Shares of Inovio Pharmaceuticals plunged more than 34% in premarket trading this morning after the company reported the U.S. Food and Drug Administration (FDA) placed a partial clinical hold on its planned Phase II/III study of the company’s COVID-19 vaccine candidate.
This morning, Pennsylvania-based Inovio said the regulatory agency has additional questions about the Phase II/III trial regarding the vaccine candidate itself, known as INO-4800, as well as the company’s Cellectra 2000 delivery device. Inovio said the partial clinical hold is not due to the occurrence of any adverse events related to the company’s ongoing expanded Phase I study of INO-4800. Inovio said the Phase I study is expected to continue. Additionally, the partial clinical hold does not impact the company’s other clinical programs, Inovio said in its announcement.
Beyond the little information above, Inovio did not disclose much regarding the partial clinical hold. The company said it is working to address the questions raised by the FDA and plans to respond to the regulatory agency in October. The FDA will then have up to 30 days to respond and notify Inovio as to whether or not the clinical trial may proceed. Inovio said it is preparing for a resumption of the trial in order to play its part in defeating the global pandemic.
In late June, Inovio announced positive interim data from the Phase I trial of INO-4800. In the interim data, 94% of the recipients demonstrated an overall immune response at Week 6 after two doses of the vaccine, the company said. At Week 8, the vaccine appeared to be both safe and well-tolerated with no serious adverse events. All of the adverse events were mild, grade 1 in severity. Most were redness at the injection site.
Earlier this month, an adverse event caused a pause in AstraZeneca’s Phase III COVID-19 vaccine study. In that study, a woman in the United Kingdom who received the experimental vaccine candidate was hospitalized with a severe neurological condition. The patient has since been released from the hospital and the vaccine trial resumed in the U.K., however it remains paused in the United States.
INO-4800 is one of the experimental vaccines included in the U.S. government’s Operation Warp Speed that has a goal of having a vaccine available by January 2021. Inovio has touted the vaccine candidate as the only nucleic acid-based vaccine that is stable at room temperature for more than a year and doesn’t need to be frozen in transport or storage like the mRNA vaccine candidates under development by Moderna and Pfizer and BioNTech.
Earlier this month, Inovio partnered with Thermo Fisher Scientific to manufacture the COVID-19 vaccine. At peak capacity, Thermo Fisher projects that it could produce at least 100 million doses of INO-4800 annually.