The drug targeted an immune checkpoint called CTLA - 4 , known as a key negative regulator of T cell activity .
The drug being trialled was a monoclonal antibody called ipilimumab , then under development at BMS with Axel Hoos as the medical lead .
The antibody targeted an immune checkpoint called CTLA - 4 , known as a key negative regulator of T cell activity .
The drug being trialled was a monoclonal antibody called ipilimumab , then under development at BMS with Axel Hoos as the medical lead .