Zogenix’s (NASDAQ:ZGNX) ZX008 (fenfluramine) is facing enrolment challenges in its North American Phase III Dravet syndrome study, said a source familiar with the situation. The trial, which is taking place in the US and Canada has yet to enrol 10 patients of its 130 patient total, the source added.
A second Phase III trial taking place in Europe and Australia (NCT02826863) has enrolled 10 Dravet syndrome patients of is 130 patient total, noted the source. A second source did not confirm patient numbers enrolled, though agreed with some of the issues surrounding recruitment in the US trial.
The US/Canada trial, otherwise known as Study 1501, began in January 2016 and has a listed primary completion date of November 2016, according to ClinicalTrials.gov. The European/Australian trial, known as Study 1502, began in June 2016 and has an estimated primary completion date of June 2017.
The company has not provided an exact public timeline for trial completion though it has noted in SEC filings that it expects 2017 US and European submissions for market authorization of ZX008 in Dravet syndrome, also known as severe myoclonic epilepsy of infancy (SMEI), a rare and castrophic form of intractable epilepsy that begins in infancy.
One of the main issues facing Study 1501 is that patients cannot take stiripentol -- a treatment sometimes used for epilepsy in the US – for the study duration, explained the first source. Patients are also excluded from 1501 trial should they test positive for cannabidiolat the screening visit, said the second source.
Stiripentol was excluded for two important reasons: firstly, stiripentol is not an approved medication in the US, said Stephen Farr, president and CEO of Zogenix. Also, stiripentol’s mode of action, whereby it changes the metabolism of other baseline anti-epileptic drugs, potentially introduces variability into the study, he explained. There is some limited use of stiripentol in the US via expanded access, as well as a couple of investigator initiated studies, he noted. However, there are plenty of patients not taking stiripentol in the US, he added.