Why Prosensa NV Shares Roared Higher

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 Prosensa (NASDAQ: RNA  ) , a clinical-stage developer of RNA-modulating therapeutic agents for genetic disorders, jumped as much as 50% after reporting additional clinical findings on drisapersen at the JPMorgan Healthcare Conference.

So what: According to Prosensa's press release, which corresponds with its earlier presentation time at the JPMorgan Healthcare Conference, further analysis from the aggregate data collected from its late-stage drisapersen trial to treat Duchenne muscular dystrophy suggest that earlier treatment of the disease, and therefore a longer duration of treatment, could delay progression of the disease. Prosensa intends to consult with clinical experts and regulators to determine if there is a path forward for drisapersen, which failed to meet its primary endpoint in a phase 3 trial in September.

Now what: Before you get too excited, my suggestion would be "Don't!" There are a lot of variables to work through here, including persuading the Food and Drug Administration that drisapersen has clinical benefits following a trial that demonstrated no benefits over the placebo, and the development of a drug that has no partner, as GlaxoSmithKline (NYSE: GSK  ) announced that it would be ending its pact with Prosensa earlier this week. To further complicate matters, Sarepta Therapeutics (NASDAQ: SRPT  ) earlier today reported 120-week results for eteplirsen, which showed continued six-minute walk test improvements relative to the placebo. In other words, drisapersen may not be a dead compound, but on a scale of dead to FDA-approved, it's a lot closer to the dead end at the moment. As such, I'd take today's gains with a grain of salt.

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