Alexion, AstraZeneca Rare Disease's Koselugo (selumetinib), an oral, selective MEK inhibitor, has been approved in the European Union (EU) for the treatment of symptomatic, inoperable plexiform neurofibromas (PN) in adult patients with neurofibromatosis type 1 (NF1). The approval by theEuropean Commissionfollows the positive opinion of the Committee for Medicinal Products for Human Use (CHMP) and is based on results from KOMET, the largest and only placebo-controlled global Phase III trial in this patient population, which were presented at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting and published in The Lancet. NF1 is a rare, progressive, genetic condition usually diagnosed in early childhood, but often progressing into adulthood, that can impact every organ system. Up to 50% of people living with NF1 may develop a type of non-malignant tumour called PN that may affect the brain, spinal cord and nerves. PN may appear later in a person’s life and can grow and become large, leading to pain, disfigurement and muscle weakness, among other debilitating symptoms. Prof. Pierre Wolkenstein, MD, PhD, Head of the Department of Dermatology at Henri Mondor Hospital, APHP, Paris East University (UPEC), and National Coordinating Investigator of the KOMET trial in Europe, said, “The approval of Koselugo for adults with NF1 PN in Europe offers patients and physicians a meaningful approach to close treatment gaps beyond childhood. As demonstrated in the KOMET Phase III trial, the most robust late-stage clinical trial conducted in this patient group to-date, adults administered Koselugo saw significant tumour volume reduction with a safety profile consistent with its established use in paediatric patients, validating the clinical benefits of Koselugo for newly diagnosed adults and those transitioning to adult care.” Marc Dunoyer, Chief Executive Officer, Alexion, said, “The European Commission approval extends the life-changing potential of Koselugo to adults with NF1 PN in the region, including continuity of care into adulthood. This milestone, along with our pioneering leadership in NF1 PN treatment landscape, embodies Alexion’s unwavering commitment to addressing the unmet needs in the rare disease community. We look forward to bringing Koselugo to those adults in need across Europe as soon as possible.” In the primary analysis of the trial, Koselugo showed a statistically significant objective response rate (ORR) of 20% (n=14/71, 95% CI: 11.2, 30.9) compared to 5% with placebo (n=4/74, 95% CI: 1.5, 13.3; p=0.01) by cycle 16. After 12 cycles, patients on placebo were switched to Koselugo and patients on Koselugo remained on treatment for an additional 12 cycles. The safety profile of Koselugo in the KOMET Phase III trial was consistent with its known profile and established use in paediatric patients. Koselugo has been recently approved in Japan and other countries for the treatment of adult patients with NF1 who have symptomatic, inoperable PN based on data from the KOMET Phase III trial, and additional regulatory reviews are ongoing. In July 2017,AstraZenecaand Merck & Co., Inc., Rahway, NJ, US, known as MSD outside the US and Canada, announced a global strategic collaboration to co-develop and co-commercialise Lynparza (olaparib), a first-in-class PARP inhibitor, and Koselugo. The companies may develop Lynparza and Koselugo in combination with other potential new medicines and as monotherapies.