A Phase III study of AstraZeneca and University of Oxford’s COVID-19 vaccine candidate is temporarily on hold while the pharmaceutical company investigates whether a recipient’s illness is a side effect of the shot or unrelated, the pharma giant announced Wednesday.
AstraZenca said the pause is a voluntary, routine action that occurs whenever there is a potentially unexplained illness during a clinical trial. To maintain the integrity of a trial, any illness must be investigated before reopening, if that is the ultimate outcome.
“At AstraZeneca we put science, safety and the interests of society at the heart of our work. This temporary pause is living proof that we follow those principles while a single event at one of our trial sites is assessed by a committee of independent experts. We will be guided by this committee as to when the trials could restart, so that we can continue our work at the earliest opportunity to provide this vaccine broadly, equitably and at no profit during this pandemic,” said Pascal Soriot, AstraZeneca’s CEO.
The unexplained illness occurred in the UK, and was isolated to a single event. Best case scenario: the participant experienced an illness event unrelated to the vaccine or COVID-19, and the trial will be restarted shortly. Worst case scenario: the illness is a side effect of the vaccine, severe enough to halt testing altogether.
The AZD1222 vaccine was co-invented by the University of Oxford and its spin-out company, Vaccitech. It uses a replication-deficient chimpanzee viral vector based on a weakened version of adenovirus that causes infections in chimpanzees and contains the genetic material of the SARS-CoV-2 virus spike protein. After vaccination, the surface spike protein is produced, priming the immune system to attack the SARS-CoV-2 virus if it later infects the body.
AZD122 expanded into a Phase III clinical trial at the end of August after interim results from Phase I/II trial showed the vaccine produced antibodies in around 90% of participants with no severe adverse events reported. Mild to moderate side effects, such as fever, headaches and muscles aches, appeared in 60% of patients but were solved before the end of the trial.
The multi-site Phase III trials aims to enroll 30,000 volunteers at 80 sites across the U.S. AstraZeneca is also testing the vaccine in thousands of volunteers in the UK, Brazil and South Africa. The pharmaceutical giant recently received $1.2 billion in funding for 300 million doses as part of Operation Warp Speed, a multi-agency effort to fast-track coronavirus vaccines.
The trial pause comes just a day after nine pharmaceutical CEOs came together to sign a historic pledge to “uphold the integrity of the scientific process” as the companies work toward a potential COVID-19 vaccine. AstraZenca’s Soriot signed the pledge, in addition to the CEOs of BioNTech, GlaxoSmithKline, Johnson & Johnson, Moderna, Novavax, Merck, Pfizer and Sanofi.
“We, the undersigned biopharmaceutical companies, want to make clear our ongoing commitment to developing and testing potential vaccines for COVID-19 in accordance with high ethical standards and sound scientific principles,” the pledge reads.
The CEOs committed to:
- Always making the safety and well-being of vaccinated individuals top priority
- Continuing to adhere to high scientific and ethical standards regarding the conduct of clinical trials and the rigor of manufacturing processes
- Only submitting for approval or emergency use authorization after demonstrating safety and efficacy through a Phase 3 clinical study that is designed and conducted to meet requirements of expert regulatory authorities, such as FDA
- Work to ensure a sufficient supply and range of vaccine options, including those suitable for global access
“We believe this pledge will help ensure public confidence in the rigorous scientific and regulatory process by which COVID-19 vaccines are evaluated and may ultimately be approved,” the pharmaceutical CEOs wrote.