The Bill & Melinda Gates Foundation has pledged an additional $750-million to the Global Fund to Fight AIDS, Tuberculosis, and Malaria, more than doubling its support as the organization struggles with reduced revenue and a leadership change, says Reuters.

The foundation has given $650-million to the fund since it was founded 10 years ago. The nonprofit agency’s executive director, Dr. Michel Kazatchkine, resigned this week amid a reorganization aimed at improving day-to-day management and reducing the Global Fund’s losses to corruption.

The fund—which handles about one-fourth of international HIV/AIDS financing and most of spending to fight malaria and tuberculosis—has also fallen short in recent fundraising rounds as weak economies squeeze the national governments that are its main donors.

“These are tough economic times, but that is no excuse for cutting aid to the world’s poorest,” Bill Gates said in Davos, Switzerland, where he is attending the World Economic Forum.