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What: Celldex Therapeutics (NASDAQ:CLDX) was down 10% at 3:25 p.m. ET even though there doesn't seem to be any new news to support a decline.

So what: Shares in Celldex Thearapeutics are down 44% this month. TheStreet published an article this morning highlighting why some investors feel that Celldex is going to get a negative readout for its clinical trial testing cancer immunotherapy Rintega, but there wasn't any new information there.

An interim analysis of the clinical trial testing Rintega in patients with a brain cancer called glioblastoma multiforme is scheduled to read out in "early 2016," so we could get results of the interim peek at the data any day now. There are three possibilities. The trial could be stopped early because it's clear the drug isn't working, it could be stopped early because it's clear the drug is working or the monitoring board could allow the trial to continue to its completion without revealing the data.

Stopping for futility would obviously be very bad, while stopping for positive efficacy would be very good for Celldex Therapeutics. And allowing the trial to continue is a mixed bag. It'll be clear the drug isn't working so well that there's a strong enough signal to stop the trial with a limited number of patients, but the final result could still be positive, especially since Rintega is an immunotherapy, which often take longer to show an effect because they work by activating the immune system rather than attacking the tumor directly.

Now what: The price of Celldex's shares on Jan. 1 or today or a year ago will have little influence on the price after the results of the interim look are announced. There doesn't seem to be much reason for investors to sell now just because short-sellers have driven down the price if they believe the trial will be stopped for efficacy -- or are willing to hold through a final readout if that's what it takes.

Brian Orelli has no position in any stocks mentioned. The Motley Fool recommends Celldex Therapeutics. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.