Inovio Pharma drops on stock offering plans
** Inovio Pharmaceuticals' INO.O shares down 22.1% to $1.13 in extended trading as it seeks equity raise
** Biotech firm announces stock offering without disclosing deal size
** Jefferies and Piper Sandler joint bookrunners
** INO shares more than tripled to close at $1.89 on Mon after the US FDA approved co's rare throat disease treatment, branded as Voceryq
** Plymouth Meeting, Pennsylvania-based INO has ~110.2 mln shares outstanding as of Sept 30, per the prospectus
** INO shares finished down 10.5% at $1.45 on Thurs