To report the results of interviews with caregivers of patients with DS and LGS debriefing the Clinical Global Impression of Improvement for Nonseizure Symptoms, a clinician-reported outcome (ClinRO) measure to assess within-patient change for communication, alertness and disruptive behavior.

DS and LGS are characterized by treatment-resistant seizures and developmental delay and/or intellectual disability. Because patients cannot self-report, caregiver feedback on the relevance of the concepts and methodology is critical to ensure (a) the measure is fit-for-purpose and (b) caregivers can assist with ClinRO measure completion.

Caregivers were recruited via advertisement by advocacy organizations (January–March 2022). Following screening, caregivers completed an online concept elicitation and cognitive debriefing interview. A qualitative analysis plan was developed to aid interview analysis.

Overall, 21 caregivers debriefed the measure (DS, n=10; LGS, n=11; 100% female; mean age 41 years); all were parents of patients (61.9% male; mean age 10.1; DS mean age 7.3; LGS mean age 12.7). Caregivers were able to describe their child’s status easily using the baseline item descriptions and to use the response scale to describe levels of change for their child. All caregivers understood the communication item (n=21) and most found it relevant (n=20). All understood and found the alertness item relevant. All understood the disruptive behavior item (n=20) and most found it relevant (n=19) (one caregiver was not debriefed). Most caregivers that were asked ranked each item as ≥7 on an importance scale of 0–10, and reported that minimal improvement in each domain would be meaningful for their child.

Caregiver feedback indicated that the measure items represented highly relevant nonseizure outcomes and were easy to understand and use; minimal improvement in each domain would represent meaningful outcomes in these core areas. Further analysis is planned following completion of ongoing phase 3 studies.

Study funded by Takeda Pharmaceutical Company Limited.