Inovio Pharmaceuticals' phase 2/3 trial is on hold after the FDA raised questions about it, and it won't restart until at least October, The Wall Street Journal reported.
Inovio didn't detail the questions from the FDA that triggered the hold, but said they involved the delivery device used to administer the shot. The hold wasn't due to any adverse event, the drugmaker said.
The trial was expected to start this month.
Inovio, which has never brought a vaccine to market, saw its shares fall 33 percent after the delay was announced, the Journal reported.
"The company is actively working to address the FDA’s questions and plans to respond in October," Inovio told the Journal.
The FDA has 30 days to tell Inovio whether its trial can continue.