UW-Madison scientist Hector DeLuca, an international authority on vitamin D whose patents have earned the university millions in royalties, will step down in July as chairman of the biochemistry department he has led for the past 35 years.

DeLuca, 74, said Friday he will still work full time at the university as a researcher and professor, but he no longer wants to run the department. DeLuca has been undergoing chemotherapy for a treatable lymphoma since early January, he said.

"I realized I ought to prioritize my life," DeLuca said. "It's time I focused on things I really love to do."

UW-Madison Provost Peter Spear said DeLuca's leadership would be a "great loss."

"He's helped to build one of the premier biochemistry departments in the country," Spear said. But I'm delighted that he'll be continuing as a faculty member, where I'm sure he'll continue to make important contributions to the education of our students and to new discoveries."

DeLuca is best known for his discoveries about the healing power of various vitamin-D compounds. One of his biggest eureka moments was in October 2002, when he announced the creation of a new drug known as 2MD, which offered hope to osteoporosis sufferers because it built bone mass in lab animals.

The drug, further developed by DeLuca's start-up company, Deltanoid Pharmaceuticals, passed a first round of clinical safety tests in May and started human trials in November. The pharmaceutical company Pfizer has purchased rights to the drug, which is one of about 300 vitamin-D compounds that DeLuca has helped developed at UW-Madison.

DeLuca on Friday said he's eager to spend more time in the lab developing additional drug treatments and getting them to market through his company.

"I've got a lot of neat things in the pipeline that I'm anxious to move out into the public domain," he said.

DeLuca's patents, which number more than 150, have brought tens of millions of dollars in royalty income to UW-Madison. He also has trained nearly 160 doctoral students.

"He's amazing," Spear said. "Some people are fortunate to have one patent in their entire careers. He seems to come up with new patent after new patent, good idea after good idea."

DeLuca said university officials would make a decision about his successor as department chair in about a month, after which he would help train the new leader. Biochemistry is one of UW-Madison's biggest departments, with about 35 professors, 175 graduate students and a total annual budget of about $20 million, mostly in federal grants.

DeLuca is being treated for his lymphoma at UW Hospital. He said it was going well and that he felt pretty good halfway through a series of four chemotherapy treatments.

"I'm optimistic," he said.

Contact Karen Rivedal at krivedal@madison.com or 252-6106.