HIV issue cans vaccine
Phase 2/3 clinical trials for the UQ/CSL vaccine will no longer proceed.
The Federal Government had committed to purchasing the vaccine, with agreements to secure 51 million doses if it proved successful.
The University of Queensland and CSL say that following consultation with the Australian Government, they will not progress the vaccine candidate to the next level of trials, after some trial participants returned false positive HIV test results.
The Phase 1 trial data showed the generation of antibodies directed towards fragments of a protein (gp41), which is a component used to stabilise the vaccine.
Trial participants were informed of the possibility of a partial immune response to this component, but the university says it was unexpected that the levels induced would interfere with certain HIV tests.
“There is no possibility the vaccine causes infection, and routine follow up tests confirmed there is no HIV virus present,” UQ said in a statement.
With advice from experts, CSL and UQ have worked through the implications that this issue presents to rolling out the vaccine into broad populations.
“It is 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,” UQ says.
“Therefore, CSL and the Australian Government have agreed vaccine development will not proceed to Phase 2/3 trials.”
The Phase 1 trial will continue, where further analysis of the data will show how long the antibodies persist, with studies so far showing that levels are already falling.
The University of Queensland says it 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,” he 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.
“So we will continue to push forward and we are confident that with further work the Molecular Clamp technology will be a robust platform for future vaccine development here in Australia and to meet future biosecurity needs.”