Joslin Diabetes Center, the Harvard-affiliated diabetes research and treatment clinic, replaced its chief executive on Tuesday, giving no reasons for his sudden departure.
In a statement, Joslin’s board of directors said only that John L. Brooks III has stepped down and that chief financial officer Eliot M. Lurier would serve as interim CEO.
“This leadership change, which is effective immediately, will have no impact on patient care in the clinic or research activities across Joslin’s laboratories,” Joslin said in the statement.
Neither Brooks nor board members, including chairman Ralph James, responded to requests for comment Tuesday. A Joslin spokesman, Jeff Bright, declined to comment beyond the statement.
Brooks’s departure comes as the center faces financial challenges in a rapidly changing health care industry. As big hospital systems get bigger, they increasingly want to keep patients in their networks instead of referring them to other clinics such as Joslin, a nonprofit in Boston’s Longwood Medical Area.
In addition, Joslin’s research funding from the National Institutes of Health has plunged to about $12.5 million this year from $17.6 million in 2010, more sharply than at other institutions. And as it seeks to replace that money with private philanthropy, it must compete with better-known institutions in the crowded world of Boston health care.
Joslin generated $95.7 million in revenue in 2013, the most recent figures available, up from $94.2 million in 2012, according to tax filings.
Its profit fell to about $3 million in 2013 from $4.3 million the previous year.
“Joslin is the national leader in diabetes research and treatment of patients,” said Michael Astrue, a former member of its board, “but it faces enormous challenges with changes in the health care environment and being successful in the highly competitive area of philanthropy.”
Joslin, founded by a physician 117 years ago, has always specialized in research and treatment of diabetes, a chronic disease that affects more than 29 million Americans, or 9 percent of the population, according to the Centers for Disease Control and Prevention.
When Brooks was named chief executive in 2011, he was the third CEO in two years. He replaced Dr. Kenneth Quickel Jr., who led Joslin for two years after the departure of Ranch C. Kimball,who was the chief executive from 2007 to 2009. Kimball served as secretary of economic development when Mitt Romney was governor.
Brooks, a former entrepreneur and venture capitalist specializing in life sciences, pushed Joslin to commercialize more of its diabetes research.
“We want to be involved in bringing innovation to the market,” he told the Globe in 2011.
Joslin is a member of a diabetes research partnership announced last week with the tech giant Google and the pharmaceutical company Sanofi.
“Technology, sensors, analytics, and digital solutions,” Brooks said in a statement on the initiative, “will revolutionize how blood sugars are managed, which will deliver improved quality of life, lowering the risk of complications and reducing the costs and barriers associated with diabetes care.”
Brooks, who had served on Joslin’s board since 2005, previously worked at medical device firms and a consultancy for life sciences companies. He also cofounded a venture capital firm called Prism VentureWorks in Needham.
In June, Brooks was among the Boston executives spotted at the Biotechnology Industry Organization’s annual convention in Philadelphia, mingling with life sciences professionals from around the world.
“John was a committed leader of Joslin,” said Jonathan P. Gertler, chief executive of Back Bay Life Science Advisors, a Boston consulting firm. “In this era where biotech has become such a prominent force, the collaboration between industry and science and clinicians has been an important part of our growth here in Boston. John was in the middle of that.”
Priyanka Dayal McCluskey can be reached at priyanka.mccluskey@globe.com. Follow her on Twitter @priyanka_dayal.