Upstream Bio
Upstream Bio is a clinical-stage biotechnology company developing verekitug, a monoclonal antibody targeting the TSLP receptor for severe asthma, CRSwNP, and COPD. The publicly traded (NASDAQ: UPB) Waltham-based biotech expects to initiate Phase 3 trials in Q1 2027.
- Company typePublic
- Founded2022
- HeadquartersWaltham, United States
- Headcount51–100
- GTM typeB2B
- OfferingHardware or Manufacturing
What Upstream Bio does
Upstream Bio is a clinical-stage biotechnology company developing verekitug (UPB-101), a recombinant fully human IgG1 monoclonal antibody that binds to and inhibits the thymic stromal lymphopoietin (TSLP) receptor. TSLP is positioned upstream in the inflammatory signaling cascade, so receptor inhibition disrupts activation of multiple downstream mediators (IL-4, IL-5, IL-13, IL-17, IgE) implicated in chronic respiratory inflammation. Verekitug is the only known clinical-stage mAb targeting the TSLP receptor and is being evaluated in three indications: severe asthma (Phase 2 VALIANT, 56% reduction in annualized exacerbation rate), chronic rhinosinusitis with nasal polyps or CRSwNP (Phase 2 VIBRANT, approximately 80% of participants achieving clinically meaningful nasal polyp improvements), and chronic obstructive pulmonary disease or COPD (Phase 2 VENTURE). Phase 3 registrational trials in CRSwNP and severe asthma are planned to initiate in Q1 2027.
The company is headquartered in Waltham, Massachusetts (890 Winter Street, Suite 200), was originally founded as Seeker Biologics, and went public on NASDAQ under the ticker UPB in 2024 after raising approximately $293 million in its IPO. Prior to the IPO, Upstream Bio raised $200 million in Series A funding in June 2022 (led by Maruho and OrbiMed) and $200 million in Series B funding in June 2023 (led by Venrock Healthcare Capital Partners and Enavate Sciences). The company has raised an additional $150 million via an at-the-market equity sales agreement with Leerink Partners entered into in March 2026. As of Q4 2025, Upstream Bio held $341.5 million in cash, which management expects will fund planned operations through 2027.
Upstream Bio's revenue model is contingent on future commercialization of verekitug following regulatory approval. The company currently generates no product revenue. Once approved, verekitug — a subcutaneous biologic dosed quarterly at 100mg — is expected to be distributed through specialty pharmacies and hospital channels, targeting pulmonologists, allergists, and ENT specialists who treat severe asthma, CRSwNP, and COPD patients. With approximately 350 million asthma patients worldwide (5–10% with severe disease), up to 4% of the general population affected by CRSwNP (40% uncontrolled), and COPD as the fourth leading cause of death globally, the addressable patient population is substantial. Strategic clinical collaboration with Maruho Co., Ltd. supports ex-US clinical execution, particularly in Japan.
Upstream Bio firmographics
Firmographics- Name
- Upstream Bio
- Legal name
- Upstream Bio, Inc.
- Website
- https://upstreambio.com
- Company type
- Public
- Founded year
- 2022
- Operating status
- Operating
- Headcount range
- 51–100 employees
- Short description
- Upstream Bio is a clinical-stage biotechnology company developing verekitug, a monoclonal antibody targeting the TSLP receptor for severe asthma, CRSwNP, and COPD. The publicly traded (NASDAQ: UPB) Waltham-based biotech expects to initiate Phase 3 trials in Q1 2027.
- Ownership category
- akta.pro rank
Upstream Bio industry classification
Industry- Product category
- Biopharmaceutical Therapeutics
- NAICS
- Biological Product (except Diagnostic) Manufacturing (325414), Research and Development in Biotechnology (except Nanobiotechnology) (541714)
- SIC
- Biological Products, (No Disgnostic Substances) (2836), Pharmaceutical Preparations (2834)
- akta.pro primary industry
- Recombinant Protein Therapeutics (enzymes, hormones, growth factors) (HLAAAAAB)
Keywords
Where Upstream Bio is headquartered
LocationHeadquarters
- HQ city
- Waltham
- HQ country
- United States
- HQ region
- North America
Offices1 record
Markets served
Upstream Bio business model
Business model- GTM type
- B2B
- Offering type
- Hardware or Manufacturing
- Cost components
- Technology or R&D, Personnel, Operations, Marketing or Sales, Others
Revenue model
- Pharmaceutical Product Sales (post-approval): Upstream Bio is a clinical-stage biotech with no current approved products. The company's revenue model is expected to be derived from the commercialization of verekitug and potentially other pipeline candidates following regulatory approval. Once approved, the company will generate revenue through prescription drug sales for severe asthma, CRSwNP, and COPD.
- At-the-Market (ATM) Equity Offering: Upstream Bio entered into a $150 million at-the-market sales agreement with Leerink Partners to raise capital through equity sales in the public market, supplementing cash reserves to fund clinical development operations.
Pricing tiers
| Model | Billing | Price |
|---|---|---|
| Other | Other | No approved products yet — pricing not established. |
Go-to-market motion1 record
Distribution channels1 record
Marketing channels5 records
Upstream Bio product offering
Product offeringCore offering
Upstream Bio is a clinical-stage biotechnology company developing verekitug (UPB-101), a novel recombinant fully human IgG1 monoclonal antibody that binds to and inhibits the TSLP (thymic stromal lymphopoietin) receptor. The company is advancing verekitug through Phase 2 and Phase 3 clinical trials as a potential treatment for chronic rhinosinusitis with nasal polyps (CRSwNP), severe asthma, and chronic obstructive pulmonary disease (COPD). Verekitug is the only known clinical-stage monoclonal antibody that potently targets and inhibits the TSLP receptor.
Product overview
Upstream Bio is a clinical-stage biotechnology company developing verekitug (UPB-101), a novel fully human IgG1 monoclonal antibody targeting the thymic stromal lymphopoietin (TSLP) receptor. Verekitug is the only known clinical-stage monoclonal antibody that potently targets and inhibits the TSLP receptor, positioned upstream in inflammatory signaling cascades. The company has advanced verekitug into multiple Phase 2 clinical trials across three respiratory indications: chronic rhinosinusitis with nasal polyps (CRSwNP), severe asthma, and chronic obstructive pulmonary disease (COPD). The company's clinical trial portfolio includes completed VIBRANT trial (CRSwNP), completed VALIANT trial (severe asthma), ongoing VALOUR long-term extension trial, and ongoing VENTURE trial (COPD). Phase 3 registrational trials are planned to initiate in Q1 2027 for both CRSwNP and severe asthma.
Differentiator
Problem solved
Functional benefit
Brands
- Verekitug (UPB-101): Novel recombinant fully human IgG1 monoclonal antibody targeting the TSLP receptor for treatment of severe respiratory diseases including asthma, CRSwNP, and COPD
Products and services
- Verekitug (UPB-101) Verekitug is a novel recombinant fully human IgG1 monoclonal antibody that binds to the TSLP receptor and inhibits pro-inflammatory signaling initiated by TSLP. It is being developed as a treatment for chronic rhinosinusitis with nasal polyps (CRSwNP), severe asthma, and chronic obstructive pulmonary disease (COPD), administered via quarterly subcutaneous dosing (100mg every 12 weeks).
Quantifiable outcome
- 56% reduction in annualized asthma exacerbation rate at 100mg q12w dosing in Phase 2 VALIANT trial (p<0.05)
- +5 more outcomes
Companies that use Upstream Bio
Customer profileSegments3 records
Ideal customer profiles2 records
Upstream Bio technology and API
TechnologyTechnology focussed Yes
API detail
- Has API
- No
- API docs
- API detail
Core technology
AI maturity
App detail
Feature3 records
Upstream Bio partnerships and signals
Strategic signalPartnerships
One partnership is on record.
- Maruho Co., Ltd.coreMaruho Co., Ltd. is Upstream Bio's clinical trial collaboration partner, specifically for conducting clinical trial activities as part of Upstream Bio's global research and development plan for verekitug. Maruho contributes to specified clinical trial activities in Japan and potentially other regions, supporting the global development strategy.
Scale indicators9 records
Recent moves8 records
Expansion highlights6 records
Upstream Bio competitors and assessment
Company assessmentMarket position
Competitive moat4 records
Key risks5 records
Key highlights7 records
Customer concentration
Upstream Bio social profiles
Digital presenceUpstream Bio compliance and trust
Trust signalCompliance3 records
Upstream Bio financial estimates
Financial estimateRevenue estimate
Valuation estimate
Upstream Bio leadership team
Management profileNumber of profiles
Profiles20 records
Upstream Bio funding detail
Funding detailFunding overview
Funding rounds4 records
Investors14 records
Funding detail is available on the Subscription and Enterprise plan.Contact sales →
Upstream Bio M&A and investment
M&A and investmentM&A
Investments
M&A and investment is available on the Subscription and Enterprise plan.Contact sales →
Frequently asked questions about Upstream Bio
What does Upstream Bio do?
Upstream Bio is a clinical-stage biotechnology company developing verekitug (UPB-101), a novel recombinant fully human IgG1 monoclonal antibody that binds to and inhibits the TSLP (thymic stromal lymphopoietin) receptor. The company is advancing verekitug through Phase 2 and Phase 3 clinical trials as a potential treatment for chronic rhinosinusitis with nasal polyps (CRSwNP), severe asthma, and chronic obstructive pulmonary disease (COPD). Verekitug is the only known clinical-stage monoclonal antibody that potently targets and inhibits the TSLP receptor.
Is Upstream Bio a public or private company?
Upstream Bio is a public company. It is classified as public and is currently operating.
When was Upstream Bio founded?
Upstream Bio was founded in 2022. It employs 51 to 100 people.
Where is Upstream Bio based?
Upstream Bio is headquartered in Waltham, United States, in the North America region.
How does Upstream Bio make money?
Two revenue lines are on record. Pharmaceutical Product Sales (post-approval) is the primary driver. The others are at-the-Market (ATM) Equity Offering.
Does Upstream Bio have an API?
No public API is recorded for Upstream Bio.
What industry is Upstream Bio in?
Upstream Bio's product category is Biopharmaceutical Therapeutics. Its primary akta.pro industry code is HLAAAAAB, Recombinant Protein Therapeutics (enzymes, hormones, growth factors). Its NAICS code is 325414 and its SIC code is 2836.