QOL-27. Effect of selumetinib treatment on long-term pain medication utilization in pediatric patients: a retrospective study of a US claims database

Abstract Selumetinib (ARRY-142886, AZD6244), an oral inhibitor of mitogen-activated protein kinase kinases 1 and 2, reduces plexiform neurofibroma size in children with neurofibromatosis type 1. A previous real-world analysis showed 6 months of selumetinib treatment led to reduced pain medication utilization (PMU). This retrospective US hybrid claims database analysis assessed the impact of continued selumetinib treatment on PMU in pediatric patients over a follow-up period of up to ~3 years. Patients treated with selumetinib (aged 2–21 years) were identified via Forian CHRONOS (an open- and closed-source hybrid claims database of data from clearinghouses, pharmacies, and healthcare payors) using national drug codes. Inclusion criteria were ≥3 selumetinib prescriptions (April 10, 2020−December 16, 2024) and ≥12 months of continuous study enrollment or claim activity before and after the index date (first selumetinib prescription). Monitoring was conducted from selumetinib initiation to last available follow-up data. Overall, 220 patients were included (2–5 years: 7%; 6–11 years: 33%; 12–18 years: 49%; 19–21 years: 11%; male: 54%). In the 3 months preceding selumetinib initiation, 24% of patients (n=42/176) were receiving prescription pain medication. The proportions of patients receiving pain medication at 3 months, 6 months, 1 year, 2 years, and 3 years post-selumetinib initiation were 17% (38/220), 15% (27/185), 20% (30/148), 15% (13/87), and 9% (3/34), respectively. Overall, 26 patients were receiving gabapentin in the 12 months prior to selumetinib initiation; 50% (n=13) discontinued use within 12 months of selumetinib initiation. For patients who continued gabapentin (n=13), the average dose declined from 802 mg/day (before selumetinib) to 675 mg/day (after selumetinib). Selumetinib was associated with a consistent and durable reduction in PMU over a follow-up period of up to ~3 years, adding to the long-term and the real-world data supporting its clinical benefits in pediatric patients with neurofibromatosis type 1-related plexiform neurofibroma.