Evaluation of the patient experience of symptomatic adverse events on Phase I clinical trials using PRO-CTCAE

Adverse event (AE) reporting in early-phase clinical trials is essential in determining the tolerability of experimental anticancer therapies. The patient-reported outcome version of the CTCAE (PRO-CTCAE) evaluates AE components such as severity and interference in daily life. The aim of this study was to correlate the grade of clinician-reported AEs with patients' reported experience of these toxicities using PRO-CTCAE. Patients with advanced solid tumours enrolled on Phase I clinical trials were surveyed using the PRO-CTCAE. Symptomatic AEs were recorded by physicians using the CTCAE. A logistic regression model was used to assess associations between CTCAE grade and PRO responses. Of 219 evaluable patients, 81 experienced a high-grade (3/4) clinician-reported symptom, and of these, only 32 (40%) and 26 (32%) patients concordantly reported these as either severe or very severe, and interfering with daily life either 'quite a bit' or 'very much', respectively. Of the 137 patients who experienced a low-grade (1/2) clinician-reported AE as their worst symptom, 98 (72%) and 118 (86%) patients concordantly reported these as either mild–moderate severity and minimally interfering with daily life, respectively. There was a statistically significant association between clinician-reported AE grade and interference. Interference scores were also associated with dose reductions. This is the first study to explore patient-reported severity and interference from symptomatic toxicities and compare clinician grading of the same toxicities. The study provided further evidence to support the added value of the PRO-CTCAE in Phase I oncology trials, which would make AE reporting patient-centred. Further work is needed to determine how this would affect the assessment of tolerability.