Sean Parker, best known as the founder of Napster, has committed $250 million of his fortune to cancer research.
The billionaire tech pioneer, who also served as the first president of Facebook, will spread the massive sum between six cancer centres in the United States.
The money will specifically go to research around cancer immunotherapy, which Parker believes is on the verge of curing the disease.
He told Fortune prior to the announcement:
"About half of all cancers, if you catch them early enough are readily treatable with chemotherapy, radiation, and surgery. The other 50% are likely going to kill you.
"Immunotherapy is the first breakthrough in recent memory that doesn’t just offer some incremental three to six months average life extension. It offers the possibility to beat cancer".
The therapy improves the body's immune system so that it can kill cancer cells itself.
The most famous success story to date came in December when former US President Jimmy Carter announced that he was cancer-free, following immune-based drug treatment.
Parker is keen to place the treatment, currently considered a "last resort", at the frontline in the fight against cancer.
Speaking to Forbes in December 2014, the businessman said:
I take a very venture-like perspective in my philanthropy - I don't just write a cheque to go to the cocktail party".
Last year, he pledged $600m to launch his Parker Foundation, which funds moonshot experiments to cure cancer, malaria and more.
Parker's pledge is the largest ever donation in the area and one of the most substantial sums invested in cancer research overall.
It comes three months on from US President Barack Obama's "moonshot" - a $1 billion injection into the federal cancer research programme.