Ovid Therapeutics is considering potentially increasing the size of its Phase III gaboxadol trial in Angelman syndrome (AS) given global interest and other considerations for the trial, said a spokesperson. Two sources familiar with the trial noted that with ten ex-US sites in Europe and Australia being added in January, recruitment might be pushed up to over 100 patients.

As of January, about a third of the original 65-patient target has been enrolled, the sources said. The Phase III NEPTUNE trial (NCT04106557) initiated in September 2019 and lists five US sites and one Israel site, according to ClinicalTrials.gov. The expanded enrollment will allow for better statistical powering for separation from placebo, especially if the effect size turns out to be small, the second source said.

The Ovid spokesperson declined to comment on NEPTUNE’s recruitment status but noted that the company expects topline results in mid-2020, as stated in its 7 January corporate presentation. The presentation also noted that the trial is recruiting approximately 60 patients in up to 15 sites in the US, Israel, Australia and Europe. AS is a genetic condition that mostly affects the nervous system.

The potential trial size expansion could make meeting the mid-2020 readout target more challenging, the first source said. However, it is still possible to achieve this deadline, especially with the new sites being added, the source noted. Additionally, it would take only about a month for topline results turnaround, since the primary outcome of clinical global impressions-improvement in AS (CGI-I-AS) has a time frame of 12 weeks, the source said.

The second source said that a mid-2020 target is ambitious yet doable, but had some reservations, especially since some ex-US sites are still in the process of being activated and not all are recruiting yet. Both sources concurred that US recruitment in the Phase III had not been particularly difficult due to strong patient awareness of gaboxadol even when it was in its 88-patient Phase II trial STARS (NCT02996305).

The site in Israel is currently active and recruiting, and the sites in Australia and the Netherlands should be active in a few weeks, the Ovid spokesperson said, adding that the sites in Italy and Germany are still in process of country approval and site activation.

Gaboxadol is a gamma-aminobutyric acid (GABA) receptor agonist, and STARS had shown improvements in one or more of the sleep, motor and behavioral domains, which are common symptoms of AS, according to the 7 January presentation.

The drug is projected to reach sales of $289m in Angelman syndrome by 2028, according to an analyst report, and Ovid has a market cap of $169m.

by Shuan Sim in New York

Shuan Sim is a Senior Reporter for Clinical Trials Arena parent company GlobalData’s investigative journalism team. A version of this article originally appeared on the Insights module of GlobalData’s Pharmaceutical Intelligence Center. To access more articles like this, visit GlobalData.