Ganaxolone is a positive allosteric modulator of synaptic and extrasynaptic GABAA receptors and exhibits both anti-seizure and anti-anxiety activity.
It is being developed in intravenous, capsule and liquid formulations to achieve maximum therapeutic reach to paediatric, as well as adult patient populations.
The global, double-blind, randomised, placebo-controlled Phase III Violet Study will involve up to 70 PCDH19-RE patients aged between one and 17 years.
An eight-week prospective baseline period to gather seizure data will be followed by a 17-week double-blind treatment phase. Certain patients will be provided an opportunity to join an open-label phase of the trial after the double-blind period.
Participants will receive ganaxolone titrate over four weeks to a dose of up to 600mg oral liquid suspension three times a day. This dose will be maintained for the following 13 weeks.
Marinus Pharmaceuticals plans to start screening patients for the Violet Study in the second quarter of this year and results are expected in 2021.
Data from the trial is intended to support the regulatory filings for ganaxolone’s approval in PCDH19-RE.
Marinus Pharmaceuticals chief medical officer Lorianne Masuoka said: “Following our end-of-Phase II meeting with the FDA and scientific advice from the EMA, we are extremely excited at the prospect of incorporating a potentially clinically useful and predictive neurosteroid biomarker into our clinical trial.
“We believe this could be the beginning of a targeted, personalised treatment for patients suffering from rare genetic epilepsies.”
In a previous open-label Phase II trial involving 11 PCDH19-RE patients, ganaxolone led to a 25% decrease in median seizure frequency compared to baseline.
The company also identified preliminary evidence of a plasma neurosteroid biomarker with potential to correlate with seizure response in ten of the 11 patients treated with ganaxolone.
A post-treatment review of baseline plasma neurosteroid levels also showed a significant link between the neurosteroid levels and response to ganaxolone therapy.