ViiV Healthcare showcases leadership in long-acting injectables innovation at CROI 2025 with data on third-generation integrase inhibitor (INSTI) and highly potent capsid inhibitor against HIV-1

Rhea-AI Summary

ViiV Healthcare announced positive results from two phase IIa studies of investigational HIV therapies at CROI 2025. The studies focused on VH4524184 (VH184), a third-generation integrase inhibitor, and VH4011499 (VH499), a capsid inhibitor, both showing promise as long-acting injectable treatments.

VH184 demonstrated significant antiviral activity across three doses (10mg, 50mg, 300mg) in 22 treatment-naive adults. The 300mg dose achieved the maximum viral load decline of -2.69 log10 copies/mL. All side effects were mild to moderate with no serious adverse events.

VH499 showed positive results in 23 treatment-naive adults across doses of 25mg, 100mg, and 250mg. The highest dose (250mg) achieved a -2.2 log10 copies/mL decrease in HIV-1 viral load. The treatment was well-tolerated with only mild to moderate adverse events reported.

Positive

• Strong antiviral activity demonstrated by VH184 with -2.69 log10 viral load reduction at 300mg dose
• No drug resistance mutations observed with VH184 treatment
• VH499 achieved significant viral load reduction of -2.2 log10 copies/mL at 250mg dose
• Both compounds showed favorable safety profiles supporting further development

Negative

• One patient developed mutation associated with reduced susceptibility to capsid inhibitors on VH499 25mg dose

Insights

Financial Analyst

ViiV Healthcare, partially owned by Pfizer as a minority shareholder (with GSK as majority owner and Shionogi as another shareholder), has reported positive Phase IIa clinical results for two HIV treatment candidates. These results represent incremental progress in ViiV's pipeline of long-acting injectable HIV medications.

The first compound, VH4524184 (VH184), a third-generation integrase inhibitor, demonstrated strong antiviral activity across multiple doses, with the highest dose achieving a -2.69 log10 reduction in viral load. The second compound, VH4011499 (VH499), a capsid inhibitor, showed viral load reductions ranging from -1.8 to -2.2 log10 across different doses. Both treatments were well-tolerated with only mild to moderate side effects.

For Pfizer investors, these results represent modest positive momentum in one of the company's partial investments. As a minority stakeholder in ViiV Healthcare, Pfizer's financial exposure to these developments is proportionately compared to majority owner GSK. Additionally, these early-stage clinical results, while promising, are still several years and multiple clinical trial phases away from potential commercialization.

While long-acting injectables represent an important growth segment in HIV treatment by potentially improving patient adherence and quality of life, the actual revenue impact to Pfizer would be determined by their ownership percentage, future trial success, regulatory approval timelines, and eventual market uptake – none of which can be definitively assessed at this early stage.

• Results illustrate ViiV Healthcare’s pipeline is generating multiple options for the development of new ultra long-acting HIV regimens
• VH4524184 (VH184), a potent, investigational third-generation integrase inhibitor (INSTI), demonstrates strong antiviral activity and positive safety results across multiple dose levels in people with HIV-1, supporting further development as a long-acting injectable antiretroviral
• VH4011499 (VH499), a promising, highly potent investigational capsid inhibitor, shows positive antiviral activity and good safety findings for treatment of HIV-1, supporting further development as a long-acting antiretroviral

LONDON--(BUSINESS WIRE)-- ViiV Healthcare, the global specialist HIV company majority owned by GSK, with Pfizer and Shionogi as shareholders, today announced positive findings from two phase IIa proof-of-concept studies of investigational antiretroviral therapies VH4524184 (VH184) and VH4011499 (VH499). These findings, presented at the Conference on Retroviruses and Opportunistic Infections (CROI 2025) in San Francisco, U.S., support the continued development of these two compounds as distinct options for a new generation of long-acting injectables for HIV, with the potential for extended dosing intervals.

Kimberly Smith, M.D., MPH, Head of Research & Development at ViiV Healthcare, said: “It’s clear long-acting injectable medicines deliver on unmet patient need and will play a critical role in achieving our ambition of ending HIV and AIDS. Our pipeline with INSTIs at the core showcases our continued leadership in long-acting injectable innovation. Data shows that the potency and tolerability of our third-generation INSTI and our capsid inhibitor will make them a major part in the development of our next generation of long-acting injectable therapies.”

VH184 demonstrated high antiviral potency¹
This study aimed to explore the antiviral activity and safety of three doses of VH184 (10mg, 50mg and 300mg taken once every three days) by assessing the maximum change in plasma HIV-1 RNA levels during a 10-day monotherapy period in 22 adults who had not previously received antiretroviral therapy. People who participated in the study had HIV-1 RNA levels of at least 3000 copies/mL.

VH184, a third-generation INSTI, demonstrated potency at all doses leading to a marked drop in the HIV-1 viral load. After 10 days of monotherapy, the average decreases were -1.17, -2.15, and -2.31 log10 copies/mL for the 10mg, 50mg, and 300mg doses, respectively. The maximum viral load decline (-2.69 log10) was observed in the 300mg dose. Additionally, no drug resistance mutations were observed at the end of the study. All side effects were mild to moderate, and no serious side effects or participant discontinuations occurred.

Long-acting formulations of VH184 in adults without HIV are being evaluated in an ongoing phase 1 study (NCT06310551). The findings of this trial support further development of VH184 as a potential long-acting injectable antiretroviral.

Higher VH499 dose correlated with greater decline in viral load²
This study evaluated the compound’s antiviral effect, safety, and tolerability by assessing the maximum change in plasma HIV-1 RNA levels from baseline through day 11 in 23 adults who had not previously received antiretroviral therapy. People who participated in the study also had HIV-1 RNA levels of at least 3000 copies/mL.

The trial of VH499, an investigational capsid inhibitor, showed that all oral doses (25mg, 100mg, and 250mg) led to a decrease in HIV-1 viral load ranging from -2.2 log10 copies/mL in the 250mg arm, to -1.8 log10 copies/mL in the 25mg and 100mg arms. VH499 was well tolerated with all adverse events being mild to moderate in severity. There were no adverse events leading to withdrawal and no serious adverse events were reported. On day 11, one individual on the 25mg dose developed a single mutation associated with reduced susceptibility to capsid inhibitors.

In a previous phase I clinical trial of adults without HIV-1, VH499 was well tolerated, and showed no induction or inhibition of CYP3A4.³ Long-acting formulations of VH499 in adults without HIV are being evaluated in ongoing phase 1 studies (NCT06012136; NCT06724640).

These findings, in combination with the potent antiviral activity in this phase IIa study, support further development of VH499 as a potential long-acting antiretroviral for HIV treatment.

About ViiV Healthcare
ViiV Healthcare is a global specialist HIV company established in November 2009 by GSK (LSE: GSK) and Pfizer (NYSE: PFE) dedicated to delivering advances in treatment and care for people living with HIV and for people who could benefit from HIV prevention. Shionogi became a ViiV shareholder in October 2012. The company’s aims are to take a deeper and broader interest in HIV and 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 viivhealthcare.com.

About GSK
GSK is a global biopharma company with a purpose to unite science, technology, and talent to get ahead of disease together. Find out more at gsk.com.

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 GSK’s Annual Report on Form 20-F for 2024.

Registered in England & Wales:
GSK plc
No. 3888792

ViiV Healthcare Limited
No. 06876960

Registered Office:
79 New Oxford Street
London
WC1A 1DG

ViiV Healthcare Limited
GSK Medicines Research Centre
Gunnels Wood Road, Stevenage
United Kingdom
SG1 2NY

References
________________________________________________________
¹ Rogg L, et al. Proof-of-Concept Trial of VH4524184 (VH-184), a Third-Generation Integrase Strand Transfer Inhibitor. Presented at the Conference on Retroviruses and Opportunistic Infections (CROI 2025), 9-12 March, San Francisco, CA (NCT06214052)
² Griesel R, et al. Proof-of-Concept Trial of Oral VH4011499 (VH-499), a New HIV-1 Capsid Inhibitor. Presented at the Conference on Retroviruses and Opportunistic Infections (CROI 2025), 9-12 March, San Francisco, CA (NCT06039579)
³ Thakkar et al. AIDS 2024; Munich, Germany. Poster WEPEB105.

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FAQ

What were the key findings of VH184 in the Phase IIa HIV trial?

VH184 showed high antiviral potency across all doses, with the 300mg dose achieving maximum viral load decline of -2.69 log10 copies/mL. No drug resistance mutations were observed.

How effective was VH499 in reducing HIV viral load in clinical trials?

VH499 demonstrated viral load reductions ranging from -2.2 log10 copies/mL at 250mg to -1.8 log10 copies/mL at lower doses (25mg and 100mg).

What are the safety profiles of VH184 and VH499 in HIV treatment?

Both compounds showed favorable safety profiles with only mild to moderate side effects and no serious adverse events or treatment discontinuations.

How does ViiV Healthcare's new HIV pipeline advance long-acting treatment options?

The pipeline features two promising compounds (VH184 and VH499) being developed as long-acting injectables with extended dosing intervals.