The CSL Limited (ASX: CSL) share price will be one to watch on Friday after the release of an update on its COVID-19 vaccine candidate.
What did CSL announce?
This morning CSL and the University of Queensland (UQ) announced results from the Phase 1 trial of the UQ-CSL v451 COVID-19 vaccine.
According to the release, the vaccine has shown that it elicits a robust response towards the virus and has a strong safety profile.
And while there were no serious adverse events or safety concerns reported, following agreement with the Australian Government, CSL will not progress the vaccine candidate to Phase 2/3 clinical trials.
Why is it not going any further?
The release explains that the Phase 1 data showed the generation of antibodies directed towards the "molecular clamp" component of the vaccine. These antibodies interfere with certain HIV diagnostic assays.
The potential for this cross-reaction had been anticipated prior to the commencement of the trial and participants were fully informed prior to their involvement.
Blood samples from participants were tested after vaccination and it was found that these molecular clamp antibodies did cause a false positive on a range of HIV assays.
Thankfully, follow up tests confirmed that there is no HIV virus present and that it was just a false positive on certain HIV tests. It stressed that there is no possibility the vaccine causes infection.
Nevertheless, following advice from experts, CSL and UQ have worked through the implications that this issue presents to rolling out the vaccine into broad populations and generally agreed that significant changes would need to be made to well-established HIV testing procedures in the healthcare setting to accommodate rollout of this vaccine.
Therefore, CSL and the Australian Government have agreed the vaccine development will not proceed to Phase 2/3 trials.
CSL's Chief Scientific Officer, Dr Andrew Nash, commented: "This outcome highlights the risk of failure associated with early vaccine development, and the rigorous assessment involved in making decisions as to what discoveries advance."
"This project has only been made possible by the innovative science developed by world-class scientists at The University of Queensland and the strong collaboration between our organisations, and many others, over the last 10 months. CSL and Seqirus are committed to continuing our work to protect the Australian population against COVID-19."
"Manufacture of approximately 30 million doses of the Oxford/AstraZeneca vaccine candidate is underway, with first doses planned for release to Australia early next year. In addition, CSL has agreed at the request of the Australian Government to manufacture an additional 20 million doses," he concluded.
CSL advised that it doesn't expect this development to have any impact on previously provided financial guidance for FY 2021.
