Upstream Bio, Inc. (UPB)

Upstream Bio, Inc. is a clinical-stage biotechnology company developing treatments for inflammatory diseases, with an initial focus on severe respiratory conditions. The company is headquartered in Waltham, Massachusetts.

Its lead product candidate is verekitug, a monoclonal antibody that blocks the receptor for thymic stromal lymphopoietin, or TSLP, a cytokine that sits upstream in the inflammatory cascade and helps drive allergic and other types of airway inflammation. By targeting the receptor rather than the cytokine itself, Upstream aims to achieve potent and long-lasting inhibition that could allow less frequent dosing.

Upstream has been studying verekitug in severe asthma, chronic rhinosinusitis with nasal polyps and chronic obstructive pulmonary disease. The company completed its initial public offering on Nasdaq in 2024.