A nonprofit cancer foundation created by former Vice President Joe Biden is shutting down after two years because of “unique circumstances.”

The Biden Cancer Initiative, a tribute to the 2020 candidate’s late son, Beau Biden, began operating in 2017 and has since pledged more than $400 million to improve cancer treatment. The nonprofit was founded as a philanthropic extension of the White House Cancer Moonshot program, an Obama-era program that seeks to accelerate a cure to cancer through public-private partnerships.