Roche Holding AG and SQZ Biotechnologies Co. expanded their collaboration to develop and commercialize cell therapies for treating cancer.

As part of the partnership, privately held SQZ Biotechnologies will use its proprietary cell therapy platform to develop cancer treatments derived from antigen presenting cells — a type of immune cell that allows the T cell to recognize antigens and trigger an immune response against them.

Under the expanded agreement, Switzerland-based Roche will give SQZ Biotechnologies up to $125 million in up-front payment and near-term milestones. SQZ Biotechnologies could also get up to $250 million in clinical, regulatory and sales milestones in each product developed from the collaboration.

SQZ Biotechnologies is eligible to receive more than $1 billion in development milestone payments.

The two companies began their partnership in 2015 to jointly develop therapies based on peripheral blood mononuclear cells, a type of cell that plays a critical role in the immune system's function to fight infection and adapt to foreign bodies. The initial agreement provides for more than $500 million in up-front and potential clinical, regulatory and sales milestone-based payments.

Watertown, Mass.-based SQZ Biotechnologies develops novel treatments targeting multiple therapeutic areas through its cell therapy platform.