Phase III Double-blind, Placebo-controlled Study of AZD1222 for the Prevention of COVID-19 in Adults
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ClinicalTrials.gov Identifier: NCT04516746 |
Recruitment Status :
Completed
First Posted : August 18, 2020
Results First Posted : April 1, 2022
Last Update Posted : April 7, 2023
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Condition or disease | Intervention/treatment | Phase |
---|---|---|
COVID-19 SARS-CoV-2 | Biological: AZD1222 Biological: Placebo | Phase 3 |
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 32459 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Intervention Model Description: | Participants are assigned to one of two or more groups in parallel for the duration of the study. |
Masking: | Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor) |
Masking Description: | Double Blind: two or more parties are unaware of the intervention assignment. |
Primary Purpose: | Treatment |
Official Title: | A Phase III Randomized, Double-blind, Placebo-controlled Multicenter Study in Adults, to Determine the Safety, Efficacy, and Immunogenicity of AZD1222, a Non-replicating ChAdOx1 Vector Vaccine, for the Prevention of COVID-19 |
Actual Study Start Date : | August 28, 2020 |
Actual Primary Completion Date : | March 5, 2021 |
Actual Study Completion Date : | February 10, 2023 |

Arm | Intervention/treatment |
---|---|
Experimental: AZD1222
Approximately 20,000 participants randomized to the AZD1222 arm
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Biological: AZD1222
AZD1222 is a recombinant replication-defective chimpanzee adenovirus expressing the SARS-CoV-2-5 surface glycoprotein. |
Placebo Comparator: Placebo
Approximately 10,000 participants randomized to the saline placebo arm
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Biological: Placebo
Commercially available 0.9% (n/V) saline for injection. |
- Number of Participants Achieving Binary Response [ Time Frame: From 15 days post second dose up to DCO of 05 March 2021 or study discontinuation or unblinding or receipt of non-study COVID-19 vaccination, up to a maximum of 17 weeks ]A binary response, whereby a participant with negative serostatus at baseline is defined as a COVID-19 case if their first case of SARS-CoV-2 RT-PCR-positive symptomatic illness occurs ≥ 15 days post second dose of study intervention. Otherwise, a participant is not defined as a COVID-19 case. The primary efficacy analysis was performed once approximately 150 events meeting the primary efficacy outcome measure definition had occurred across the AZD1222 and placebo groups.
- Number of Participants With Adverse Events (AEs) Occurring Post Each Dose of Study Intervention [ Time Frame: From Day 1 up to 28 days post second dose of study intervention, approximately 57 days ]An AE is the development of any untoward medical occurrence in a clinical study participant administered medicinal product and which does not necessarily have a causal relationship with this medicinal product. An AE can therefore be any unfavorable and unintended sign, symptom, or disease temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product.
- Number of Participants With Serious Adverse Events (SAE), Medically Attended Adverse Events (MAAE), and Adverse Event of Special Interest (AESI) Occurring Throughout the Study [ Time Frame: From Day 1 up to DCO of 05 March 2021 or study discontinuation or unblinding or receipt of non-study COVID-19 vaccination, up to a maximum of approximately 27 weeks ]An SAE is an AE occurring during any study phase that fulfils one or more of the following criteria: death; immediately life-threatening; in-participant hospitalization or prolongation of existing hospitalization; persistent or significant disability or incapacity; congenital abnormality or birth defect; an important medical event. AESIs were events of scientific and medical interest specific to the further understanding of the study intervention safety profile and required close monitoring and rapid communication by the investigators to the sponsor. MAAEs are defined as AEs leading to medically-attended visits that were not routine visits for physical examination or vaccination, such as an emergency room visit, or an otherwise unscheduled visit to or from medical personnel (medical doctor) for any reason.
- Number of Participants With Local and Systemic Solicited AEs in the Substudy Only [ Time Frame: From Day 1 up to 7 days post each dose of study intervention, approximately 14 days ]Solicited AEs are local or systemic predefined events for assessment of reactogenicity. Solicited AEs were collected in a e-Diary only for participants in the substudy.
- Number of Participants With First Post-intervention Response for SARS-CoV-2 Nucleocapsid Antibodies Occurring Post Second Dose of Study Intervention [ Time Frame: From 15 days post second dose up to DCO of 05 March 2021 or study discontinuation or unblinding or receipt of non-study COVID-19 vaccination, up to a maximum of 17 weeks ]The incidence of the first post-intervention response (negative at baseline to positive post intervention with study intervention) for SARS-CoV-2 nucleocapsid antibodies occurring ≥ 15 days post second dose of study intervention (key secondary endpoint).
- Number of Participants With First COVID-19 Symptomatic Illness Using Centers for Disease Control and Prevention (CDC) Criteria Occurring Post Second Dose of Study Intervention [ Time Frame: From 15 days post second dose up to DCO of 05 March 2021 or study discontinuation or unblinding or receipt of non-study COVID-19 vaccination, up to a maximum of 17 weeks ]The incidence of the first case of SARS-CoV-2 RT-PCR-positive symptomatic illness occurring ≥ 15 days post second dose of study intervention using CDC criteria. Participant must present with at least one of the following symptoms per CDC criteria: fever, shortness of breath, difficulty breathing, chills, cough, fatigue, muscle aches, body aches, headache, new loss of taste, new loss of smell, sore throat, congestion, runny nose, nausea, vomiting, or diarrhea.
- Number of Participants With First COVID-19 Symptomatic Illness Using University of Oxford-Defined Symptom Criteria Occurring Post Second Dose of Study Intervention [ Time Frame: From 15 days post second dose up to DCO of 05 March 2021 or study discontinuation or unblinding or receipt of non-study COVID-19 vaccination, up to a maximum of 17 weeks ]The incidence of the first case of SARS-CoV-2 RT-PCR-positive symptomatic illness occurring ≥ 15 days post second dose of study intervention using University of Oxford-defined symptom criteria: new onset of fever (> 100 °Fahrenheit [> 37.8 °Celsius]), cough, shortness of breath, or anosmia/ageusia.
- Number of Participants With First Symptomatic COVID-19 Regardless of Evidence of Prior SARS-CoV-2 Infection Occurring Post Second Dose of Study Intervention [ Time Frame: From 15 days post second dose up to DCO of 05 March 2021 or study discontinuation or unblinding or receipt of non-study COVID-19 vaccination, up to a maximum of 17 weeks ]The incidence of the first case of SARS-CoV-2 RT-PCR-positive symptomatic illness occurring ≥ 15 days post second dose of study intervention regardless of evidence of prior SARS-CoV-2 infection (key secondary endpoint).
- Number of Participants With COVID-19 Severe or Critical Symptomatic Illness Occurring Post Second Dose of Study Intervention [ Time Frame: From 15 days post second dose up to DCO of 05 March 2021 or study discontinuation or unblinding or receipt of non-study COVID-19 vaccination, up to a maximum of 17 weeks ]The incidence of SARS-CoV-2 RT-PCR-positive severe or critical symptomatic illness occurring ≥ 15 days post second dose of study intervention. The severity of COVID-19 was evaluated in participants with symptoms of COVID-19. Following are the findings regarding severe of critical symptomatic COVID-19: clinical signs at rest indicative of severe systemic illness; respiratory failure; evidence of shock; significant acute renal, hepatic, or neurologic dysfunction; admission to an intensive care unit; and death (key secondary endpoint).
- Number of Participants With COVID-19 Severe or Critical Symptomatic Illness Occurring Post First Dose of Study Intervention [ Time Frame: From Day 1 up to DCO of 05 March 2021 or study discontinuation or unblinding or receipt of non-study COVID-19 vaccination, up to a maximum of approximately 27 weeks ]The incidence of SARS-CoV-2 RT-PCR-positive severe or critical symptomatic illness occurring post first dose of study intervention. The severity of COVID-19 was evaluated in participants with symptoms of COVID-19. Following are the findings regarding severe of critical symptomatic COVID-19: clinical signs at rest indicative of severe systemic illness; respiratory failure; evidence of shock; significant acute renal, hepatic, or neurologic dysfunction; admission to an intensive care unit; and death.
- Number of Participants With COVID-19-Related Emergency Department Visits Occurring Post Second Dose of Study Intervention [ Time Frame: From 15 days post second dose up to DCO of 05 March 2021 or study discontinuation or unblinding or receipt of non-study COVID-19 vaccination, up to a maximum of 17 weeks ]The incidence of COVID-19-related emergency department visits occurring ≥ 15 days post second dose of study intervention (key secondary endpoint).
- Geometric Mean Titers (GMTs) for SARS-CoV-2 Spike (S) and Receptor Binding Domain (RBD) Antibodies as Measured by Meso Scale Discovery (MSD) Serology Assay [ Time Frame: Baseline (Day 1) and Days 15, 29, 43, and 57 ]The GMT was calculated as the antilogarithm of Σ(log base 2 transformed titer/n), i.e. as the anti-logarithm transformation of the mean of the log-transformed titer, where 'n' is the number of participants with titer information.
- Geometric Mean Fold Rise (GMFR) for SARS-CoV-2 S and RBD Antibodies as Measured by MSD Serology Assay [ Time Frame: Baseline (Day 1) and Days 15, 29, 43, and 57 ]The fold rise was calculated as the ratio of the post-vaccination titer level to the pre-vaccination titer level. GMFR was calculated as anti-logarithm of Σ (log base 2 transformed (post-vaccination titer/ pre-vaccination titer)/n). Where 'n' is the number of participants with titer information.
- Percentage of Participants With Seroresponse to the S and RBD Antigens of AZD1222 as Measured by MSD Serology Assay [ Time Frame: Baseline (Day 1) and Days 15, 29, 43, and 57 ]The fold rise was calculated as the ratio of the post-vaccination titer level to the pre-vaccination titer level. The percentage of participants with a post-intervention seroresponse (≥ 4-fold rise in titers from baseline value to 28 days post each dose) to the S and RBD antigens of AZD1222 as measured by MSD serology assay is reported.
- GMTs for SARS-CoV-2 Neutralizing Antibodies as Measured by Pseudo-neutralization Assay [ Time Frame: Baseline (Day 1) and Days 15, 29, 43, and 57 ]The GMT was calculated as the antilogarithm of Σ(log base 2 transformed titer/n), i.e. as the anti-logarithm transformation of the mean of the log-transformed titer, where 'n' is the number of participants with titer information.
- GMFR for SARS-CoV-2 Neutralizing Antibodies as Measured by Pseudo-neutralization Assay [ Time Frame: Baseline (Day 1) and Days 15, 29, 43, and 57 ]The fold rise was calculated as the ratio of the post-vaccination titer level to the pre-vaccination titer level. GMFR was calculated as anti-logarithm of Σ (log base 2 transformed (post-vaccination titer/ pre-vaccination titer)/n). Where 'n' is the number of participants with titer information.
- Percentage of Participants With Seroresponse to SARS-CoV-2 Neutralizing Antibodies of AZD1222 as Measured by Pseudo-neutralization Assay [ Time Frame: Baseline (Day 1) and Days 15, 29, 43, and 57 ]The fold rise was calculated as the ratio of the post-vaccination titer level to the pre-vaccination titer level. The percentage of participants with a post-intervention seroresponse (≥ 4-fold rise in titers from baseline value to 28 days post each dose) to SARS-CoV-2 neutralizing antibodies of AZD1222 as measured by pseudo-neutralization assay is reported.
- Number of Participants With COVID-19 Symptomatic Illness Occurring Post First Dose of Study Intervention [ Time Frame: From Day 1 up to DCO of 05 March 2021 or study discontinuation or unblinding or receipt of non-study COVID-19 vaccination, up to a maximum of approximately 27 weeks ]The incidence of SARS-CoV-2 RT-PCR-positive symptomatic illness occurring post first dose of study intervention.

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Ages Eligible for Study: | 18 Years to 130 Years (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
- Increased risk of SARS-CoV-2 infection
- Medically stable
Exclusion Criteria:
- confirmed or suspected immunosuppressive or immunodeficient state
- significant disease, disorder, or finding
- Prior or concomitant vaccine therapy for COVID-19

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04516746

Principal Investigator: | Ann Falsey, MD | University of Rochester | |
Principal Investigator: | Magda Sobieszczyk, MD | Columbia University |
Documents provided by AstraZeneca:
Publications:
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: | AstraZeneca |
ClinicalTrials.gov Identifier: | NCT04516746 |
Other Study ID Numbers: |
D8110C00001 |
First Posted: | August 18, 2020 Key Record Dates |
Results First Posted: | April 1, 2022 |
Last Update Posted: | April 7, 2023 |
Last Verified: | March 2023 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | Yes |
Plan Description: | Qualified researchers can request access to anonymized individual patient-level data from AstraZeneca group of companies sponsored clinical trials via the request portal. All request will be evaluated as per the AZ disclosure commitment: https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure |
Supporting Materials: |
Study Protocol Statistical Analysis Plan (SAP) |
Time Frame: | AstraZeneca will meet or exceed data availability as per the commitments made to the EFPIA Pharma Data Sharing Principles. For details of our timelines, please rerefer to our disclosure commitment at https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure |
Access Criteria: | When a request has been approved AstraZeneca will provide access to the de-identified individual patient-level data in an approved sponsored tool . Signed Data Sharing Agreement (non-negotiable contract for data accessors) must be in place before accessing requested information. Additionally, all users will need to accept the terms and conditions of the SAS MSE to gain access. For additional details, please review the Disclosure Statements at https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure |
URL: | https://astrazenecagroup-dt.pharmacm.com/DT/Home |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
COVID-19 Vaccine |
COVID-19 Pneumonia, Viral Pneumonia Respiratory Tract Infections Infections Virus Diseases |
Coronavirus Infections Coronaviridae Infections Nidovirales Infections RNA Virus Infections Lung Diseases Respiratory Tract Diseases |