Acadia Pharmaceuticals’ trofinetide for Rett syndrome

Twice now, the FDA has turned back attempts by Acadia to secure an expanded approval for a Parkinson’s disease drug it sells as Nuplazid. In April 2021 and again last August, the agency rejected the company’s applications to extend use of Nuplazid to treat psychosis related to dementia.

Acadia’s regulatory difficulties have weighed on the company, as shares have sunk by nearly two-thirds since the initial signs trouble with the first application.

But the company is hoping for a different outcome with its drug trofinetide, which it has been developing for a neurodevelopmental disorder called Rett syndrome. Its application is now under review by the FDA, with a target decision date of March 12.

In clinical testing, treatment with trofinetide improved scores on two assessments of Rett syndrome symptoms compared to placebo among girls and young women with the disorder.

If approved, trofinetide would become the first treatment for Rett, giving patients a needed option. For Acadia, success would also be a boon, potentially offsetting struggles the company has had selling Nuplazid in its approved Parkinson’s disease indication. An approval could also come with a special regulatory voucher that can be resold.

Acadia acquired North American rights to trofinetide in a 2018 deal with Neuren Pharmaceuticals. If the drug is approved and the FDA issues a voucher, Neuren would be due one-third of its value.