Clinical Trial Failure Risk: Clinical trials for Arcus's lead drug candidates (e.g., domvanalimab, etrumadenant) may not demonstrate sufficient efficacy or safety to achieve regulatory approval or market acceptance, leading to significant delays or discontinuation of development.

Regulatory Approval Uncertainty Risk: Even if clinical trials are successful, Arcus may fail to obtain necessary regulatory approvals from agencies like the FDA or EMA, due to various factors including review standards, manufacturing issues, or post-marketing commitments.

Funding and Liquidity Risk: Arcus Biosciences is a pre-revenue company that relies heavily on external funding. It may face challenges in securing additional capital through equity offerings, debt, or partnerships if its cash reserves dwindle, potentially impacting its ability to fund ongoing research and development.