On March 6, 2018, the FDA approved a new type of HIV medication called ibalizumab for people who have few to no treatment options due to multi-drug resistant virus. The approval was based on results from the TMB-301 study that showed that adding the drug to a failing regimen may help some treatment-experienced people control their virus.
As people living with HIV continue to age, some are now faced with having to use failing regimens that do not fully control the virus to undetectable levels; and adding ibalizumab to these failing regimens may help.
Ibalizumab is a monoclonal antibody and works by attaching itself to the CD4 receptor on the outside of immune cells to prevent HIV’s entry into the cell. In earlier study ibalizumab was effective against a wide range of HIV strains.
Ibalizumab is given intravenously every 14 days by a trained medical staff person, which means biweekly medical visits are needed when taking the drug.
The 24-week TMB-301 enrolled 40 people on failing regimens and added ibalizumab to those regimens. Those enrolled had been on stable treatment for at least 8 weeks but had an HIV strain that was resistant to three (53%) or four (35%) classes or all HIV meds (16%). Average CD4 counts were low (<100) and average viral load was 35,000 copies.
By week 24, the average decrease in viral load was 55% for those with a 1 log reduction and 48% for those with a 2 log reduction. In addition, half the participants saw their viral loads drop below 200 copies while 43% dropped below 50.
Small average increases of 15 CD4 cells occurred for those who started with <50 cells. For those with higher CD4s, the average increase was 75–81 cells. There was no evidence that antibodies to ibalizumab developed in any participant, which is possible with a monoclonal antibody.
Most side effects were mild to moderate, and nine patients reported serious side effects. The most common side effects were diarrhea, dizziness, nausea and rash.
For more information on ibalizumab from Project Inform, read our article here.
For more information on the drug, read the product insert.