The long-acting injectable antiretroviral drug cabotegravir, which is being developed by the National Institute of Allergy and Infectious Diseases (NIAID) as a potential for pre-exposure prophylaxis (PrEP) in those at risk of contracting human immunodeficiency virus (HIV), may be preferable to the currently approved PrEP, Gilead’s Truvada (emtricitabine/tenofovir disoproxil fumarate).
The integrase inhibitor is administered as an injection every two months. It showed meaningful protection against contracting HIV in a large-scale study that was ultimately disrupted by the Covid-19 pandemic. The trial, which is being sponsored by NIAID, began in 2016 and enrolled more than 4,500 participants worldwide who were randomly assigned to Truvada, cabotegravir, placebo pills, or placebo injections. As of 12 April, the cabotegravir group had 12 HIV infections versus 38 in the equally sized Truvada group. Their incidence of HIV was 0.38% in the cabotegravir arm versus 1.21% in the Truvada arm, representing a 69% difference in new infections. These data have yet to be published.
The study, HPTN 083, has 43 sites in the US, South Africa, Argentina, Brazil, Peru, Vietnam, and Thailand. However, due to the Covid-19 pandemic, 11 of the sites have been forced to close. Other sites are struggling due to difficulties in participant enrolment.
GlobalData believes that although the results of this study did not show cabotegravir to be statistically superior to Truvada, it did demonstrate that the drug works as well as Truvada. Additionally, a preventative long-acting injectable given once every two months may be more favourable than taking a daily pill. Because an individual may forget to take the pill every day, the injectable may increase drug compliance and may be more ideal for participants. Additionally, an injectable gives the option of another form of therapy if patients cannot or do not want to take a pill.
Furthermore, the results have shown that cabotegravir is also more effective than Truvada, as only 12 participants on cabotegravir were infected, whereas 38 participants on Truvada were infected. Although Truvada is one of only two approved options for PrEP, GlobalData expects that if cabotegravir gains approval, it could become preferred as it has a significant reduction in the frequency of drug administration and increased efficacy in preventing HIV infection. While it is still unclear whether individuals will respond positively to taking an injection over a pill, a majority of those at risk of contracting HIV are likely to favour cabotegravir’s reduced administration frequency.