Pharmaceuticals – Zolpidem

ReGen and the Zolpidem Project

The sedative zolpidem (marketed by Sanofi-Aventis under the trade names Stilnox™ and Ambien™) has been used for the last twenty years as a hypnotic/sedative by millions of people.  It is now off patent and an alternative use has now been discovered which is owned by ReGen.

In a case report published in a South African medical journal in 2000, Dr Nel, a South African General Practitioner and his co-worker Dr Ralf Clauss described how approximately fifteen minutes after an oral dose of zolpidem was administered to a patient who had suffered a road traffic accident three years previously, he awoke from his semi-comatose condition and remained awake for the next 3-4 hours and when drug action subsided he returned to his previous state. That same patient is now awake for up to 10 hours a day on a daily treatment with zolpidem. Further studies in Dr Nel’s clinic have now shown that many subjects with brain-injury caused in various ways and with various degrees of severity have consistent and reproducible improvement in their clinical features when given zolpidem.

While Dr Nel continued his work in South Africa, Dr Clauss moved to the UK, where he teamed up with Dr Andrew Sutton (a medical consultant to ReGen). Together with Dr Nel, they formed Sciencom Ltd and filed an international patent application covering this new use for zolpidem. This patent has since been approved in South Africa and is still pending in other countries. In February 2006, ReGen Therapeutics Plc acquired the entire share capital of Sciencom and with it the rights to the company’s patent application and the rights to continue to develop its zolpidem project.

In August 2007, ReGen reported on a clinical study, which confirmed that a 2.5mg novel formulation of zolpidem is non-sedating when used on conscious, fully perceptive, ambulant patients having various debilities as a consequence of brain damage. The study was performed by investigators at the Walko Medical Centre in Springs, South Africa where the ‘antidormancy’ effect of zolpidem was first discovered. Investigators compared various single doses of a novel sublingual spray formulation (placebo, 2.5mg, 5mg, 10mg) with an existing tablet formulation (placebo, 10mg) in terms of the onset and degree of sedation. It also looked for preliminary signs of efficacy.

The results showed that a 2.5mg spray was no more sedating than a placebo. The 10mg and 5mg sprays induced sedation in a dose responsive manner and the spray showed faster onset of action (sedative effect) than the tablet. The 5mg spray induced the same peak level of sedation as the 10mg tablet – 15 minutes compared with 90 minutes respectively.

Most recently, in November 2009, the Company reported the findings of a completely independent study at the University of Pretoria, South Africa, which gave further evidence of the activity of zolpidem in this area. The University plans a further study in 2010.

ReGen believes that both a clear “therapeutic need” and a significant commercial opportunity exist for new, low-dose, non-sedating formulations of zolpidem, to enable this important clinical benefit to be optimally delivered to a diverse range of patients. Stroke alone is the largest single cause of severe disability in England and Wales, with over 250,000 people being affected at any one time. The Company is now seeking industry partners to continue the development of this new use of Zolpidem.

Although the Company is not currently doing additional research work on the use of zolpidem in brain trauma others are and the latest information can be obtained at