Researchers Not Giving Up On Imbokodo HIV Vaccine Study

PERSISTENT researchers feel the halted HTVN 702 study on the efficacy of an HIV vaccine will not affect the Imbokodo Vaccine Trial study launched in 2017.

By Kudakwashe Pembere

HVTN  702 study was stopped following an interim analysis conducted on 23 January 2020 by an independent Data and Safety Monitoring Board (DSMB) that reviews all data regularly to ensure the safety of participants and determine if the study should continue. The DSMB assessment concluded that the experimental vaccine regimen used in the trial did not prevent HIV infection. The vaccine did not increase or decrease the risk of acquiring HIV. Additionally, the DSMB expressed no concerns related to the safety of study participants.

The HVTN 702 study, also called Uhambo, meaning travel or a journey in Zulu, enrolled 5,407 HIV-negative volunteers at 14 sites across South Africa, beginning in 2016. Participants were sexually active men and women aged 18 to 35 years, who were randomly assigned to receive six injections over 18 months of either the investigational vaccine regimen or a placebo.

A Zimbabwean researcher from the UZ College of Health Sciences, Clinical Trials Research Centre Dr Portia Hunidzarira at a Media Science Café organised by the Humanitarian Information Facilitation Centre (HFIC) on Tuesday said,

This is not the result for which we had so urgently hoped. However, a negative result still advances the science. We still believe that a safe and effective HIV vaccine is an achievable goal and is needed to address the epidemic. This result is specific to this particular vaccine regimen in this study population and should not be generalized to other HIV vaccine candidates or other prevention tools.”   she said. “Other global efforts underway in pursuit of a safe and globally effective preventive HIV vaccine and we will continue working to  achieve this goal ”.

One of the HIV vaccine studies currently ongoing is called HVTN 705 also known as Imbokodo which comes from an African proverb, “You strike a woman, you strike a rock.”  Imbokodo is testing an experimental vaccine regimen designed to offer protection against a variety of global HIV strains. This study is now fully enrolled, with 2,637 healthy, HIV-negative women in South Africa, Malawi, Mozambique, Zambia, and Zimbabwe between the ages of 18-35 years.

Dr Hunidzarira said they expect the results for this study by end of 2022.

“Imbokodo study is ongoing in Sub Saharan Africa and as Zimbabwe we are the exciting to be a part of this trial that can potentially lead us to a global HIV vaccine. Just to a reminder , HTVN 702 study used a different vaccine from the one being tested in Imbokodo so the result of HTVN702 do not affect Imbokodo study,” she said.

Another HIV vaccine study although not occurring in Sub-Saharan Africa is testing the same vaccine used in Imbokodo but in a different population and it is called the Mosaico study.   The study team aims to enroll 3,800 cisgender men and transgender people between the ages of 18-60 years who have sex with cisgender men and/or transgender people. The study will take place at 57 trial sites in Argentina, Brazil, Italy, Mexico, Peru, Poland, Spain and the U.S.  Cisgender means denoting or relating to a person whose sense of personal identity and gender corresponds with their birth sex.

“This study started a bit later than Imbokodo, but they are using the same product. The study is expected to conclude 2023 a year after we get the Imbokodo results,” she said.

Zimbabwe is also participating in the The Antibody Mediated Prevention (AMP) study whose results are expected late 2020.

“This is a proof-of-concept study to see whether antibodies can be used to prevent an individual from getting HIV infection”.

“The Antibody Mediated Prevention (AMP) study is being done in sub Saharan Africa and Zimbabwe is one of the sites, and also in  Brazil, Peru, the US, and Switzerland. So to date, this study is fully enrolled, with 4,625 healthy, HIV-negative populations consisting of: 1) women in Sub-Saharan Africa between the ages of 18-40 years; and 2) men and transgender individuals in the Americas and Switzerland between the ages of 18-50 years who have sex with men the women in Sub Saharan Africa, and the men and transgender individuals in the Americas and Switzerland.

“The two studies are underway in 11 countries: Botswana, Brazil, Kenya, Malawi, Mozambique, Peru, South Africa, Switzerland, Tanzania, United States and Zimbabwe, “said Dr Hunidzarira.

Advocacy Core Team Coordinator Mr Chamunorwa Mashoko said despite the saddening results of the Uhambo study, this calls for SADC leaders to show financial and political will  in the establishment of an HIV research centre.

The latest trial of a vaccine against HIV was early this month been halted because interim results showed it not working, as announced by the the National Institutes of Health in the United States.

“An HIV vaccine is essential to end the global pandemic, and we hoped this vaccine candidate would work. Regrettably, it does not,” said the director of the National Institute of Allergy and Infectious Diseases, Anthony S. Fauci. “Research continues on other approaches to a safe and effective HIV vaccine, which I still believe can be achieved.”

“The people of South Africa have made history by answering this important scientific question. Sadly, we wish the answer was different,” said Glenda Gray, president of the South African Medical Research Council and the study’s chair of protocol. “We will continue to explore promising avenues for preventing HIV with other vaccines and tools, both in South Africa and around the world.”

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