The average phase 2 trial involved a cumulative 11 patient-months of planned visits.

Patients in phase 2 cancer trials commit a substantial amount of time to research participation. Further work is needed to compare these estimates to time spent in standard of care and to find ways to reduce the time toxicity of trial participation.