A single item for overall side effect impact: Association with clinician-reported adverse events and global health

There is growing recognition of the importance of patient-reported tolerability in complementing traditional clinician-reported safety evaluation of cancer therapies. Recent regulatory guidance listed the evaluation of overall side effect impact as a core patient-reported outcome in oncology clinical trials. A single item ('GP5') that asks about side effect bother is included in the Functional Assessment of Chronic Illness Therapy and has been used to capture overall side effect impact. This paper sought to expand the evidence base for GP5 by examining its association with clinician-reported treatment-emergent adverse events and patient-reported global health.

We examined six commercial cancer clinical trials that collected GP5. The patient population was drawn from the safety population and the analysis focused on the first on-treatment assessment. Clinician-reported adverse events were classified as symptomatic if such adverse events were considered amenable to patient self-reporting (e.g. nausea). Chi-square tests and Pearson's correlation were used to examine associations. We considered adverse event grade and frequency, both for symptomatic adverse events and any type of adverse events. Global health was measured using the visual analogue scale of the EuroQol-5 Dimensions-3 Levels measure. 'Moderate-severe' bother was characterised as scores of 2-4 on a 0-4 point scale for GP5, and 'severe' bother was characterised as scores of 3-4. Analyses were conducted separately for each trial.

Data from 3,557 patients were included. Across the trials, most (71.7%-94.2%) patients had an adverse event of some kind, but fewer (17.1%-44.4%) had an adverse event of grade 3 or higher. In general, fewer than 50% of patients (20.6%-44.2%) reported moderate-severe bother and 5.8%-17.% reported severe bother. There were consistent, albeit not always statistically significant, associations between GP5 and adverse events, and GP5/global health correlations ranged from -0.17 to -0.41.

GP5 is associated with both clinician- and patient-reported symptoms, suggesting its validity and usefulness as part of comprehensive tolerability assessment of cancer trials.