OBJECTIVES: To quantitatively evaluate the factors driving subject preferences for recombinant human growth hormone (r-hGH) injection and injection device features among patients with growth hormone deficiency (GHD).

METHODS: A cross-sectional, observational Web-based study involving adult and pediatric patients (and their caregivers) receiving daily r-hGH injections for GHD was conducted. Patients/caregivers were screened by physicians at eight clinical locations in the United States and emailed unique URLs. Consented participants completed a discrete choice exercise (DCE) to indicate their preferred option from a choice of two across 20 tasks, trading off the following six attributes: Storage (Refrigerated vs. Room Temperature); Preparation (Mix vs. Mix, then Room Temperature vs. Ready to Use); Injection Device (Continuous Push Needle Device vs. Autoinjector vs. Needle Free Device); Maintenance (Single Use, Disposable Pen vs. Multiple Use, Disposable Pen vs. Multiple Use, Reusable Pen); Dose Setting (Set the Dose vs. Dose Memory vs. Pre-set Dose), and Injection Schedule (Once Daily vs. Once Weekly vs. Once Every Two Weeks vs. Once a Month). The conjoint analysis used a part-worth model and Hierarchical Bayesian (HB) analysis to evaluate relative importance of the attributes as choice drivers. Aggregate relative importance (ARI) across all attributes sums to 100%.

RESULTS: In total, 224 patients (n=70 children/caregiver dyads, n=79 adolescents/caregiver dyads, n=75 adults) completed the DCE. Injection Schedule emerged as the strongest predictor (ARI: 48%), with greater preference for less frequent administration. Preparation was the next strongest predictor (ARI: 22%), as a “Ready to Use” device was more desired than one that involves reconstitution. The remaining four attributes had <10% ARI.

CONCLUSIONS: Patients prefer a weekly (or less frequent) r-hGH injection regimen to a daily regimen and a ready to use device to one that requires reconstitution. Addressing patient preferences for treatment delivery may improve compliance, adherence, and, ultimately, clinical outcomes.