Source: Celldex Therapeutics

What: Sellers indiscriminately punished stocks today, and Celldex Therapeutics (NASDAQ:CLDX) didn't escape today's stock market rout unscathed. Despite no new news to digest, the company's shares tumbled 12.1% in today's session.

So what: The clinical-stage drug developer is working on cancer treatments, and its most advanced drug in development is Rintega, a therapy for the treatment of a rare form of brain cancer known as glioblastoma.

Last year, independent monitors took an interim look at data from Rintega's ongoing phase 3 trial and recommended the trial continue as planned. Another interim review is expected early this year, and the trial is slated to wrap up completely in November.

Now what: Investors are derisking their portfolios to play defense, and that means they're exiting shares in companies where binary events, such as the planned completion of Rintega's trial, could expose them to hit-or-miss returns.

No one knows whether Rintega's trial will show that it helps glioblastoma patients live longer or if the drug will prove to be safe enough to pass muster with regulators, but investors can speculate that a FDA decision on Rintega won't happen until 2017 (unless the trial is halted early), and that means there's not a whole heck of a lot of incentive for short-term investors to stick around.

This shortsightedness, however, could present an opportunity for risk-tolerant investors who approach the markets with a longer time horizon. After all, the need for new glioblastoma therapies is big, and Celldex Therapeutics' shares have retreated 52% since last June and nearly 23% already this year.