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AstraZeneca Oxford

AstraZeneca Oxford COVID-19 Vaccine (AZD1222) Updates

  • January 5, 2021: The Medicines and Healthcare products Regulatory Agency (MHRA) in the United Kingdom published the full Public Assessment Report for the AstraZeneca vaccine candidate, AZD1222. It can be accessed here.
  • December 30, 2020: The Medicines and Healthcare products Regulatory Agency (MHRA) in the United Kingdom granted temporary approval for the AstraZeneca vaccine candidate, AZD1222, to be used in the UK. The conditions for the approval are available here. The Information for Healthcare Professionals sheet contains information from the interim analyses reported on November 23, 2020. To the best of our knowledge, findings from the final efficacy analyses are not yet available.
  • November 30, 2020: Since AstraZeneca released the findings from the first interim analysis for its COVID-19 vaccine candidate, AZD1222, on November 23rd, it has been reported that the most promising finding announced by the company (90% efficacy among people who received a half dose of the vaccine, followed by a full dose one month later) occurred by mistake. No one in the study was supposed to receive a half dose of the vaccine before the full dose. A company spokesperson quoted by Reuters said that all participants were supposed to receive two full doses of the vaccine. However, that does not match the information the company provided in ClinicalTrials.Gov. According to ClinicalTrials.Gov, the study being conducted in the United Kingdom was designed to test: (1) a single full dose of the vaccine; (2) a single full dose of the vaccine, followed by a half dose “booster” 4-6 weeks later; (3) two full doses of the vaccine, separated by a 4-6 week period; and (4) a single half dose vaccine for children age 5-12. The study being conducted in Brazil was designed to test: (1) a single full dose of the vaccine and (2) two full doses of the vaccine, separated by a 4-12 week period.In addition, after the company released its interim findings, it was discovered that only participants who were 55 years old or younger had received the half dose vaccine. So, we have no way to know if the vaccine would have been equally effective in older adults, who are most likely to develop severe COVID-19.Astra-Zeneca did not initially disclose the dosing mistake, contending that it didn’t matter whether the dosing change was done on purpose or not. However, it does matter!Scientific studies are designed to test specific hypotheses. These hypotheses must be stated at the start of the study, before any data are collected. If the scientists discover other interesting things when they are conducting the study, they use these discoveries to develop new hypotheses and design new studies to test them. That is simply how the scientific process works. For this reason, the 90% efficacy reported for people who received the half dose vaccine should be viewed with skepticism.Notably, AstraZeneca has not published the full protocols for the studies being conducted in the United Kingdom or Brazil. Hopefully, they will make these available to the public soon. It would also be helpful to see the interim findings broken down by: (1) country (United Kingdom/Brazil), (2) age groups identified in the ClinicalTrials.Gov records for these studies, and (3) each dosing regimen examined.Despite these concerns, the interim analyses suggest that the 2 full dose regimen of AZD1222 may reduce the risk of developing symptomatic COVID-19 by 62%. This is better than the minimal threshold of 50% efficacy recommended by the Food and Drug Administration (FDA). Although this level of efficacy is lower than the vaccines developed by Pfizer and Moderna, the AstraZeneca vaccine can be stored at normal refrigerator temperatures (36-46° F) for at least six months and is less expensive to manufacture than the Pfizer and Moderna vaccines. Therefore, the AstraZeneca vaccine still has the potential to play a significant role in bringing the COVID-19 pandemic under control.
  • November 23, 2020: AstraZeneca announced results from an interim analysis of its COVID-19 vaccine candidate, AZD1222. The analysis included data from studies being conducted in the United Kingdom and Brazil. A total of 131 COVID-19 cases were included in the interim analysis. The company reported findings from two different dosing regimens. Among participants who received a half-dose of the vaccine, followed by a full dose one month later, vaccine efficacy was 90%. Among participants who received a full dose of the vaccine followed by a full dose one month later, vaccine efficacy was 62%. These findings are difficult to interpret because data from two countries were combined and different dosage regimens are being tested in these countries. It would be helpful to have the efficacy estimates reported separately for each country. In addition, in both countries, the studies are also evaluating the efficacy of a single dose regimen. No data concerning the effectiveness of the single dose regimen were reported.  
  • November 5, 2020: First results from Phase 3 trials for the AstraZeneca Oxford COVID-19 vaccine, AZD1222, are expected in the fourth quarter of 2020. (Note: This link opens to a slide presentation in pdf format. Information about AZD1222 appears on Slides 25 and 31.)
  • October 23, 2020: Clinical trials for the AstraZeneca Oxford COVID-19 vaccine candidate, AZD1222, resumed in the United States after the Food and Drug Administration (FDA) completed review of all safety data from trials being conducted around the world and determined that it was safe to resume the trial.
  • October 2, 2020: A Phase I/II clinical trial for the AstraZeneca Oxford COVID-19 vaccine candidate, AZD1222, resumed in Japan, with approval of the Japanese Pharmaceuticals and Medical Devices Agency (PMDA). Trials had previously been resumed in the United Kingdom, Brazil, South Africa, and India.
  • September 12, 2020: Clinical trials for the AstraZeneca Oxford coronavirus vaccine candidate, AZD1222, resumed in the United Kingdom after the Medicines Health Regulatory Authority (MHRA) determined that it was safe to do so.
  • September 9, 2020: A participant in a clinical trial for the AstraZeneca Oxford COVID-19 vaccine candidate, AZD1222, developed an unexplained illness. The illness was identified as part of standard procedures used in all clinical trials to ensure the safety of study participants. Immediately after the illness was identified, the developers voluntarily paused all clinical trials of the vaccine being conducted around the world. In an interview with NBC News, Dr. Francis Collins, Director of the National Institutes of Health, identified the illness as transverse myelitis and explained that the illness may not have been caused by the vaccine. In large clinical trials, illnesses often happen by chance. This pause in the study will allow data safety committees and regulatory agencies like the FDA an opportunity to review data from the trials to determine if it is safe to continue enrolling participants.
  • August 31, 2020: Enrollment began in the US Phase 3 trial for the AstraZeneca Oxford COVID-19 vaccine candidate, AZD1222.  Phase 3 trials of AZD1222 had begun previously in the UK, Brazil and South Africa.

Around the World

  • October 1, 2020: The European Medicines Agency (EMA) announced that it had started a “rolling review” of data from studies involving AstraZeneca’s vaccine candidate, AZD1222. The EMA is the equivalent of the Food and Drug Administration in the United States. According to the EMA announcement, “A rolling review is one of the regulatory tools that EMA uses to speed up the assessment of a promising medicine or vaccine during a public health emergency. Normally, all data on a medicine’s effectiveness, safety and quality and all required documents must be submitted at the start of the evaluation in a formal application for marketing authorisation. In the case of a rolling review, EMA’s human medicines committee (CHMP) reviews data as they become available from ongoing studies, before a formal application is submitted. Once the CHMP decides that sufficient data are available, the formal application should be submitted by the company. By reviewing the data as they become available, the CHMP can reach its opinion sooner on whether or not the medicine or vaccine should be authorised.”