The U.S. Food and Drug Administration (FDA) has approved Koselugo (selumetinib) for the treatment of adult patients with neurofibromatosis type 1 (NF1) who have symptomatic, inoperable plexiform neurofibromas (PN). Selumetinib was first approved in 2020 for pediatric patients ages 2 years and older. The indication was expanded in September 2025 to include patients ages 1 year and older.
NF1 is a genetic condition that affects the skin, the skeleton and the peripheral nervous system. The main signs and symptoms of NF1 include dark colored spots on the skin, benign growths along the nerves (neurofibromas), and freckles in the underarm and groin. Other symptoms may include colored spots in the eye, curvature of the spine, learning disabilities, and an increased risk for cancer. The number of neurofibromas typically increases over time, and some can get large or turn cancerous and need to be removed. PNs occur in about 30-50% of patients with NF1. These tumors are often larger, diffuse growths with less well-defined borders than cutaneous neurofibromas. The severity and symptoms can vary greatly from person to person. This condition is caused by genetic changes in the NF1 gene.
Selumetinib is an oral, selective MEK inhibitor that targets and slows down the growth of tumor cells and PN growth. The FDA approval follows positive results from the KOMET clinical trial, a phase 3, randomized, double-blind, placebo-controlled, multicenter study evaluating the safety and efficacy of selumetinib in adult patients with NF1 who have PN.
A total of 145 adults were enrolled in the trial. In the primary analysis, selumetinib illustrated a statistically significant and clinically meaningful overall response rate of 20% compared to 5% with placebo by cycle 16. Additionally, 86% of patients on selumetinib had a duration of response of at least 6 months.
The safety profile of selumetinib was consistent with its known profile and established use in pediatric patients.
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To learn more about NF1 and other rare genetic conditions, visit https://checkrare.com/diseases/congenital-and-genetic-conditions/
Tags: cancer, genetic, neuro, skin, treatment, regulations