The executive director of the Geneva-based Global Forum for Health Research has stepped down.
Anthony Mbewu, a former president of South Africa's Medical Research Council, resigned from the post following "management issues" and amid allegations of misconduct.
The forum, a widely respected body, has the mission to demonstrate "the essential role of research and innovation for health and health equity, benefiting poor and marginalised populations".
Mbewu was an influential, and controversial, figure during Thabo Mbeki's term as South African president. He came under fire for his support for Matthias Rath, a campaigner against anti-retroviral drugs, who influenced Mbeki's stance on HIV/AIDS.
A forum spokesperson said Mbewu voluntarily resigned following a series of management issues, some of which he inherited when he took the job ten months ago.
In a written response to the newspaper, Mbewu denied he was leaving under a cloud, saying he chose to resign because he wanted to reunite with his family.