Opinion & Columnist

Further Evidence: Long-acting injectable cabotegravir prevents HIV infection in women

Roselyne Sachiti Features, Health and Society Editor

• CAB was superior to TDF/FTC; women in the CAB group had an 89 percent lower risk of HIV infection compared to the TDF/FTC group, likely because of the adherence advantage conferred by 8 weekly injections
• Updated data confirm CAB as the first safe and effective injectable HIV prevention agent for cisgender women (people whose gender identity matches their sex assigned at birth).

• CAB was superior to TDF/FTC; women in the CAB group had an 89 percent lower risk of HIV infection compared to the TDF/FTC group, likely because of the adherence advantage conferred by 8 weekly injections

In the midst of the Covid-19 pandemic, women, especially in sub Saharan Africa also burdened by HIV and Aids and most vulnerable have something to smile about.

Today, important advances in HIV prevention research were announced at the 4th HIV Research for Prevention Conference (HIVR4P // Virtual), convened by IAS – the International AIDS Society.

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The most exciting highlights for women who have been waiting with bated breath are findings from a pair of trials evaluating whether infusions with a broadly neutralizing antibody (bNAb) can prevent HIV acquisition and positive interim results from a study of long-acting injectable pre-exposure prophylaxis (PrEP) in women.

Final updated results from the blinded phase of the HPTN 084 trial, including new data on weight gain, pregnancy, and STI incidence, provide further evidence that a PrEP regimen of long-acting injectable cabotegravir (CAB) is safe and superior to daily oral tenofovir/emtricitabine (TDF/FTC) in preventing HIV among cisgender women in Africa.

“COVID-19 has disrupted research around the world, so it’s especially exciting to see this new progress,” said IAS President Adeeba Kamarulzaman.

“These research advances on options like broadly neutralizing antibodies and injectable PrEP could help significantly strengthen our HIV prevention toolkit.”

The blinded phase of HPTN 084 was stopped early last year after an interim analysis by the trial’s data safety monitoring board. The said the trial enrolled 3,224 HIV-negative, sexually active cisgender women in sub-Saharan Africa.

Participants were randomized to either active CAB plus TDF/FTC placebo or active TDF/FTC plus CAB placebo. They received five weeks of daily oral product followed by intramuscular injections every eight weeks after an initial four-week interval load, alongside daily oral pills.

According to presenter Sinead Delany-Moretlwe of the University of the Witwatersrand, these updated data confirm CAB as the first safe and effective injectable HIV prevention agent for cisgender women (people whose gender identity matches their sex assigned at birth).
Highlights:
• CAB and TDF/FTC were both highly effective in preventing HIV. A total of 40 HIV
infections were observed (4 in the CAB group; 36 in the TDF/FTC group) over 3,892 person-years; pooled HIV incidence was 1.03 per 100 person-years.
However, CAB was superior to TDF/FTC; women in the CAB group had an 89 percent lower risk of HIV infection compared to the TDF/FTC group, likely because of the adherence advantage conferred by 8 weekly injections
• Both products were safe and well tolerated, with few differences in Grade 2+ adverse
events by arm – apart from injection site reactions, which were higher in the CAB group but generally mild.
An immediate increase in body weight (about 0.4 kg) was observed in the CAB arm, but it was small compared to the weight gain in both arms over the course of the study (+2.4 kg / year in the CAB arm; +2.2 kg / year in the TDF/FTC arm).
• Pregnancy incidence per 100 person-years was 1.3 total (1.5 in the CAB group, 1.1 in
the TDF/FTC group); no congenital anomalies were reported.
• The incidence of chlamydia and gonorrhea was similar in both study arms; using these
STIs as a marker of risk compensation, there was no evidence of differences in risk by
arm.
These results complement those from HPTN 083, which reported last year that long-acting
injectable CAB was superior to daily oral TDF/FTC in preventing HIV among cisgender men and transgender women who have sex with men.

HERALD