Ann: PTX unveils new clinic-ready CAR-T enhancement platform, page-28

Markets are illiquid ..it does not take much volume on either side of the price to drive price action higher and lower. You may be seeing a combination of profit taking from short term position takers and risk off trades due to recession fears and interest rates rising.
Early stage Biotech shares are a target for both long term investors and active traders....do not sweat the intra-day jitters unless they are accompanied by negative announcements if you are an investor. Traders make money through Volatility, and illiquid markets amplify the impact they have.