What question did this study set out to answer?

To evaluate the clinical outcomes of mirdametinib in NF1-PN patients previously treated with MEK inhibitors.

June 26, 2026Open Access

ID #479 Use of Mirdametinib for the Treatment of Neurofibromatosis Type 1–Associated Plexiform Neurofibromas (NF1-PN) in Patients with Prior Mitogen-Activated Protein Kinase (MAPK) Kinase Inhibitor (MEKi) Exposure

Key Points

To evaluate the clinical outcomes of mirdametinib in NF1-PN patients previously treated with MEK inhibitors.
Patients with NF1-PN and prior MEKi exposure enrolled in the pivotal ReNeu trial (n=10).
Clinical outcomes were assessed post hoc for mirdametinib treatment.
All mirdametinib-treated patients had a best overall response (BOR) of partial response (PR) or stable disease (SD).
Treatment duration ranged from approximately 8 to 40 months.
Of 5 patients who discontinued prior MEKi for progressive disease (PD) or pain, 1 discontinued mirdametinib for PD.

Abstract

Abstract Background Mirdametinib is the first approved MEKi for NF1-PN in adults and children. MEKis differ in selectivity, potency, and pharmacokinetics—characteristics that may impact efficacy and toxicity. However, data are limited on patient experiences with different MEKis after MEKi failure due to lack of efficacy or tolerability. Methods Patients with NF1-PN and prior MEKi exposure enrolled in the pivotal ReNeu trial of mirdametinib (n = 6 children; n = 4 adults) were evaluated post hoc for clinical outcomes (Table). Patient cases from SpringWorks Early Access Program will be described in the presentation. Results Four patients had PD at baseline. Mirdametinib treatment duration ranged from ∼8-40mo. All mirdametinib-treated patients had a BOR of PR or SD. Time to best percentage target PN volume change was 4.0-32.7mo. Of 5 patients who discontinued prior MEKi for PD or pain, 1 discontinued mirdametinib for PD. Of 3 patients who discontinued prior MEKi for toxicity, 2 discontinued mirdametinib for TRAEs. Conclusions In MEKi-exposed patients with NF1-PN, including those who discontinued prior MEKi due to toxicity/PD, observed mirdametinib outcomes suggest MEKi-exposed patients can benefit from mirdametinib treatment. Support SpringWorks Therapeutics, Inc

Read Full Paperexternally

Ask AI

Helpful

Bookmark

View Full Paper