Upstream Bio's Selloff May Be 'Overdone,' But Analyst Highlights Asthma Drug's Competitive Edge Concerns

Upstream Bio Inc. (NASDAQ:UPB) shares are trading lower during Friday’s session as the stock reacts to recent developments in its clinical trials.

Over the last few days, the stock has plunged more than 54%.

The decline follows a report highlighting the company’s results for its asthma treatment.

VALIANT Trial Shows 56% Reduction in Asthma Attacks

The VALIANT trial demonstrated statistically significant reductions in the annualized asthma exacerbation rate (AAER) of 56% for the 100 mg every 12 weeks dosing compared to placebo.

Additionally, the drug showed improvements in lung function and was well-tolerated, with over 90% of eligible patients transitioning to the long-term extension study.

Analyst Take

William Blair, in an investor note on Wednesday, wrote, “While the biomarker results looked strong at both the 100 mg Q3M and 400 mg Q6M arms for verekitug, the lower exacerbation reduction seen at 400 mg Q6M has raised concerns on the competitive positioning of verekitug versus others in Phase II/III development.”

The broader market experienced a mixed performance on the previous trading day, with the Healthcare sector remaining flat, gaining 0.00%. Upstream Bio’s decline comes as the broader market showed resilience, suggesting that company-specific factors may be influencing the stock’s movement.

Analyst Matt Phipps wrote that shares trading down almost 50% ‘is overdone’, as some investors view the thymic stromal lymphopoietin (TSLP) space

as a winner-take-all for the one who can first commercialize a Q6M dosing regimen

UPB Stock Shows Strong Short-Term Momentum

Currently, the stock is trading 10.2% above its 20-day simple moving average (SMA) and 30.5% above its 100-day SMA, indicating strong short-term momentum. Over the past 12 months, shares have surged 292.24% and are currently positioned closer to their 52-week highs than lows.

The RSI is at 45.37, which is considered neutral territory, while MACD is below its signal line, indicating bearish pressure on the stock. The combination of neutral RSI and bearish MACD suggests mixed momentum.

• Key Resistance: $33.50
• Key Support: $12.00

Analyst Consensus & Recent Actions:

The stock carries a Strong Buy rating with an average price forecast of $49.00. Recent analyst moves include:

• Mizuho: Initiated with Outperform (Target $51.00) (Dec. 18, 2025)
• LifeSci Capital: Initiated with Outperform (Target $43.00) (Dec. 2, 2025)
• Evercore ISI Group: Initiated with Outperform (Target $40.00) (Nov. 18, 2025)

UPB Price Action: Upstream Bio shares were down 11.33% at $12.69 at the time of publication on Friday.

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