Upstream Bio, Inc., a clinical-stage biotechnology company, develops treatments for inflammatory diseases focusing on severe respiratory disorders. It offers verekitug, which is in Phase 2 clinical development for the treatment of severe asthma and chronic rhinosinusitis with nasal polyps, and in Phase I clinical trial for treating chronic obstructive pulmonary disease. The company was incorporated in 2021 and is headquartered in Waltham, Massachusetts.