What medication is used to treat neurofibromas?: A Guide to FDA-Approved MEK Inhibitors

October 10, 2025 •

2 min read

As of early 2025, two MEK inhibitor medications have received FDA approval for the treatment of certain neurofibromas. The advent of these drugs has transformed the treatment landscape for individuals with neurofibromatosis type 1 (NF1), offering a targeted, non-surgical option for specific tumor types. This is a significant shift from previous approaches and addresses the key question of what medication is used to treat neurofibromas?

Quick Summary

FDA-approved MEK inhibitors selumetinib (Koselugo) and mirdametinib (Gomekli) are used to treat inoperable, symptomatic plexiform neurofibromas in patients with neurofibromatosis type 1 (NF1). These medications work by targeting the underlying cellular pathway that drives tumor growth.

Key Points

MEK Inhibitors are Key: FDA-approved MEK inhibitors like selumetinib (Koselugo) and mirdametinib (Gomekli) are the primary medications used for symptomatic, inoperable plexiform neurofibromas.
Targeted Therapy: These medications work by blocking the MEK protein in the hyperactive RAS pathway, which drives tumor growth in NF1.
Patient Eligibility Varies: Koselugo is approved for pediatric patients aged 1+, while Gomekli is approved for both pediatric patients aged 2+ and adults with specific tumors.
Addressing Different Tumor Types: Current approved oral medications target plexiform neurofibromas, while other neurofibromas, like cutaneous ones, are the focus of ongoing clinical trials for topical treatments.
Consider Side Effects: Common side effects include rash, gastrointestinal issues, and fatigue, which require careful monitoring and management by a healthcare provider.
Not a Cure: MEK inhibitors can shrink tumors and reduce symptoms but do not cure neurofibromatosis, and growth may resume if treatment is stopped.
Monitoring is Essential: Regular checkups and imaging are crucial for tracking tumor changes and managing side effects for patients on MEK inhibitor therapy.

Understanding Neurofibromas and the Need for Medication

Neurofibromas are benign tumors that grow on nerves and are characteristic of neurofibromatosis type 1 (NF1), a genetic disorder. These tumors vary in size and can cause significant issues, including pain, disfigurement, and loss of function, especially the type known as plexiform neurofibromas (PN). Historically, surgery was the main treatment for symptomatic plexiform neurofibromas, but complete removal was often difficult or risky. This highlighted the need for medical therapies targeting the root cause of these tumors.

The Role of MEK Inhibitors

Neurofibromas in NF1 arise due to a mutation in the NF1 gene, which overactivates the RAS-MAPK signaling pathway. This pathway promotes excessive cell growth. MEK is a critical enzyme in this pathway, and blocking it with MEK inhibitors can help control tumor growth.

FDA-Approved Medications for Neurofibromas

The FDA has approved two oral MEK inhibitors for specific neurofibromas in NF1 patients:

Selumetinib (Koselugo): Approved for pediatric patients aged 1 year and older with symptomatic, inoperable plexiform neurofibromas. Studies show it can shrink tumors and improve symptoms.
Mirdametinib (Gomekli): Approved in February 2025 for adults and children aged 2 and older with symptomatic, inoperable plexiform neurofibromas in NF1.

Comparison of FDA-Approved MEK Inhibitors


Feature	Selumetinib (Koselugo)	Mirdametinib (Gomekli)
Approval Date	April 2020 (initial); Sept 2025 (expanded)	Feb 2025
Eligible Age Range	Pediatric patients 1 year and older	Pediatric patients 2 years and older, and adults
Targeted Tumor	Symptomatic, inoperable plexiform neurofibromas (PN)	Symptomatic, inoperable plexiform neurofibromas (PN)
Route of Administration	Oral capsules or oral granules for younger children	Oral capsules
Manufacturer	AstraZeneca/Alexion	SpringWorks Therapeutics

Common Side Effects and Monitoring

MEK inhibitors can cause side effects. Common ones include gastrointestinal issues, skin reactions (rashes, acneiform rashes, nail infections), fatigue, and pain. Healthcare providers monitor for these and more serious effects like heart problems, eye issues, and potential muscle damage. Regular check-ups are vital for managing side effects and ensuring safety.

Other Neurofibroma Treatments and Ongoing Research

MEK inhibitors are not the only treatment for neurofibromas. Surgery is still used for tumors that can be safely removed. Monitoring is often sufficient for small, asymptomatic neurofibromas, particularly cutaneous neurofibromas (cNFs). There are currently no approved oral medications for cNFs, but research is exploring topical treatments like NFX-179. Other compounds are also being studied to address various NF1 symptoms and related conditions.

Conclusion

The approval of MEK inhibitors has significantly improved treatment options for symptomatic, inoperable plexiform neurofibromas in NF1 patients. Selumetinib (Koselugo) and mirdametinib (Gomekli) offer a targeted medical approach beyond surgery. However, treatment decisions depend on the specific neurofibroma characteristics. Surgery and monitoring remain important, and ongoing research is expanding future treatment possibilities, especially for cutaneous tumors.

More Information

For more detailed information about neurofibromatosis and the latest treatments, the Children's Tumor Foundation (CTF) is an excellent resource: CTF - Progress in NF1

Frequently Asked Questions

The primary medications are MEK inhibitors, specifically FDA-approved selumetinib (Koselugo) and mirdametinib (Gomekli), which are used for symptomatic, inoperable plexiform neurofibromas in NF1 patients.

No, these medications do not cure neurofibromatosis. They are used to help shrink tumors or slow their growth and manage associated symptoms like pain and disfigurement.

For symptomatic plexiform neurofibromas that are inoperable or carry significant risk of nerve damage with surgery, MEK inhibitors offer a viable alternative. However, surgery remains an important treatment option for tumors that can be safely removed.

Yes, mirdametinib (Gomekli) was approved in early 2025 for both adult and pediatric patients aged 2 years and older with specific neurofibromas. Selumetinib (Koselugo) is currently indicated for pediatric patients aged 1 year and older.

Common side effects include gastrointestinal issues (diarrhea, nausea, vomiting), skin reactions (rash, acneiform rash, paronychia), fatigue, and musculoskeletal pain.

Currently, no oral medications are FDA-approved specifically for cutaneous neurofibromas. However, topical MEK inhibitors like NFX-179 are being investigated in clinical trials for their potential to treat these skin-level tumors.

In NF1, a mutated gene leads to an overactive RAS-MAPK signaling pathway, which drives tumor growth. MEK inhibitors work by blocking the MEK protein within this pathway, thereby slowing down or stopping the abnormal cell proliferation.