Koselugo Now EU Approved for NF1 and PN


On June 22, 2021, PharmaTimes Online reported that the European Commission (EC) granted conditional approval to Koselugo (selumetinib), an orally administered therapy, for use in pediatric patients with neurofibromatosis type 1 (NF1) and plexiform neurofibromas (PN). Altogether, the approval hinged on data from the Phase 2 SPRINT Stratum 1 clinical trial. The drug was developed by AstraZeneca and MSD.


According to AstraZeneca, Koselugo is:

an inhibitor of mitogen-activated protein kinase kinases 1 and 2 (MEK1/2) [which] are upstream regulators of the extracellular signal-related kinase (ERK) pathway. Both MEK and ERK are critical components of the RAS-regulated RAF-MEK-ERK pathway, which is often activated in different types of cancers.

Currently, Koselugo has earned Breakthrough Therapy, Rare Pediatric Disease, and Orphan Drug designations within the United States. Additionally, it earned an Orphan Drug status in the EU. It is also the first approved medication within the EU for patients with NF1.

The recent conditional marketing authorization was granted as:

the benefit of immediate availability of the medicine outweighs the risk inherent in the fact that additional data are still required.

However, data from the Phase 2 clinical trial was promising. During the trial, pediatric patients with plexiform neurofibromas related to NF1 were treated with Koselugo. Researchers determined that:

  • The study achieved an overall response rate of 66% when patients were treated 2x daily.
  • In addition to reducing inoperable tumor size, Koselugo therapy also improved patients’ quality of life (QOL).
  • Finally, Koselugo lowered pain levels in pediatric patients.


Altogether, there are three forms of neurofibromatosis, a rare genetic disorder affecting the nervous system. In type 1 neurofibromatosis (NF1), symptoms typically appear between birth and early childhood. Neurofibromatosis results in tumors forming on healthy nerve tissue. Although the tumors are often benign, they can become malignant.

Patients with NF1, caused by NF1 gene mutations, also experience:

  • Learning disabilities
  • Bone deformities
  • Soft bumps on/under the skin (neurofibromas)
  • Short stature
  • Larger-sized head
  • Tiny bumps on the irises
  • Flat, light brown spots on the skin and freckling in the armpits/groins

Next, in NF2, caused by NF2 mutations, patients experience:

  • Hearing loss
  • Tinnitus (ringing in the ears)
  • Issues with balance and coordination
  • Headaches

In many cases, patients become symptomatic during their teenage years. Finally, SMARCB1 or NF2 gene mutations cause schwannomatosis, the most severe and rare form characterized by:

  • Intense pain
  • Muscle loss
  • Bodily numbness/weakness
  • Tumors on the skull, spinal nerves, and peripheral nerves

Learn more about neurofibromatosis here.

Jessica Lynn

Jessica Lynn

Jessica Lynn has an educational background in writing and marketing. She firmly believes in the power of writing in amplifying voices, and looks forward to doing so for the rare disease community.

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