The University of Queensland (UQ) on Friday announced that it has stopped the further development of its COVID-19 vaccine candidate as several participants in the early-stage trials generated antibodies for HIV after receiving the potential therapeutic. The university said in a statement that there were no serious adverse events or safety concerns reported in the 216 participants of the phase 1 trial of the v451 COVID-19 vaccine candidate being developed in collaboration with biotech company CSL.
However, data showed that some patients developed antibodies towards fragments of a HIV protein (gp41), which was used to stabilise the vaccine, it said. Following consultation with the Australian Government, UQ and CSL decided not to progress the vaccine candidate to phase 2 and 3 clinical trials, according to the statement.
UQ said the trial participants were fully informed of the possibility of a partial immune response to this protein component, however, it was unexpected that the antibody levels induced would interfere with certain HIV tests. The university said there is no possibility the vaccine causes infection, and routine follow-up tests confirmed there is no HIV virus present.
The decision was taken after the makers consulted experts who worked out the ”implications” that this issue presents to rolling out the vaccine into broad populations, it said. The University of Queensland commenced the phase 1 trial of v451 in July 2020, to assess its safety and immunogenicity in healthy volunteers.
It said the vaccine candidate has shown that it elicits a robust response towards the novel coronavirus and has a strong safety profile. However, significant changes would need to be made to well-established HIV testing procedures in the healthcare setting to accommodate the rollout of this vaccine, according to the statement.
Although the makers have abandoned further trials, the university said the phase 1 trial will continue, to assess how long the HIV antibodies persist, adding studies so far show that the levels are already falling. The University of Queensland also plans to submit the full data for peer-review publication. UQ vaccine co-lead, Professor Paul Young, said that although it was possible to re-engineer the vaccine, the team did not have the luxury of time needed.
”Doing so would set back development by another 12 or so months, and while this is a tough decision to take, the urgent need for a vaccine has to be everyone’s priority, Young said. ”I said at the start of vaccine development that there were no guarantees, but what is really encouraging is that the core technology approach we used has passed the major clinical test. It is a safe and well-tolerated vaccine, producing the strong virus-neutralising effect that we were hoping to see,” he said.
Andrew Nash, Chief Scientific Officer for CSL noted that 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. UQ Vice-Chancellor, Professor Deborah Terry, said while the outcome was disappointing, she was immensely proud of the UQ team who had shouldered a heavy burden of responsibility while the world watched on.