AstraZeneca’s COVID-19 vaccine candidate induced significant immune responses in the majority of patients following a single dose in a Phase I study. The preventative medication also proved to be fairly safe, study results showed.
AstraZeneca and its development partner, the Jenner Institute from Oxford University, published the results of the Phase I study in The Lancet this morning. The vaccine candidate, dubbed AZD1222, generated both neutralizing antibodies and immune T-cells that target the virus that causes COVID-19, the researchers said. Initial results of the vaccine candidate were hinted at last week and the journal publication affirmed those rumors.
The vaccine induced seroconversion of the neutralizing antibodies in 59% and 47% of participants, and seroconversion of binding antibody in 96% and 97% of participants, depending on dose levels. Additionally, the research showed positive specific T-cell responses were found in 90% and 88% of participants receiving the different dose levels of the vaccine.
Andrew Pollard, an Oxford researcher who is also the lead study author, told Reuters that the results seen in the Phase I study could mean the body’s immune system will remember the virus and provide extended protection from COVID-19.
“However, we need more research before we can confirm the vaccine effectively protects against SARS-CoV-2 (COVID-19) infection, and for how long any protection lasts,” he added, Reuters said. Some reports have suggested that antibodies found in recovered COVID-19 patients may not last for a while, but the hope of T-cells is that they can remain active in the body for years.
AstraZeneca and the Jenner Institute have already moved into a Phase II/III study of the vaccine candidate with about 30,000 expected participants. AstraZeneca announced last month that it planned to manufacture two billion doses of its vaccine, with 400 million slated for the U.S. and UK, and one billion allotted for low- and middle-income countries.
The positive news from AstraZeneca’s Phase I program follows hopeful news regarding the clinical efficacy of other vaccine candidates in development.
Earlier this month, BioNTech and Pfizer released early data from the study of BNT162b1 that showed neutralizing antibodies were observed at 1.8- to 2.7-times the level of those found in patients who recovered from COVID-19. This morning, the two companies published additional data regarding its candidate, BNT162b1. The vaccine produced high, dose level-dependent neutralizing antibodies against SARS-CoV-2 and RBD-binding IgG concentrations after the second date. The titers of neutralizing antibodies were comparable to a group of convalescent antibody titers from patients who recovered from COVID-19. A Phase IIb/III program is expected to being this month with 30,000 patients. BioNTech Chief Executive Officer Ugur Sahin predicted that, if the late-stage research goes smoothly, the vaccine could be ready for regulatory approval by the end of 2020, with about 100 million doses ready for immediate use. By the end of 2021, Sahin said the companies could manufacture about 1.2 billion doses of the vaccine candidate.
Moderna’s mRNA vaccine candidate also showed positive results in its early-stage study. The Massachusetts company developed neutralizing antibodies similar to what has been observed in people who had naturally recovered from COVID-19. A Phase III study is expected to begin by the end of this month. Moderna has also promised to manufacture hundreds of millions of doses if it proves to be effective against the virus in the late-stage study.