Mapping immune checkpoint inhibitor side effects to item libraries for use in real-time side effect monitoring systems.

Background: Monitoring for the side effects of novel therapies using patient-reported outcomes (PROs) is critical for ensuring patient safety. Existing static patient-reported outcome measures may not provide adequate coverage of novel side effects. Item libraries provide a flexible approach to monitoring for side effects using customized item lists, but the ideal process for matching side effects to items sourced from multiple item libraries is yet to be established. We sought to develop a pragmatic process for mapping side effects to items from three major item libraries using immune checkpoint inhibitor (ICI) side effects as an example.

Methods: Using a consumer- and clinician-driven list of 36 ICI side effects, two authors independently mapped side effects to Common Terminology Criteria for Adverse Event (CTCAE) terms, and then to three item libraries: the Patient-Reported Outcome version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE), the European Organisation for Research and Treatment of Cancer (EORTC) Item Library, and the Functional Assessment of Chronic Illness Therapy (FACIT) searchable library. The rates of inter-rater agreement were recorded. Following item collation from the item libraries, we devised criteria for selecting the optimal item for each side effect for inclusion in a future electronic PRO system based on guidance from the above groups.

Results: All 36 side effects mapped to at least one CTCAE term, with eight mapping to more than one term. Twenty-three side effects mapped to at least one PRO-CTCAE term, 35 side effects mapped to at least one EORTC item, and 31 side effects mapped to at least one FACIT item. The inter-rater agreement rate was 100% (PRO-CTCAE), 83% (EORTC) and 75% (FACIT). Pre-determined criteria were applied to select the optimal item for each side effect from the three item libraries, producing a final 61-item list.

Conclusion: Using ICI side effects as an example, we developed a pragmatic approach to creating customized item lists from three major item libraries to monitor for side effects of novel therapies in routine care. This process highlighted the challenges of using item libraries and priorities for future work to improve their usability.