SCHEDULE 13G

Upstream Bio Inc

Common Stock, par value $0.001 per share · CUSIP: 91678A107

Event date: 2024-12-31

Reporting persons may disclose overlapping interests. Their amounts are shown individually and are not added into a filing total.

Filing-level shares

Unavailable

Percent of class

Unavailable

• Decheng Capital Global Life Sciences Fund IV, L.P.

  Shares: 3,085,293.00 · Class: 5.8%

• Decheng Capital Management IV (Cayman), LLC

  Shares: 3,085,293.00 · Class: 5.8%

• Decheng Capital Global Healthcare Fund (Master), LP

  Shares: 200,000.00 · Class: 0.4%

• Decheng Capital Global Healthcare GP, LLC

  Shares: 200,000.00 · Class: 0.4%

• Xiangmin Cui

  Shares: 3,285,293.00 · Class: 6.1%

Amounts are as disclosed in this filing. Schedule type alone does not establish investment intent.