AstraZeneca pauses trials after ‘unexplained illness’
Shares of AstraZeneca tumbled more than 8% in after-hours US trading following the announcement. Shares of rival vaccine developers rose with Moderna Inc. gaining more than 4%, and Pfizer around 1%.Updated: Sep 10, 2020, 00:25 IST
UK-based drugmaker AstraZeneca Plc. voluntarily suspended global trials of its experimental Covid-19 vaccine after one volunteer developed an unexplained illness on Wednesday, which experts say may delay the discovery of a vaccine, but wouldn’t necessarily set back international efforts to develop one.
“This is a routine action which has to happen whenever there is a potentially unexplained illness in one of the trials, while it is investigated, ensuring we maintain the integrity of the trials,” AstraZeneca spokesperson Michele Meixell said in a statement.
Shares of AstraZeneca tumbled more than 8% in after-hours US trading following the announcement. Shares of rival vaccine developers rose with Moderna Inc. gaining more than 4%, and Pfizer around 1%.
AstraZeneca’s vaccine candidate, which has been developed with researchers from the University of Oxford, had been in the most advanced stage multi-country trials when the abrupt suspension was announced. Trials of the vaccine, called AZD1222, were underway at different stages in the UK, US, Brazil, South Africa and India, where it has partnered with Pune-based Serum Institute of India (SII). Trials have also been planned in Japan and Russia.
SII plans to continue with its 2-3 trials in India once it gets approval from the Data and Safety Monitoring Board (DSMB) “We can’t comment much on the UK trials, but they have been paused for further review and they hope to restart soon. As far as Indian trials are concerned, it is continuing and we have faced no issues at all,” SII said in an emailed statement.
Vaccine trials were paused after a participant in the UK was diagnosed with transverse myelitis, an inflammation of the spinal cord usually caused by infections. The data will be reviewed by the DSMB, which is a panel of independent experts that monitors potential harmful effects of from experimental drugs and vaccines during clinical trials.
“A clinical trial being paused is uncommon but it has happened before in other clinical trials. There will now be an investigation by the adverse events committee of the trial to see if this is causal or coincidental. Since transverse myelitis is known to be caused by viruses, this demands a thorough review, including tests for other viruses. Till a clear determination is made, the trial has to be suspended,” said Dr K Srinath Reddy, president, Public Health Foundation of India.
Dr Anurag Agrawal, director of the Institute of Genomics and Integrative Biology, New Delhi, said the pause was a result of routine precaution and not a major setback.
“The suspension of the trial is because of just one unexplained illness. This is required by safety guidelines while the case is analysed further. Just one person having unexplained illness is not something that should make us worry unduly about vaccine safety,” said Dr Agrawal.
Dr Gagandeep Kang, professor in the department of gastrointestinal sciences at the Christian Medical College, Vellore, Tamil Nadu, agreed : “It is not a major setback as clinical holds on trials do happen to protect participants out of an abundance of caution. The DSMB will assess the data and look at relatedness to the vaccine and then take a call on how the trial should go ahead,” said Dr Kang.
Investigating whether an adverse effect is or is not be related to the vaccine must be done to establish its safety. “The trials can be resumed only if the cause of the adverse event is unrelated to the vaccine. You can compromise on efficacy and produce a vaccine that has 70% efficacy, but you can’t take a chance with 100% safety,” said Dr Randeep Guleria, director, All India Institute of Medial Sciences, New Delhi, which is one of the dozen sites for the Indian Council of Medical Research-Bharat Biotech Covaxin, which began Phase 2 trials this week.
“One adverse reaction among a few thousands could potentially mean many thousands getting sick when billions get vaccinated. Compromising on safety can potentially kill the Covid-19 vaccine programme as doubts about safety would lead to people refusing to get vaccinated when we do have a vaccine, which would be counterproductive,” said Dr Guleria.
Even misplaced fear of adverse reactions can lead to people refusing to get vaccinated, as seen in the recent past against vaccines to protect against Measles Rubella (MR), human papillomavirus (HPV) against cervical cancer, and polio, among others.
Several governments, pharmaceutical and biotech companies, and not-for-profit organisations and international partners are racing against time to develop an effective vaccine to stop the spread of Covid-19. Thirty-four experimental vaccines are undergoing clinical evaluation, and 145 are in preclinical evaluation stages within nine months of the virus being identified. Eleven candidates, including Astra Zeneca’s vaccine, are in late-stage trials, according to the World Health Organisation’s draft landscape of Covid-19 candidate vaccines on September 8.
Nine leading US and European vaccine developers on Tuesday pledged to “uphold the integrity of the scientific process as they work towards potential global regulatory filings and approvals of the first Covid-19 vaccines.” The companies included AstraZeneca, Moderna, Pfizer, Johnson & Johnson, Merck & Co Inc., GlaxoSmithKline Plc., Novavax Inc, Sanofi SA and BioNTech SE.
Apart from SII’s vaccine, two other experimental Covid-19 vaccines are in or entering late-stage trials in India. The first doses of the Phase 2-3 trials of the Indian Council of Medical Research-Bharat Biotech experimental vaccine Covaxin were given on Tuesday while Zydus Cadila’s ZyCoV-D vaccine has successfully completed Phase 1 and progressed to Phase 2.