Cambridge, UK, 8th June 2005 - CeNeS Pharmaceuticals plc (AIM: CEN) (CeNeS or the Company) today announced successful results from its Phase IIa proof of concept study of CNS 5161, its potent and selective NMDA antagonist, in neuropathic pain. In the study, which was designed to establish the therapeutic window of CNS 5161, the product was associated with a clear trend to improvement in pain levels and was well tolerated with no instances of the psychotomimetic side effects associated with some NMDA antagonists.
The Phase IIa study was a 48-patient, European multi-centre, double blind, cross-over, dose escalating, preliminary safety and efficacy study, comparing a single dose of CNS 5161 to placebo in order to establish a maximum tolerated dose of CNS 5161. Intractable chronic neuropathic pain patients of varied aetiology (such as diabetic neuropathy and post-traumatic neuropathy) were investigated in the study. Four escalating dose levels (125, 250, 500 and 750 ug) of CNS 5161 were planned to be administered by intravenous infusion over six hours, with study continuation to each higher dose subject to a satisfactory safety review after each cohort of 12 patients had been completed. Recruitment to the final cohort (750ug) was not completed due to hypertensive events (high blood pressure), an expected outcome at higher doses. There were no psychotomimetic side effects with CNS 5161, an important finding as such events have been associated with some NMDA antagonists, causing them to be dropped from development. This latter finding confirms CeNeS understanding that CNS 5161 occupies a unique position in its class.
In terms of pain relief, the study showed that 500ug of CNS 5161 was associated with a clear trend to improvements in pain levels (measured using a Visual Analogue Scale (VAS) ) at two, six and twelve hours after the start of the intravenous infusion, when compared to placebo. The results were not statistically significant as may be expected with small group sizes (12 patients per dose group) in a proof of concept study. The analgesic effects of CNS 5161, however, appeared to be demonstrated predominantly in the group of patients with diabetic neuropathy. Further analysis of the data will be carried out to investigate the apparent selectivity of CNS 5161 activity to the diabetic neuropathy group. Compared to placebo, the lowest dose of 125ug showed no effect on pain scores whilst the 250ug dose showed an improvement in pain scores that was most evident at 24 hours. This latter observation supports previous clinical findings with this compound. At all dose levels, CNS 5161 was well tolerated and demonstrated a safety profile similar to that observed in earlier clinical studies.
Neil Clark, CEO of CeNeS, said "CeNeS is very pleased that this proof of concept dose escalating study has successfully established a therapeutic window for the use of CNS 5161 as a potential treatment for neuropathic pain a serious chronic condition which is poorly treated at present. CeNeS will continue to analyse the data from this and previous studies in order to plan the next steps in the clinical development of this compound."
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CeNeS Pharmaceuticals plc
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