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 Cytokinetics (CYTK -1.37%), a clinical-stage biopharmaceutical company focused on developing therapies for serious diseases, tanked as much as 38% after reporting mid-stage top-line data from acute heart failure drug, omecamtiv mecarbil.

So what: According to the press releases, omecamtiv mecarbil, which Cytokinetics has partnered with Amgen (AMGN -0.50%) in developing, failed to meet its primary endpoint of creating a significant difference from the placebo with regard to dyspnea system response (or in English, helping improve a patient's ability to breathe). Improvement in dyspnea was noted in the highest dosing group with little effect seen in the lowest dose. On the other hand, the drug proved to be as safe as the placebo and was well-tolerated.

Now what: Despite failing to meet its primary endpoint, all hope may not be lost. Amgen partnered with Cytokinetics for a reason, and there's a good chance it and Cytokinetics will focus on the higher dosage of omecamtiv mecarbil now that it's been proven safe. There's of course no guarantee that the drug will move into phase 3 trials, but it seems illogical that Amgen would expand its collaboration in June if it had the expectation of shelving omecamtiv mecarbil now. For Cytokinetics' shareholders, it's once again a watch and wait game with no FDA-approved drugs and the fate of omecamtiv mecarbil now up in the air.