Trogarzo (ibalizumab) suppressed HIV for 48 weeks in nearly half of people with highly drug-resistant virus.

The monoclonal antibody, which is injected every two weeks, was approved in 2018 for people who have taken multiple antiretroviral regimens and have multidrug-resistant HIV.

The study included 38 people with a median CD4 count of 26 and a median viral load of 50,000. Their virus was resistant to antiretrovirals from at least three classes but remained fully sensitive to at least one drug. They received Trogarzo plus a daily oral antiretroviral regimen optimized to work as well as possible.

Among the 24 participants who completed 24 weeks of treatment, 46% had viral loads below 50. The median CD4 count rose by about 30. Among the 17 people who stayed on Trogarzo for 48 weeks, 47% maintained an undetectable viral load.

These findings were similar to those of the Phase III clinical trial of 40 individuals that led to Trogarzo’s approval.

Trogarzo was generally safe and well tolerated. The most common adverse events in both studies were diarrhea, headache, nausea, cough, skin rash and fatigue, which were mostly mild or moderate.

According to the new study’s lead author, Brinda Emu, MD, an associate professor of medicine at Yale University, Trogarzo “provides an important opportunity for patients with drug-resistant HIV to get significant virologic benefit.”