Variation in Toxicity Reporting Methods for Early Phase Lung Cancer Treatment Trials at Oncology Conferences

Phase I and II trials provide the initial human safety and tolerability data for new drugs. Nevertheless, the methods for presenting toxicity data are not standardized. Clinicians often first encounter these data at professional conferences. We sought to characterize how the burden of adverse events (AEs) is reported at the largest professional conference in clinical oncology.

We collected toxicity data from all lung cancer-associated phase I and II trial presentations and posters at the American Society for Clinical Oncology annual meetings from 2017 to 2019. We captured the various AE features, including the minimum incidence used for reporting; whether AEs found were treatment emergent or treatment related, grouped by organ system or separated by individual descriptors; whether combined or separated across dose levels when a dose-escalation component was included; and whether dose-limiting toxicities, serious AE, dose-reduction rules, and denominators for laboratory tests were described.

A total of 209 trials were analyzed. There was wide variability in toxicity reporting practices. Six different thresholds for reporting AEs of any grade were used. Treatment-related AEs were reported twice as frequently as treatment-emergent AEs. Toxicities were as likely to be reported across dose levels as by dose level. Terms such as dose-limiting toxicity and serious AE were rarely defined. Dose-reduction rules and denominators for laboratory tests were never defined.

Standardization of methods for reporting toxicities could improve the quality and ease of comparability of data on adverse effects in early phase therapeutic trials. A minimal AE data disclosure template is proposed.