ViiV Healthcare announces superior efficacy of investigational, long-acting injectable formulation of cabotegravir dosed every two months over daily oral PrEP

Final data analysis from HPTN 083 study at AIDS 2020 shows investigational, long-acting injectable cabotegravir administered every two months is 66% more effective than daily pills in preventing HIV-1 acquisition

London, 7 July 2020 – ViiV Healthcare, the global specialist HIV company majority owned by GSK, with Pfizer Inc. and Shionogi Limited as shareholders, today announced that data presented from the HIV Prevention Trials Network (HPTN) 083 study demonstrated the superior efficacy of investigational, long-acting, injectable cabotegravir administered every two months when compared to daily oral emtricitabine/tenofovir disoproxil fumarate 200 mg and 300 mg (FTC/TDF) tablets for HIV prevention.

HPTN 083 is a Phase IIb/III randomized, multicentre, double-blind, clinical trial that is evaluating the safety and efficacy of long-acting, injectable cabotegravir for HIV pre-exposure prophylaxis (PrEP) among men who have sex with men (MSM) and transgender women who have sex with men. The blinded phase of the study was stopped early in May 2020 following a pre-planned independent Data and Safety Monitoring Board review, which showed that long-acting cabotegravir was highly effective at preventing HIV in the study population. Final analysis has since confirmed the superiority of long-acting cabotegravir, which was 66% more effective at preventing HIV when compared to daily oral FTC/TDF tablets. Study results were announced today at a press conference at the virtual 23^rd International AIDS Conference (AIDS 2020) and will be presented at the conference on 8 July.

Kimberly Smith, M.D., MPH, Head of Research & Development at ViiV Healthcare, said: “These data are truly ground-breaking, demonstrating that long-acting injectable cabotegravir dosed every two months is superior to daily oral FTC/TDF at preventing HIV in at-risk men and transgender women who have sex with men. This advancement has the potential to be a game-changer for HIV prevention, offering an option with very high rates of effectiveness and the convenience of reduced dosing from daily to just six times per year. We are thrilled with the results not only because of the high effectiveness of cabotegravir but also because this study adequately represents some of the populations most disproportionately impacted by HIV -- black MSM in the US, young MSM globally and transgender women.”

In the final data analysis, 52 documented cases of HIV were observed in the HPTN 083 trial, with 13 cases occurring in the long-acting cabotegravir arm and 39 cases occurring in the daily, oral FTC/TDF arm. This translated to an HIV incidence rate of 0.41% in the cabotegravir group (95% confidence interval [CI] 0.22%-0.69%) and 1.22% in the FTC/TDF group (95% CI 0.87%-1.67%). Preliminary assessment of adherence to oral FTC/TDF was high, based on a random subset of 372 FTC/TDF participants that measured any detectable (> 0.31 ng/ml) tenofovir in 87% of participants and concentrations consistent with daily dosing levels (> 40 ng/ml) in 75% of all samples tested. Despite this high level of adherence to oral therapy, long-acting cabotegravir demonstrated superiority in the primary efficacy endpoint of documented HIV incident infections, and was 66% (95% CI 38%-82%) more effective than FTC/TDF in preventing HIV acquisition in the study population. 

Long-acting cabotegravir and FTC/TDF tablets were both well tolerated throughout the study, with most adverse events being mild or moderate in nature and balanced between both treatment arms. Injection site reactions, pyrexia, and hypertension were more common in the cabotegravir arm while nausea was more common in the FTC/TDF arm. Most participants in the cabotegravir group (80%) reported pain or tenderness at the injection site, compared to 31% of those in the FTC/TDF arm, who received placebo injections.  Discontinuation due to injection site reactions or injection intolerance in the cabotegravir arm of the study was 2.2% and there were no discontinuations due to ISRs in the FTC/TDF arm.

The HPTN 083 study enrolled HIV-negative men and transgender women who have sex with men, participants considered at increased risk for HIV acquisition. Two-thirds of study participants were under 30 years of age (median age of 26 years), and 12% were transgender women (n=567). Half of the participants in the United States identified as Black or African American (n=844).