Pharmaceutical giant Pfizer Inc. has spun out Esperion Therapeutics Inc. again as a separate company.

Financial terms weren't disclosed, but Esperion officials said they raised $22.75 million in Series A investment to finance operations.

Pfizer bought Esperion for $1.3 billion in 2003 in what was described as a model transaction for the way Michigan biotech startups could create serious wealth and a bigger life sciences sector in the state.

Pfizer had operated Esperion as a separate research division. Pfizer said it retains a financial interest in the new enterprise.

The financing was co-led by Aisling Capital, Alta Partners and Domain Assocaites. Ann Arbor's Arboretum Ventures also participated.

The company said the funding will allow continued development of Esperion's lead products, including drug candidates for the treatment of cholesterol imbalances.

Esperion will again be led by Dr. Roger Newton, the original co-founder, CEO and president of the company, and will remain in Ann Arbor.

"We are extremely pleased to be working with such a strong group of investors as Esperion Therapeutics continues our important work in treating cardiovascular and metabolic disease," Newton said in a statement. "Re-establishing Esperion as a privately held entity ensures that the programs we have obtained will continue to advance as potentially important therapeutics. Without Pfizer's support, we would not have this opportunity to focus on these potential opportunities."

Added Martin Mackay, president of Pfizer Global Research and Development: "This transaction also enables Esperion to pursue its interests as a Michigan-based life science company while allowing Pfizer to support a new research venture and be involved in Esperion's potential success."
 
Esperion's Newton has 27 years experience in the pharmaceutical and life sciences industries, including a long stint at Warner-Lambert/Parke-Davis, now part of Pfizer, from 1981 to 1998. During that time he co-discovered and led the development of the cholesterol-lowering drug Lipitor.