GSK’s ViiV Healthcare has shared clinical data on three potential long-acting HIV treatments, providing a look at how its plans to create a six-month regimen are shaping up.
ViiV, which is majority owned by GSK with Pfizer and Shionogi as shareholders, has identified demand for long-acting HIV treatments that are less burdensome for patients. With Gilead fighting hard for market share, ViiV is racing on multiple fronts to meet the demand. The company used the 2025 Conference on Retroviruses and Opportunistic Infections (CROI) in San Francisco to share data on three parts of its plan.
Wednesday, ViiV published phase 2b data on its investigational broadly neutralizing antibody N6LS. The study randomized 134 adults living with HIV to receive the CD4-binding antibody intravenously or subcutaneously or continue on pre-baseline, standard-of-care antiretroviral therapy. Patients in the N6LS groups received the antibody every six months and long-acting cabotegravir every month.
After six months, 96% of people on intravenous N6LS, also called VH109, maintained HIV-1 RNA levels below 50 copies/mL. The result in the standard of care group was identical. However, only 88% of people on subcutaneous N6LS maintained HIV-1 RNA levels below the threshold. Confirmed virologic failure was seen in two patients from each N6LS group.
Tolerability was worse in the subcutaneous group, with 16% of patients having grade 3 or 4 redness of the skin. The results informed ViiV’s decision to take a six-month intravenous formulation of N6LS into part two of the trial. Halozyme provided the technology that enabled subcutaneous delivery.
ViiV shared the N6LS data the day after publishing results from studies of two other molecules that could form part of its six-month treatment regimen. The N6LS trial used monthly cabotegravir long-acting as its integrase strand transfer inhibitor (INSTI), but ViiV could combine the antibody with its third-generation candidate VH184 down the line.
At CROI, ViiV showed viral load dropped after 22 adults, who had not previously received antiretroviral therapy, started on VH184. The study provided early evidence that the INSTI can drive down viral load without causing drug resistance mutations or serious side effects. But more work is needed to show the asset can be the backbone of ViiV’s regimen, starting with a phase 1 trial of long-acting formulations.
ViiV is considering N6LS and its investigational capsid inhibitor VH499 as potential partners for VH184 in its planned six-month treatment regimen. The company shared data on VH499 at CROI, linking the asset to falls in the viral loads of 23 adults who received the candidate in a phase 2 trial. One person on the low dose developed a single mutation associated with reduced susceptibility to capsid inhibitors.
ViiV said the data support further development of VH499 as a potential long-acting antiretroviral for HIV treatment. A phase 1 trial is assessing long-acting formulations of the capsid inhibitor. Data from studies of VH499 and N6LS will inform the decision about which molecule to combine with VH184.
Talking on a GSK earnings call last month, ViiV Chairman David Redfern said (PDF) “the aim is to look at that data this year and then make a regimen selection for treatment ... next year.” ViiV could potentially start running pivotal studies in 2027, Redfern said.