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Randomized Controlled Trial Multicenter Study
Photosensitive epilepsy: Robust clinical efficacy of a selective GABA potentiator.
- Rachel Gurrell, Donal Gorman, Mark Whitlock, Adam Ogden, David S Reynolds, Bree DiVentura, Bassel Abou-Khalil, Michael Gelfand, John Pollard, R Edward Hogan, Gregory Krauss, Michael Sperling, Blanca Vazque... more
- From Pfizer Inc. (R.G., D.G., M.W., D.S.R., R.P.B.), Cambridge, UK; Pfizer Inc. (A.O.), Groton, CT; The Epilepsy Study Consortium (B.D.), Reston, VA; Department of Neurology (B.A.-K.), Vanderbilt Universit... more
- Neurology. 2019 Apr 9; 92 (15): e1786-e1795.
ObjectiveThe objective of this phase 2a study was to assess the activity of PF-06372865, a positive allosteric modulator (PAM) of α2/3/5 subunit-containing GABAA receptors with minimal activity at α1-containing receptors, which are believed to mediate many of the adverse events associated with benzodiazepines, in the epilepsy photosensitivity model as a proof-of-principle of efficacy.MethodsSeven participants with a photoparoxysmal response to intermittent photic stimulation (IPS) at baseline were randomized in a double-blind, 4-period cross-over study examining single doses of 17.5 and 52.5 mg PF-06372865, 2 mg lorazepam (active control), and placebo. Standardized photosensitivity ranges (SPRs) to IPS were recorded at screening, predose, and 1, 2, 4, and 6 hours postdose. The primary endpoint was the average least squares mean change in the SPR in the participant's most sensitive eye condition, across all time points.ResultsBoth doses of PF-06372865 produced a marked and statistically significant mean reduction in SPR compared to placebo, which was similar in degree to lorazepam. There was complete suppression of SPR in 6/7 participants following PF-06372865 or lorazepam administration. PF-06372865 was safe and well-tolerated.ConclusionPF-06372865 demonstrated highly robust efficacy. This demonstrates anticonvulsant activity of a novel α2/3/5-subtype selective GABAA PAM in humans. Further study of the antiepileptic properties of PF-06372865 is warranted.Clinicaltrialsgov IdentifierNCT02564029.Classification Of EvidenceThis study provides Class II evidence that for people with a stable photoparoxysmal response to intermittent photic stimulation, PF-06372865 reduces the SPR.© 2019 American Academy of Neurology.
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