To assess the efficacy of CM40907--a new antiepileptic drug--in suppressing inter-ictal spikes, 6 patients with severe intractable epilepsy and frequent spikes in their inter-ictal EEGs were entered in a double-blind placebo-controlled trial. The results show that CM40907 is efficacious in reducing spike counts in the first hour after oral administration. The results of the study are presented and inter-ictal spike counting as a method is discussed.