The company said Thursday it has closed $200 million in Series B financing—on top of last year’s $200 million Series A haul—to help initiate a registrational Phase II study for its lead candidate UPB-101.
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Massachusetts-based Upstream Bio announced Thursday it has closed a $200 million Series B funding round, which the company will use to push its investigational antibody UPB-101 to mid-stage studies in asthma and chronic rhinosinusitis with nasal polyps.
Alongside these Phase II studies, which Upstream expects to form the basis for regulatory applications, the start-up will also undergo “translational, manufacturing and device development activities” meant to help the company launch its Phase III development program more quickly, according to the news release.
In addition, Thursday’s Series B raise will allow Upstream to develop a “highly differentiated target product profile” for UPB-101, the company said.
With a hefty $200 million Series A haul and armed with a promising early candidate licensed from Astellas, Upstream launched in June 2022 with the goal of taking a new and innovative approach to severe asthma. The Astellas molecule worked by targeting the thymic stromal lymphopoietin (TSLP), a cytokine that is an upstream player in the body’s chemical signaling cascade- inducing inflammatory responses.
This mechanism is central to Upstream’s drug discovery philosophy—targeting key upstream players, or those that occur early on in the inflammation signaling cascade—and is the basis for the company’s name.
Upstream’s pipeline strategy, along with promising pre-clinical data from Astellas and a highly experienced leadership team, landed the company in fifth place on BioSpace’s list of the Top Life Sciences Startups to Watch in 2023.
Since it licensed the candidate from Astellas, Upstream has seen UPB-101 through Phase I assessments. According to data presented in May at the American Thoracic Society International Conference, a single dose of the investigational antibody had a favorable safety and tolerability profile in healthy volunteers.
Moreover, simulations showed that repeated subcutaneous doses of UPB-101 at 12-week intervals could achieve serum levels above the predicted therapeutic threshold. A post-hoc analysis also found that blood eosinophil levels dropped substantially after treatment.
Pre-clinical studies also showed that UPB-101 could inhibit the production of cytokines and completely suppressed allergic skin reactions in monkey models, suggesting that the candidate could also have therapeutic potential in other inflammatory conditions.
Upstream is currently running a randomized, double-blinded, placebo-controlled and multiple ascending dose Phase Ib study to better characterize the candidate. Enrollment for this study started in August 2022.
Thursday’s Series B was co-led by Enavate Sciences and Venrock Healthcare Capital Partners. Upstream gained new supporters during the financing round, including Bain Capital Life Sciences and Wellington Management.
As part of the fundraising push, Enavate’s Edd Fleming and Venrock’s Alex Rosen are now part of Upstream’s board of directors.
Tristan Manalac is an independent science writer based in metro Manila, Philippines. He can be reached at tristan@tristanmanalac.com or tristan.manalac@biospace.com.
