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 Isis Pharmaceuticals (NASDAQ:IONS), a developer of in-house and partnered therapies utilizing its antisense drug-technology platform, spiked higher by as much as 20% after reporting interim results from its multiple dose study of ISIS-SMN Rx in children with spinal muscular atrophy (SMA).

So what: According to the press release from Isis, ISIS-SMN Rx was well-tolerated at all dose levels, and "consistent with single-dose observations, time and dose-dependent increases in muscle function were observed in children treated with multiple doses of ISIS-SMN Rx." Isis also notes an assay test designed to measure SMN protein in the cerebral spinal fluid showed time and dose-dependent increase in both single- and multiple-dose studies. SMN protein levels were observed to be 120% and 160% above baseline in the two highest doses nine to 14 months after first dosing. Utilizing the Hammersmith Functional Motor Scale-Expanded point scale to measure changes in muscle function for patients with SMA, the treated children in the 3 mg, 6 mg, and 9 mg cohorts achieved mean increases in HFMSE scores of 1.5 points, 2.3 points, and 3.7 points, respectively, nine months following their first dose of ISIS-SMN Rx. Isis plans to give children rolling over into an extension study a 12 mg dose every six months.

Now what: Isis is truly one of a handful of remarkable biotech companies in that it's set up with a number of development partners and also has a number of in-house drugs in its pipeline. ISIS-SMN Rx is a drug being co-developed with Biogen Idec (NASDAQ:BIIB), with Biogen holding the option to license the compound until completion of the first successful phase 2/3 study or the completion of two phase 2/3 studies. There are few therapies on the market to treat SMA, so ISIS-SMN Rx is providing genuine hope for improvement to current sufferers. Safety doesn't appear to be an issue at the moment, and its impressive half-life -- Isis mentions muscle function scores were improved up to 14 months after the first dose -- certainly gives the impression that it could make for a fantastic long-term maintenance therapy. Because of its extensive pipeline, I'd postulate that Isis could have additional upside even following today's large move higher.