Gilead Up as Twice-Yearly HIV Shot Prevents Infection

Gilead Sciences, Inc. GILD announced upbeat top-line results from an interim analysis of its late-stage study PURPOSE 1.

PURPOSE 1 is a phase III, double-blind, randomized study 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 years across 25 sites in South Africa and three sites in Uganda.

Both the drugs are being tested simultaneously. While one group received twice-yearly lenacapavir, the other was given once-daily oral Descovy parallelly. In addition, a third group was assigned once-daily oral Truvada (emtricitabine 200mg and tenofovir disoproxil fumarate 300mg; F/TDF).

All the study participants were randomized to receive lenacapavir, Descovy and Truvada in a 2:2:1 ratio.

Top-line results indicate that the company's twice-yearly injectable HIV-1 capsid inhibitor, lenacapavir, demonstrated 100% efficacy for the investigational use of HIV prevention in cisgender women. There were zero incident cases of HIV infection among 2,134 women in the lenacapavir group and 16 incident cases among 1,068 women in the Truvada group.

Thus, PURPOSE 1 study achieved its key efficacy endpoints of the superiority of twice-yearly lenacapavir to once-daily oral Truvada and background HIV incidence (bHIV). Results demonstrated the superiority of twice-yearly lenacapavir over bHIV (primary endpoint) and that of twice-yearly lenacapavir over once-daily Truvada (secondary endpoint).

On the basis of these results, the independent Data Monitoring Committee recommended that Gilead stop the blinded phase of the trial and offer open-label lenacapavir to all participants.

Shares of Gilead rose 8.46% on these strong study results as twice-yearly lenacapavir demonstrated its potential as a new tool to help prevent HIV infections with zero infections and 100% efficacy.

Per Gilead, this is the first phase III HIV prevention study ever to show zero infections.  Lenacapavir was generally well-tolerated without any significant or new safety concerns.

HIV incidence in the Descovy group was numerically similar to that in the Truvada group and was not statistically superior to bHIV.

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.

Another pivotal trial, PURPOSE 2, 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. 

Results from this study are expected in late 2024 or early 2025.  Gilead stated that the regulatory filing for lenacapavir for PrEP will include the results of both PURPOSE 1 and PURPOSE 2, if positive. This will ensure that lenacapavir for PrEP can be approved for multiple populations and communities most in need of additional HIV prevention options.

In the year-to-date period, shares of Gilead have lost 15.4% compared with the industry's decline of 7.8%.

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Gilead is a dominant player in the HIV market. The company developed the first single-tablet regimen to treat HIV, the first antiretroviral for PrEP, to help reduce new HIV infections, and the first long-acting injectable HIV treatment medication administered twice yearly.

PrEP, or pre-exposure prophylaxis, is a medicine taken by people at risk for HIV to prevent getting HIV from sex or injection drug use. PrEP can stop HIV from taking hold and spreading throughout the body. PrEP can be pills or shots.

At present, there are two FDA-approved daily oral medications for PrEP — Truvada and Descovy.

Please note that Descovy for PrEP is indicated in at-risk adults and adolescents (≥35 kg) to reduce the risk of sexually acquired HIV-1 infection, excluding individuals at risk from receptive vaginal sex.

The development and approval of lenacapavir should solidify GILD's HIV franchise, as lenacapavir needs to be taken twice yearly, unlike daily oral pills.

A long-acting injectable form of PrEP was also approved by the FDA. In 2021, the regulatory body approved ViiV Healthcare's Apretude (cabotegravir extended-release injectable suspension) for use in at-risk adults and adolescents weighing at least 35 kilograms for PrEP to reduce the risk of sexually acquired HIV.

ViiV Healthcare is a global specialist HIV company, majorly owned by GSK plc GSK, with Pfizer and Shionogi as shareholders.

Apretude is given first as two initiation injections administered a month apart and then every two months thereafter. Patients in need can either start their treatment with Apretude or take oral cabotegravir (Vocabria) for four weeks to understand how well they tolerate the drug.

GSK is a key competitor for GILD in the HIV market. It recorded double digit growth for its HIV franchise in the first quarter, primarily driven by strong patient demand for it oral two-drug regimen (Dovato and Juluca) and long-acting medicines (Cabenuva, Apretude).

Zacks Rank & Stocks to Consider

Gilead currently carries a Zacks Rank #3 (Hold). A couple of better-ranked stocks from the biotech sector are Ligand Pharmaceuticals LGND and ALX Oncology Holdings ALXO, each carrying a Zacks Rank #2 (Buy) at present.

In the past 30 days, the Zacks Consensus Estimate for Ligand's 2024 earnings per share has increased 15 cents to $4.71. During the same time frame, the consensus estimate for 2025 EPS has increased 70 cents to $5.90. Year to date, shares of LGND have risen 11.8%.

Ligand beat on earnings in each of the trailing four quarters, delivering an average surprise of 56.02%.

In the past 60 days, the Zacks Consensus Estimate for ALX Oncology's 2024 loss per share has narrowed from $3.33 to $2.89. During the same period, the consensus estimate for 2025 loss per share has narrowed from $2.85 to $2.73.

ALX Oncology beat on earnings in two of the trailing four quarters and missed the mark in the other two, delivering an average negative surprise of 8.83%.

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