Shares of the clinical-stage biotech Inovio Pharmaceuticals (NASDAQ: INO) gained as much as 38% today due to a positive early-stage readout for its experimental HIV vaccine called Pennvax-GP.Digging into the details, the company reported that 71 out of 76 (93%) evaluable participants exhibited either a CD4+ or CD8+ cellular immune response to at least one of the vaccine's four antigens.