The U.S. Food and Drug Administration (FDA) has approved Koselugo (selumetinib), an oral MEK inhibitor developed by Alexion, AstraZeneca Rare Disease, for adults with neurofibromatosis type 1 (NF1) who have symptomatic, inoperable plexiform neurofibromas (PN). As reported on PharmaBiz, this marks the first approved therapy for NF1 PN in adults.

The decision was based on results from KOMET, the largest placebo-controlled phase III trial in this population. The study demonstrated a significant overall response rate of 20% with Koselugo versus 5% with placebo, along with sustained responses lasting six months or longer in most patients. Safety findings were consistent with prior pediatric use.

NF1 is a rare genetic disorder that can cause progressive, non-malignant tumors affecting nerves and multiple organ systems. Up to half of patients develop PN, which may lead to pain, disfigurement, and functional impairment.

Experts highlight that this approval extends Koselugo’s established role in pediatric care to adults, ensuring continuity of treatment. Advocacy groups, including the Children’s Tumor Foundation, hailed the milestone as a major advance for NF1 patients.

Koselugo is already approved in several regions, including the EU and Japan, and has orphan drug designation globally. Additional regulatory reviews are ongoing.