Selurampanel

To evaluate efficacy and safety of BGG492 (selurampanel; an orally active, competitive AMPA glutamate receptor antagonist) in patients with moderate-to-catastrophic chronic subjective tinnitus. Study (NCT01302873) enrolled patients with subjective tinnitus based on THI severity grade 3, 4 or 5 (moderate, severe or catastrophic), and those with chronic (>6 and <36 months) tinnitus. Primary endpoints were clinical status of tinnitus using TBF-12 and tinnitus loudness using VAS after multiple dose 2-week BGG492 treatment. Safety was assessed by recording all adverse events (AEs). After a single dose of BGG492 VAS scores for tinnitus loudness (P=0.012) and tinnitus annoyance (P=0.004) were significantly reduced vs placebo. After 2 weeks treatment a significantly greater proportion of patients showed improvement of ≥4 points from baseline in TBF-12 (stringent responder definition) with BGG492 vs placebo (26.7% [n=23] vs 14% [n=12], respectively; odds ratio [OR] (90% CI):2.30 (1.10, 4.83); P=0.064), fulfilling proof-of-concept achievement criteria. No notable difference in proportion of responders to BGG492 vs placebo was observed as assessed using VAS (26.7% [n=23] vs 27.6% [n=24], respectively; OR (90% CI):0.94 (0.52, 1.67); P=0.848). Dizziness was the most frequently reported AE in 50% [n=21] and 31.5% [n=17] patients on BGG492 100 and 50mg TID, respectively vs 9.6% [n=9] on placebo. In conclusion, BGG492 showed reduction of both tinnitus loudness and annoyance after a single dose and reduction of tinnitus handicap after 2 weeks of treatment in patients with chronic subjective tinnitus, thereby supporting further clinical investigation of AMPA receptor antagonists with an improved benefit/risk ratio. A dose of 100mg TID BGG492 showed higher efficacy but somewhat lower tolerability compared to 50mg TID.

Epilepsy is a neurological disorder that significantly impacts the quality of life of affected persons. Despite advances in research, nearly a third of patients have refractory or pharmacoresistant epilepsy. Even though numerous antiepileptic drugs (AEDs) have been approved over the past decade, there are no agents that halt the development of epilepsy. Thus, new and improved AEDs to prevent these conditions are necessary.

We highlight recent advances in new and innovative drugs for epilepsy disorders. We review three small molecule drugs in phase II clinical trials: Cannabidivarin, BGG492 (Selurampanel) and Ganaloxone.

The full potential of Cannabidivarin will be realized by testing in other types of treatment-resistant seizures; if they are beneficial, larger phase III clinical trials would probably be undertaken in the same patient population. About BGG492, the challenge will be to find 'superselective' AMPAR antagonists targeting only calcium-permeable receptors, with specific mechanisms, that may be attractive partners for drugs in polytherapy. Moreover, there is anew interest surrounding Ganaloxone because of a new submicron formulation that improves its absorption and pharmacokinetic profile, but new studies are necessary before progressing. Further clinical innovations will define the future for these small molecule-type drugs in epilepsy therapeutics.