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 Raptor Pharmaceuticals (NASDAQ:RPTP), a clinical-stage biopharmaceutical company focused on developing therapies to treat a number of serious diseases, including Huntington's disease and nonalcoholic steathohepatitis, jumped as much as 19% after announcing its clinical results from its phase 2/3 trial involving RP103 for Huntington's disease.

So what: To add some context to these results, this data is from the 18-month mark of a planned 36-month study. Thus far, 89 of 96 enrolled patients have reached the halfway point, speaking to the tolerability of Raptor's experimental treatment. The results, so far, demonstrate a "positive trend toward slower progression of Total Motor Score (TMS) in patients treated with RP103 vs. those patients on placebo, the primary endpoint of the study." Raptor notes TMS progression was 32% slower in patients treated with RP103 versus the placebo after 18 months, while the 66 patients not taking tetrabenazine (a treatment for chorea associated with Huntington's disease) demonstrated a "statistically significant slower progression in TMS vs. the placebo group."

Now what: It's a bit early to break out the pompons, but these results are certainly encouraging, and I fully understand why Raptor shares are clawing their way higher today. Safety and tolerability do not appear to be an issue with RP103. As a reminder for investors, Huntington's disease is an incredibly difficult disease to treat, so the failure rate of experimental therapies tends to be high. If Raptor can somehow succeed here where others have failed, it could certainly head much higher from its current valuation. Realistically, though, investors will have to wait for quite some time before the drug can hit the market, so I'd suggest you keep your expectations tempered in the meantime.

Editor's Note: A previous version of this article suggested that the remainder of the RP103 clinical trial will be placebo-controlled. The article has been updated to provide more clarity.

Sean Williams has no material interest in any companies mentioned in this article. You can follow him on CAPS under the screen name TMFUltraLong, track every pick he makes under the screen name TrackUltraLong, and check him out on Twitter, where he goes by the handle @TMFUltraLong.

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