A life sciences executive who played a key role in the development of local biotech success Esperion Therapeutics is assuming the top job at an Ann Arbor personalized medicine company, officials announced today.

Timothy Mayleben, a founding member of Esperion, will become chief executive officer of Aastrom Biosciences when CEO and chief financial officer George Dunbar steps aside in December. Dunbar will become chairman of Aastrom. Nelson Sims, the current chairman, will become lead director.

The leadership transition comes as Aastrom has encountered a series of obstacles in the clinical development of its therapeutic technology, which involves tissue cell repair and stem cell therapies.

Dunbar led the company through an intense financial storm, which led the company to lay off 35 of its personnel in 2008.

Earlier this year Aastrom had to temporarily halt a Phase 2 clinical trial after the death of a participating patient. The FDA later determined the death was not related to the company's drug technology, and the trial resumed.

In November, the company celebrated Michigan voters' approval of Proposal 2, which lifted the statewide ban on stem cell research, which results in the destruction of embryos. Aastrom does not conduct embryonic stem cell research, but Dunbar long argued that Michigan's anti-stem cell research image hurt his company.

Mayleben expressed confidence the company could navigate the turbulent economic conditions threatening biotech companies.

"Our strategy to focus clinical development on cardiovascular indications is showing considerable strength, and I am looking forward to building on the momentum of these clinical programs," he said in a statement. "This is a very exciting time for the company and I am pleased to be taking a more active role."

Mayleben, with then-partner Roger Newton, helped Esperion raise more than $200 million during the company's first life before Pfizer acquired it for $1.3 billion in February 2004. Pfizer closed Esperion and laid off its 60 workers in 2007 when it shuttered its Ann Arbor operations, but Newton has since relaunched the company as a startup.

Contact AnnArbor.com's Nathan Bomey at nathanbomey@annarbor.com or (734) 623-2587 or follow him on Twitter.