FDA Approves Selumetinib in Patients 1 Year and Older for NF1 with PN

The FDA has approved selumetinib (Koselugo) for the treatment of pediatric patients 1 year of age and older with neurofibromatosis type 1 (NF1) with symptomatic, inoperable plexiform neurofibromas (PN).¹

In April 2020, the FDA previously selumetinib capsules for pediatric patients 2 years of age and older with NF1 who have symptomatic, inoperable PN.²

This new approval is supported by adequate bridging between the oral granule and approved capsule formulations in a relative bioavailability study in health adults and exposure matching between pediatric patient populations in the SPRINT phase 2 stratum 1 study (NCT01362803), evaluating the capsule formulation in patients at least 2 years of age, and the SPRINKLE study (NCT05309668), evaluating the oral granule formulation in patients at least 1 year of age.¹

The SPRINT study showed that 74% of patients (n = 37/50; 95% CI, 60%–85%) had a confirmed partial response, and 56% (n = 28) had a durable response.³ The median time to initial response was 8 cycles (range, 4–20), and the median time to best response was 16 cycles (range, 4–36). The median change in PN volume at best response was –27.9% (range, –55.1% to 2.2%). Further, the median duration of response and progression-free survival (PFS) were not reached, and the PFS rate at 3 years post treatment initiation was 84%.

Regarding patient-reported outcomes, the child-reported tumor pain intensity was substantially decreased after 12 months of treatment, with a mean change in NRS-11 score of –2.15 points. Forty-eight percent of pediatric patients and 58% of parents reported meaningful improvements in their quality-of-life score after 12 months of treatment.

The SPRINKLE study is ongoing, with an estimated completion date of April 2028.⁴

The recommended dose of selumetinib is 25 mg/m² orally twice daily until disease progression or unacceptable toxicity.¹

Selumetinib previously received breakthrough therapy and orphan drug designations, highlighting its importance in filling an unmet need for this patient population.

REFERENCES:

1. FDA approves selumetinib for pediatric patients 1 year of age and older with neurofibromatosis type 1 with symptomatic, inoperable plexiform neurofibromas. News release. US FDA. September 10, 2025. Accessed September 10, 2025. https://tinyurl.com/3szc889p

2. FDA approves selumetinib for neurofibromatosis type 1 with symptomatic, inoperable plexiform neurofibromas. News release. US FDA. April 10, 2020. Accessed September 10, 2025. https://tinyurl.com/2yhsxxfk

3. Gross AM, Wolters P, Dombi E, et al. Selumetinib in Children with Inoperable Plexiform Neurofibromas.
N Engl J Med. 2020 Apr 9;382(15):1430-1442. doi: 10.1056/NEJMoa1912735. Epub 2020 Mar 18.

4. Pharmacokinetics, Safety and Efficacy of the Selumetinib Granule Formulation in Children aged ≥1 to <7 years with NF1-related Symptomatic, Inoperable PN - SPRINKLE. AstraZeneca. Accessed September 10, 2025. https://tinyurl.com/4t46rvb6