Alternatives to Gomekli If You Can't Fill Your Prescription

Gomekli (mirdametinib) is one of only two FDA-approved medications for neurofibromatosis type 1 with plexiform neurofibromas (NF1-PN). For patients who are having difficulty accessing Gomekli due to prior authorization delays, insurance coverage gaps, or specialty pharmacy challenges, it's important to know your options. This guide walks through the alternatives — both approved and in discussion — and what each means for NF1 patients.

The Only Two FDA-Approved Medications for NF1-PN

As of 2026, only two medications are FDA-approved specifically for NF1 with plexiform neurofibromas:

Gomekli (mirdametinib) — approved February 2025 for adults and children aged 2 and older. Dosed at 2 mg/m² twice daily on a 21-day-on, 7-day-off (28-day cycle) schedule.

Koselugo (selumetinib) — originally approved in April 2020 for children aged 2 and older with NF1-PN; subsequently also approved for adults. Dosed continuously at 25 mg/m² twice daily.

Both are oral MEK inhibitors that work by blocking MEK1 and MEK2 proteins in the MAPK/ERK signaling pathway, which is overactive in NF1. The key differences lie in their dosing schedules, approval timelines, and clinical trial data. Gomekli is the first approved for adults without requiring off-label use.

Koselugo (Selumetinib): The Primary Alternative

Koselugo (selumetinib) is the most clinically meaningful alternative to Gomekli for NF1-PN. Developed by AstraZeneca/Alexion, Koselugo demonstrated a 68% partial response rate in the pivotal SPRINT trial in pediatric patients. It is available as capsules and oral granules, making it easier for children who have difficulty swallowing pills.

One meaningful practical difference: Koselugo is taken continuously (every day), whereas Gomekli is taken on a 3-weeks-on, 1-week-off cycle. Some patients and physicians prefer the break period that comes with Gomekli, as it may allow some side effects like rash and nausea to improve during the off week.

Common side effects of Koselugo include rash, nausea, vomiting, diarrhea, and elevated creatine phosphokinase levels. Like Gomekli, it also carries warnings for cardiac and ocular toxicity.

Gomekli vs. Koselugo: How Do They Compare?

Here is a quick comparison of the two approved options for NF1-PN:

Age range: Both approved for ages 2 and older. Gomekli is explicitly approved for adults; Koselugo was first a pediatric approval.

Dosing schedule: Gomekli is 21 days on / 7 days off; Koselugo is continuous daily dosing.

Response rates: Gomekli showed 41% ORR in adults and 52% in children; Koselugo showed 68% ORR in children.

Formulations: Gomekli: capsules and dispersible tablets. Koselugo: capsules and oral granules.

Side effect profile: Similar class-related effects (rash, GI side effects, cardiac and ocular risks). Gomekli's off-week may help with milder AEs.

What About Surgery as an Option?

Surgery (gross-total resection) remains the first-line treatment for NF1 with plexiform neurofibromas when the tumor can be completely removed without significant risk. However, many plexiform neurofibromas are infiltrative — they grow along nerves and into surrounding tissue — making complete surgical removal impossible or too risky.

For patients whose PNs are not amenable to complete resection, Gomekli or Koselugo are the appropriate systemic treatment options. In some cases, debulking surgery to reduce tumor size may be performed alongside or after MEK inhibitor therapy.

Off-Label MEK Inhibitors: Are They Used?

Other MEK inhibitors such as trametinib (Mekinist) and cobimetinib (Cotellic) are FDA-approved for other cancers (such as BRAF-mutant melanoma) and have been used off-label in NF1. However, these do not have FDA approval for NF1-PN and can face significant insurance coverage challenges. With both Gomekli and Koselugo now approved for NF1-PN, off-label use of other MEK inhibitors is much less common.

Clinical Trials: Another Option to Explore

For patients who have not responded to approved therapies or who are experiencing intolerable side effects, clinical trials may offer access to investigational treatments. The Children's Tumor Foundation (ctf.org) maintains a registry of NF-related clinical trials and is a useful resource for finding active studies.

What to Do If You Can't Access Gomekli Right Now

If you're experiencing delays in getting your Gomekli prescription filled, here are immediate steps to take: First, call SpringWorks CareConnections (844-227-3755) — they may be able to provide bridge supply while insurance processes. Second, discuss switching to Koselugo with your specialist if delays are prolonged. Third, use medfinder to identify specialty pharmacies near you that can fill your prescription, saving you the time-consuming process of calling each one individually.

For more background on why Gomekli is difficult to access, see our article on why Gomekli is hard to find.