A biotech stock just rocketed 608% after announcing positive phase 3 trial data

• Seres Therapeutics soared as much as 608% on Monday after the company announced positive phase 3 trial data for its drug SER-109.
• SER-109 was developed for the potential treatment of C. difficile, which is a bacterial infection of the colon that leads to inflammation and can be deadly.
• Seres said that SER-109 was well tolerated by its trial participants and that it led to a 30.2% decline in the rate of C. difficile recurrence relative to the placebo.
• Seres' market valuation soared from $354 million on Friday to more than $1.5 billion as of Monday afternoon, according to data from YCharts.com
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A tiny biotech stock rewarded investors on Monday after it announced positive phase 3 trial data.

The company, Seres Therapeutics, released positive phase 3 trial data for its SER-109 drug, which was being tested for potential treatment of C. difficile.

C. difficile is a bacterial infection of the colon that leads to inflammation and can be deadly.

Shares of Seres rocketed as much as 608% to $33 on Monday. Investors seem to be impressed by the results. According to Seres, SER-109 was well tolerated by its trial participants and the drug led to a 30% decline in the recurrence of C. difficile relative to the placebo.

The biotech's market valuation soared from $354 million as of Friday's close to more than $1.5 billion as of Monday afternoon, according to data from YCharts.com.

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Meanwhile, some investors were betting on the opposite outcome for Seres' clinical trial data. According to ShortSqueeze.com, as of Monday the percentage of shares sold short stood at 17.7%, or 7.4 million shares.

The shares sold short that represented a market value of $43.7 million on Friday represented a market value of as much as $245.5 million at Monday's high. That indicates a loss of as much as $201.8 million, assuming no shares sold short were bought back to cover.

Short investors may have piled into the stock due to Seres' clinical failure four years earlier for the same drug in a phase 2 trial, which led to shares plummeting more than 70%.

Seres said it will meet with the FDA to talk about filing for product approval "as soon as possible," according to the news release.