Key measurement concepts and appropriate clinical outcome assessments in pediatric achondroplasia clinical trials.

BACKGROUND

This study aimed to identify fit-for-purpose clinical outcome assessments (COAs) to evaluate physical function, as well as social and emotional well-being in clinical trials enrolling a pediatric population with achondroplasia. Qualitative interviews lasting up to 90 min were conducted in the US with children/adolescents with achondroplasia and/or their caregivers. Interviews utilized concept elicitation methodology to explore experiences and priorities for treatment outcomes. Cognitive debriefing methodology explored relevance and understanding of selected COAs.

RESULTS

Interviews (N = 36) were conducted with caregivers of children age 0-2 years (n = 8) and 3-7 years (n = 7) and child/caregiver dyads with children age 8-11 years (n = 15) and 12-17 years (n = 6). Children/caregivers identified pain, short stature, impacts on physical functioning, and impacts on well-being (e.g. negative attention/comments) as key bothersome aspects of achondroplasia. Caregivers considered an increase in height (n = 9/14, 64%) and an improvement in limb proportion (n = 11/14, 71%) as successful treatment outcomes. The Childhood Health Assessment Questionnaire (CHAQ) and Quality of Life in Short Stature Youth (QoLISSY-Brief) were cognitively debriefed. CHAQ items evaluating activities, reaching, and hygiene were most relevant. QoLISSY-Brief items evaluating reaching, height bother, being treated differently, and height preventing doing things others could were most relevant. The CHAQ and QoLISSY-Brief instructions, item wording, response scales/options and recall period were well understood by caregivers and adolescents age 12-17. Some children aged 8-11 had difficulty reading, understanding, or required caregiver input. Feedback informed minor amendments to the CHAQ and the addition of a 7-day recall period to the QoLISSY-Brief. These amendments were subsequently reviewed and confirmed in N = 12 interviews with caregivers of children age 0-11 (n = 9) and adolescents age 12-17 (n = 3).

CONCLUSIONS

Achondroplasia impacts physical functioning and emotional/social well-being. An increase in height and improvement in limb proportion are considered to be important treatment outcomes, but children/adolescents and their caregivers expect that a successful treatment should also improve important functional outcomes such as reach. The CHAQ (adapted for achondroplasia) and QoLISSY-Brief are relevant and appropriate measures of physical function and emotional/social well-being for pediatric achondroplasia trials; patient-report is recommended for age 12-17 years and caregiver-report is recommended for age 0-11 years.