The US Food and Drug Administration (FDA) has asked Newron Pharmaceuticals to delay its proposed Phase II/III pivotal clinical trials for evenamide due to concerns about central nervous system (CNS) events.

The regulator raised concerns about data from studies in rats and dogs, questioning the potential implication of these findings for human patients. The planned trials will be delayed until study data is obtained from additional short-term explanatory studies in rats and human subjects.

Newron Pharmaceuticals chief medical officer Ravi Anand said: “Based on the issues raised by the FDA letter, Newron is confident that they can be addressed satisfactorily.”

Evenamide is an oral molecule designed to selectively target voltage-gated sodium channels. It is being developed as an add-on therapy for schizophrenia patients.

According to Newron, the compound controls sustained repetitive firing without triggering an impairment of normal neuronal excitability. It also normalises glutamate release caused by abnormal sodium channel activity.

In 2017, the company reported favourable data from a double-blind, placebo-controlled, randomised, multi-national Phase IIa trial involving 89 schizophrenia patients. The drug candidate is said to have met objectives for good tolerability, safety and preliminary evidence of efficacy as an add-on therapy. It led to an improvement in schizophrenia symptoms as assessed using the Positive and Negative Syndrome Scale (PANSS).

Newron planned to initiate a Phase III development programme in Q2 2019.

One trial under the programme is intended for patients that are experiencing worsening psychosis on atypical antipsychotics, while another will enrol treatment-resistant patients that are not responding to the antipsychotic drug clozapine.