A planned later-stage trial for a Covid-19 vaccine from Inovio Pharmaceuticals Inc. is on hold, after U.S. health regulators raised questions, the company said.
The delay means the Phase 2/3 trial for Inovio’s experimental vaccine won’t begin until October at the earliest.
Inovio shares fell as much as 33% on Monday after the trial hold was announced. The stock was down nearly 30% in the midmorning. Through Friday’s close, the stock price had soared more than 400% this year.
Inovio didn’t detail the questions from the U.S. Food and Drug Administration that triggered the partial hold except to say that they included the delivery device used in administering the shot.
It is the latest setback to Inovio’s study launch. In June, Inovio said the trial had been planned to start in the summer, but in August the company pushed back the start, saying it was still in talks with the FDA.