Only about week after the release of Moderna’s Phase III interim results, Astra Zeneca published the interim results from its Phase 3 clinical trial of AZD1222.
The AZD1222 vaccine was co-invented by University of Oxford and its spin out, Vaccitech and is being developed under collaboration with University of Oxford. It utilized replication-deficient chimpanzee viral vector–based on a weakened version of adenovirus that contains the spike protein of SARS-CoV-2 virus. After vaccination, the surface spike protein is produced, priming the immune system to attack the virus if it later infects the body.
Astra Zeneca’s press release of the interim clinical trial analysis of AZD1222 in the UK (COV002) and Brazil (COV003) showed the vaccine met the primary end point by preventing COVID-19. No hospitalisations or severe cases of the disease were reported in the participants receiving the vaccine.
There were two dosing regimens tested among 11,636 participants of which 2,741 participants with were administered half dose, followed by a full dose at least one month apart and 8,895 participants administered with two full doses at least one-month apart. While the former group showed 90% efficacy, the latter group showed 62% efficacy, resulting in an average of 70.4% efficacy. An Independent Data Safety Monitoring Board (DSMB) assessed the vaccine efficacy on patients after 14 days or more post receiving two doses of the vaccine and AZD1222 was well tolerated across both dosing regimens. There was a total of 131 COVID-19 cases in the interim analysis with no serious safety events. Over 23,000 participants are being assessed over the two dosing regimens in COV002 Phase II/III trial in the UK and COV003 Phase III trial in Brazil aged 18 years and above from diverse racial and geographic groups.
The trials are presently are also being conducted in the US, Japan, Russia, South Africa, Kenya and Latin America along with other Asian and European countries. The company expects to enrol up to 60,000 patients globally. While the technology of AZD1222 is different from Moderna and Pfizer’s m-RNA vaccines, Astra Zeneca indicated that AZD1222 can be stored, transported and handled at normal refrigerated conditions (2-8 degrees Celsius/ 36-46 degrees Fahrenheit) for at least six months addressing a major logistic hurdle for vaccine delivery unlike the other two vaccines which require sub-zero temperatures.