Neuren Pharmaceuticals (ASX:NEU) said its partner, Acadia Pharmaceuticals, confirmed that it plans to request a re-examination of the European Medicines Agency's Committee for Medicinal Products for Human Use's opinion regarding the marketing authorization application for trofinetide for the treatment of Rett syndrome in patients aged two years and older, according to a Tuesday Australian bourse filing.

The committee issued a refusal, saying that the treatment effect observed with trofinetide after 12 weeks, while measurable, was viewed as limited in magnitude, that the Lavender clinical trial did not capture all core symptoms of Rett syndrome, and that the assessment of longer‑term outcomes was influenced by patient discontinuations over time.

Trofinetide is approved in the US, Canada, and Israel, per the filing.

Neuren Pharmaceuticals' shares fell 5% in early trading on Tuesday.