The UC Davis neurosurgeon at the center of a widening scandal over his experimental treatments of dying brain cancer patients is taking a leave of absence from the medical center staff, a university official announced Thursday.

Dr. J. Paul Muizelaar, who headed the neurological surgery department until his controversial work became public this summer, will not be seeing patients at the university hospital or in clinics, Anne Madden Rice, the medical center's chief executive officer, said in a statement posted on a UC Davis intranet site.

Rice said that Muizelaar was taking his leave, effective Thursday, "pending a review of four new (malpractice) claims" in which the neurosurgeon was involved in the patients' care.

In her announcement, Rice acknowledged that Muizelaar's departure comes as the university braces for the public release of a federal investigation into his and another doctor's work at the medical center.

The federal Centers for Medicare and Medicaid Services warned the university in a Nov. 13 letter that it had uncovered "serious deficiencies" and that the hospital's Medicare funding was in jeopardy unless it comes into "full compliance."

Muizelaar, 65, declined an interview request Thursday, saying he did not want to influence the ongoing investigation. But he told The Bee that "I will give you all the information as soon as the university has concluded its investigation.

"I think you will be surprised," he added.

In a July interview with The Bee, Muizelaar said he did nothing wrong when he and a colleague obtained the consent of three terminally ill patients in 2010 and 2011 to open their skulls and infect them with bacteria.

Muizelaar and a fellow UC Davis neurosurgeon, Dr. Rudolph J. Schrot, had theorized that post-operative infections might trigger an immune response in patients with deadly glioblastomas and prolong their lives.

Two of the patients quickly developed sepsis and died, university documents show. A third patient lived for about a year after being intentionally infected.

The university made no announcement Thursday about Schrot, who could not be reached for comment.

Use of humans to test experimental drugs or procedures is tightly controlled in the United States to prevent subjects from being harmed or exploited.

Since 2011, Muizelaar's and Schrot's unusual work has triggered at least four investigations: two internally, one by the independent body that accredits hospitals and another by the federal watchdog agency.

A key issue is whether the doctors crossed medical, ethical and legal boundaries in pursuit of their theory, documents show.

Thursday's announcement marks more upheaval within the UC Davis Health System. Last month, Dr. Claire Pomeroy, dean of the School of Medicine, announced she was resigning after seven years in the post.

Muizelaar is one of the highest paid employees in the University of California system, earning $859,000 in 2011, according to UC salary data. He received a base salary of $287,234 last year, with the remainder based on a negotiated formula of various factors and national benchmarks, said Bonnie Hyatt, spokeswoman for UC Davis Health System.

Although Muizelaar is now on leave from the medical center, Hyatt said, he retains his faculty appointment in the School of Medicine.

Muizelaar and Schrot were first sanctioned by the university in September 2011, when a six-month internal investigation concluded they had conducted improper research on human subjects without required approval from the university or the federal government.

At the time, both were banned from performing any further medical research involving human subjects. UC Davis then reported the doctors' "serious and continuing noncompliance" to the U.S. Food and Drug Administration.

Despite the university's report, Muizelaar remained the department chairman and, a few months later, was honored with an additional academic role at UC Davis as the first holder of the Julian R. Youmans endowed chair.

In July, Muizelaar "temporarily relinquished" his position as department chairman after The Bee began publishing a series of stories about the case. But he continued to see patients.

Spokeswoman Hyatt explained Thursday that medical professionals automatically are subject to "peer review" if the university gets three or more new malpractice claims involving someone in a rolling 12-month period. That happened in Muizelaar's case, she said, and the surgeon requested a leave of absence while a medical staff committee reviews the cases.

Details of the new malpractice claims were not immediately available Thursday.

However, court documents show that Muizelaar has been named in at least 12 medical malpractice cases in state and federal courts in California since 1998, a year after his arrival at UC Davis.

In her announcement to faculty and staff, Rice said the medical center was submitting its "comprehensive plan of correction" Thursday to CMS, the federal agency that initiated its investigation in August. Rice stated that she was confident the corrective actions "are fully responsive to issues raised in the CMS report."

She also said the university was notifying Muizelaar's patients about his leave and "taking steps to minimize disruption of their care."

"The safety of each of our patients and their confidence in us is, as always, our top priority," she stated.

In addition to the federal probe, the Joint Commission – the nonprofit organization that accredits hospitals nationwide – notified the university last month it was issuing "requirements for improvement." The university must also respond to that body with a detailed corrective plan, but a Joint Commission spokesman told The Bee the hospital remains fully accredited.

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