The Strength of Women
The Imbokodo Study launches in Southern Africa
by Jeannie Wraight
In Zulu, the word “Imbokodo” means “rock” and is part of a well-known Zulu proverb that translates to “you strike a woman, you strike a rock,” referring to the strength of a woman and her importance in the community. Imbokodo is also now the name of a new preventive vaccine clinical trial enrolling 2,600 sexually active women, ages eighteen to thirty-five, in Southern Africa.
“We are excited that South Africa has started [enrolling] and is ahead of schedule. We are very proud of the people locally who are so motivated to make this happen,” stated Dr. Hanneke Schuitemaker, PhD, VP and Global Head of Viral Vaccine Discovery and Translational Medicine at Janssen Vaccines. Dr. Schuitemaker was present for the opening of one of the South African clinics where the Imokodo study will take place, and was emotionally moved by the willingness of the volunteers to participate in the vaccine trial and the motivations behind their dedication. “These were young girls who when asked why they were participating, said it was for their communities. Because they’ve seen enough of HIV and want it to end.”
The large-scale, NIH- and Gates Foundation-backed clinical trial has been launched to evaluate the safety and efficacy of a preventive vaccine designed to protect against all strains of HIV. The multi-country, HIV Treatment Network Study (HVTN) is sponsored by Janssen Vaccines & Prevention BV, a part of Janssen Pharmaceutical Companies of Johnson & Johnson.
The study will evaluate a combination of two vaccines—the prime vaccine Ad26.Mos4.HIV (Ad26 vaccine) and adjuvant Clade C gp140 (protein vaccine).
Ad26 is made from a weakened strain of the adenovirus type 26 which is the virus responsible for colds and upper respiratory infections. In its altered state, it is unable to cause infection from either the adenovirus or from HIV. HIV antigens from different subtypes are inserted into the adenovirus to elicit an immune response. By doing so, the immune system becomes primed to recognize and quickly attack HIV, hopefully preventing HIV infection.
The Clade C gp140 contains envelope proteins and an aluminum adjuvant to boost immune responses.
Participants will receive 4 injections of the Ad26 vaccine at months 0, 3, 6 and 12, as well as two injections of the protein vaccine given simultaneously with the AD26 vaccine at months 6 and 12. The vaccines have been shown to be safe with no serious adverse events seen in earlier studies.
The vaccine used in the Imbokodo study is one of seven “mosaic” vaccine regimens studied in the NIH-sponsored APPROACH study. In this study, various regimens that contained components of the Ad26 vaccine were evaluated. Most of the regimens showed high levels of immunogenicity. The regimen that showed the highest level of immune response, as well as dual success in animal studies, was selected for further evaluation in the Imbokodo study.
In addition, the vaccine is currently being studied in a smaller ongoing vaccine trial called TRAVERSE in which it is being compared to a similar AD26 vaccine containing 3 mosaic antigens verses the four antigens in the Imbokodo vaccine. The adjunct protein virus is used in both arms. Results have thus far shown both vaccines to be safe and able to elicit anti-HIV immune responses.
Enrollment for the South African sites of the five-country clinical trial is complete, and participants have begun receiving their first injections. The study will also enroll women in Malawi, Mozambique, Zambia and Zimbabwe, pending regulatory approval. There will be a total of twenty-six sites throughout the five countries.
The rate of HIV prevalence in women in Southern and Eastern Africa is extremely high. The 2017 UNAIDS report “When Women Lead, Change Happens” stated that “[w]omen accounted for 59% of all adults aged 15 years and older living with HIV in eastern and southern Africa, and the rate of new HIV infections remained high among young women aged 15–24 years. There were approximately 4,500 new HIV infections weekly among young women in the region, which is double the number seen in young men.”
According to Dr. Schuitemaker, in addition to the high HIV prevalence among women in Southern and Eastern Africa, researchers felt that women in many of the targeted areas showed a higher likelihood of completing the entire study and follow-up than did their male counterparts. Experiences with other clinical trials in these regions suggest men are more often lost to follow-up due, in part, to relocation for employment and transient work such as truck driving.
Components from Janssen’s adenovirus platform similar to the vaccine regimen used in the Imbokodo study, have also shown promise as a potential therapeutic vaccine. A study performed in primates, and detailed in Nature Magazine (www.nature.com/articles/nature20583) showed the AD26 virus in conjunction with the modified vaccinia virus Ankara (MVA) and an immune stimulant TLR7, elicited strong immunogenicity in SIV infected primates. According to researchers of the study the vaccine combo “resulted in decreased levels of viral DNA in lymph nodes and peripheral blood, and improved virologic control and delayed viral rebound following discontinuation of antiretroviral therapy.”
Results from the Imbokodo study are expected in 2021.
Jeannie Wraight is the former editor-in-chief and co-founder of HIV and HCV Haven (www.hivhaven.com) and a blogger and writer for TheBody.com. She is a member of the Board of Directors of Health People, a community-based organization in the South Bronx and an advisor to TRW (Teach me to Read and Write), a community-based organization in Kampala, Uganda. She lives with her husband in New York City.