The HIV-suppressing benefits of the newly approved antibody treatment Trogarzo (ibalizumab), which is given via intravenous infusion every two weeks, can last for at least a year.

Researchers enrolled 40 people with considerable experience taking antiretrovirals and who had multidrug-resistant HIV into a Phase III study of the treatment. This trial ran for 24 weeks and was followed by an expanded access program during which participants could continue on Trogarzo therapy.

Study author Edwin DeJesus, MD, medical director of the Orlando Immunology Center in Florida, notes that some of the participants “had extremely high viral loads and significantly impaired immune systems.” During the study, he says, “We observed marked improvements in patients’ health.”

Seventeen participants (43 percent) achieved a fully suppressed viral load 24 weeks into the study. Of the 31 participants who finished the 24-week study, 27 entered the expanded access phase. Twenty-four of them completed the additional 24 weeks of follow-up; of these, 16 (67 percent) had a viral load below 50 at the 48-week mark, including all 15 people who had a fully suppressed viral load at week 24. One additional person had a viral load between 50 and 200 at week 48.

Of those still on treatment, by the end of the expanded access phase, the median reduction in viral load was 2.8log10, or a 99.84 percent reduction.

All 15 of those who entered the expanded access phase with a fully suppressed viral load maintained that status 24 weeks later.

Trogarzo was well tolerated. The most common adverse events, which occurred in more than 5 percent of participants, included upper respiratory infection, diarrhea and rash.