Inovio Pharmaceuticals said that the FDA placed a partial clinical hold on a planned phase 2/3 study of its COVID-19 vaccine candidate INO-4800.
According to Inovio, the FDA has “additional questions” about the planned trial, including the CELLECTRA 2000 delivery device to be used in the study. The drugmaker noted that it is working to address the issues and plans to respond to the agency in October.
Unrelated to adverse events
Inovio noted that the FDA’s move is not due to the occurrence of any adverse events related to the ongoing phase 1 study of INO-4800, which is not impacted by the partial hold. Earlier this year, the company reported interim phase 1 data indicating that INO-4800 was “deemed safe and well-tolerated” through 8 weeks, but did not give any details about participants’ antibody response. Inovio later announced that the DNA vaccine was “effective” at protecting non-human primates from live virus challenge 13 weeks after the last vaccination, with results “mediated by memory T and B cell immune responses.”
FDA ‘increasingly cautious’
Cantor analyst Charles Duncan suggested the delay creates a “management credibility challenge” for Inovio. He also said the FDA “appears increasingly cautious on COVID-19 vaccine programs,” pointing to recent reported plans by the agency to increase the number of severe cases of the disease needed to show efficacy, as well as the prudence with which it is handling a hold on AstraZeneca’s coronavirus vaccine trial, which has resumed in other countries, but not in the US.