Why Shares of Arrowhead Research Corp. Briefly Spiked Today

Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of the clinical-stage biotech Arrowhead Research Corp. briefly spiked by 12.5% this morning following an announcement that the company's lead hepatitis B product candidate,ARC-520, was permitted by the Food and Drug Administration, or FDA, to enter into a small, multiple-dose phase 2b study that will enroll 12 patients in total. Eight patients in the study will receive 3 doses of 1mg/kg of ARC-520, and the other four will receive a placebo.

The proposed study will be called "Heparc-2004" and will assess ARC-520's ability to reduce the hepatitis B surface antigen over the course of multiple doses, compared to patients receiving placebo. Secondary objectives of the study will be to examine ARC-520's safety and pharmacokinetic profile.

So what: Arrowhead's shares have had a rough couple of months due to the less than spectacular results of ARC-520's phase IIa trial released last year, where it showed only modest efficacy in terms of reducing the hepatitis B surface antigen, especially at the low dose of 1mg/kg. And then shares took another leg down earlier this year when the FDA placed a partial clinical hold on ARC-520 because of concerns over organ-level toxicity at higher doses. So today's news marks the company's first real steps in getting this pivotal experimental product back on track in terms of its clinical testing.

Now what: Arrowhead's management said, via the press release, that they are working diligently toward launching this latest clinical trial, with the hope that it can get under way within a month from this announcement.

While that's certainly good news for investors currently in this stock, I wouldn't exactly be in a hurry to buy more shares or open a position. ARC-520 has exhibited an uneven performance in the clinic thus far, and this latest trial is extremely small, meaning that its forthcoming takeaways will be limited in nature. In short, Arrowhead is still years away from a pivotal clinical trial for its experimental hep B product, suggesting that this stock is perhaps best left on the watchlist.

The article Why Shares of Arrowhead Research Corp. Briefly Spiked Today originally appeared on Fool.com.

George Budwell has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. 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.

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