Upstream Bio Reports Positive Top-line Results from the Phase 2 VALIANT Trial of Verekitug for the Treatment of Severe Asthma

Rhea-AI Summary

Upstream Bio (Nasdaq: UPB) reported positive top-line Phase 2 VALIANT results for verekitug in severe asthma, showing statistically significant reductions in annualized asthma exacerbation rate (AAER): 56% reduction at 100 mg q12w and 39% at 400 mg q24w versus placebo.

Verekitug also improved lung function (FEV1: +122 mL and +139 mL at week 60) and reduced FeNO (20.4 ppb and 26.3 ppb), was generally well tolerated, has >90% rollover into the VALOUR LTE, and will advance toward Phase 3 in severe asthma and CRSwNP following regulatory interactions.

Positive

• AAER reduced by 56% at 100 mg q12w versus placebo
• AAER reduced by 39% at 400 mg q24w versus placebo
• FEV1 improved by 122 mL (100 mg q12w) and 139 mL (400 mg q24w)
• FeNO suppressed by 20.4 ppb and 26.3 ppb
• >90% of eligible patients rolled over into the VALOUR long-term extension
• Company intends to advance verekitug into Phase 3 trials in two indications

Negative

• Low-dose 100 mg q24w showed inconsistent improvements across endpoints
• VALIANT is Phase 2; Phase 3 and regulatory approvals remain required

Market Reaction

-23.59% $21.25

15m delay 12 alerts

-23.59% Since News

-42.2% Trough in 40 min

$21.25 Last Price

$18.50 $32.00 Day Range

-$464M Valuation Impact

$1.50B Market Cap

0.1x Rel. Volume

Following this news, UPB has declined 23.59%, reflecting a significant negative market reaction. Argus tracked a trough of -42.2% from its starting point during tracking. Our momentum scanner has triggered 12 alerts so far, indicating notable trading interest and price volatility. The stock is currently trading at $21.25. This price movement has removed approximately $464M from the company's valuation.

Data tracked by StockTitan Argus (15 min delayed). Upgrade to Silver for real-time data.

Key Figures

AAER reduction (100 mg q12w): 56% (p<0.0003) AAER reduction (400 mg q24w): 39% (p<0.02) FEV1 improvement 100 mg: 122 mL +5 more

8 metrics

AAER reduction (100 mg q12w) 56% (p<0.0003) Placebo-adjusted reduction in annualized asthma exacerbation rate

AAER reduction (400 mg q24w) 39% (p<0.02) Placebo-adjusted reduction in annualized asthma exacerbation rate

FEV1 improvement 100 mg 122 mL Placebo-adjusted change at week 60, 100 mg q12w

FEV1 improvement 400 mg 139 mL Placebo-adjusted change at week 60, 400 mg q24w

FeNO suppression 100 mg 20.4 ppb (p<0.0003) Placebo-adjusted change at week 60, 100 mg q12w

FeNO suppression 400 mg 26.3 ppb (p<0.0001) Placebo-adjusted change at week 60, 400 mg q24w

FeNO reduction from baseline 43.5% and 44.9% (p=0.03) Mean reductions in FeNO for 100 mg q12w and 400 mg q24w

VALIANT enrollment 478 patients Global Phase 2 VALIANT trial in severe asthma

Market Reality Check

Price: $27.81 Vol: Volume 814,002 is above t...

normal vol

$27.81 Last Close

Volume Volume 814,002 is above the 20-day average of 624,959, indicating elevated interest ahead of the data. normal

Technical Shares at $27.81 are trading above the 200-day MA of $19.15, reflecting a pre-existing uptrend into this catalyst.

Peers on Argus

UPB is up 6.47% while key biotech peers show mixed moves: SYRE -2.1%, QURE -3.29...

UPB is up 6.47% while key biotech peers show mixed moves: SYRE -2.1%, QURE -3.29%, RAPP +3.44%, TRML flat, VERV -0.09%, pointing to a stock-specific reaction.

Previous Clinical trial Reports

2 past events · Latest: Sep 02 (Positive)

Same Type Pattern 2 events

Date	Event	Sentiment	Move	Catalyst
Sep 02	CRSwNP Phase 2 data	Positive	+18.3%	Positive VIBRANT Phase 2 CRSwNP results with strong efficacy and safety profile.
Jul 08	COPD trial start	Positive	-0.7%	Initiation of VENTURE Phase 2 COPD trial expanding verekitug into third indication.

Pattern Detected

Clinical trial milestones for verekitug have often produced positive price reactions, though not uniformly.

Recent Company History

Over recent months, UPB has advanced verekitug across multiple Phase 2 programs in CRSwNP, COPD, and severe asthma. Prior clinical readouts, such as the Sep 2, 2025 VIBRANT Phase 2 data, drove double‑digit gains, while the Jul 8, 2025 COPD trial initiation saw a mild decline. Today’s severe asthma VALIANT results extend this sequence of clinical catalysts, reinforcing the multi‑indication development strategy and building on earlier efficacy and safety signals.

Historical Comparison

clinical trial

+8.8 %

Average Historical Move

Historical Analysis

In the past year, UPB’s clinical trial updates moved the stock an average of 8.77%. The current 6.47% gain on VALIANT asthma data falls slightly below that historical reaction.

Typical Pattern

Clinical news shows progression from Phase 2 efficacy in CRSwNP and COPD trial initiation toward broader, multi‑indication development for verekitug, now including severe asthma Phase 2 results guiding planned Phase 3 designs.

Market Pulse Summary

The stock is dropping -23.6% following this news. A negative reaction despite positive VALIANT data ...

Analysis

The stock is dropping -23.6% following this news. A negative reaction despite positive VALIANT data would contrast with the strong response to prior Phase 2 CRSwNP results, which saw a 18.27% gain, and sit closer to the mild decline after the COPD trial initiation. That pattern would underscore how expectations and valuation entering a catalyst can matter as much as headline efficacy. Biotech history for this name shows that even encouraging trial updates have not always translated into sustained price strength.

Key Terms

fev1, randomized, double-blind, placebo-controlled, copd

3 terms

fev1 medical

"Placebo-adjusted improvement in lung function, as measured by the forced expiratory volume in one second (FEV1)"

FEV1 stands for forced expiratory volume in one second, a medical measurement of how much air a person can forcibly exhale in one second during a breathing test. Think of it like timing how quickly someone can blow out a candle — it gives a clear snapshot of lung strength and airflow. Investors watch FEV1 because changes in this measure are used to judge whether respiratory drugs or devices work, which affects regulatory approval, market potential, and sales forecasts.

randomized, double-blind, placebo-controlled medical

"Phase 2 global, randomized, double-blind, placebo-controlled, dose-ranging, parallel group clinical trial"

A "randomized, double-blind, placebo-controlled" process is a method used to test the effectiveness of a new treatment or intervention. Participants are randomly assigned to different groups, with one receiving the real treatment and the other a fake version, called a placebo. Neither the participants nor the researchers know who is receiving which, which helps ensure unbiased results. For investors, this rigorous approach increases confidence that the findings are accurate and not influenced by guesswork or bias.

copd medical

"ongoing Phase 2 VENTURE trial in patients with COPD"

Chronic obstructive pulmonary disease (COPD) is a long-term lung condition that progressively narrows airways and reduces the ability to breathe, causing persistent cough, shortness of breath and fatigue. It matters to investors because a large and growing patient population creates steady demand for drugs, medical devices and care services, influences healthcare spending and regulatory decisions, and offers clear market opportunities—similar to a leaking engine that requires ongoing fixes and replacement parts.

AI-generated analysis. Not financial advice.

– Verekitug provided statistically significant and clinically meaningful reductions in annualized asthma exacerbation rate (AAER) with 100 mg q12 and 400 mg q24 week dosing –

– Verekitug also delivered clinically meaningful improvements in lung function (FEV₁) and exhaled nitric oxide (FeNO) with both dose regimens –

– Verekitug was generally well tolerated, with a safety profile consistent with prior studies –

– Over 90% of eligible patients have rolled over to the Phase 2 VALOUR long-term extension study –

– Upstream Bio to advance verekitug into Phase 3 trials in severe asthma and CRSwNP following planned regulatory interactions –

– Management will host a live webcast today at 8:00 a.m. ET –

WALTHAM, Mass., Feb. 11, 2026 (GLOBE NEWSWIRE) -- Upstream Bio, Inc. (Nasdaq: UPB), a clinical-stage company developing treatments for inflammatory diseases, with an initial focus on severe respiratory disorders, today announced positive top-line results from the Phase 2 VALIANT clinical trial evaluating the safety and efficacy of verekitug in adults with severe asthma. Verekitug is the only known clinical-stage antagonist targeting the receptor for thymic stromal lymphopoietin (TSLP).

VALIANT met the study’s primary endpoint of a statistically significant and clinically meaningful reduction in the annualized asthma exacerbation rate (AAER) with both every 12 week (q12w) and every 24 week (q24w) dosing, with verekitug demonstrating a reduction in AAER of 56% (p<0.0003) when dosed at 100 mg q12w and 39% (p<0.02) when dosed at 400 mg q24w, as compared with placebo.

Placebo-adjusted improvement in lung function, as measured by the forced expiratory volume in one second (FEV₁), was 122 mL at week 60 with verekitug 100 mg q12w, and 139 mL at week 60 with 400 mg q24w. At week 60, verekitug also suppressed exhaled nitric oxide (FeNO) compared to placebo by 20.4 ppb (p<0.0003) when dosed at 100 mg q12w, and by 26.3 ppb (p<0.0001) when dosed at 400 mg q24w. These data represented a mean 43.5% (p=0.03) reduction from baseline in the 100 mg q12w group and a mean 44.9% (p=0.03) reduction from baseline in the 400 mg q24w group. A third low-dose treatment group, 100 mg q24w, demonstrated a statistically significant effect on AAER, but did not provide consistent improvements in other endpoints.

Additional pre-specified analyses of secondary outcomes at week 24 revealed statistically significant placebo-adjusted improvements compared to baseline in both FEV₁ and FeNO with the 100 mg q12w and 400 mg q24w dose regimens.

Verekitug was generally well tolerated across all active doses, demonstrating a favorable safety profile consistent with previous studies.

“We are excited to share these robust data from VALIANT, which indicate the potential of verekitug’s meaningful clinical effect in severe asthma and provide a strong foundation as we advance verekitug into Phase 3 clinical trials as quickly as possible,” said Aaron Deykin, MD, Chief Medical Officer and Head of Research & Development at Upstream Bio. “We are deeply grateful to the patients, investigators, and study teams whose participation made this progress possible. With the completion of our VALIANT trial, hundreds of patients have now been dosed with verekitug across our clinical programs, providing a growing body of clinical experience that reinforces our confidence in its potential and its differentiated product profile. Together with the positive results from our VIBRANT trial in CRSwNP, we now have an opportunity to incorporate both strong clinical data sets with an in-depth analysis of the aggregate pharmacology findings to guide data-driven decisions about dose selection and trial design for Phase 3.”

“These compelling findings from VALIANT strengthen verekitug’s potential to advance the standard of care with a highly competitive efficacy profile and less frequent dosing—an important combination for people living with severe asthma,” stated Rand Sutherland, MD, Chief Executive Officer of Upstream Bio. “We intend to rapidly advance verekitug into Phase 3 trials in severe asthma and CRSwNP. In parallel, we also continue to progress verekitug in our ongoing Phase 2 VENTURE trial in patients with COPD, where we have enrolled more than 60% of patients to date. As we transition into a late clinical-stage company pursuing substantial market opportunities, our focus remains on disciplined execution and expanding Upstream Bio’s capabilities to support long-term growth.”

VALIANT (NCT06196879) is a Phase 2 global, randomized, double-blind, placebo-controlled, dose-ranging, parallel group clinical trial that evaluated the safety and efficacy of verekitug for up to 60 weeks, with a minimum of 24 weeks of treatment, in 478 patients with severe asthma.

Eligible participants who completed the Phase 2 VALIANT clinical trial were offered enrollment in VALOUR (NCT06966479), a long-term extension (LTE) study designed to evaluate the long-term safety and efficacy of verekitug. Current transition rates indicate more than 90% of eligible patients have rolled over to the Phase 2 VALOUR LTE study.

“Severe asthma, when unable to be controlled by standard of care measures, can significantly and chronically disrupt patients’ quality of life, and put them at risk for potentially life-threatening exacerbation events that can lead to emergency rooms visits and hospitalizations,” said Michael Wechsler, MD, MMSc, Professor of Medicine, Director of National Jewish Cohen Family Asthma Institute. “These data suggest that verekitug can potentially offer patients meaningful improvements in their breathing and asthma symptoms with less frequent dosing than the currently available biologics, and I believe that verekitug could represent an important advancement for individuals living with severe asthma.”

Upstream Bio designed the VALIANT trial using endpoints that, pending interactions with regulatory authorities, could produce data to support submissions for product approval. Planning activities for Phase 3 trials in severe asthma and CRSwNP have commenced, and the Company intends to initiate registrational trials in both indications following planned regulatory interactions.

Additional details from the VALIANT trial will be presented at a future medical conference.

Webcast Details
Upstream Bio’s webcast to discuss the top-line results from the Phase 2 VALIANT trial will begin today at 8:00 a.m. ET. The live webcast can be accessed via this link or on the Events tab on the Investors section of the Company’s website at https://investors.upstreambio.com/news-events/events. A replay of the webcast will be available on the website following the call.

About Severe Asthma
Severe asthma is a complex, chronic inflammatory disease of the airways characterized by persistent symptoms, recurrent exacerbations, and impaired quality of life despite treatment with high-dose corticosteroids and other long-acting medication that accounts for a disproportionate share of asthma-related costs and healthcare utilization. Severe asthma is a heterogeneous disease driven by multiple inflammatory pathways, including both Type 2 and non-Type 2 mechanisms.

Asthma affects approximately 350 million people worldwide, with five to 10 percent suffering from severe asthma. Currently, there are approximately 1.3 million biologic-eligible severe asthma patients in the US, though the use of biologic therapies remains limited relative to the size of the eligible population. We believe new treatment options for severe asthma are needed to further improve control of exacerbations and symptoms, and reduce the treatment burden, such as the need for frequent injections.

About the Phase 2 VALIANT Trial
The Phase 2 VALIANT trial (NCT06196879) is a global, randomized, placebo-controlled, dose-finding, parallel group clinical trial, designed to assess the efficacy and safety of verekitug in adults with severe asthma. Participants were randomized into one of four groups, receiving either 100 mg of verekitug every 24 weeks, 400 mg of verekitug every 24 weeks, 100 mg of verekitug every 12 weeks, or placebo administered subcutaneously. The study evaluated verekitug’s efficacy in the treatment of severe asthma during a treatment period up to 60 weeks with a minimum of 24 weeks, with the primary endpoint of reduction of the annualized asthma exacerbation rate (AAER). Secondary endpoints included changes in air exhalation, nitric oxide exhalation, and a patient-reported assessment of asthma control, though these were not designed with sufficient power to detect statistically significant effects.

About Verekitug
Verekitug is a novel recombinant fully human immunoglobulin G1 (IgG1) monoclonal antibody that binds to the thymic stromal lymphopoietin (TSLP) receptor and inhibits proinflammatory signaling initiated by TSLP. It is the only known antagonist currently in clinical development that targets and inhibits the TSLP receptor.

TSLP is a cytokine that is a key driver of the inflammatory response in major allergic and inflammatory diseases, such as asthma, where disruption of TSLP signaling has been clinically validated as an effective therapeutic strategy. TSLP activation is one of the first events in the inflammatory cascade stimulated by allergens, viruses and other triggers, initiating the activation of downstream targets such as IL-4, IL-5, IL-13, IL-17 and IgE. Because TSLP is a target upstream in the inflammatory cascade, blocking the TSLP receptor presents an opportunity for a single treatment to impact the drivers of multiple pathological inflammatory processes across a broad set of diseases.

Verekitug has advanced into three separate global, placebo-controlled, randomized Phase 2 clinical trials including the recently completed positive VIBRANT trial (NCT06164704) in patients with CRSwNP and VALIANT trial (NCT06196879) in patients with severe asthma. The VENTURE trial (NCT06981078) in patients with moderate-to-severe chronic obstructive pulmonary disease (COPD) is ongoing. Additionally, in May 2025, Upstream Bio initiated the VALOUR trial (NCT06966479), a long-term extension study in eligible participants with severe asthma who completed the VALIANT Phase 2 clinical trial.

About Upstream Bio
Upstream Bio is a clinical-stage biotechnology company developing treatments for inflammatory diseases, with an initial focus on severe respiratory disorders. The Company is developing verekitug, the only known antagonist currently in clinical development that targets the receptor for thymic stromal lymphopoietin (TSLP), a cytokine which is a clinically validated driver of inflammatory response positioned upstream of multiple signaling cascades that affect a variety of immune mediated diseases. The Company has advanced this highly potent monoclonal antibody into separate Phase 2 trials for the treatment of chronic rhinosinusitis with nasal polyps (CRSwNP), severe asthma, and chronic obstructive pulmonary disease (COPD). Upstream Bio’s team is committed to maximizing verekitug’s unique attributes to address the substantial unmet needs for patients underserved by today’s standard of care. To learn more, please visit www.upstreambio.com.

Forward-Looking Statements
This press release contains “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934, each as amended. These statements may be identified by words such as “aims,” “anticipates,” “believes,” “continue,” “could,” “estimates,” “expects,” “forecasts,” “goal,” “intends,” “may,” “plans,” “possible,” “potential,” “predict,” “project,” “seeks,” “should,” “target,” “will” and variations of these words or similar expressions. Any statements in this press release that are not statements of historical fact may be deemed to be forward-looking statements. These forward-looking statements include, without limitation, express or implied statements regarding: the clinical development of verekitug for the treatment of severe asthma, CRSwNP and COPD, including the timing, progress and results of ongoing and planned clinical trials; expectations for future discussions with regulatory authorities and the potential of the endpoints of the Company’s clinical trials to produce data that could support submissions for product approval; expectations regarding the differentiation, safety, efficacy, tolerability, or extended dosing interval of verekitug; expectations for the size and growth potential of the market for verekitug and the Company’s ability to serve that market; certain activities and next steps to support the Company’s maturation into a late clinical-stage company; and participation at upcoming investor conferences and medical congresses. Any forward-looking statements in this press release are based on the Company’s current expectations, estimates and projections only as of the date of this release and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. Readers are cautioned that actual results, levels of activity, safety, efficacy, performance or events and circumstances could differ materially from those expressed or implied in the Company’s forward-looking statements due to a variety of risks and uncertainties, which include, without limitation, risks and uncertainties related to: Upstream Bio’s ability to advance verekitug through clinical development, and to obtain regulatory approval of and ultimately commercialize verekitug on the expected timeline, if at all; the results of preclinical studies, or clinical studies not being predictive of future results in connection with future studies; the initiation, timing, progress and results of clinical trials; Upstream Bio’s ability to fund its development activities and achieve development goals; Upstream Bio’s dependence on third parties to conduct clinical trials and manufacture verekitug, and commercialize verekitug, if approved; Upstream Bio’s ability to attract, hire and retain key personnel, and protect its intellectual property; Upstream Bio’s financial condition and need for substantial additional funds in order to complete development activities and commercialize verekitug, if approved; regulatory developments and approval processes of the U.S. Food and Drug Administration and comparable foreign regulatory authorities; Upstream Bio’s competitors and industry; and other risks and uncertainties described in greater detail under the caption “Risk Factors” in Upstream Bio’s most recent Annual Report on Form 10-K and Quarterly Report on Form 10-Q, as well as any subsequent filings with the SEC. Any forward-looking statements represent Upstream Bio’s views only as of today and should not be relied upon as representing its views as of any subsequent date. Upstream Bio explicitly disclaims any obligation or undertaking to update any forward-looking statements contained herein to reflect any change in its expectations or any changes in events, conditions or circumstances on which any such statement is based except to the extent required by law, and claims the protection of the safe harbor for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995.

Investor and Media Contact:
Meggan Buckwell
Director, Corporate Communications and Investor Relations
ir@upstreambio.com

FAQ

What were the AAER results for Upstream Bio (UPB) in the Phase 2 VALIANT trial?

Verekitug reduced annualized asthma exacerbation rate by 56% at 100 mg q12w and by 39% at 400 mg q24w versus placebo. According to Upstream Bio, both doses met the primary endpoint with statistically significant, clinically meaningful AAER reductions in the VALIANT study.

How did verekitug (UPB) affect lung function and FeNO in VALIANT at week 60?

Verekitug improved FEV1 by 122 mL (100 mg q12w) and 139 mL (400 mg q24w) at week 60. According to Upstream Bio, it also reduced FeNO by 20.4 ppb and 26.3 ppb respectively, with statistically significant placebo-adjusted changes.

What safety and tolerability did Upstream Bio (UPB) report for verekitug in VALIANT?

Verekitug was generally well tolerated with a safety profile consistent with prior studies. According to Upstream Bio, no new safety signals were reported across active doses and tolerability aligned with earlier clinical experience.

Will Upstream Bio (UPB) advance verekitug to Phase 3 trials after VALIANT?

Yes. Upstream Bio intends to advance verekitug into Phase 3 trials in severe asthma and CRSwNP after planned regulatory interactions. According to Upstream Bio, Phase 3 planning has commenced and registrational trials are intended to start following those interactions.

How many patients transitioned from VALIANT to the VALOUR long-term extension for UPB's verekitug?

More than 90% of eligible VALIANT patients rolled over into the VALOUR LTE study. According to Upstream Bio, this high transition rate supports continued long-term safety and efficacy evaluation of verekitug.