Dr. Patrick Soon-Shiong, chief executive of Abraxis BioScience Inc., said Thursday that he’s stepping down to focus on a spinoff company targeting cutting-edge personalized medicine technologies.

Leon O. Moulder Jr. has been appointed Abraxis BioScience’s chief executive, and also will hold the titles of vice chairman and president. Soon-Shiong, founder of Abraxis, will remain Abraxis BioScience’s chairman and become chief executive and chairman of Abraxis Health, which was formed in January to develop experimental treatments.

“Abraxis Health will become one of the first biotech companies to really take on the mantra that regardless of the size of the patient population, if there’s a drug that can help them we should be developing it and use biomarkers in the body to determine who can best be treated with it,” Soon-Shiong said. “We hope to create a new paradigm in medical care.”

Soon-Shiong controls about 83 percent of Abraxis BioScience and also will be the majority shareholder of Abraxis Health. Bruce Wendel, Abraxis BioScience’s executive vice president of operations, will become vice chairman and executive vice president of global business development at the new company.

Moulder, 51, most recently served as vice chairman of Eisai Corp. of North America following that company’s acquisition of MGI Pharma Inc., where he had been CEO since 2003. Moulder joined MGI Pharma in 1999. Earlier, he was a founding member of the management team and vice president of business development and commercial affairs at Eligx Inc., a venture-stage biomedical company.

Abraxis announced in January that it was spinning off its experimental research into the new Abraxis Health so Abraxis BioScience could focus on building the franchise for its Abraxane cancer drug. Abraxane is approved for advanced breast cancer, but the company is hoping to also market it as a treatment for several other cancers.

The drug, introduced in 2006, had sales of $335 million in 2008.