The United States Food and Drug Administration (FDA) has granted United Kingdom-based AstraZeneca and United States-based Merck a New Drug Application (NDA) and priority review for the MEK 1/2 inhibitor Selumetinib as a potential new medicine for paediatric patients aged three years and older with neurofibromatosis (NF1) type one and symptomatic, inoperable plexiform neurofibromas (PFs), it was reported on Friday.

This is the first acceptance of a regulatory submission for an oral MEK 1/2 monotherapy for patients with NF1, a rare and incurable genetic condition. A Prescription Drug User Fee Act (PDUFA) date is scheduled for the second quarter of 2020.

This regulatory submission was based on positive results from the National Cancer Institute (NCI) Cancer Therapy Evaluation Program (CTEP)-sponsored SPRINT Phase two Stratum one trial. An objective response rate (ORR) was achieved in 66% of paediatric patients with neurofibromatosis type 1 and symptomatic, inoperable PNs (n=33/50 patients) when treated with selumetinib as a twice-daily oral monotherapy. ORR was defined as the percentage of patients with a confirmed complete or partial response of greater than 20% tumour volume reduction.

AstraZeneca and Merck have a strategic collaboration agreement to co-develop and co-commercialize selumetinib globally.