Shares of Heron Therapeutics (HRTX) were up 22% in after hours trade after announcing positive phase 2 results for post-operative pain. These positive results stem from a phase 2 trial with the company's HTX-011 drug formulation. The company uses its own proprietary BioChronomer drug delivery technology as the delivery vehicle for HTX-011. 

HTX-011 is a local anesthetic in a fixed dose combination with an anti-inflammatory molecule known as meloxicam. The phase 2 study recruited 64 patients who received HTX-011, that contained 200 mg or 400 mg bupivacaine combined with meloxicam against a placebo compound for a comparison. The primary endpoint was testing for the difference of pain intensity between Heron's drug and a placebo compound as measured by the Summed Pain Intensity -- SPI -- score. 

The company's drug combination together with HTX-011 displayed a SPI score of 38.5 versus placebo achieving a SPI score of 124.2, meaning that the HTX-011 drug combo displayed a 69% decrease in pain compared to the placebo compound in the first 24 hour period post surgery. This means that the p-value obtained was p < 0.0001 , which is below 0.01 for statistical significance. Thus the primary endpoint of the trial was met. 

In addition the company also passed on multiple secondary endpoints  which measured pain in the first 48 hours and 78 hours post surgery. Once again the drug proved to be  more effective than its placebo counterpart. While this trial tested patients that had bunionectomies performed these clinical results could also potentially be tested in other post operative pain surgery trials as well. This first trial was just a stepping stone which now allows the company to branch out to post operative pain in other areas.