Acadia’s drive to extend use of Nuplazid hits a wall

Acadia Pharmaceutical’s Nuplazid was the first-ever drug to be approved to treat psychosis associated with Parkinson’s disease, but the company’s hopes of extending its use to a larger patient population have stalled.

The drug has failed the late-stage ENHANCE trial in schizophrenia inadequately controlled by currently-approved drugs, viewed as one of Acadia’s biggest opportunities to extend the franchise.

Nuplazid (pimavanserin) is Acadia’s only approved medicine, and has carved out a niche in tackling the psychotic symptoms that can emerge with protracted dopamine agonist therapy for Parkinson’s, without aggravating motor symptoms.

The drug is growing nicely in that setting, bringing in $224m last year which was a rise of 79% over 2017, but Acadia has ambitions to grow still further as a treatment for psychotic symptoms in other diseases, including schizophrenia, dementia and major depressive disorder.

The latest study, called ENHANCE, was the most advanced attempt by Acadia to extend Nuplazid’s base and grow the drug’s revenues beyond the $275m-$300m it expects to bring in form the Parkinson’s indication this year.

Nuplazid wasn’t able to show a significant improvement compared to placebo on the widely-used Positive and Negative Symptoms of Schizophrenia (PANSS) scale, which is most commonly used to measure the efficacy of schizophrenia drugs.

Acadia has another mid-stage trial in schizophrenia on the go however, zeroing in on the negative symptoms of schizophrenia – such as social withdrawal and lack of motivation – which could potentially rescue the programme.

Positive symptoms of schizophrenia such as hallucinations and delusions are fairly well-managed with existing anti-psychotic medicines, but negative symptoms have proved a tougher challenge and persist in around two-thirds of patients despite current drug treatment.

Last year, Acadia reported positive top-line results from a phase 2 trial of Nuplazid for adjunctive treatment of MDD, and recently started a pair of phase 3 trials in this indication. A pivotal trial is also ongoing in dementia-related psychosis that is due to complete next year.

Shares in Acadia were down 16% remarket in the wake of the ENHANCE trial news.