Abstract
BACKGROUND: Neurofibromatosis type 1 (NF1) is a multisystem genetic condition. Up to 50% of individuals with NF1 develop plexiform neurofibromas (PN) that can cause pain and significant morbidity, impairing quality of life. As of December 2025, only a limited number of countries have an approved medical treatment for adults with NF1-PN. A systematic literature review (PROSPERO CRD42023463980) was conducted to better understand disease burden and unmet need in this population. METHODS: An evidence prioritization strategy identified studies reporting on NF1-PN populations with ≥50% adults from database searches conducted between 1988 and July 20, 2023. Studies published in the last 15 years were extracted. RESULTS: Of 3242 identified sources, 57 publications (53 unique studies) were included. The proportion of adults with NF1 who had PN ranged from 11.8% to 84.9% (n = 9 studies). Annual median change in untreated PN volume was -3.7% to +8.3% (n = 5 articles). Pain was the most common PN-related manifestation (32.0%-38.4% of patients; n = 12 articles). Malignant PN transformation occurred in 2.0%-4.1% of patients (n = 5 cohorts); 3 shorter-term studies reported no transformation. Surgery was performed in 69.5% of patients (n = 7 cohorts); post-operative complications occurred in 13.0%-30.0% (n = 3 articles). Analgesia was the most reported pharmacological treatment (37.9% of patients; n = 7 articles). Limited data indicated that PN monitoring and surgery cause substantial resource use. No studies reported on caregiver burden, healthcare costs, or transition from pediatric to adult care. CONCLUSIONS: Adults with NF1-PN experience high disease burden. Data gaps exist for epidemiology, transition of care, caregiver burden, healthcare cost, and resource use.