Long-acting cabotegravir significantly decreases incidence of HIV compared to daily oral tenofovir

1. Cabotegravir was shown to be superior to TDF-FTC in preventing HIV infection in women.

2. Both drugs were well tolerated and had similar adverse effects; however, there was a greater incidence of injection site reactions in the cabotegravir group.

Evidence Rating Level: 1 (Excellent)

Study Rundown: HIV pre-exposure prophylaxis (PrEP), including oral tenofovir diphosphate plus emtricitabine (TDF-FTC), is available across sub-Saharan Africa. Unfortunately, many factors can contribute to poor compliance which may reduce the efficacy of these drugs. This phase 3 drug study evaluated the efficacy of a long-acting injection, cabotegravir, compared to daily TDF-FTC. Participants were randomly assigned 1:1 and received sham-controls of the non-assigned drug. The HIV incidence in the cabotegravir group was significantly lower than the TDF-FTC group. The study also demonstrated through drug screening blood tests that in the TDF-FTC group, daily drug compliance was less than 50%. Adverse events were similar between the two groups, except injection site reactions which were more frequent in the cabotegravir group. Limitations of this study include the lack of monitoring for oral daily pill taking; however, this provided an interesting finding in of itself. This study provides promising evidence for a safe, long-acting PrEP which could be used as an alternative to daily oral medication.

Click to read the study in the Lancet

Relevant Reading: HIV pre-exposure prophylaxis for adolescent girls and young women in Africa: from efficacy trials to delivery

In-Depth [randomized controlled trial]: HPTN 084 is a phase 3, randomized HIV prevention drug superiority trial across seven countries in sub-Saharan Africa. Eligible female participants were aged 18-45, at risk of HIV infection based on a risk score, reported at least two episodes of vaginal intercourse in the past 30 days, and consented to a long-acting contraceptive method. 3224 patients were randomized 1:1 to either cabotegravir injection with TDF-FTC placebo pill or TDF-FTC pill with cabotegravir injection placebo. The median age of participants was 25 years. The initial treatment plan was 5 weeks orally of both drugs to confirm cabotegravir tolerability before injection formulation. The injection was given at weeks 5, 9, and every 8 weeks thereafter. The following tail phase was open-label oral TDF-FTC daily for 48 weeks.

Participants were monitored and tested for HIV at each follow-up visit. The HIV incidence in the cabotegravir group (0.2 cases per 100 person-years [0.06-0.52]) was significantly lower than the TDF-FTC group (1.82 cases per 100 person-years [1.3-2.57]; hazard ratio 0.12, p<0.0001). A randomly selected 405 of the TDF-FTC group had tenofovir levels tested, 42.1% of blood samples demonstrated consistent daily use. Injection site reactions were more frequent in the cabotegravir group (38.0% vs. 10.7%) compared to placebo injection; however, they did not affect treatment.

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