Merck KGaA gets EU nod for SpringWorks' neurofibromas drug

The European Commission has conditionally approved Ezmekly (mirdametinib) as a treatment for inoperable, symptomatic plexiform neurofibromas (PN) in paediatric and adult patients with neurofibromatosis type 1 (NF1) aged two and older. The oral MEK inhibitor was developed by SpringWorks Therapeutics before its recent $3.9-billion takeout by Merck KGaA.

The approval, which follows backing by the EU's drug advisory panel in May, is supported by results from the single-arm Phase IIb ReNeu trial. In the study, which included 58 adults and 56 children with NF1-PN, the drug shrank target tumours by at least 20% in 41% of adults and 52% of children. The median best percentage change in target PN volume was -41% in adults and -42% in children.

Among responders, 88% of adults and 90% of children sustained their response for at least 12 months, with roughly half maintaining benefit for two years or longer.

"With the European approval of Ezmekly, the first therapy approved for both adults and children with NF1-PN, we are taking a major step toward improving care for this underserved community," said Jan Kirsten, global head of Merck's rare tumour business, in a release Friday.

Ezmekly was approved earlier this year in the US under the brand name Gomekli. It's SpringWorks' second marketed drug, joining oral gamma secretase inhibitor Ogsiveo (nirogacestat), which was approved in 2023 for desmoid tumours.