What happened Shares of Inovio Pharmaceuticals (NASDAQ: INO) were sinking 8.8% as of 11:13 a.m. EDT on Thursday. The company didn't announce any new developments, and today's sell-off appears to be due to investors taking profits after Inovio's shares jumped nearly 17% yesterday. So what Inovio did have big news on Wednesday that caused the biotech stock to soar. The company announced that it's partnering with Advaccine Biopharmaceuticals Suzhou to evaluate COVID-19 vaccine candidate INO-4800 in a global late-stage clinical study. Advaccine was already collaborating with Inovio to develop and market INO-4800 in the greater China market. Image source: Getty Images. This expanded partnership was exactly what Inovio needed. The company had planned on financial assistance from the U.S. Department of Defense for a late-stage study of INO-4800. But in April, the Defense Department told Inovio that it wouldn't fund the phase 3 segment of the study because of "the changing environment of COVID-19 with the rapid deployment of vaccines." It's not all that surprising that investors would engage in some profit-taking. Inovio's shares were up more than 40% over the last month as of the market close on Wednesday, including yesterday's big gain. Now what Inovio and Advaccine plan to advance INO-4800 into the global late-stage study this summer. How Inovio's shares perform will depend on how well this trial goes. 10 stocks we like better than Inovio PharmaceuticalsWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and Inovio Pharmaceuticals wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of June 7, 2021 Keith Speights has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.Source