From 2 Years to 1: Selumetinib Gains Earlier Access and Granule Formulation
🔔 Update — Approved for ≥1 year (Capsules & Oral Granules)
September 10, 2025: FDA expanded selumetinib (KOSELUGO) to pediatric ≥1y with NF1 and symptomatic, inoperable PN; added oral granules to capsules (prior: ≥2y, capsules only).
- Age expansion: earlier intervention window.
- Granules: toddler-friendly; exposure matched to capsules.
- Bridge: SPRINT (≥2y) ↔ SPRINKLE (≥1y) + adult BA Study 89.
- Safety: incidences updated in a larger pediatric set; no new signals.
💊 New Drugs for a Hereditary Disease
Feb 11, 2025: FDA approved mirdametinib for NF1 + symptomatic, inoperable PN in pediatrics. Alongside selumetinib, it broadens individualized choices (age, adherence needs, co-morbidities, toxicity profile).
- Why it matters: alternative MEK inhibitor with distinct tolerability characteristics.
- Clinical tip: select based on patient goals and AE patterns.
🧬 What Are NF1 and Plexiform Neurofibromas?
NF1 stems from variants in the NF1 tumor-suppressor gene. Plexiform neurofibromas (PN) are benign yet diffuse nerve-sheath tumors causing disfigurement, pain and functional loss; surgery is often high-risk or infeasible.
📜 2020 First Approval
Apr 10, 2020: Selumetinib capsules approved for ≥2y with NF1 + symptomatic, inoperable PN — first targeted therapy for this setting.
🔬 SPRINT Phase 2 Highlights
- n=50 children; selumetinib 25 mg/m² PO BID.
- ORR 66% by volumetric MRI (≥20% reduction maintained ≥3–6 mo).
- Duration: 82% of responses lasted ≥12 months.
🛡️ Safety — Key Precautions
- Cardiomyopathy; ocular toxicity (RVO, RPE detachment); GI & skin toxicities; ↑ CPK.
- KOSELUGO capsules: ↑ vitamin E → bleeding risk. Embryo-fetal toxicity.
- Management: hold, reduce, or discontinue based on severity.
💊 Dosing & Forms
| Form | Age | Dose | Notes |
|---|---|---|---|
| Capsules | ≥1y (≥2y in 2020) | 25 mg/m² PO BID | Empty stomach; until PD or unacceptable toxicity |
| Oral granules | ≥1y | 25 mg/m² PO BID | Exposure matched to capsules (SPRINKLE ↔ SPRINT) |
No new safety signals in expanded pediatric dataset.
🧭 Why This Update Matters
- Earlier access: treat before severe disfigurement/functional loss.
- Adherence: granules simplify dosing in young children.
- Choice: mirdametinib provides a viable MEK inhibitor alternative for individualized care.
Refer to KOSELUGO Full Prescribing Information for complete labeling.
1. FDA approves selumetinib for pediatric patients 1 year of age and older with neurofibromatosis type 1 with symptomatic, inoperable plexiform neurofibromas. 9 Sep 2025. https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-selumetinib-pediatric-patients-1-year-age-and-older-neurofibromatosis-type-1
2. FDA approves selumetinib for neurofibromatosis type 1 with symptomatic, inoperable plexiform neurofibromas.
fda.gov - 10 Nisan 2020.
