Upstream Bio, a clinical-stage biotech company, has announced the successful completion of a $200 million Series B financing round. This funding will primarily support the advancement of UPB-101, a novel monoclonal antibody targeting the thymic stromal lymphopoietin (TSLP) receptor (TSLPR), currently in Phase 1b development for asthma treatment. The financing was led by Enavate Sciences and Venrock Healthcare Capital Partners.
Clinical Development Plans for UPB-101
The raised capital is earmarked for initiating registrational Phase 2 clinical trials of UPB-101 in both asthma and chronic rhinosinusitis with nasal polyps (CRSwNP). These trials aim to evaluate the efficacy and safety of UPB-101 in these patient populations. In parallel with Phase 2 studies, Upstream Bio intends to conduct translational research, manufacturing optimizations, and device development activities to prepare for a seamless transition to Phase 3 development.
Rationale Behind TSLP Receptor Inhibition
Thymic Stromal Lymphopoietin (TSLP) is a cytokine that plays a crucial role in driving inflammatory responses in allergic and inflammatory diseases. Blocking the TSLP receptor offers a therapeutic strategy to address the root cause of multiple pathological inflammatory processes across a broad spectrum of diseases. TSLP signaling is one of the initial events in the inflammatory cascade, stimulated by allergens, viruses, and other triggers, activating downstream targets such as IL-4, IL-5, IL-13, IL-17, and IgE.
About UPB-101
UPB-101 is a recombinant fully human immunoglobulin G1 (IgG1) monoclonal antibody (mAb) designed to bind to the human TSLP receptor (TSLPR) and inhibit its signaling. Pre-clinical studies have demonstrated UPB-101's ability to inhibit cytokine production from CD4+ T cells and ILC2s, as well as suppress skin allergic reactions in a monkey model. A Phase 1 randomized, placebo-controlled, single-dose escalation study in healthy volunteers indicated that UPB-101 was safe and well-tolerated. A Phase 1b multiple ascending dose study in individuals diagnosed with asthma is currently underway.
Market Context and Disease Burden
Asthma, the company's lead indication, affects approximately 260 million people worldwide. In the U.S., over 25 million individuals live with asthma, with 5-10% suffering from severe asthma. CRSwNP is a chronic upper airway disease that obstructs the sinuses and nasal passages and is highly comorbid with asthma; up to 65% of CRSwNP patients also have asthma. A study found that 43% of patients with severe asthma also suffered from CRSwNP.
