Please ensure Javascript is enabled for purposes of website accessibility

Why Seres Therapeutics Stock Is Crashing Today

By Keith Speights - Jul 22, 2021 at 10:51AM

Key Points

  • Seres announced that SER-287 didn't meet the primary endpoint of a phase 2b study targeting ulcerative colitis.
  • The company now hopes to win approval for SER-109 in treating C. diff infection after inking a deal to co-market the drug with Nestlé Health Science.

Motley Fool Issues Rare “All In” Buy Alert

You’re reading a free article with opinions that may differ from The Motley Fool’s Premium Investing Services. Become a Motley Fool member today to get instant access to our top analyst recommendations, in-depth research, investing resources, and more. Learn More

The company reported disappointing results from a phase 2b clinical study.

What happened

Shares of Seres Therapeutics (MCRB 5.92%) were crashing 57.3% lower as of 11 a.m. EDT on Thursday. The steep decline came after the company announced top-line results from a phase 2b clinical study evaluating SER-287 in treating ulcerative colitis (UC).

So what

With the biotech stock losing more than half of its value today, it's no surprise that Seres' clinical results weren't good. The company reported that the primary endpoint of improving clinical remission rates wasn't met.

Four scientists with concerned expressions on their faces.

Image source: Getty Images.

There were three patient cohorts in the clinical study. Sixty-eight patients were given a full induction dose of SER-287. Another 66 patients were given a step-down induction dose. Placebo was administered to the remaining 69 patients. Seres said that there were "no meaningful clinical differences" observed between these three cohorts. 

Seres CEO Eric Shaff acknowledged that "these outcomes were not what we, nor the UC community, were hoping for." Because of the poor results, the company is closing the open-label and maintenance parts of the phase 2b study.

Now what

The main thing to watch with Seres now is its anticipated regulatory filing for approval of SER-109 in treating recurrent Clostridioides difficile infection. The company recently signed a deal with Nestlé Health Science to co-market the drug pending approval. 

Keith Speights has no position in any of the stocks mentioned. The Motley Fool recommends Nestle. The Motley Fool has a disclosure policy.

Invest Smarter with The Motley Fool

Join Over 1 Million Premium Members Receiving…

  • New Stock Picks Each Month
  • Detailed Analysis of Companies
  • Model Portfolios
  • Live Streaming During Market Hours
  • And Much More
Get Started Now

Stocks Mentioned

Seres Therapeutics Stock Quote
Seres Therapeutics
$5.37 (5.92%) $0.30
Nestle S.A. Stock Quote
Nestle S.A.
$121.99 (0.01%) $0.01

*Average returns of all recommendations since inception. Cost basis and return based on previous market day close.

Related Articles

Motley Fool Returns

Motley Fool Stock Advisor

Market-beating stocks from our award-winning analyst team.

Stock Advisor Returns
S&P 500 Returns

Calculated by average return of all stock recommendations since inception of the Stock Advisor service in February of 2002. Returns as of 08/14/2022.

Discounted offers are only available to new members. Stock Advisor list price is $199 per year.

Premium Investing Services

Invest better with The Motley Fool. Get stock recommendations, portfolio guidance, and more from The Motley Fool's premium services.