AstraZeneca Secures FDA Approval for Koselugo to Treat Adults with NF1 Plexiform Neurofibromas Following Positive Phase III KOMET Results

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Photo by Anthony Devlin/Getty Images for AstraZeneca

(IN BRIEF) AstraZeneca’s Alexion division has received FDA approval for Koselugo (selumetinib) to treat adults with NF1 who have symptomatic, inoperable plexiform neurofibromas. The decision is based on strong results from the Phase III KOMET trial, which showed a 20% response rate compared with 5% for placebo and confirmed durable tumour reductions alongside a consistent safety profile. Experts from the KOMET study, Alexion leadership, and the Children’s Tumor Foundation emphasized that this approval provides continuity of care across age groups and represents a major advancement for the NF community. Koselugo has already been approved in multiple global markets for adult NF1 PN, complementing its established role in paediatric treatment.

(PRESS RELEASE) CAMBRIDGE, 20-Nov-2025 — /EuropaWire/ — AstraZeneca has announced that its rare disease division, Alexion, has received US Food and Drug Administration (FDA) approval for Koselugo (selumetinib) for use in adults with neurofibromatosis type 1 (NF1) who suffer from symptomatic, inoperable plexiform neurofibromas (PN). Koselugo, an oral and selective MEK inhibitor, previously transformed care for paediatric patients with NF1 PN, and this new approval now extends its recognized clinical benefits to adults across the United States.

This regulatory decision is grounded in results from KOMET, the largest and only placebo-controlled global Phase III trial ever conducted for adult NF1 PN. Findings from the study, presented at the 2025 ASCO Annual Meeting and published in The Lancet, confirmed that Koselugo offers a meaningful reduction in tumour size in this challenging patient population. The trial demonstrated a 20% overall response rate in adults treated with Koselugo, compared with just 5% among those receiving placebo, alongside durable responses lasting at least six months for the vast majority of responders.

NF1 is a complex, progressive genetic condition that typically emerges in childhood and continues to evolve throughout adult life. Up to half of individuals living with NF1 develop plexiform neurofibromas—non-cancerous tumours that can expand over time and impact major nerves, leading to pain, mobility issues, disfigurement, and other serious complications that significantly affect daily functioning.

Professor Pierre Wolkenstein, MD, PhD, Head of the Dermatology Department at Henri Mondor Hospital and a KOMET trial investigator, noted that the study reinforces Koselugo’s established clinical role and demonstrates its ability to address the substantial and often worsening burdens faced by adults with NF1 PN. He emphasized that this approval strengthens Koselugo’s value as a therapeutic option for both adult and paediatric patients.

Marc Dunoyer, Chief Executive Officer at Alexion, highlighted that expanding access to Koselugo in adult populations—paired with the recently approved granule formulation for children aged one year and older—ensures continuity of care across all disease stages. He added that Koselugo, supported by more than a decade of clinical research, has reshaped the treatment landscape for this rare condition.

Annette Bakker, PhD, CEO of the Children’s Tumor Foundation, welcomed the approval as a critical milestone for the NF community. She stressed that the progress Koselugo has delivered for paediatric patients is now being extended to adults, demonstrating the power of coordinated efforts among researchers, clinicians, industry partners, and patient organizations.

In the KOMET trial’s primary analysis, Koselugo confirmed statistically significant benefit with a 20% overall response rate by cycle 16 and durable tumour shrinkage in most patients, while maintaining a safety profile consistent with its established paediatric use. After completing 12 cycles on placebo, trial participants were switched to Koselugo for a further 12 cycles, enabling additional clinical assessment.

Koselugo has also recently received regulatory approvals in the EU, Japan, and several other regions for adult NF1 PN based on the KOMET results, with further reviews ongoing globally. In the United States, Koselugo granules were recently approved for paediatric patients aged one year and older with symptomatic, inoperable PN—broadening its reach and reinforcing its role as the first approved therapy for NF1 PN.

Notes

NF1
NF1 is a rare, progressive, genetic condition that is caused by a spontaneous or inherited mutation in the NF1 gene.3,4 NF1 is associated with a variety of symptoms, including soft lumps on and under the skin (cutaneous neurofibromas) and, in up to 50% of patients, tumours called plexiform neurofibromas (PN) may develop on the nerve sheaths.4,5 These PN can cause clinical issues such as disfigurement, motor dysfunction, pain, airway dysfunction, visual impairment and bladder or bowel dysfunction.4,5

KOMET
KOMET is a global Phase III randomised, double-blind, placebo-controlled, multicentre trial designed to evaluate the efficacy and safety of Koselugo in adults with NF1 who have symptomatic, inoperable PN. The trial enrolled 145 adults from 13 countries across North America, South America, Europe, Asia and Australia, with participants’ baseline characteristics, including gender and distribution of PN, reflective of the global adult NF1 patient population. Patients were enrolled and randomised to receive Koselugo or placebo (1:1) for 12 28-day cycles. Participants were required to have diagnosis of NF1, at least one symptomatic, inoperable PN measurable by volumetric MRI analysis, chronic PN pain score documented during screening, adequate organ and marrow function and stable chronic PN pain medication use at enrolment.2,6

The primary endpoint is confirmed overall response rate (ORR) by cycle 16 as assessed by ICR. ORR is defined as the percentage of patients with confirmed complete response (disappearance of PNs) or partial response (at least 20% reduction in tumour volume). Secondary endpoints include improved PN-related pain and health-related quality of life (HRQoL) at cycle 12.2,6

After 12 cycles, patients on placebo were switched to Koselugo and patients on Koselugo remained on treatment for an additional 12 cycles. Patients who had the opportunity to complete 24 cycles of treatment have the option to participate in a long-term extension period and continue to receive Koselugo.2,6

Koselugo
Koselugo (selumetinib) is a kinase inhibitor that blocks specific enzymes (MEK1 and MEK2), which are involved in stimulating cells to grow. In NF1, these enzymes are overactive, causing tumour cells to grow in an unregulated way creating so-called plexiform neurofibromas (PN). By blocking these enzymes, Koselugo slows down the growth of tumour cells and, therefore, the PN growth.

Koselugo is approved in the US, EU, Japan, China and other countries for the treatment of certain paediatric patients with NF1 who have symptomatic, inoperable PN.

Koselugo is approved in the US, EU, Japan and other countries for the treatment of adult patients with NF1 who have symptomatic, inoperable PN, and additional regulatory reviews are ongoing.

Koselugo has been granted Orphan Drug Designation in the US, EU, Japan and other countries for the treatment of NF1.

Alexion
Alexion, AstraZeneca Rare Disease, is focused on serving patients and families affected by rare diseases and devastating conditions through the discovery, development and delivery of life-changing medicines. A pioneering leader in rare disease for more than three decades, Alexion was the first to translate the complex biology of the complement system into transformative medicines, and today it continues to build a diversified pipeline across disease areas with significant unmet need, using an array of innovative modalities. As part of AstraZeneca, Alexion is continually expanding its global geographic footprint to serve more rare disease patients around the world. It is headquartered in Boston, US.

AstraZeneca
AstraZeneca (LSE/STO/Nasdaq: AZN) is a global, science-led biopharmaceutical company that focuses on the discovery, development, and commercialisation of prescription medicines in Oncology, Rare Diseases, and BioPharmaceuticals, including Cardiovascular, Renal & Metabolism, and Respiratory & Immunology. Based in Cambridge, UK, AstraZeneca’s innovative medicines are sold in more than 125 countries and used by millions of patients worldwide. Please visit astrazeneca.com and follow the Company on Social Media @AstraZeneca.

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References

  1. Koselugo (selumetinib) US prescribing information; November 2025.
  2. Chen, AP, et al. KOMET: a phase 3, multicentre, international, randomised, placebo-controlled study to assess the efficacy and safety of selumetinib in adults with neurofibromatosis type 1 and symptomatic, inoperable plexiform neurofibromas. The Lancet. 2025;405(10496):2217-2230.
  3. Tamura R. Current understanding of neurofibromatosis type 1, 2, and schwannomatosis. Int J Mol Sci. 2021;22(11):5850.
  4. Hirbe AC, et al. Neurofibromatosis type 1: a multidisciplinary approach to care. Lancet Neurol. 2014;13:834-843.
  5. Bergqvist C, et al. Neurofibromatosis 1 French national guidelines based on an extensive literature review since 1966. Orphanet J Rare Dis. 2020;15(1):37.
  6. ClinicalTrials.gov. Efficacy and safety of selumetinib in adults with NF1 who have symptomatic, inoperable plexiform neurofibromas (KOMET). NCT Identifier: NCT04924608. Available here. Accessed November 2025.

SOURCE: AstraZeneca

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