A phase 1b trial has linked Xenon’s epilepsy candidate XEN1101 to statistically significant declines in measures of corticospinal and cortical excitability. The data tee Xenon up to move the Kv7 potassium channel opener into a phase 2 trial in adult focal seizures by the end of the year.
Researchers linked potassium channel dysfunction to epilepsy years ago, leading to the development of drugs designed to mitigate these problems. GlaxoSmithKline won approval for the first potassium channel opener, ezogabine, in 2011 but discontinued the product last year in response to weak, falling sales. Xenon thinks XEN1101 will fare better because of its superior pharmacokinetics, selectivity and pharmacology.
The phase 1b marks an early step in Xenon’s attempts to back up that belief with clinical data. The trial enrolled 20 healthy volunteers and randomized them to receive a 20 mg dose of XEN1101 or placebo. After a wash-out period, the volunteers switched over to the other arm.
Subjects who took XEN1101 experienced a statistically significant change in markers of corticospinal and cortical excitability over the following six hours. As increased excitability is thought to contribute to seizures, the finding suggests XEN1101 may be able to help bring forms of epilepsy under control.
“These positive results from our randomized, placebo-controlled [transcranial magnetic stimulation] study demonstrate that XEN1101 can impact the key EMG output—the resting motor threshold, or RMT—in a concentration-dependent manner with statistical significance over placebo at each time point measured, and to a greater extent than historical data for ezogabine, an earlier generation potassium channel modulator,” Xenon CEO Simon Pimstone said in a statement.
Xenon is now preparing for the next stage in the development of XEN1101. A phase 1 ascending-dose trial that is evaluating a powder-in-capsule formulation of XEN1101 is fully enrolled, setting Xenon up to learn more about the safety, tolerability and pharmacokinetics of its asset. Beyond that, Xenon is gearing up to start a phase 2 trial in patients in the fourth quarter.
Shares in Xenon rose 5% in premarket trading. The stock has risen by more than 300% this year.