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

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 randomised, 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).

Myron S. Cohen, M.D., Co-Principal Investigator of the HPTN and the Yeargan-Bate Distinguished Professor of Medicine, Microbiology and Immunology and Epidemiology at the University of North Carolina (UNC) at Chapel Hill, said: "Medicines that help prevent new HIV incidence are essential to our ongoing global fight to end the HIV epidemic. It's exciting to discover that with injectable, long-acting cabotegravir, we now have compelling clinical evidence of another effective PrEP option that could play a critical role in helping to reduce HIV transmission that will ultimately save lives."

HPTN 083 was jointly funded by the U.S. NIAID, part of the NIH, and ViiV Healthcare, and was conducted by the HPTN. Study product was provided by ViiV Healthcare and Gilead Sciences.

In addition to the findings of HPTN 083, an additional study evaluating the safety and efficacy of long-acting cabotegravir for HIV prevention is being conducted in sexually active women (HPTN 084). To date, more than 3,000 sexually active women in seven African countries have enrolled in HPTN 084, which is co-funded by NIAID, ViiV Healthcare and the Bill Melinda Gates Foundation.

ViiV Healthcare plans to use the data from HPTN 083 for future regulatory submissions. Cabotegravir has not yet been approved for the treatment or prevention of HIV as a single agent by regulatory authorities anywhere in the world.

About HPTN 083 (NCT02720094)
The HPTN 083 study is a phase IIb/III double-blind study designed to evaluate the safety and efficacy of long-acting injectable cabotegravir for HIV prevention administered every eight weeks compared to daily oral FTC/TDF tablets (200 mg/300 mg). Each participant was to receive a maximum of three years of blinded study medication. The study opened to enrolment in November 2016. HPTN 083 was conducted in approximately 4,566 men who have sex with men and transgender women who have sex with men at research centres in Argentina, Brazil, Peru, United States, South Africa, Thailand and Vietnam.

For further information on HPTN 083 please visit https://clinicaltrials.gov/ct2/show/NCT02720094.

About HIV Prevention Trials Network (HPTN)
The HIV Prevention Trials Network (HPTN) is a worldwide collaborative clinical trials network that brings together investigators, ethicists, community members and other partners to develop and test the safety and efficacy of interventions designed to prevent the acquisition and transmission of HIV. The National Institutes of Health (NIH), the National Institute of Mental Health (NIMH) and the National Institute on Drug Abuse (NIDA) co-fund the HPTN. The HPTN has collaborated with more than 85 clinical research sites in 19 countries to evaluate new HIV prevention interventions and strategies in populations that bear a disproportionate burden of infection. The HPTN research agenda more than 50 trials ongoing or completed with over 161,000 participants enrolled and evaluated is focused primarily on the use of antiretroviral drugs (antiretroviral therapy and pre-exposure prophylaxis); and integrated strategies including interventions for substance abuse, particularly injection drug use; behavioural risk reduction interventions and structural interventions. For more information, visit hptn.org.

About ViiV Healthcare
ViiV Healthcare is a global specialist HIV company established in November 2009 by GlaxoSmithKline (LSE: GSK) and Pfizer (NYSE: PFE) dedicated to delivering advances in treatment and care for people living with HIV and for people who are at risk of becoming infected with HIV. Shionogi joined in October 2012. The company's aim is to take a deeper and broader interest in HIV/AIDS than any company has done before and take a new approach to deliver effective and innovative medicines for HIV treatment and prevention, as well as support communities affected by HIV.

For more information on the company, its management, portfolio, pipeline and commitment, please visit www.viivhealthcare.com.

About GSK
GSK is a science-led global healthcare company with a special purpose: to help people do more, feel better, live longer. For further information please visit www.gsk.com/about-us.

Cautionary statement regarding forward-looking statements
GSK cautions investors that any forward-looking statements or projections made by GSK, including those made in this announcement, are subject to risks and uncertainties that may cause actual results to differ materially from those projected. Such factors include, but are not limited to, those described under Item 3.D "Risk Factors" in the company's Annual Report on Form 20-F for 2019 and any impacts of the COVID-19 pandemic.

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