What happened Shares of Agenus (NASDAQ: AGEN) were jumping 8.2% as of 11:24 a.m. EDT on Tuesday. The only news related to the company was VBI Vaccines' (NASDAQ: VBIV) announcement that the U.S. Food and Drug Administration (FDA) granted Fast Track designation for cancer vaccine candidate VBI-1901 in treating recurrent glioblastoma, an aggressive type of brain cancer. VBI's experimental vaccine uses GlaxoSmithKline's AS01 adjuvant system, which contains Agenus' QS-21 Stimulon adjuvant. So what VBI stock rose a little with the FDA's decision to give Fast Track designation to VBI-1901. The designation could lead to a shorter path to potential approval of the experimental drug. Image source: Getty Images. Why would Agenus deliver an even bigger gain than VBI? After all, Agenus stands to benefit less than VBI might from the FDA's move. The most likely answer is that the surge in Agenus' share price really didn't stem primarily from the good news for VBI-1901. Instead, today's jump for Agenus probably just reflects run-of-the-mill volatility. Agenus didn't have any other news that would serve as a catalyst. It's not unusual for clinical-stage biotech stocks to experience big price swings for no apparent reason. Now what The main thing to watch with Agenus now is the FDA's decision on accelerated approval of balstilimab in treating cervical cancer. VBI Vaccines also expects an FDA approval decision on its hepatitis B vaccine candidate later this year. 10 stocks we like better than AgenusWhen 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 Agenus 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 recommends GlaxoSmithKline. The Motley Fool has a disclosure policy.Source