MEI Pharma, Inc., an oncology company focused on the clinical development of novel therapies for the treatment of cancer, has entered into a definitive asset purchase agreement with S*BIO Pte Ltd, a privately held biotechnology company, pursuant to which MEI Pharma will acquire S*BIO’s exclusive worldwide rights to Pracinostat, an investigational, potential best-in-class, oral histone deacetylase (HDAC) inhibitor.

“We are excited to seize this opportunity to bolster our pipeline with a potential best-in-class, late-stage compound with activity against a validated target, under favourable terms,” said Daniel P Gold, PhD, president and chief executive officer of MEI Pharma. “The acquisition of Pracinostat broadens our potential addressable market in oncology with applications in both haematologic disorders and solid tumours. We believe that the addition of this targeted small molecule to our existing portfolio of novel isoflavone-based drug candidates, ME-143 and ME-344, will significantly enhance shareholder value."

Pracinostat is an orally available, selective HDAC inhibitor that has demonstrated clinical evidence of single-agent activity, including studies in patients with advanced haematologic disorders such as acute myeloid leukaemia and myelofibrosis. In addition, Pracinostat has demonstrated pharmacokinetic properties in the clinic that compare favourably to other compounds of this class.

Pursuant to the terms of the agreement, MEI Pharma will issue $500,000 of common stock to S*BIO. The agreement also includes potential success-based clinical, regulatory and sales milestone payments of up to $75.2 million, as well as low single-digit contingent earn-out payments based on net sales. The transaction is expected to close on or about August 28, 2012, subject to S*BIO shareholder approval and certain customary closing conditions.

Pracinostat is a selective inhibitor of a group of enzymes called histone deacetylases (HDAC). HDACs belong to a larger set of proteins collectively known as epigenetic regulators that can alter gene expression by chemically modifying DNA or its associated chromosomal proteins. Abnormal activity of these regulators is believed to play an important role in cancer and other diseases. There are currently two HDAC inhibitors approved by the US Food and Drug Administration (FDA) for the treatment of cutaneous T-cell lymphoma, one of which is also approved for the treatment of peripheral T-cell lymphoma. Pracinostat has been generally well tolerated in clinical testing of more than 150 patients, with readily manageable side effects often associated with drugs of this class. The most common adverse event (all grades) is fatigue.

Data from a phase II clinical trial of oral Pracinostat showed evidence of single-agent activity in heavily pre-treated patients with intermediate or high-risk myelofibrosis, with two patients showing a clinical improvement. These results are scheduled for publication in the September 2012 issue of Leukaemia Research. Pracinostat has also demonstrated pre-clinical activity in both haematologic disorders and solid tumours when used alone or in combination with a wide range of therapies in laboratory studies. Data recently published in the May 2012 issue of Blood Cancer Journal demonstrated synergistic pre-clinical activity when Pracinostat was combined with an experimental JAK2 inhibitor, also developed by S*BIO and recently acquired by Cell Therapeutics, Inc. Pracinostat has not been approved for commercial distribution.

S*BIO Pte Ltd is focused on the research and clinical development of novel targeted small molecule drugs for the treatment of cancer, with leading programs around kinases and histone deacetylases (HDAC).