– First Phase 3 HIV Prevention Trial to Show Zero Infections –

– Independent Data Monitoring Committee Recommended That Gilead Stop the Blinded Phase of the PURPOSE 1 Trial at Interim Analysis and Offer Open-Label Lenacapavir to All Participants –

MISSISSAUGA, ON, June 26, 2024 /CNW/ - Gilead Sciences Canada announced topline results from an interim analysis of its pivotal, Phase 3 PURPOSE 1 trial indicating that the company's twice-yearly injectable HIV-1 capsid inhibitor, lenacapavir, demonstrated 100 per cent efficacy for the investigational use of HIV prevention in cisgender women.

HIV remains an epidemic in Canada, with six Canadians dying on average every week of HIV-related illnesses and 35 more diagnosed with HIV each week.ⁱ While currently available oral HIV prevention options can reduce the risk of acquiring sexually transmitted HIV by more than 90 per cent when taken as prescribed,ⁱⁱ barriers remain including low awareness of transmission behaviours and prevention, recurring medication use, stigma and discrimination.ⁱⁱⁱ

PURPOSE 1 met its key efficacy endpoints of superiority of twice-yearly lenacapavir to once-daily oral Truvada^® (emtricitabine 200mg and tenofovir disoproxil fumarate 300mg; F/TDF) and background HIV incidence (bHIV). Based on these results, the independent Data Monitoring Committee (DMC) recommended that Gilead stop the blinded phase of the trial and offer open-label lenacapavir to all participants.

"With early data showing zero infections and 100 per cent efficacy, twice-yearly lenacapavir has potential as a new option to prevent HIV transmission," said Wendy Arnott, Executive Director of Medical Affairs, Gilead Sciences Canada. "We remain focused on our goal of ending the HIV epidemic globally and here in Canada. We look forward to seeing further results from the PURPOSE clinical program."

These are the first data generated from Gilead's landmark PURPOSE program, which is the most comprehensive and diverse HIV prevention trial program ever conducted. The PURPOSE program comprises five HIV prevention trials around the world that are focused on innovation in science, trial design, community engagement and health equity.

Topline PURPOSE 1 data

PURPOSE 1, a Phase 3, double-blind, randomized study, is evaluating the safety and efficacy of twice-yearly, subcutaneous lenacapavir for pre-exposure prophylaxis (PrEP) and once-daily oral Descovy^® (emtricitabine 200mg and tenofovir alafenamide 25mg; F/TAF) in more than 5,300 cisgender women and adolescent girls aged 16-25 across 25 sites in South Africa and three sites in Uganda. The drugs are being tested in parallel, with one group receiving twice-yearly lenacapavir and one group taking once-daily oral Descovy. Additionally, a third group was assigned once-daily oral Truvada. Study participants were randomized in a 2:2:1 ratio to lenacapavir, Descovy and Truvada, respectively. Because effective PrEP options already exist, there is broad consensus in the PrEP field that a placebo group would be unethical; thus, the trial used bHIV as the primary comparator and Truvada as a secondary comparator.

There were 0 incident cases of HIV infection among 2,134 women in the lenacapavir group (incidence 0.00 per 100 person-years). There were 16 incident cases among 1,068 women in the Truvada group (incidence 1.69 per 100 person-years). The results demonstrated superiority of twice-yearly lenacapavir over bHIV (primary endpoint, incidence 2.41 per 100 person-years) and superiority of twice-yearly lenacapavir over once-daily Truvada (secondary endpoint), with p<0.0001 for both endpoints. In the trial, lenacapavir was generally well-tolerated and no significant or new safety concerns were identified.

HIV incidence in the Descovy group was numerically similar (39 incident cases among 2,136 women, incidence 2.02 per 100 person-years) to that in the Truvada group and was not statistically superior to bHIV. Previous clinical trials among cisgender women have commonly found challenges with adherence to daily oral pills for PrEP, and adherence analyses for Descovy and Truvada from PURPOSE 1 are ongoing. In the trial, both Descovy and Truvada were generally well-tolerated and no new safety concerns were identified. More detailed data from PURPOSE 1 will be presented at a future conference.

The use of lenacapavir and the use of Descovy for the prevention of HIV in cisgender women are investigational and have not been determined to be safe or efficacious and are not approved anywhere globally.

In Canada, Truvada^® is indicated in combination with safer sex practices for PrEP to reduce the risk of sexually acquired HIV -1 infection in adults at high risk.^iv

Descovy^® is indicated for pre-exposure prophylaxis (PrEP) to reduce the risk of sexually acquired HIV-1 in at-risk adults and adolescents weighing ≥ 35 kg, excluding individuals at risk from receptive vaginal sex.^v

Additional PURPOSE trials assessing twice-yearly lenacapavir for PrEP are ongoing

Gilead expects results in late 2024/early 2025 from the program's other pivotal trial, PURPOSE 2, which is assessing twice-yearly lenacapavir for PrEP among cisgender men who have sex with men, transgender men, transgender women and gender non-binary individuals who have sex with partners assigned male at birth in Argentina, Brazil, Mexico, Peru, South Africa, Thailand and the United States. The regulatory filing for lenacapavir for PrEP will include the results of both PURPOSE 1 and PURPOSE 2, if positive, in order to ensure lenacapavir for PrEP can be approved for multiple populations and communities most in need of additional HIV prevention options.

Gilead is committed to partnering with communities that are disproportionately affected by HIV in their respective countries and regions, and community input on the PURPOSE trials has been instrumental in factors ranging from program design to participant recruitment strategies. This kind of collaborative approach will continue to help Gilead implement clinical trials with rigor, innovation and intentional inclusion of communities that have historically been underrepresented in HIV prevention research. It will also help bolster the post-implementation science activities that Gilead will conduct for PURPOSE 1 and future successful trials. More information about the PURPOSE program can be found at Clinicaltrials.gov.

Important Safety Information about TRUVADA^®

For all important safety information for TRUVADA, including conditions of clinical use, contraindications, warnings and precautions, adverse reactions and drug interactions, please see the Canadian Product Monograph at www.gilead.ca.

Important Safety Information about DESCOVY^®

Safety and efficacy of DESCOVY for HIV-1 PrEP in children weighing <35 kg have not been established.

DESCOVY does not prevent other sexually transmitted infections or cure HIV infection or AIDS.

The DESCOVY Product Monograph includes a Serious Warnings and Precautions Box:

Post-treatment Exacerbation of Hepatitis B Virus: DESCOVY is not approved for the treatment of chronic hepatitis B virus (HBV) infection and the safety and efficacy of DESCOVY have not been established in individuals infected with HBV. Discontinuation of DESCOVY therapy in individuals infected with HBV may be associated with severe acute exacerbations of hepatitis due to the emtricitabine (FTC) or tenofovir alafenamide (TAF) components of DESCOVY. Hepatic function should be monitored closely with both clinical and laboratory follow-up for at least several months in individuals infected with HBV who discontinue DESCOVY. If appropriate, initiation of anti-hepatitis B therapy may be warranted.

Risk of Drug Resistance with Use of DESCOVY for HIV-1 PrEP in Undiagnosed Early HIV-1 Infection: DESCOVY used for HIV-1 PrEP must only be prescribed to individuals confirmed to be HIV-negative immediately prior to initiating and at least every 3 months during use. Drug-resistant HIV-1 variants have been identified with use of FTC/TDF for HIV-1 PrEP following undetected acute HIV-1 infection. Do not initiate DESCOVY for HIV-1 PrEP if signs or symptoms of acute HIV-1 infection are present unless negative infection status is confirmed.

The safety and efficacy of DESCOVY for HIV-1 PrEP in individuals at risk from receptive vaginal sex have not been studied.

DESCOVY should not be coadministered with products containing any of the same components, or with products containing lamivudine or tenofovir disoproxil fumarate. In addition, DESCOVY should not be administered with adefovir dipivoxil.

For all important safety information for DESCOVY, including contraindications, additional warnings and precautions, adverse reactions and drug interactions, please see the Canadian Product Monograph at www.gilead.ca.

About Gilead Sciences

Gilead Sciences, Inc. is a biopharmaceutical company that has pursued and achieved breakthroughs in medicine for more than three decades, with the goal of creating a healthier world for all people. The company is committed to advancing innovative medicines to prevent and treat life-threatening diseases, including HIV, viral hepatitis, COVID-19 and cancer. Gilead operates in more than 35 countries worldwide, with headquarters in Foster City, California. For more information, visit https://gilead.ca 

For more information about Gilead, please visit the company's website at https://www.gilead.ca/, follow Gilead on Twitter (@Gilead Sciences) and LinkedIn, or email Gilead Public Affairs at publicaffairscanada@gilead.com.

SOURCE Gilead Sciences, Inc.