Johnson & Johnson has completed enrolment in its phase 2b trial of its preventive HIV vaccine, setting up a readout from the much-anticipated study in 2021.
The Imbokodo trial (also known as HVTN 705), sponsored by J&J’s Janssen pharma unit, is evaluating the company’s based vaccine in 2,600 young women in five southern African countries with high rates of HIV infection.
It is estimated that women and girls account for almost two-thirds of HIV infections in eastern and southern Africa, where more than 40% of new HIV infections occur each year. Antiretroviral drugs can keep HIV under control in people already infected with the virus, but there’s still no cure and therefore a critical need for a vaccine that can prevent new infections.
The trial is testing a new approach to HIV vaccination, based on a blend or ‘mosaic’ of genes taken from a range of different subtypes of HIV found around the world. The hope is that this will stimulate a broad range of HIV-targeting antibodies that will protect women from just about any HIV strain to which they are exposed.
The high tendency of the virus to mutate means that conventional approaches to vaccine design have been ineffective, and at least four prior vaccine candidates have failed in clinical trials to date.
Janssen has tested several different formulations of mosaic-based HIV in two phase 1/2 trials, APPROACH and TRAVERSE, and based on that data selected a vaccine regimen containing four mosaic antigens (Ad26.Mos4.HIV) and a soluble protein (Clade C gp140), using aluminium phosphate as an antigen.
Imbokodo is one of three HIV vaccine vaccines currently underway. The largest is HVTN 702, which began enrolling 5,400 South African men and women in 2016 and is due to report results late next year. The regimen in that study is a modified version of the so-called Thai combination of Sanofi Pasteur’s ALVAC-HIV and GlaxoSmithKline’s bivalent gp120/MF59 that showed modest 31% efficacy in a 2009 trial.
Also ongoing are a pair of studies collectively known as AMP, which started in southern Africa, Brazil, Peru, Switzerland and the US in 2016 and are testing whether administration of broadly neutralising antibodies that bind to molecules on the HIV surface can provide passive protection against infection. The studies have completed enrolment of 4,600 subjects with results due next year.
“Achieving full enrolment in Imbokodo is an important step forward in our work to advance a universal vaccine that could ultimately help turn the tide on HIV,” said Paul Stoffels, J&J’s chief scientific officer.
In 2017, 1.8 million people were newly infected with HIV and nearly 1 million people died of AIDS, according to UNAIDS figures.
“Finding a safe and effective vaccine has proven to be one of the greatest public health challenges of our time,” added Stoffels. “J&J stands with other stakeholders in ensuring that this scientific effort remains a top global priority.”
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