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.

Shares in Regulus Therapeutics (NASDAQ:RGLS) have slid by 12% this afternoon after the company reported that president and CEO Kleanthis Xanthopoulos, Ph.D., has resigned, while chief scientific officer Neil Gibson will leave at the end of this month.

So what
Regulus Therapeutics has said Xanthopoulos will be pursuing other biotechnology investment opportunities. That could suggest to investors that Xanthopoulos doesn't feel that Regulus Therapeutics' potential is as great as previously believed -- especially given that Gibson is also leaving and that both of them have been automatically executing sales of exercised options since at least last fall.

Uncertainty is never a good thing for any investor, so Regulus' new CEO, former chief medical officer Paul Grint, M.D., will need to act quickly to restore confidence among investors. Regulus Therapeutics would also likely benefit from some good news out of its pipeline, which could also ease investors' fears.

That pipeline includes a slate of micro-RNA targeting medicines using research provided by its founding fathers, ISIS Pharmaceuticals and Alnylam Pharmaceuticals -- two Goliaths in RNA research that, along with AstraZeneca and Sanofi, own big stakes in Regulus Therapeutics.

Now what
One of Regulus Therapeutics' most intriguing drugs in development is RG-101, a micro-RNA targeting therapy for the treatment of hepatitis C.

Previously, the company reported that in a very early-stage trial, nine of 14 patients treated with a single 4 mg dose of RG-101 were disease-free after 57 days. That success has Regulus Therapeutics expecting to launch phase 2 studies of the drug soon. Additionally, early-stage results from a four-week study evaluating RG-101 alongside other hepatitis C drugs are expected to be released by year-end.

Further behind RG-101 is RG-125, a therapy for nonalcoholic steatohepatitis that development partner AstraZeneca reported would advance into a phase 1 trial soon.

Although these are intriguing drugs, neither is at an advanced enough stage for me to be confident that either could become a commercially viable therapy. Because of that and the fact that there's a changing of the guard in the C-suite, I'm content to sit on the sidelines until we get more trial data to digest.