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Injectable anti-HIV drug signals hope for prevention

By Clifford Akumu
Monday, August 17th, 2020
Belianne Onyango, a HIV and PrEP advocate in Homa Bay conducts a sesion on PrEP. Photo/PD/Clifford Akumu
In summary

A study testing the medication and comparing it against the oral pill currently in use shows increased efficacy, with experts saying it is a step in the right direction…

Hopes have been renewed after an injectable antiretroviral, the HIV pre-exposure prophylaxis (PrEP), showed it could protect certain populations against the virus that causes Aids. 

The United States National Institute of Allergy and Infectious Diseases (NIAD), the HIV Prevention Trials Network and ViiV Healthcare announced recently that a bi-monthly injection of cabotegravir (CAB-LA) is effective in preventing HIV infection than the daily oral PrEP, under the name Truvada. 

Truphena Adoyo*, a PrEP user is happy. Adoyo, 24, from Arujo village, Homa Bay county, who started using oral pills two and a half years ago, knew it was a start of a new dawn

“It has not been a walk in the park... Since I started taking the pills, I am able to take control of my sex life,” said Adoyo.

These findings demonstrated safety and efficacy raising hopes of “high potential for an additional HIV prevention tool.” 

Prof Kenneth Ngure from the Jomo Kenyatta University of Agriculture and Technology’s School of Public Health said the clinical trial indicated the injectable PrEP is more superior to the daily oral pill. 

“This is exciting news for people at risk of HIV infection,” said Prof Ngure, a researcher with keen interest in HIV-self testing and antiretroviral based HIV prevention, especially PrEP. 

These promising early news, Prof Ngure noted during the Media for Environment, Science, Health and Agriculture in Kenya monthly science café held recently, is signaling a clear path that, “In the not so distant future, we may have an additional HIV prevention method, which is long-acting and could be especially desirable for people who have challenges in taking daily pills.”

The long-acting injectable is administered after every two months. The idea behind PrEP is simple: high-risk persons who are HIV-negative take Truvada, normally prescribed to patients already infected, to prevent the virus from taking hold.

The study, known as HPTN 083, is the first trial to compare the efficacy of the injectable CAB-LA to daily oral Truvada for HIV PrEP. It enrolled 4,570 cisgender (people who identify with their gender) men who have sex with men and transgender women (men assigned as female at birth) who have sex with men at 43 sites in Brazil, Argentina, Peru, United States, Thailand, Vietnam and South Africa. 

Two-thirds of study participants were under 30 years old, and 12 per cent were transgender women. 

In the study, participants were assigned randomly to either the CAB-LA or oral Truvada group.

In each group the participants received both injections and oral tablets: one active drug and one placebo (not active drug or anything that seems to a ‘real’ medical treatment) to maintain the blinded nature of the study. 

According to the study, whose results was the hallmark of AIDS 2020 conference, out of 52 participants who got HIV infection during the trial, 13 were given  the long-acting injectable CAB-LA and 39 took the daily oral Truvada. 

Simply put, the number of incident HIV infections was approximately three times in the Truvada group than in the CAB-LA one, demonstrating that the latter, administered every eight weeks is highly effective for the prevention of HIV acquisition in cisgender men and transgender women. 

Experts agree that to help eliminate HIV, additional treatment and prevention options are needed to improve uptake and continuation across different individuals. 

Good alternative

In Kenya close to 2,000 facilities are offering PrEP services to an estimated over 20,000 current users.

Overall about 63,000 Kenyans have used PrEP since it was launched in Kenya three years ago, according to latest figures from PrEP Watch, recently launched by Aids Vaccine Advocacy Coalition, the organisation working to accelerate ethics development and distribution of an Aids vaccine. 

Professor Ngure noted that for some, taking a daily pill can be challenging thus impacting on adherence of antiretroviral therapy (ART), and PrEP negatively.  Adoyo agrees.

“Injectable PrEP will be a good alternative for those who want to take HIV prevention discretely,” she said.

“A long-acting injectable for PrEP that does not require adherence to an oral daily pill is a great addition to the HIV prevention toolbox,” said Beatriz Grinsztejn, protocol co-chair in the HPTN 083 study.

“Prevention strategies have never been one-size-fits-all,” added Grinsztejn in a statement. 

Mitchell Warren, AVAC executive director said in a statement, “This is encouraging news for the HIV prevention field. We need additional prevention options to help people protect themselves from HIV.” 

Noting that the HPTN 083 study did not include women, Prof Ngure said a sister study, HPTN 084, will provide more data of safety and efficacy of the injectables for women in sub- Saharan Africa.

“This now remains an urgent priority for many communities where women are at very high risk of HIV infection and have few options for HIV prevention,” he noted.

HPTN 084, is comparing the efficacy and safety of injectable to daily oral pill among women aged 18 to 45 years old in Botswana, Kenya, Malawi, South Africa, Swaziland, Uganda and Zimbabwe.  

Other tools

The HPTN 083 is not the only HIV prevention tool that has shown progress.

And more great news for HIV prevention; the European Medicines Agency has adopted a positive opinion for the Dapivirine vaginal ring, which moves far closer to approval in African countries, where women and girls are at a high risk of contracting HIV.

Additionally, a new HIV prevention implant (islatravir/MK-8591) that can provide protection for up to one year has demonstrated safety in an early phase study and will soon be moving to testing for efficacy and safety in larger studies, making the field look even brighter, said Ngure. 

“I foresee the HIV prevention field looking like the family planning field where people at risk of contracting HIV will have multiple products to choose from that fit within their lifestyle just like what women currently do with contraceptives,” he said. 

Despite PrEP being a key intervention in the prevention of HIV infection, adherence is still a big challenge.

Belianne Onyango, a HIV and PrEP advocate based in Homa Bay county, lamented that misconceptions are a major contributor to youths discontinuing PrEP use, especially adolescent girls and young women. 

“Many people believe that PrEP is meant for sex workers and many don’t want to be associated with sex work,” she said, adding that even parents associate the drug with prostitution, thus discouraging the youth from taking it. 

“Everyone should get to understand PrEP. It is not meant for sex workers only. Anybody who feels they are at risk should feel free to take it,” Onyango said.

The side effects of the drug also pose a challenge for adolescents and young women, who opt to discontinue use instead of feeling uncomfortable. 

“I started taking PrEP with some colleagues; unfortunately, I am now the only one using it,” said Adoyo.

“When we started using it, we felt dizzy, and would vomit a lot. This made many people discontinue it,” she added, noting healthcare workers attitude is also a turn off.

Prof Ngure said only about one out of 10 people experience these transient side effects. 

“The side effects are often mild, associated with vomit and diarrhoea and experienced mainly in the first one month.

We counsel anyone experiencing those challenges and tell them to bear with them for one month,” he said.

*An earlier version of this article indicated that the Dapivirine vaginal ring was still under regulatory approval by the European Medicines Agency. The ring received a positive opinion from the agency.