PROMETHERA Biosciences S.A./N.V. Treats First Patients With Promethera(R) HepaStem

Mont-Saint-Guibert, Belgium, May 14, 2012 – Promethera Biosciences, a Belgian biotechnology company developing Promethera(R) HepaStem, a cell-based therapy for the treatment of liver-based metabolic diseases including Crigler-Najjar Syndrome and Urea Cycle Disorders, today announces it has treated its first two patients with its innovative treatment based on allogeneic adult liver stem cell technology (HepaStem). These patients were treated and are followed at the Cliniques Universitaires Saint-Luc (Brussels, Belgium).

The trial, a prospective, open label multicenter phase I/II study testing Promethera(R) HepaStem is designed to evaluate the safety and the preliminary efficacy of Promethera(R) HepaStem in Urea Cycle Disorders and Crigler-Najjar Syndrome patients.

“We are delighted to have achieved this important milestone in HepaStem’s development” said Eric Halioua, co-founder and CEO of Promethera Biosciences.

“HepaStem is an innovation in the field of liver-based metabolic diseases,” said Dr. Beatrice De Vos, chief medical officer of Promethera Biosciences. “This clinical trial will be the very first to apply allogeneic liver progenitor cells. This treatment with progenitor cells will contribute to restore a deficient enzyme function in Urea Cycle Diseases or in a Crigler-Najjar syndrome.”

The major innovation of Promethera(R) HepaStem resides in the simplicity of the treatment. This consists of a simple injection into the vein leading to the liver, which may make it possible to avoid radical and invasive surgery such as a liver transplant. Promethera(R) HepaStem could be used to treat a wide variety of liver pathologies. Thanks to the industrial development, if this therapy proves to be safe and effective, as many as a hundred patients could be treated from a single liver, thus largely overcoming the organ shortage problem.

"There is a real need for medical innovation to treat metabolic diseases in children; too many diseases are still intractable," said Professor Etienne Sokal, co-founder and chief scientific officer at Promethera Biosciences, paediatric hepatologist at Cliniques Universitaires St Luc and director of UCL's cell therapy research lab. "This first study represents a major step in the development of Hepastem towards a therapy that could transform positively the prognosis of these diseases."

About the phase I/II clinical trial

Since the discovery of HHALPC (Heterologous Human Adult Liver Progenitor Cells, which forms the basis for the Promethera(R) HepaStem product) by Professor Etienne Sokal and Doctor Najimi at the UCL laboratories (Brussels) in 2005, Promethera Biosciences has made considerable scientific advances. The proof of concept for the therapeutic use of the cells has been demonstrated in different animal models. Between 2009 and 2011, the ‘proof of concept’ in man has been studied by treating three patients suffering respectively from Ornithine Transcarbamylase deficiency (a form of Urea Cycle Disorders), Crigler Najjar syndrome, and type I glucogenosis with HHALPC by Professor Etienne Sokal at Cliniques Universitaires Saint-Luc (Brussels, Belgium) within the framework of the hospital exemption rules and the approval of the Ethics Committee.

These various achievements have enabled Promethera Biosciences to obtain the first authorizations from the British (MHRA) and Belgian (AFMPS) regulatory authorities to begin the phase I/II clinical study with Promethera(R) HepaStem. As part of the clinical study, the product is assessed in a paediatric setting involving children suffering from Crigler-Najjar syndrome or urea cycle disorders. Most young patients have only limited alternative therapeutic options and may die at an early age.

About Promethera Biosciences:

Promethera Biosciences is a pharmaceutical company that develops innovative therapies for the treatment of liver disease. It is currently developing two products based on a newly discovered and patented cell, the Heterologous Human Adult Liver Progenitor Cells (HHALPC):

• Promethera(R) HepaStem is a cell therapy product based on the use of allogeneic stem cells isolated from healthy adult human livers (Heterologous Human Adult Liver Progenitor Cells, HHALPC). These cells can be used to treat a wide variety of liver diseases, from rare inborn metabolic diseases (which can be classified as "orphan diseases" and mainly affect children), to acquired deficiencies affecting adults, such as fulminant hepatitis or liver fibrosis. This treatment has already received the orphan drug designation from the European Medicines Agency for the treatment of two very debilitating paediatric pathologies and from the Food and Drug Administration (USA) for both indications.

• Promethera(R) HepaScreen is a different, non-therapeutic product that uses the same adult human liver-derived stem cells as a biotechnology tool designed for evaluation of new chemical entities. This product meets a real need in the market, which currently lacks sufficiently predictive models to assess the hepatic metabolism of chemical compounds in the body. This unique cell model will be made available to the pharmaceutical industry to evaluate the metabolism and toxicity of new drugs in humans in a more reliable way than animal experimentation, thereby reducing the need and number of animals for such experiments.

Promethera Biosciences is a spin-off of the Université Catholique de Louvain (UCL), founded in 2009 by Sopartec S.A., UCL's technology transfer company, and Professor Etienne Sokal, a leading expert in pediatric liver disease and cell therapy. The company, under the direction of Eric Halioua, CEO, is located in Mont-Saint-Guibert.

For more information, please visit http://www.promethera.com

Press contact - for any further information, please contact:

Promethera Biosciences SA - Watson & Crick Hill

Rue Granbonpré 11

B-1435 Mont-Saint-Guibert - Belgium

Tel: +32(0)10 394 300

Media: Frédérique Ramon

Frederique.ramon@promethera.com

Mark Tidmarsh

ANDREW LLOYD & ASSOCIATES

http://www.ala.com

mark@ala.com

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