GlaxoSmithKline and Valeant Pharmaceuticals announce worldwide collaboration agreement for breakthrough epilepsy treatment

GlaxoSmithKline (GSK) and Valeant Pharmaceuticals International recently announced that they have entered into an exclusive worldwide collaboration agreement for the investigational drug retigabine, a first-in-class neuronal potassium channel opener for treatment of adult epilepsy patients with refractory partial onset seizures. Retigabine has shown robust efficacy and safety as demonstrated in two large, completed Phase III trials conducted in patients with refractory epilepsy receiving treatment with up to three antiepileptic drugs (AEDs). Valeant and GSK plan to file a New Drug Application in the US and a Marketing Authorization Application in Europe by early 2009. The retigabine programme also includes an ongoing study in patients with post-herpetic neuralgia (PHN), a painful and common complication of shingles.

Under the terms of the agreement, Valeant will grant GSK worldwide development and commercialization rights to retigabine, VRX698 and the other back-up compounds from the potassium channel opener discovery program in exchange for an upfront payment of $125 million to Valeant. Additionally, GSK will pay Valeant up to $545 million based on the achievement of certain regulatory, development and commercialization milestones and the development of additional indications for retigabine. Valeant will co-market the drug with GSK and will jointly fund all global research and development expenses for retigabine. GSK will completely fund the development of VRX698 and other back-up compounds from the potassium channel opener discovery program.

“GSK is looking forward to working with Valeant to provide important medicines like retigabine to the medical community and to the patients we serve,” commented Steve Stefano, Senior Vice President, GSK US NeuroHealth Division. “There is a significant need for novel anti-epileptic drugs, as almost one-third of patients with epilepsy continue to experience seizures despite treatment with currently available medications. We believe that retigabine could potentially play a significant role in improving the management of epilepsy and is a welcome addition to GSK’s portfolio.”

“We were pleased with the significant interest shown in retigabine, and we have selected GSK as a collaborator because we believe they are ideally suited and strongly committed to the continued development of this important compound,” stated J. Michael Pearson, Chairman and Chief Executive Officer of Valeant. “GSK’s development expertise and strong commercial infrastructure will be critical to maximizing the worldwide potential of retigabine. We believe this collaboration will strengthen our ability to bring this medicine to patients suffering from epilepsy and a variety of other conditions.”

As one of the world’s leading research-based pharmaceutical and healthcare companies, GSK is committed to improving the quality of human life by enabling people to do more, feel better and live longer. For further information please visit www.gsk.com.

Valeant Pharmaceuticals International is a global specialty pharmaceutical company that develops, manufactures and markets a broad range of pharmaceutical products primarily in the areas of neurology, infectious disease and dermatology. More information about Valeant can be found at www.valeant.com.

About epilepsy

Epilepsy, defined by recurrent unprovoked seizures, is a change in sensation, awareness, or behaviour brought about by an electrical disturbance in the brain. The kind of seizure a person has depends on which part and how much of the brain is affected by the disturbance that produces seizures. Primary generalized seizures are those that involve the entire brain from the outset, while partial onset seizures begin in a focal area of the cerebral cortex. In most cases the cause of epilepsy is unknown. Epilepsy affects over 50 million people of all ages worldwide. Approximately 30% of people with epilepsy experience seizures that are not adequately controlled with currently prescribed AEDs; the results of which are substantial deleterious effects on individual health and quality of life.

About potassium channel openers

Potassium channels are one of the voltage-gated ion channels found in neuronal cells and are an important determinant of neuronal activity. Numerous ion-channel mutations have been linked to epilepsy, and many antiepileptic medications modulate sodium or calcium channels. Potassium channels have been demonstrated in animal models to be critical in regulating membrane potential.

Retigabine is the first potassium channel opener to reach late stage clinical development. It is believed that by facilitating the opening of specific neuronal potassium channels, retigabine causes a hyperpolarising shift in the potassium current and thereby reduces the excitability of neuronal cells. Dampening of neuronal excitability is an important mechanism for reducing the potential for seizures.